cold start issues....
Thread Starter
Pro
Joined: Jul 2002
Posts: 703
Likes: 0
From: Milwaukee Wi
cold start issues....
This is my latest problem. Maybe someone can offer some tip.
Cold Start: Sometimes engine cranks but will not start. Other times I try 5-10 cranks and it starts but immediately dies. Start again and it runs but need to hold idle at 1500rpms and eventually it runs wont die and all is well. When it wont start I let it be and later that day my wife cranks and I expect no start as I im looking for fuel (or spark) and it starts fine.
Cold start: Once it starts normally as expected it never dies. Runs fine. Bumpy roads no issues.
I drop at mechanic last week as almost was stranded at office that day with issues. He trys to start in morning no start. Next day and every day after it starts. he needs to move indoors at closing. He say running fine.
Now I did cut 12V switched to provide power to N20 relay 30 days ago but just started this crap 2 weeks ago. loose connection? Unlikely as bumpy roads has no effect. Problem only cold start or sitting for 8 hours.
coil pickup original 26 years old! coil/module is Accel and 7 years old. TPI pump is seven years old.
Cold Start: Sometimes engine cranks but will not start. Other times I try 5-10 cranks and it starts but immediately dies. Start again and it runs but need to hold idle at 1500rpms and eventually it runs wont die and all is well. When it wont start I let it be and later that day my wife cranks and I expect no start as I im looking for fuel (or spark) and it starts fine.
Cold start: Once it starts normally as expected it never dies. Runs fine. Bumpy roads no issues.
I drop at mechanic last week as almost was stranded at office that day with issues. He trys to start in morning no start. Next day and every day after it starts. he needs to move indoors at closing. He say running fine.
Now I did cut 12V switched to provide power to N20 relay 30 days ago but just started this crap 2 weeks ago. loose connection? Unlikely as bumpy roads has no effect. Problem only cold start or sitting for 8 hours.
coil pickup original 26 years old! coil/module is Accel and 7 years old. TPI pump is seven years old.
Racer
Joined: May 2006
Posts: 426
Likes: 16
From: Concord CA
Coud be a lot of things, even new parts causing or failing right away. Any DTC Codes ?
Hard starting is many times due to bad or leaky injectors, But all of these come into play, vacuum leaks, Bad MAF Relays, Dirty MAF.
Check all of the other sensors. check the Ohm reading on the Injectors (14 ohm standard ?). Are you getting a good signal for the injectors ?
Check your fuel pressure (#47 ?) Weak on startup, is the pressure dropping after sitting for a short or long time ? (leaky injectors or regulator)
Could be a bad Ing Module in the Distributor, Check for burn marks on the Rotor center area (HEI have been know to burn through) or arc'ing on the Cap.
Suggest you use the FSM to run down the hard/cold starting Diagnotics steps.
Hard starting is many times due to bad or leaky injectors, But all of these come into play, vacuum leaks, Bad MAF Relays, Dirty MAF.
Check all of the other sensors. check the Ohm reading on the Injectors (14 ohm standard ?). Are you getting a good signal for the injectors ?
Check your fuel pressure (#47 ?) Weak on startup, is the pressure dropping after sitting for a short or long time ? (leaky injectors or regulator)
Could be a bad Ing Module in the Distributor, Check for burn marks on the Rotor center area (HEI have been know to burn through) or arc'ing on the Cap.
Suggest you use the FSM to run down the hard/cold starting Diagnotics steps.
Thread Starter
Pro
Joined: Jul 2002
Posts: 703
Likes: 0
From: Milwaukee Wi
Last time I drove car to office it thru a code for IAT. And CE came on. I checked IAT and it may have rubbed on serp belt or is just defective. That did not affect how car drove. I was in CL per my datalog....
Pickup coil is 26 years old. Coil module 7 years or so.
