1986 Corvette NO injector pules
Thread Starter
Intermediate
Joined: Dec 2019
Posts: 35
Likes: 6
From: Maple ridge BC
1986 Corvette NO injector pules
PLEASE READ ENTIRE POST BEFORE COMMENTING.
I bought this 1986 Corvette as a runner. Now it will only Fire if I put quickstart in the intake, and then it dies. in short, It has spark, but the injectors are not pulsing.
I have read the internet in many places and have come to the conclusion it is either the Ignition module ( replaced with new one), the pick up, the wire from the dizzy to the comp, or the comp or security. But I have to say, the security system has NEVER been the cause in any of the forums I have read. and rarely is it the comp
I bought this car as a runner driver, and NEVER did anything to it, till one day, It wouldn't start easy, and then it just stopped starting all together. it has now sat for 4 years and I am determined to fix it.
I know I can take the TPI intake off and switch to a carbureted system, but I don't really want to do it. I think it is a simple fix, I just want to try and diagnose it rather than throw parts at it.
At first I thought it was the fuel pump, because it was not turning on. so I replaced it with a new one. The pump now works and I get fuel preasure at the injector rails on the engine.
Like I said, the car will start if I put fuel down the intake, it has an MSD distributer and I have already replaced the ignition module with no change...it still wont start. this car uses the 7 pin ign module FYI
I have tested all injectors by disconnecting the injector wiring plug and testing for Ohmes at the injector and all injectors read 16.5 Ohmes.
I have tested all injector pig tails at the wiring harness with a test light by looping the two leads, and NO PULSE HAPPENS!
BOTH prongs of the pig tail for the injectors test CONSTANT NEGATIVE with the key off (Put one side of test light on positive lead of battery, and touch either prong on injector pig tail, it lights up)
BOTH prongs of pig tail are CONSTANT POSITIVE when key is on or cranking ( put test light on neg and the other end on either prong of the pig tail and crank engine with key)
****UPDATE*** I was able to test the pick up. I tested for resistance between the crongs on the pick up plug and the distributer housing, and it tested 0. ( it should test 0)
I also tested the resistance of the pick up at the prongs and it tested 789 ( it should test 500-1500 ohmes) so it tested good as well.
from my understanding, you should have a constant POS+ and a pulsing NEG - while cranking.
I want to know what wire goes from the dizzy to the comp?
I have checked fuse's for injectors and they are good!
ANY HELP IS GREATLY APPRECIATED!
THE SEARCH CONTINUES!
I bought this 1986 Corvette as a runner. Now it will only Fire if I put quickstart in the intake, and then it dies. in short, It has spark, but the injectors are not pulsing.
I have read the internet in many places and have come to the conclusion it is either the Ignition module ( replaced with new one), the pick up, the wire from the dizzy to the comp, or the comp or security. But I have to say, the security system has NEVER been the cause in any of the forums I have read. and rarely is it the comp
I bought this car as a runner driver, and NEVER did anything to it, till one day, It wouldn't start easy, and then it just stopped starting all together. it has now sat for 4 years and I am determined to fix it.
I know I can take the TPI intake off and switch to a carbureted system, but I don't really want to do it. I think it is a simple fix, I just want to try and diagnose it rather than throw parts at it.
At first I thought it was the fuel pump, because it was not turning on. so I replaced it with a new one. The pump now works and I get fuel preasure at the injector rails on the engine.
Like I said, the car will start if I put fuel down the intake, it has an MSD distributer and I have already replaced the ignition module with no change...it still wont start. this car uses the 7 pin ign module FYI
I have tested all injectors by disconnecting the injector wiring plug and testing for Ohmes at the injector and all injectors read 16.5 Ohmes.
I have tested all injector pig tails at the wiring harness with a test light by looping the two leads, and NO PULSE HAPPENS!
