1982 Stingray Starting Problems and plug/wire identification
Thread Starter
Instructor
Joined: Jun 2013
Posts: 119
Likes: 3
Where is the oil pressure switch? If I pull it the engine won't start but I should still get the fuel pulse yes?
When you are talking about the pump kicking in, you are referring to the prime pulse correct?
Does anyone have a pin layout diagram or are they easily marked?
When you are talking about the pump kicking in, you are referring to the prime pulse correct?
Does anyone have a pin layout diagram or are they easily marked?
Burning Brakes
Joined: Feb 2013
Posts: 1,062
Likes: 28
From: Burkburnett TX
Jdp has a good suggestion here. Use an ink pen eraser to clean the contacts on the ecm. It will shine them up fast. Learned that in a nasa derived board repair course. I use emery cloth on a tiny screwdriver to clean out the connector ends. I am suspect of the relay still. If you were closer I would play swaptronics and try one of my good relays. Heck, parts store might just have that blower motor relay and its not listed as a pump relay. Also, fwiw, mine has been working without being mounted to the case...i can credit you for that discovery as I went to look at mine today and saw that it had fallen down. Silly 420 pound rear spring is beating the car to death!
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
At this point, I'm totally impressed by the fact that the OP is sticking with it and not giving up!! I've sure seen lots of guys give up and farm it out to a shop, spend some big bucks, and never get it right!
And even better, he's following suggestions!
And even better, he's following suggestions!
Thread Starter
Instructor
Joined: Jun 2013
Posts: 119
Likes: 3
The two screws on the relay are only into the plastic cap of the relay, and not for grounding. I popped it off and figured out which wires were the signal and what not. I ran 12V across the green/white and black/white pins and saw the relay switch over. Unless it is just not allowing enough current...?
I will check the ECU and oil pressure switch tomorrow.
Here is a simplified version of what I take from the wiring diagram.
I have a good 12V on the Tan/White coming off the relay. If it's not making it to the pump then maybe its just between the fuse and pump or even the fuse itself. I will check this first.
Where does the light blue wire from the fuse turn into tan/white? Is there a connector or just a hard soldered joint?
I will check the ECU and oil pressure switch tomorrow.
Here is a simplified version of what I take from the wiring diagram.
I have a good 12V on the Tan/White coming off the relay. If it's not making it to the pump then maybe its just between the fuse and pump or even the fuse itself. I will check this first.
Where does the light blue wire from the fuse turn into tan/white? Is there a connector or just a hard soldered joint?
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
Your mixing up two things. The fuel pressure relay has nothing to do with the injectors.
Listen carefully. When you turn the car to on the fuel pump buzzes for two seconds, right after and before you crank the car both injectors make a funny noise....the prime pulse. If you are not getting a buzz and are not getting a prime pulse its likely not the relay. I say this because these two things not happening relate to different things. The buzz from the injectors comes from the ECM and has nothing to do with the fuel pump relay directly.
There are two connectors on the ECM. One connector C451 has the injector drives they are numbers 467 and 468. 455 and 465 are the fuel pump relay return and fuel pump relay drive. If you are not getting a buzz from the fuel pump and no pulse from the injectors I strongly suggest you clean this connector. You have two problems that tie to one thing.....connector C451. Clean it....clean it....clean it.....
AND
Check the oil pressure sensor
Last edited by jdp6000; Jun 14, 2013 at 08:04 PM.
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
The two screws on the relay are only into the plastic cap of the relay, and not for grounding. I popped it off and figured out which wires were the signal and what not. I ran 12V across the green/white and black/white pins and saw the relay switch over. Unless it is just not allowing enough current...?
I will check the ECU and oil pressure switch tomorrow.
Here is a simplified version of what I take from the wiring diagram.
I have a good 12V on the Tan/White coming off the relay. If it's not making it to the pump then maybe its just between the fuse and pump or even the fuse itself. I will check this first.
Where does the light blue wire from the fuse turn into tan/white? Is there a connector or just a hard soldered joint?
I will check the ECU and oil pressure switch tomorrow.
Here is a simplified version of what I take from the wiring diagram.