Car is at my mechanic and I offerred pickup coil as a possibility as it is 26 years old. Problem is can runs well Mon-Tues this week in-out his shop. Starting restarting. Day I dropped it off it would not start later that day but mechanic did not have time to diagnose. that is a missed opportunity.
This car is TBI. Injectors are 7 years old and throw a nice spray. That i witnessed last week. FP comes up to 20 and bleeds off as expected with engine off. Car runs fine once it starts. WOT and all that. TPI pump Aeromotive VAFPR.
Rotor cap module coil are all 7 years old. Coil is Acell in cap. That is all being checked at shop I presume. I am awaiting a call.
Thank you.
Pickup coil is 26 years old. Coil module 7 years or so.
Car is at my mechanic and I offerred pickup coil as a possibility as it is 26 years old. Problem is can runs well Mon-Tues this week in-out his shop. Starting restarting. Day I dropped it off it would not start later that day but mechanic did not have time to diagnose. that is a missed opportunity.
This car is TBI. Injectors are 7 years old and throw a nice spray. That i witnessed last week. FP comes up to 20 and bleeds off as expected with engine off. Car runs fine once it starts. WOT and all that. TPI pump Aeromotive VAFPR.
Rotor cap module coil are all 7 years old. Coil is Acell in cap. That is all being checked at shop I presume. I am awaiting a call.
Thank you.
Last edited by Rohn; Aug 30, 2010 at 05:44 PM. Reason: ttt
Melting Slicks
Joined: Jan 2005
Posts: 2,658
Likes: 4
From: Clifton Park NY
Funny you mention IAT sensor code. I know we run the same ecm. Last Friday my SES light came on ... code 23. Then had problems with starting. IAT ohm'd out at 1.66 and had 5 volts on the harness that connects to the sensor. When ahead and changed the sensor. SES went away (new sensor ohm'd the same). Car would start then die. Went in the direction of Igntion Module. Fired right up and ran great. 45 min's later SES light... code 23. Gonna change the connector in hopes that that may be the problem..
Can't help but wonder why we may be getting the same codes, similar problem with the cold start, and same ecm.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Always include the year vette you are asking help for. When it won't start, THAT is the time to do diagnostic tests to find out what vital element is missing. Engines need hot spark, spark at the right time, fuel and air and in the correct ratio, and cylinder compression in order to start and continue to run. What is your fuel pressure? Are you getting injector pulses? Can spark jump at least 1/2 inch? Plug wires should measure about 5000 ohms per foot. Are any plug wires touching metal and are all the wire looms in place and in good condition? In the dark can you see any sparks along any plug wires?
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Thread Starter
Pro
Joined: Jul 2002
Posts: 703
Likes: 0
From: Milwaukee Wi
I took to a shop a week ago. Shop owner has not seen a failure. started prob 15 times. BUT I dont believe he has driven it other than in parking lot. Unfortunately every time it would not start I was alone and had no helper to crank while I witness spark/fuel.
QWS. Is yours intermittant and still having issues? I dont see a code as I use EBL-ECU which has a table of CE codes with three levels of failure. When code was thrown it was a soft failure of IAT. Eventually all three codes were shown as a hard failure. I find it hard to believe a IAT will prevent fuel or spark. I am leaning toward spark but the mechanic has 30 years working with GM brand exclusively.
1984...
QWS. Is yours intermittant and still having issues? I dont see a code as I use EBL-ECU which has a table of CE codes with three levels of failure. When code was thrown it was a soft failure of IAT. Eventually all three codes were shown as a hard failure. I find it hard to believe a IAT will prevent fuel or spark. I am leaning toward spark but the mechanic has 30 years working with GM brand exclusively.
1984...
Melting Slicks
Joined: Jan 2005
Posts: 2,658
Likes: 4
From: Clifton Park NY
I took to a shop a week ago. Shop owner has not seen a failure. started prob 15 times. BUT I dont believe he has driven it other than in parking lot. Unfortunately every time it would not start I was alone and had no helper to crank while I witness spark/fuel.