BOTH prongs of the pig tail for the injectors test CONSTANT NEGATIVE with the key off (Put one side of test light on positive lead of battery, and touch either prong on injector pig tail, it lights up)
BOTH prongs of pig tail are CONSTANT POSITIVE when key is on or cranking ( put test light on neg and the other end on either prong of the pig tail and crank engine with key)
****UPDATE*** I was able to test the pick up. I tested for resistance between the crongs on the pick up plug and the distributer housing, and it tested 0. ( it should test 0)
I also tested the resistance of the pick up at the prongs and it tested 789 ( it should test 500-1500 ohmes) so it tested good as well.
from my understanding, you should have a constant POS+ and a pulsing NEG - while cranking.
I want to know what wire goes from the dizzy to the comp?
I have checked fuse's for injectors and they are good!
ANY HELP IS GREATLY APPRECIATED!
THE SEARCH CONTINUES!
Last edited by Philip Pires; Dec 6, 2019 at 05:55 PM.
Melting Slicks
Joined: Nov 2007
Posts: 2,830
Likes: 147
From: Gainesville FL
All terminals were open and it smelled burnt.
When it began to fail it was intermittent and then it just completely died.
Last edited by 3D-Aircrew; Dec 6, 2019 at 05:31 PM.
Thread Starter
Intermediate
Joined: Dec 2019
Posts: 35
Likes: 6
From: Maple ridge BC
Melting Slicks
Joined: Jun 2011
Posts: 2,383
Likes: 385
From: Leland , North Carolina
Check the fuel pressure on the shrader valve on the fuel rail. If that's ok the ninth injector my be the culprit. It's been a long time since I had my 85 . Maybe someone else can chime in.
Thread Starter
Intermediate
Joined: Dec 2019
Posts: 35
Likes: 6
From: Maple ridge BC
Drifting
Joined: Feb 2006
Posts: 1,423
Likes: 96
From: Magnolia Tx
The 4 wires from the distributor (A B C & D) go to the ECM. If that plug isn't connected to the harness it won't pulse the injectors. The wires are
A -white wire # 423 - goes to D4 on the ECM
B -purple/wht # 430 to B5 on the ECM
C - tan/blk #424 to D5 on the ECM (the set timing connector)
D -black/red # 453 to B3 on the ECM
All this is on page 6E3-A-24 of the service manual. The diagnostic tree points to the ECM being the likely problem.
A -white wire # 423 - goes to D4 on the ECM
B -purple/wht # 430 to B5 on the ECM
C - tan/blk #424 to D5 on the ECM (the set timing connector)
D -black/red # 453 to B3 on the ECM
All this is on page 6E3-A-24 of the service manual. The diagnostic tree points to the ECM being the likely problem.
Thread Starter
Intermediate
Joined: Dec 2019
Posts: 35
Likes: 6
From: Maple ridge BC
The 4 wires from the distributor (A B C & D) go to the ECM. If that plug isn't connected to the harness it won't pulse the injectors. The wires are
A -white wire # 423 - goes to D4 on the ECM
B -purple/wht # 430 to B5 on the ECM
C - tan/blk #424 to D5 on the ECM (the set timing connector)
D -black/red # 453 to B3 on the ECM
All this is on page 6E3-A-24 of the service manual. The diagnostic tree points to the ECM being the likely problem.
A -white wire # 423 - goes to D4 on the ECM
B -purple/wht # 430 to B5 on the ECM
C - tan/blk #424 to D5 on the ECM (the set timing connector)
D -black/red # 453 to B3 on the ECM
All this is on page 6E3-A-24 of the service manual. The diagnostic tree points to the ECM being the likely problem.
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Thread Starter
Intermediate
Joined: Dec 2019
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From: Maple ridge BC
Safety Car
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From: Indianapolis IN
Finalist 2020 C4 of the Year - Unmodified
C4 of Year Finalist (stock) 2019
Do you have a Factory Service Manual? By your questions I'm guessing you don't. IF you are truly determined to fix and maintain your car, you NEED to get one. The manual explains every system in your car in detail. Relying on internet forums as your sole source if information for repair and troubleshooting of your vehicle is NOT the right way to approach problems. The internet should be used as a source of supplemental information but should in no way be used as a primary source.
