86 start problem!!!!!
Thread Starter
Instructor
Joined: Mar 2005
Posts: 217
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From: 86 Z51 Coupe Branson,MO
86 start problem!!!!!
My 86 vette just had all relays replaced,MAF.The car ran and I drove to get the exaust fixed.The car Starts running poorly and dies.Won't start!!!Just turns over.I replaced the ECM,O2,plugs.I pull the plugs and they are full of fuel.So then I check the vacuum hose to the FPR.No gas here.Experts please help!!!! 
Thread Starter
Instructor
Joined: Mar 2005
Posts: 217
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From: 86 Z51 Coupe Branson,MO
Would all 8 injectors do the same thing if they were leaking?All the plugs were full of gas.I had to dump the gas out of the plugs.I know I have spark.But is it enough?The car turns over but does not even catch.What about the ICM.I'm lost!!!!
Racer
Joined: Dec 2003
Posts: 277
Likes: 3
Originally Posted by AFogleman
Would all 8 injectors do the same thing if they were leaking?All the plugs were full of gas.I had to dump the gas out of the plugs.I know I have spark.But is it enough?The car turns over but does not even catch.What about the ICM.I'm lost!!!!
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Team Owner
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
What I'm hearing is that you have fuel, just no spark?
Engine is cranking fine?
Any sputtering like the plugs are getting fire?
If you pull off a spark wire and set it close to ground are you hearing it pop?
Engine is cranking fine?
Any sputtering like the plugs are getting fire?
If you pull off a spark wire and set it close to ground are you hearing it pop?
Safety Car
Joined: Apr 2004
Posts: 4,532
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From: Lahaina Hi
Fuel presure regulator will fill engine with fuel.
Your dist moduel is known for not being able to produce enough dwell to keep a hot spark going.
1.What is fuel presure?
2.With gauge hooked up to fuel how long does it take for the fuel presure to drop?
3.Have you removed the dist cap and checked the rotor and carbon center?
4.Why did you replace the ecm and other items?
5.Is the motor stock?
6.Have you checked all the fusses?
7.Have you checked all 3 wire connections at the distributor?
Let us know how these checks went.
Your dist moduel is known for not being able to produce enough dwell to keep a hot spark going.
1.What is fuel presure?
2.With gauge hooked up to fuel how long does it take for the fuel presure to drop?
3.Have you removed the dist cap and checked the rotor and carbon center?
4.Why did you replace the ecm and other items?
5.Is the motor stock?
6.Have you checked all the fusses?
7.Have you checked all 3 wire connections at the distributor?
Let us know how these checks went.
Thread Starter
Instructor
Joined: Mar 2005
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From: 86 Z51 Coupe Branson,MO
The relays ect were replaced due to all going out after car had been sitting about a year.I replaced the ECM thinking that may be it.Where on the rail do I check for fuel pressure.Definately getting spark,Placed next to a ground and it shocked the crap out of me. 
The plug wire that is.The car just turns over,Never hitting on any cylinder.Can too much fuel cause not enough spark.I've also been told it's not the FPR because there is no gas in the vacuum line.Thanks for all the advice! 
The plug wire that is.The car just turns over,Never hitting on any cylinder.Can too much fuel cause not enough spark.I've also been told it's not the FPR because there is no gas in the vacuum line.Thanks for all the advice!
Team Owner
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Originally Posted by AFogleman
Placed next to a ground and it shocked the crap out of me. The plug wire that is.The car just turns over,Never hitting on any cylinder. Can too much fuel cause not enough spark.
The plug wire that is.The car just turns over,Never hitting on any cylinder. Can too much fuel cause not enough spark.
Team Owner
Joined: Sep 2003
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
When the switch is turned on, the pump comes on to presurize the fuel rail. The pressure should stay up during the cranking and start. Lots of more experienced guys on the CF that can pick it up from here.
Team Owner
Joined: Jan 2003
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From: Summerland B.C. Canada
My pressure dropped faster than that and caused no starting issues. I had 4 out of 8 that couldn't hold 30lbs (tested after removal) and still started great. I have new injectors and still have a pressure loss probably due to a bad check valve at the pump. Have you tested to see if your injectors are recieving a constant ground from the ECM thereby staying open and flooding the motor ??
Thread Starter
Instructor
Joined: Mar 2005
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From: 86 Z51 Coupe Branson,MO
Just got it started.I double cleaned the rotor with never dull,pulled all injectors,plugs cleaned,Didn't replace the injectors.Put all back together and she ran.NOW.....Here are the codes I threw.32-EGR,34 MAF low,25 Mat High,42 Electric spark Something!!!So I probably need a new rotor cap,But what else????Thank you guys for all of your help.I've always loved Vettes,And obviously so do you guys...Thanks
Team Owner
Joined: Mar 2000
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From: Boston, MA
Well, if you want to determine the cause of your pressure loss you can do the following.
Run the fuel pump and pinch the fuel supply soft line by the fuel tank. If the pressure holds then it is a leaking pump coupling hose or pulsator or a faulty in-tank pump.
Continue if necessary...
Run the fuel pump and this time the fuel return soft line back by the fuel tank. Kill the pump and the pressure should hold. If it doesn't then your injectors are leaking. If the pressure DOES hold then it is your fuel pressure regulator leaking.
Run the fuel pump and pinch the fuel supply soft line by the fuel tank. If the pressure holds then it is a leaking pump coupling hose or pulsator or a faulty in-tank pump.
Continue if necessary...
Run the fuel pump and this time the fuel return soft line back by the fuel tank. Kill the pump and the pressure should hold. If it doesn't then your injectors are leaking. If the pressure DOES hold then it is your fuel pressure regulator leaking.
Team Owner
Joined: Sep 2003
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Originally Posted by AFogleman
Just got it started.I double cleaned the rotor with never dull,pulled all injectors,plugs cleaned,Didn't replace the injectors.Put all back together and she ran.NOW.....Here are the codes I threw.32-EGR,34 MAF low,25 Mat High,42 Electric spark Something!!!So I probably need a new rotor cap,But what else????Thank you guys for all of your help.I've always loved Vettes,And obviously so do you guys...Thanks
Drifting
Joined: Mar 2005
Posts: 1,923
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From: GA
Originally Posted by AFogleman
Just got it started.I double cleaned the rotor with never dull,pulled all injectors,plugs cleaned,Didn't replace the injectors.Put all back together and she ran.NOW.....Here are the codes I threw.32-EGR,34 MAF low,25 Mat High,42 Electric spark Something!!!So I probably need a new rotor cap,But what else????Thank you guys for all of your help.I've always loved Vettes,And obviously so do you guys...Thanks
MAT high, replace the sensor on the underside of the plenum ($7 at advance auto, if they say they don't have it, ask for a coolant temp sensor for your car, they are the same P/N)
Code 42, Electronic spark control. This could be the box or the ignition module. (or connections to either)
Code 32, EGR. Do a search on here for it, I posted a lengthy ops check of the system for troubleshooting.