Round Two 89 corvette No start
Thread Starter
Burning Brakes
Joined: Sep 2010
Posts: 799
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From: Lexington Park Maryland
Round Two 89 corvette No start
I managed to get the car to start after long trouble shoot of No Start, boy what an accomplishment especially three other local garage could not get it started. After I got it to start, I could not get it to stay running unless I spray carb cleaner in the intake. I could not hear the fuel pump so I replaced it, it doing the same thing.
I feel like I am back to square one, has anyone experience this before. Would a faulty mass air flow contribute? thank in advance.
I feel like I am back to square one, has anyone experience this before. Would a faulty mass air flow contribute? thank in advance.
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
But is the pump running now?
Have you checked the fuel pressure at the rail?
Have you pulled the codes ?
http://www.corvettephotographs.com/c4vettes/codes.htm
Have you checked the fuel pressure at the rail?
Have you pulled the codes ?
http://www.corvettephotographs.com/c4vettes/codes.htm
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From: Out Where the Buses Don't Run, Eglin AFB/ Niceville FL
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I had a fuel pressure regulator cause the same symptoms on my 89.
Thread Starter
Burning Brakes
Joined: Sep 2010
Posts: 799
Likes: 26
From: Lexington Park Maryland
Since this car sat for several years after it stopped running, I thought I go the easy route and replace the fuel filter. No joy there.
The fuel pump does run, I can hear it as I turn the key on then shuts off as schedule. I did apply vacuum to the fuel pressure regulator around 25 hg, with the vacuum applied it will start on the second crank, then it will die. So, what kind of sign from applying vacuum to the regulator to determine it is bad?
If it is bad, any tips on replacing it, it's very tight in that area.
The fuel pump does run, I can hear it as I turn the key on then shuts off as schedule. I did apply vacuum to the fuel pressure regulator around 25 hg, with the vacuum applied it will start on the second crank, then it will die. So, what kind of sign from applying vacuum to the regulator to determine it is bad?
If it is bad, any tips on replacing it, it's very tight in that area.
Melting Slicks
Joined: May 2010
Posts: 2,082
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From: Conowingo Maryland
just because it is running does not mean you have pressure or the volume you need to run the car. What about the fuel is it contaminated? These things are not that difficult to get running. Check fuel pressure and volume, check for the proper amout of spark at the right time. I would also hook a scanner up to it so you know what the sensors are reading into relation to what they should be
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From: Out Where the Buses Don't Run, Eglin AFB/ Niceville FL
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Le Mans Master
Joined: Sep 2013
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From: near the thumb in the mitten
FPR regulator diagphams will rupture and fuel will pass thru vac hose into intake. You need to find out what rail pressure is. Should be 40+psi when pump with key on engine off. Has car been drivable since being parked years ago and for how long?
Thread Starter
Burning Brakes
Joined: Sep 2010
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From: Lexington Park Maryland
To my knowledge the sat ever since it stopped running, from my conversation with the owner. This is the first time it ran in several years.
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Le Mans Master
Joined: Sep 2013
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From: near the thumb in the mitten
You may have more than one problem - the one that caused the car to be parked and one from the car sitting for so long. Do injectors click - have power to them - check both right and left banks( 2 fused strands of 4 injectors) ecm grounds the to turn them on. You want to make sure both side are working. It wont start with just 4. Ecm grounds both strands at the same time every time ignition is triggered (4 times per revolution) A noid light will plug into injector connector make it easier to check. MAF can cause no starts - relays fail more than sensor - unplug sensor ecm will default to tps and map sensor for fuel control.
Thread Starter
Burning Brakes
Joined: Sep 2010
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From: Lexington Park Maryland
I did not have much time this evening, but enough time to check fuel pressure. The gauges reached 38 psi, but it bleed down to 10 psi. Will a MAF from an 1986 work for trouble shooting on this 1989? I have a friend is willing to loan me his from his 86 to see if the MAF on this 89 is good.
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In my case the fuel burped up through the throttle body and out the air filter assy. Left a puddle of fuel under the car. My injectors and fuel pump were new so after checking pressure I isolated it to the FPR.
Le Mans Master
Joined: Sep 2013
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From: near the thumb in the mitten
The fuel pressure is lower than it should be and not holding. Possible causes pump, FPR, or leaking injector(s). If car has rubber fuel hoses ( Do Not clamp/crush nylon fuel lines if present) you could block return line to tank fuel pressure would be pump max >45psi and should hold. If not fuel pump or leak possibly between pump and sender, or fuel inectors. In the 80's a dampner or pulsator was used to quiet fuel pump noise it was between pump and sender. It should be replaced with hose if present and retest. You could disconnect return line and see if fuel leaks out, if shouldn't at 38psi. if it doesn't FPR is weak and need replaced and retest. To check injectors unbolt fuel rail and carefully lift injectors away from intake. Look for fuel dripping from injector(s). You need to make sure O rings stay in injectors and debris doesn't fall into injector holes. If one is leaking replace all with new injectors, mostly be cause of the fuel we use now.
Team Owner
Joined: Jan 2003
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From: Summerland B.C. Canada
38# should be enough to make it run.
Since 89 injectors are known for failure, you may want to disconnect them and ohm test each one. One bad injector can knock out the ECM injector driver.
Since 89 injectors are known for failure, you may want to disconnect them and ohm test each one. One bad injector can knock out the ECM injector driver.
Thread Starter
Burning Brakes
Joined: Sep 2010
Posts: 799
Likes: 26
From: Lexington Park Maryland
The fuel pressure is lower than it should be and not holding. Possible causes pump, FPR, or leaking injector(s). If car has rubber fuel hoses ( Do Not clamp/crush nylon fuel lines if present) you could block return line to tank fuel pressure would be pump max >45psi and should hold. If not fuel pump or leak possibly between pump and sender, or fuel inectors. In the 80's a dampner or pulsator was used to quiet fuel pump noise it was between pump and sender. It should be replaced with hose if present and retest. You could disconnect return line and see if fuel leaks out, if shouldn't at 38psi. if it doesn't FPR is weak and need replaced and retest. To check injectors unbolt fuel rail and carefully lift injectors away from intake. Look for fuel dripping from injector(s). You need to make sure O rings stay in injectors and debris doesn't fall into injector holes. If one is leaking replace all with new injectors, mostly be cause of the fuel we use now.