Thread Starter
Intermediate
Joined: Dec 2019
Posts: 35
Likes: 6
From: Maple ridge BC
Do you have a Factory Service Manual? By your questions I'm guessing you don't. IF you are truly determined to fix and maintain your car, you NEED to get one. The manual explains every system in your car in detail. Relying on internet forums as your sole source if information for repair and troubleshooting of your vehicle is NOT the right way to approach problems. The internet should be used as a source of supplemental information but should in no way be used as a primary source.
Safety Car
Joined: May 2001
Posts: 4,759
Likes: 1,647
From: Fairfax Virginia
I am not sure if the 1986 C4 had the oil pressure "switch" and oil pressure "sensor" on them. This system is not supposed to supply power to the fuel pump if the oil pressure is not sensed while cranking. On my 1988 I had an intermittent problem with my car not starting and running poorly when it did. I found that the previous owner did not know much about crimp on connectors. I found a wire loose on the pressure switch and that was enough to not make the car run at all. The switches are mounted on the rear of the engine near the left side of the distributor. Take a look at those wires and be sure all of them are connected. Your fuel pump relay is another suspect, if you had a schematic I would say to apply power at the Fuel Pump Relay output and see if the fuel pump energizes.
Like Red86Z51 so wisely suggested be sure to get the Factory Service Manuals for your 1986 Corvette!! It is virtually impossible to fix a C4 Corvette without the FSM. The Electrical supplement is the best of all as it has the schematics and can point out where the connections are on the Corvette. On the 1988 C4 the manuals come with two books. One is mechanical and the second is for the electrical system of the C4. It changes each year so be sure to get the 1986 Version. You can find it in hard copy or on DVD on Fleabay. I have two sets, one clean set and one working set so I have the information I need where I need it.
Swapping this car over to a carburetor would be a horrible thing to do to a C4. The fuel injection system is not that complicated and is easier to work on than most big old Holley Double Pumpers. Your emissions and performance might suffer unless you do the conversion completely. The original fuel injection systems seems to work well when it is working. I get 30 mpg with my 1988 C4 automatic Coupe on the highways with the AC blowing and the stereo a Rockin.
You are correct the ECM will supply 12 Vdc constantly on the injectors while the key is on the Start or Run mode. The ECM supplies a ground to inject fuel into the cylinder. This engine uses "Batch Fire" and will fire four injectors at a time twice for each revolution of the engine. The power is sent using Pulse Width Modulation and is hard to measure with a basic multi-meter. There are gadgets called NOID Lights and they can show you if an injector is firing or not. You might try some NOID lights to be sure but I have a feeling that your injectors are waiting for fuel pressure not a signal.
Starting at the battery, what is the battery open circuit (no load) voltage? Now take your multi-meter's red lead and keep it on the battery Positive post and put the black lead on the engine and verify that you have the same voltage. If the engine is not grounded properly then nothing will work properly. If the engine ground is okay take the meter and measure the voltage available at the fuse block. It should be the same as the batteries or you might have a issue with corrosion at the Fusible link power post. When you first turn the key to start the car do you hear the fuel pump cycling on for a few seconds?
I left my 1988 for a couple years and when I tried to start it I got nothing but cranking. I did the test at the fuse panel and there was close to a 2 volt voltage drop between the battery and the fuse panel. On my car the post where the fusible links get their power was encrusted in corrosion. After cleaning it off the Full voltage returned to the fuse panel. That is something to consider and check if you have a difference between the battery and fuse panel voltage. The voltage drop was making the pump run slower then normal. A voltage drop can have serious effects on the Corvette.