QWS. Is yours intermittant and still having issues? I dont see a code as I use EBL-ECU which has a table of CE codes with three levels of failure. When code was thrown it was a soft failure of IAT. Eventually all three codes were shown as a hard failure. I find it hard to believe a IAT will prevent fuel or spark. I am leaning toward spark but the mechanic has 30 years working with GM brand exclusively.
1984...
QWS. Is yours intermittant and still having issues? I dont see a code as I use EBL-ECU which has a table of CE codes with three levels of failure. When code was thrown it was a soft failure of IAT. Eventually all three codes were shown as a hard failure. I find it hard to believe a IAT will prevent fuel or spark. I am leaning toward spark but the mechanic has 30 years working with GM brand exclusively.
1984...
My assumption was that since the ecm was seeing a failure in the code 23 it was creating a rich condition. ( I was seeing 11's on the WB02. on cranking)... so it would in turn flood it out sort of speak then put it into limp mode.
I think that maybe could of overheated and burnt up the ignition module. Took it in to get tested. Out of 4 tests it failed once. Thats all it took for me to be convinced that it was a intermittant problem. So I bought a new one. Put it and started fine.... then again a little while later Code 23 reappeared. So I'm still having issues with that situation.
Le Mans Master
Joined: Dec 2006
Posts: 5,139
Likes: 482
From: H-Town Texas
I'm just throwing this out there as a possibility and of course could be way off.
But if you have recently installed a nitrous kit, and consequently used it. It may be possible that you are experiencing the beginning stages of head gasket failure? I say this because if a head gasket is starting to fail, when the car sits for a period of time after running, the pressure from the cooling system could leak coolant into the cylinder causing it not to fire and then run like crap when it does. I would have your mechanic pull the plugs and check for any signs of coolant, along with coolant in oil and oil in coolant. It could be that at this point when the car heats up and everything expands it seals back up.
Like i said, I could be way off, and I hope I am. But I know that adding nitrous adds alot of pressure to the chamber and stress to the head gaskets. Also check engine temps and see if they increase more quickly than before. If the head gasket is good, then at least you'll know this isn't a problem but considering the potential it's worth investigating.
But if you have recently installed a nitrous kit, and consequently used it. It may be possible that you are experiencing the beginning stages of head gasket failure? I say this because if a head gasket is starting to fail, when the car sits for a period of time after running, the pressure from the cooling system could leak coolant into the cylinder causing it not to fire and then run like crap when it does. I would have your mechanic pull the plugs and check for any signs of coolant, along with coolant in oil and oil in coolant. It could be that at this point when the car heats up and everything expands it seals back up.
Like i said, I could be way off, and I hope I am. But I know that adding nitrous adds alot of pressure to the chamber and stress to the head gaskets. Also check engine temps and see if they increase more quickly than before. If the head gasket is good, then at least you'll know this isn't a problem but considering the potential it's worth investigating.
Thread Starter
Pro
Joined: Jul 2002
Posts: 703
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From: Milwaukee Wi
Thanks for the tip. No I have not yet used the bottle. This is a terrible coincedence as issues developed a week after install.
A side note. I cant get solenoids to function so no I never was able to spray. The ECU triggers the solenoids. No micro switch. First I had a successful indicator of ECU - N20 signal in logs then when I opened bottle and armed system it did not work and ECU signal was not there? So the bigger issue is gettin car to run for now. Head gasket is Felpro and 7 seasons old. Car never got over 205dF past 7 seasons. Car is not using coolant as I monitor weekly.
A side note. I cant get solenoids to function so no I never was able to spray. The ECU triggers the solenoids. No micro switch. First I had a successful indicator of ECU - N20 signal in logs then when I opened bottle and armed system it did not work and ECU signal was not there? So the bigger issue is gettin car to run for now. Head gasket is Felpro and 7 seasons old. Car never got over 205dF past 7 seasons. Car is not using coolant as I monitor weekly.
