L98 Engine Won't Start
Team Owner
Joined: Jul 2004
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From: Hartford WI
Thread Starter
Instructor
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From: Miramar Florida
Ok, I worked on the car for a little while today. I checked the TPS and it is working fine, measured .54v at idle and increased as I moved the throttle. I also measured the fuel pressure as I turned the engine over, at one point I was able to make it run for a moment. What I saw happening was that the fuel pressure would drop down to around 30psi, but if I pumped the gas pedal it would go back up to 40psi & try to keep running. Then when the engine died it would also go back up to 40psi. Could it be a bad fuel pump?
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Instructor
Joined: May 2011
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From: Miramar Florida
Ok, I replaced the fuel pump but got the same result as before. The car will turn over & start but dies, I can keep it running if If I pump the gas pedal. It will also die if I try to hold the pedal at a constant RPM, at or above idle.
What should I try next?
What should I try next?
Team Owner
Joined: Jul 2004
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From: Hartford WI
Have you confirmed that the regulator is in good shape? Pull hose and if you smell fuel, it's toast. If that is ok. Turn on the car and see what the pressure is. DO NOT CRANK. See if it holds pressure. IT should hold for several hours. If not, clamp off the fuel return line at the tank area and see what happens. If it holds pressure, you have a weak regulator spring.
Thread Starter
Instructor
Joined: May 2011
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From: Miramar Florida
Have you confirmed that the regulator is in good shape? Pull hose and if you smell fuel, it's toast. If that is ok. Turn on the car and see what the pressure is. DO NOT CRANK. See if it holds pressure. IT should hold for several hours. If not, clamp off the fuel return line at the tank area and see what happens. If it holds pressure, you have a weak regulator spring.
Drifting
Joined: May 2013
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From: Reno Nevada
Maybe reading through some of this may help:
http://www.chevythunder.com/Flow%20c...roubleshooting Flow Chart Pages
http://www.chevythunder.com/Flow%20c...roubleshooting Flow Chart Pages
Team Owner
Joined: Jul 2004
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From: Hartford WI
Like I was saying, turn the engine to run mode but do not crank. Pressure should go up to 40+. Lets see how long it holds.
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Instructor
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From: Miramar Florida
Ok, The pressure went up to 40psi, and I let it sit with theignitions off. The pressure began to drop after about a minute & a half down to 37psi and down to 28psi after 10 minutes. Would this be due to a bad regulator?
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Thread Starter
Instructor
Joined: May 2011
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From: Miramar Florida
Thread Starter
Instructor
Joined: May 2011
Posts: 213
Likes: 0
From: Miramar Florida
Thread Starter
Instructor
Joined: May 2011
Posts: 213
Likes: 0
From: Miramar Florida
Ok, I did another test with these results. When I turn the key to run, I get 40psi fuel pressure, after turning the key to off and letting it sit, I get these results: after 2 minutes-30psi, after 3.5 minutes-25psi, after 8 minutes it was down to 20psi. Are these results good or bad?
Drifting
Joined: May 2013
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From: Reno Nevada
Sounds like they're leaking. I always thought you should be closer to 43, 44, but who know. They should have ohm'd closer to 16.
http://www.witchhunter.com/flowdatapix/rp5235302.jpg
http://www.witchhunter.com/flowdatapix/rp5235302.jpg
Team Owner
Joined: Jul 2004
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From: Hartford WI
Possibly. Clamp off the return line and repeat test. If it holds much longer than that, the regulator is bad, assuming it is a stock regulator.
Drifting
Joined: May 2013
Posts: 1,736
Likes: 31
From: Reno Nevada