Check your battery connections and be sure to clean them every couple years at least. I read that 1 out of 4 car breakdowns are related to the battery. Be sure your battery is completely charged before working on the Corvette!
Be absolutely sure that none of the insulation came off the ground wires feeding the injectors. This area gets hot and can cause the insulation to break down and fall off effectively grounding the wires.
Hopefully there might be a helpful hint among all these thoughts...
Best regards,
Chris
I am thinking a bad oil pressure switch keeping the fuel from getting into the cylinders.
Like Red86Z51 so wisely suggested be sure to get the Factory Service Manuals for your 1986 Corvette!! It is virtually impossible to fix a C4 Corvette without the FSM. The Electrical supplement is the best of all as it has the schematics and can point out where the connections are on the Corvette. On the 1988 C4 the manuals come with two books. One is mechanical and the second is for the electrical system of the C4. It changes each year so be sure to get the 1986 Version. You can find it in hard copy or on DVD on Fleabay. I have two sets, one clean set and one working set so I have the information I need where I need it.
Swapping this car over to a carburetor would be a horrible thing to do to a C4. The fuel injection system is not that complicated and is easier to work on than most big old Holley Double Pumpers. Your emissions and performance might suffer unless you do the conversion completely. The original fuel injection systems seems to work well when it is working. I get 30 mpg with my 1988 C4 automatic Coupe on the highways with the AC blowing and the stereo a Rockin.
You are correct the ECM will supply 12 Vdc constantly on the injectors while the key is on the Start or Run mode. The ECM supplies a ground to inject fuel into the cylinder. This engine uses "Batch Fire" and will fire four injectors at a time twice for each revolution of the engine. The power is sent using Pulse Width Modulation and is hard to measure with a basic multi-meter. There are gadgets called NOID Lights and they can show you if an injector is firing or not. You might try some NOID lights to be sure but I have a feeling that your injectors are waiting for fuel pressure not a signal.
Starting at the battery, what is the battery open circuit (no load) voltage? Now take your multi-meter's red lead and keep it on the battery Positive post and put the black lead on the engine and verify that you have the same voltage. If the engine is not grounded properly then nothing will work properly. If the engine ground is okay take the meter and measure the voltage available at the fuse block. It should be the same as the batteries or you might have a issue with corrosion at the Fusible link power post. When you first turn the key to start the car do you hear the fuel pump cycling on for a few seconds?
I left my 1988 for a couple years and when I tried to start it I got nothing but cranking. I did the test at the fuse panel and there was close to a 2 volt voltage drop between the battery and the fuse panel. On my car the post where the fusible links get their power was encrusted in corrosion. After cleaning it off the Full voltage returned to the fuse panel. That is something to consider and check if you have a difference between the battery and fuse panel voltage. The voltage drop was making the pump run slower then normal. A voltage drop can have serious effects on the Corvette.
Check your battery connections and be sure to clean them every couple years at least. I read that 1 out of 4 car breakdowns are related to the battery. Be sure your battery is completely charged before working on the Corvette!
Be absolutely sure that none of the insulation came off the ground wires feeding the injectors. This area gets hot and can cause the insulation to break down and fall off effectively grounding the wires.
Hopefully there might be a helpful hint among all these thoughts...
Best regards,
Chris
I am thinking a bad oil pressure switch keeping the fuel from getting into the cylinders.
Last edited by ctmccloskey; Dec 7, 2019 at 06:14 PM.
Thread Starter
Intermediate
Joined: Dec 2019
Posts: 35
Likes: 6
From: Maple ridge BC
I am not sure if the 1986 C4 had the oil pressure "switch" and oil pressure "sensor" on them. This system is not supposed to supply power to the fuel pump if the oil pressure is not sensed while cranking. On my 1988 I had an intermittent problem with my car not starting and running poorly when it did. I found that the previous owner did not know much about crimp on connectors. I found a wire loose on the pressure switch and that was enough to not make the car run at all. The switches are mounted on the rear of the engine near the left side of the distributor. Take a look at those wires and be sure all of them are connected. Your fuel pump relay is another suspect, if you had a schematic I would say to apply power at the Fuel Pump Relay output and see if the fuel pump energizes.