I have a good 12V on the Tan/White coming off the relay. If it's not making it to the pump then maybe its just between the fuse and pump or even the fuse itself. I will check this first.
Where does the light blue wire from the fuse turn into tan/white? Is there a connector or just a hard soldered joint?
Thread Starter
Instructor
Joined: Jun 2013
Posts: 119
Likes: 3
In order to bypass the oil pressure switch all I need to do is jump the two wires right? Ill check for my 12V signal at the oil pressure switch and compare it to what I get at the pump and relay.
What I was referring to as far as the blue wire was... on my wiring diagram I show a light blue wire coming out of the fuse box and then right before the fuel pump it changes to tan/white without a distinct junction/change point.
jdp6000, so if the oil pressure switch is tripped it will draw the current from the fuel pump? Hrmmm, i got some digging to do...
What I was referring to as far as the blue wire was... on my wiring diagram I show a light blue wire coming out of the fuse box and then right before the fuel pump it changes to tan/white without a distinct junction/change point.
jdp6000, so if the oil pressure switch is tripped it will draw the current from the fuel pump? Hrmmm, i got some digging to do...
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Thread Starter
Instructor
Joined: Jun 2013
Posts: 119
Likes: 3
I wonder what's going on between the fuse box and the fuel pump... From the wiring diagram it shows the tan/white-light blue going straight from fuse to pump but physically I wonder how it routes...?
Melting Slicks
Joined: Mar 2006
Posts: 2,248
Likes: 67
From: Warrington PA
Finalist 2020 C4 of the Year - Unmodified
You know I was supposed to go to bed earlier and get some rest, but before I do that, I have to ask one of the dumbest questions in this thread.....
How much fuel is in your tank?
And on that note, I need some sleep......
hope this vehicle will be running sometime this weekend.....
How much fuel is in your tank?
And on that note, I need some sleep......
hope this vehicle will be running sometime this weekend.....
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
In order to bypass the oil pressure switch all I need to do is jump the two wires right? Ill check for my 12V signal at the oil pressure switch and compare it to what I get at the pump and relay.
What I was referring to as far as the blue wire was... on my wiring diagram I show a light blue wire coming out of the fuse box and then right before the fuel pump it changes to tan/white without a distinct junction/change point.
jdp6000, so if the oil pressure switch is tripped it will draw the current from the fuel pump? Hrmmm, i got some digging to do...
What I was referring to as far as the blue wire was... on my wiring diagram I show a light blue wire coming out of the fuse box and then right before the fuel pump it changes to tan/white without a distinct junction/change point.
jdp6000, so if the oil pressure switch is tripped it will draw the current from the fuel pump? Hrmmm, i got some digging to do...
I don't think the oil pressure sensor does anything during cranking only after the car starts. Try disconnecting it and cranking.
Lastly if the pressure is moving up during cranking this may not be the problem. Look at your gauge.
Try pouring gas down the TBI's and looking at your gauge. If it goes over 10 or gets up to 20 it's not the problem. Unless its faulty.
Last edited by jdp6000; Jun 15, 2013 at 09:15 AM.
Burning Brakes
Joined: Feb 2013
Posts: 1,062
Likes: 28
From: Burkburnett TX
I think I would try to feed your power supply 12 volts to the pump manually, and see if the car will run off of its own fuel supply. That would eliminate some things, let you see oil pressure, etc. If that worked, I would move on to the fuel pump relay. Try adding your power there. If fuel pump works, change relay, if it doesn't, chase down the wire between.
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
The oil pressure switch is just a cut off. When the car starts it measures the oil pressure. If its too low it stops the voltage to the pump. The book doesn't show the inside of that sensor so I can't say if the kill is in it. Looking at the schematic it suggests it tells the fuel relay to turn off on the tan/white.
I don't think the oil pressure sensor does anything during cranking only after the car starts. Try disconnecting it and cranking.
Lastly if the pressure is moving up during cranking this may not be the problem. Look at your gauge.
Try pouring gas down the TBI's and looking at your gauge. If it goes over 10 or gets up to 20 it's not the problem. Unless its faulty.
