86 no start
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Intermediate
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86 no start
My fathers 86 has been sitting for four years. So I towed it to my house, tank was full of water. So I pulled the pump, cleaned the tank, changed the fuel filter and plugs. But no start. Fuel pressure is about 45psi, good spark, no codes. It ran fine when he parked it. It cranks over, catches coughs and dies. Its an 86 all stock except for a zz4 I put in about five years ago. Any thoughts guys?
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From: Freedom is never more than one generation away from extinction.
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If you have good spark then its a fuel issue.
Watch fuel pressure during the start attempts to ensure its not dropping off.
I'd have purged the fuel at the fuel rail. Just to make sure there is fresh fuel at the injectors.
Injectors bad?
Watch fuel pressure during the start attempts to ensure its not dropping off.
I'd have purged the fuel at the fuel rail. Just to make sure there is fresh fuel at the injectors.
Injectors bad?
Thread Starter
Intermediate
Joined: Sep 2010
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It will run with gas sprayed in the intake. So no fuel or not enough to the cylinders. I noticed the 02 sensor is broke off. This wouldn't tell the computer it's too rich and not give fuel would it?
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From: Charlotte NC
Team Owner
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From: Summerland B.C. Canada
If you have a noid light, check for a pulse at injector. The cold start valve may be the only fuel source, allowing for an almost start situation.
Have you tested both injector fuses ?
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Ok so I'm back at it for a few more hours. Inj fuses are good. I don't have a noid light but with the key on I have power to both wires at the injector. I have some weird reading off of my scanner.
manifold air temp -34.6
throttle 0.0v
coolant temp 124.7 this is in my 70degree garage
inj pulse 1.8ms
Anything else to look for before I rule out injectors? It appears obvious the plenum has to come off to do injectors.
manifold air temp -34.6
throttle 0.0v
coolant temp 124.7 this is in my 70degree garage
inj pulse 1.8ms
Anything else to look for before I rule out injectors? It appears obvious the plenum has to come off to do injectors.
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Alright guys, sorry for all the questions. I'm just trying to help out dad. He has done a lot for me so I owe him. I cleaned some grounds got 5 volts to the tps but it still reads zero on the scanner. I have 45 psi of fuel while cranking. But the fuel put won't stop running with the key on until I pinch the return line. I pulled the vacuum off the regulator and its dry. Pulsator bad?
Edit- I replaced the pulsator with fi hose, no change. Then I realized pinching the return side has no effect on the pulsator. So would a bad pressure regulator cause a no start? Or do I have some injectors stuck open? I'm totally lost now. I started thinking bad ground due to the crazy scanner readings.
Edit- I replaced the pulsator with fi hose, no change. Then I realized pinching the return side has no effect on the pulsator. So would a bad pressure regulator cause a no start? Or do I have some injectors stuck open? I'm totally lost now. I started thinking bad ground due to the crazy scanner readings.
Last edited by teamtopless; Sep 23, 2010 at 11:49 AM. Reason: edit
Team Owner
Joined: Jan 2003
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From: Summerland B.C. Canada
You will have 12v on both sides of injector until ECM applies ground to the one side. You really need a noid light to see if the ECM is pulsing injectors.
The fuel pump should only run for 2 seconds when ignition switch is turned to "run". Yours runs not stop with key in "run" ?
The ECM looks for a reference signal from ignition module, before it will fire the injectors. Be sure the 4 pin connector at base of dizzy is clean and tight.
The fuel pump should only run for 2 seconds when ignition switch is turned to "run". Yours runs not stop with key in "run" ?
The ECM looks for a reference signal from ignition module, before it will fire the injectors. Be sure the 4 pin connector at base of dizzy is clean and tight.
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Agent 86, Yes the pump runs non stop with the key in the run position until I pinch the return line. I guess I need to find a noid light to continue my hunt. A friend of mine if a GM master tech and thinks I have a bad ground somewhere giving my crazy sensor readings. May or may not be related to the no start. Hard to diagnose over the phone. If my regulator is bad would that cause a no start? I can literally here the fuel flowing through the rail when the key is turned on. I appreciate all the info I can get.
Team Owner
Joined: Jan 2003
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From: Summerland B.C. Canada
The pump should not run non stop. You should diagnose that, but it shouldn't cause a no start if you have 45 lbs. A bad reg should not cause a no start. It sounds like your injectors are not firing.
I have a lot of 86 FSM info on my site, it should help a lot, but you need to have a noid light to get past some of the early diagnosis.
Read all of this >>> http://members.shaw.ca/corvette86/
I have a lot of 86 FSM info on my site, it should help a lot, but you need to have a noid light to get past some of the early diagnosis.
Read all of this >>> http://members.shaw.ca/corvette86/
Team Owner
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From: Cincinnati, Oh USA
You can make your own noid light with an LED and a series 680 ohm resistor. The short lead on the LED is the cathode and it gets connected to the inj socket pin that has no voltage on it and the other lead goes to the inj socket pin that has 12v on it. During cranking the LED should pulse which shows that the ECM is getting reference pulses from the distributor and the ECM is pulsing the injectors to provide fuel to the engine so it will start.
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Well I can stop worrying about my crazy scanner readings. I dug out my fsm and from 4 years ago I had the exact same readings wrote down on a piece of paper. And it ran great then. I called 5 parts store this morning looking for a noid light. 2 guys knew what I was looking for. The manager at autozone was like duh, It does what? No sir only spark testers. So I ordered a set for monday from Bond. So until then thanks for the help guys.