Like Red86Z51 so wisely suggested be sure to get the Factory Service Manuals for your 1986 Corvette!! It is virtually impossible to fix a C4 Corvette without the FSM. The Electrical supplement is the best of all as it has the schematics and can point out where the connections are on the Corvette. On the 1988 C4 the manuals come with two books. One is mechanical and the second is for the electrical system of the C4. It changes each year so be sure to get the 1986 Version. You can find it in hard copy or on DVD on Fleabay. I have two sets, one clean set and one working set so I have the information I need where I need it.
Swapping this car over to a carburetor would be a horrible thing to do to a C4. The fuel injection system is not that complicated and is easier to work on than most big old Holley Double Pumpers. Your emissions and performance might suffer unless you do the conversion completely. The original fuel injection systems seems to work well when it is working. I get 30 mpg with my 1988 C4 automatic Coupe on the highways with the AC blowing and the stereo a Rockin.
You are correct the ECM will supply 12 Vdc constantly on the injectors while the key is on the Start or Run mode. The ECM supplies a ground to inject fuel into the cylinder. This engine uses "Batch Fire" and will fire four injectors at a time twice for each revolution of the engine. The power is sent using Pulse Width Modulation and is hard to measure with a basic multi-meter. There are gadgets called NOID Lights and they can show you if an injector is firing or not. You might try some NOID lights to be sure but I have a feeling that your injectors are waiting for fuel pressure not a signal.
Starting at the battery, what is the battery open circuit (no load) voltage? Now take your multi-meter's red lead and keep it on the battery Positive post and put the black lead on the engine and verify that you have the same voltage. If the engine is not grounded properly then nothing will work properly. If the engine ground is okay take the meter and measure the voltage available at the fuse block. It should be the same as the batteries or you might have a issue with corrosion at the Fusible link power post. When you first turn the key to start the car do you hear the fuel pump cycling on for a few seconds?
I left my 1988 for a couple years and when I tried to start it I got nothing but cranking. I did the test at the fuse panel and there was close to a 2 volt voltage drop between the battery and the fuse panel. On my car the post where the fusible links get their power was encrusted in corrosion. After cleaning it off the Full voltage returned to the fuse panel. That is something to consider and check if you have a difference between the battery and fuse panel voltage. The voltage drop was making the pump run slower then normal. A voltage drop can have serious effects on the Corvette.
Check your battery connections and be sure to clean them every couple years at least. I read that 1 out of 4 car breakdowns are related to the battery. Be sure your battery is completely charged before working on the Corvette!
Be absolutely sure that none of the insulation came off the ground wires feeding the injectors. This area gets hot and can cause the insulation to break down and fall off effectively grounding the wires.
Hopefully there might be a helpful hint among all these thoughts...
Best regards,
Chris
If the engine runs on Ether then it has to be getting the pulses which pretty much eliminates ignition associated issues. I am thinking a bad oil pressure switch keeping the fuel from getting into the cylinders.
Like Red86Z51 so wisely suggested be sure to get the Factory Service Manuals for your 1986 Corvette!! It is virtually impossible to fix a C4 Corvette without the FSM. The Electrical supplement is the best of all as it has the schematics and can point out where the connections are on the Corvette. On the 1988 C4 the manuals come with two books. One is mechanical and the second is for the electrical system of the C4. It changes each year so be sure to get the 1986 Version. You can find it in hard copy or on DVD on Fleabay. I have two sets, one clean set and one working set so I have the information I need where I need it.
Swapping this car over to a carburetor would be a horrible thing to do to a C4. The fuel injection system is not that complicated and is easier to work on than most big old Holley Double Pumpers. Your emissions and performance might suffer unless you do the conversion completely. The original fuel injection systems seems to work well when it is working. I get 30 mpg with my 1988 C4 automatic Coupe on the highways with the AC blowing and the stereo a Rockin.