I don't think the oil pressure sensor does anything during cranking only after the car starts. Try disconnecting it and cranking.
Lastly if the pressure is moving up during cranking this may not be the problem. Look at your gauge.
Try pouring gas down the TBI's and looking at your gauge. If it goes over 10 or gets up to 20 it's not the problem. Unless its faulty.
Thread Starter
Instructor
Joined: Jun 2013
Posts: 119
Likes: 3
After running a jumper wire from the tan/white wire of the fuel pump fuse in the fuse box to the tan/white wire at the sending unit connector the car fired up like a charm and runs on its on volition. It's definitely in need of some nursing but it idles well and sounds like its all there.
All I need to do is confirm that I'm making a good connection across the fuse and then from the fuse to the sending unit connector. Or... I could run my own wire like I am currently doing (????). heh.
I must say.... thank you to all of you for helping me get this far. Without all of the great input from everyone this would have never happened. Thanks a million and I plan on pushing this thread forward throughout the rest of the process!
All I need to do is confirm that I'm making a good connection across the fuse and then from the fuse to the sending unit connector. Or... I could run my own wire like I am currently doing (????). heh.
I must say.... thank you to all of you for helping me get this far. Without all of the great input from everyone this would have never happened. Thanks a million and I plan on pushing this thread forward throughout the rest of the process!
Le Mans Master
Joined: Aug 2006
Posts: 7,427
Likes: 1,560
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Mission Accomplished.
5 stars for sticking with it!
That must have put a big smile on your face when it fired up!
That must have put a big smile on your face when it fired up!
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
After running a jumper wire from the tan/white wire of the fuel pump fuse in the fuse box to the tan/white wire at the sending unit connector the car fired up like a charm and runs on its on volition. It's definitely in need of some nursing but it idles well and sounds like its all there.
All I need to do is confirm that I'm making a good connection across the fuse and then from the fuse to the sending unit connector. Or... I could run my own wire like I am currently doing (????). heh.
I must say.... thank you to all of you for helping me get this far. Without all of the great input from everyone this would have never happened. Thanks a million and I plan on pushing this thread forward throughout the rest of the process!
All I need to do is confirm that I'm making a good connection across the fuse and then from the fuse to the sending unit connector. Or... I could run my own wire like I am currently doing (????). heh.
I must say.... thank you to all of you for helping me get this far. Without all of the great input from everyone this would have never happened. Thanks a million and I plan on pushing this thread forward throughout the rest of the process!
Jim
Thread Starter
Instructor
Joined: Jun 2013
Posts: 119
Likes: 3
I messed with the connection at the fuse box and sure enough there was a bad connection at that fuse. After doing that I plugged a fuse in and it starts right up. I've attached some photos of the car. I apologize for the lighting... a bunch of clouds had just rolled in and sort of messed it up.
You'll notice that the rear end is dropped. I was told that there were bad leaf springs in it and after inspection it seems like the shocks are about toast also. After checking out underneath the car it doesn't seem like the frame is damaged or anything and I don't see any immediately noticeable damage to the leaf springs... any rec's on where to start with inspecting the leaf springs and shocks?
Also, when the engine is idling I measure about 40 PSI of oil pressure. Also, the brake light stays illuminated all the time... is that an indication of a problem with the brake system?
You'll notice that the rear end is dropped. I was told that there were bad leaf springs in it and after inspection it seems like the shocks are about toast also. After checking out underneath the car it doesn't seem like the frame is damaged or anything and I don't see any immediately noticeable damage to the leaf springs... any rec's on where to start with inspecting the leaf springs and shocks?
Also, when the engine is idling I measure about 40 PSI of oil pressure. Also, the brake light stays illuminated all the time... is that an indication of a problem with the brake system?
Burning Brakes
Joined: Feb 2013
Posts: 1,062
Likes: 28
From: Burkburnett TX
Nice car. Should be a fiberglass spring in rear unless its the upgraded suspension. Someone may have lowered with bolts or something. Post up a shot of the rear suspension looking forward. The brakes is probably bad calipers that have your proportion valve out of center. If you have a leaky caliper, fixing them will be first on the list along with the rubber brake hoses.