You are correct the ECM will supply 12 Vdc constantly on the injectors while the key is on the Start or Run mode. The ECM supplies a ground to inject fuel into the cylinder. This engine uses "Batch Fire" and will fire four injectors at a time twice for each revolution of the engine. The power is sent using Pulse Width Modulation and is hard to measure with a basic multi-meter. There are gadgets called NOID Lights and they can show you if an injector is firing or not. You might try some NOID lights to be sure but I have a feeling that your injectors are waiting for fuel pressure not a signal.
Starting at the battery, what is the battery open circuit (no load) voltage? Now take your multi-meter's red lead and keep it on the battery Positive post and put the black lead on the engine and verify that you have the same voltage. If the engine is not grounded properly then nothing will work properly. If the engine ground is okay take the meter and measure the voltage available at the fuse block. It should be the same as the batteries or you might have a issue with corrosion at the Fusible link power post. When you first turn the key to start the car do you hear the fuel pump cycling on for a few seconds?
I left my 1988 for a couple years and when I tried to start it I got nothing but cranking. I did the test at the fuse panel and there was close to a 2 volt voltage drop between the battery and the fuse panel. On my car the post where the fusible links get their power was encrusted in corrosion. After cleaning it off the Full voltage returned to the fuse panel. That is something to consider and check if you have a difference between the battery and fuse panel voltage. The voltage drop was making the pump run slower then normal. A voltage drop can have serious effects on the Corvette.
Check your battery connections and be sure to clean them every couple years at least. I read that 1 out of 4 car breakdowns are related to the battery. Be sure your battery is completely charged before working on the Corvette!
Be absolutely sure that none of the insulation came off the ground wires feeding the injectors. This area gets hot and can cause the insulation to break down and fall off effectively grounding the wires.
Hopefully there might be a helpful hint among all these thoughts...
Best regards,
Chris
If the engine runs on Ether then it has to be getting the pulses which pretty much eliminates ignition associated issues. I am thinking a bad oil pressure switch keeping the fuel from getting into the cylinders.
the fuel pump is NOT the issue as it is functioning as it should be.
I appreciate your other suggestions and will look into them. do you know what main wire powers the fuse box?
Thread Starter
Intermediate
Joined: Dec 2019
Posts: 35
Likes: 6
From: Maple ridge BC
I was able to test some things.
so far everything is checking out ok on the car, yet it still will not fire. Please keep the suggestions coming. Many thanks!
Phil
- As for battery voltage, the battery reads 12.7v at the battery, and if I use the positive of the batery and the negative of the engine, it still reads 12.7. The instrument cluster is reading 9v. but I want to test the fuse pannel with a multi meter, but dont know where to check as of right now.
- The security alarm does NOT flash while cranking.
- I was able to borrow a computer from my uncle and I switched the prom and installed it...Still did NOT start.
so far everything is checking out ok on the car, yet it still will not fire. Please keep the suggestions coming. Many thanks!
Phil
Thread Starter
Intermediate
Joined: Dec 2019
Posts: 35
Likes: 6
From: Maple ridge BC
Well, I was told by someone through facebook to test the key for resistance. what I did was...
Thanks
- Tested for ohms with one lead of the multi meter on one side of the chip and the other end of the multimeter on the other side of the chip. a youtube video showed that I should get 1.3 ohms( or something as many are different) I changed the ohms to 20k and it read 7.53 ohms.
- I then tested with one lead on the chip, and the other lead on the key itself, it didn't read anything. ( not sure if it should read anything or not.)
Thanks
Last edited by Philip Pires; Dec 9, 2019 at 07:01 PM.
Team Owner
Joined: Jul 2004
Posts: 28,475
Likes: 3,291
From: Hartford WI
Well, I was told by someone through facebook to test the key for resistance. what I did was...
Thanks
- Tested for ohms with one lead of the multi meter on one side of the chip and the other end of the multimeter on the other side of the chip. a youtube video showed that I should get 1.3 ohms( or something as many are different) I changed the ohms to 20k and it read 7.53 ohms.
- I then tested with one lead on the chip, and the other lead on the key itself, it didn't read anything. ( not sure if it should read anything or not.)
Thanks
Safety Car
Joined: May 2001
Posts: 4,759
Likes: 1,647
From: Fairfax Virginia
Hello again Philip,
There is a wire from the Red battery connector that goes to a post where you will find a group of 7 fusible Links (on my C4). The post is on the frame rail behind the battery area on the 1988 C4. On my Corvette you follow the smaller red wire from the battery positive and you will find the post. The battery feeds power to the post which then distributes it to the fuse panel. From the fuse panel it supplies the entire car. The post location will be identified in the Factory Service Manual electrical supplement. It is a important connection point and needs to be clean for the car to work properly.
On my 1988 C4 the post is mounted vertically and had a lot of corrosion on it. After taking it apart and cleaning the connectors I re-assembled them and then put battery grease over them to keep the air out. At that time I saw full battery voltage at the fuse panel and my dash board as well.
To make things worse for me the fuses had power going TO them but not THRU them. My fuses had corrosion on the surfaces of the blades as well. The aluminum had a light coating of corrosion that prevented power from getting thru them. I cleaned a fuse and it worked okay but ended up cleaning the fuse connections in the fuse box with a points file. New fuses solved the problem of aluminum bladed fuses.
On my Corvette after cleaning the post and fuse block I found full battery voltage everywhere in the Corvette. That post supplies all the power going to the fuses and if it is compromised then the voltage drops begin. I had 9-10 volts at my radio before and after it was full battery voltage. Funny thing was everything worked a bit faster and better when they have full power available to them. I did find a broken ground strap under the rear of the car, be sure they are okay and all is connected. After reconnecting the ground strap my radio antenna started working again.
Best regards,
Chris
Don't forget to clean any major ground connectors as well. If your ECM is not grounded properly maybe it can't send ground pulses to the injectors. Good Luck!
There is a wire from the Red battery connector that goes to a post where you will find a group of 7 fusible Links (on my C4). The post is on the frame rail behind the battery area on the 1988 C4. On my Corvette you follow the smaller red wire from the battery positive and you will find the post. The battery feeds power to the post which then distributes it to the fuse panel. From the fuse panel it supplies the entire car. The post location will be identified in the Factory Service Manual electrical supplement. It is a important connection point and needs to be clean for the car to work properly.
On my 1988 C4 the post is mounted vertically and had a lot of corrosion on it. After taking it apart and cleaning the connectors I re-assembled them and then put battery grease over them to keep the air out. At that time I saw full battery voltage at the fuse panel and my dash board as well.
To make things worse for me the fuses had power going TO them but not THRU them. My fuses had corrosion on the surfaces of the blades as well. The aluminum had a light coating of corrosion that prevented power from getting thru them. I cleaned a fuse and it worked okay but ended up cleaning the fuse connections in the fuse box with a points file. New fuses solved the problem of aluminum bladed fuses.
On my Corvette after cleaning the post and fuse block I found full battery voltage everywhere in the Corvette. That post supplies all the power going to the fuses and if it is compromised then the voltage drops begin. I had 9-10 volts at my radio before and after it was full battery voltage. Funny thing was everything worked a bit faster and better when they have full power available to them. I did find a broken ground strap under the rear of the car, be sure they are okay and all is connected. After reconnecting the ground strap my radio antenna started working again.
Best regards,
Chris
Don't forget to clean any major ground connectors as well. If your ECM is not grounded properly maybe it can't send ground pulses to the injectors. Good Luck!
Last edited by ctmccloskey; Dec 10, 2019 at 10:13 AM.
