Hard start when hot
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Senior Member
Joined: Oct 2005
Posts: 113
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Hard start when hot
Hey all, its been a while but I have just been REALLY busy! Heres the problem: when my 89 vette gets warm ( +205F ) and I turn it off and then i go to drive it again, doesnt matter if its 30mins later or 2 days, it starts, struggles and then dies. I then have to start it again and keep the gas down and let off just in time to put it in gear. It will run like s*#t for about 5-10 mins while it idles and then it will smooth out when im driving. I really dont want to take it to the shop again and was hoping anyone can help!
ALWAYS apperciated,
Ian
ALWAYS apperciated,
Ian
Senior Member
Joined: May 2007
Posts: 1,567
From: eastern NC
RE: Hard start when hot
ORIGINAL: imb1987
Hey all, its been a while but I have just been REALLY busy! Heres the problem: when my 89 vette gets warm ( +205F ) and I turn it off and then i go to drive it again, doesnt matter if its 30mins later or 2 days, it starts, struggles and then dies. I then have to start it again and keep the gas down and let off just in time to put it in gear. It will run like s*#t for about 5-10 mins while it idles and then it will smooth out when im driving. I really dont want to take it to the shop again and was hoping anyone can help!
ALWAYS apperciated,
Ian
Hey all, its been a while but I have just been REALLY busy! Heres the problem: when my 89 vette gets warm ( +205F ) and I turn it off and then i go to drive it again, doesnt matter if its 30mins later or 2 days, it starts, struggles and then dies. I then have to start it again and keep the gas down and let off just in time to put it in gear. It will run like s*#t for about 5-10 mins while it idles and then it will smooth out when im driving. I really dont want to take it to the shop again and was hoping anyone can help!
ALWAYS apperciated,
Ian
Title says hard 'hot' start. But you say after 2 days it's a hard start too. Right off hand, I'm guessin' injectors are dribblein' a little gas into the cylinders. That's the only thing that would affect a hot start, and a cold start, that comes to mind...
A definite clue is if you get excessive black exhaust AT START-UP. You need to watch the exhaust, as someone else pulls the trigger.
Super Moderator
Joined: Jan 2006
Posts: 1,858
From: Lumberton, Texas
RE: Hard start when hot
Put a fuel pressure gauge on @ startup. Need to find a way to check CTS (Coolant Temp Sensor) readings. Also, try tapping on MAF to see if you get any stutter or even disconnect it to see if performance is any better. [8D]
Joined: Jan 2007
Posts: 236
From:
RE: Hard start when hot
on the cts your looking for the correct readings eg the sensor is telling the ecm that the motor is cold when its really hot. also get test procedure for the fuel sys. a good psi gauge and after shutting off look how long it holds psi. light tapping on maf/mas see if motor want to stall
Super Moderator
Joined: Jan 2006
Posts: 1,858
From: Lumberton, Texas
RE: Hard start when hot
2 things on the black smoke, either fuel injector(s) leaking raw fuel into plenum, probably not since you just replaced them with new ones, I hope, or fuel pressure regulator diaphram leaking raw fuel into vacuum system. Might also unplug vacuum line to EGR valve to see if that improves startup quality. I'm afraid you are going to have to have a scanner to see what the CTS is reporting to the ECM.
Thread Starter
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Senior Member
Joined: Oct 2005
Posts: 113
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RE: Hard start when hot
Thanks for all the help guys! Unfortuatly I dont have a scanner and dont really have the money to get one (maybe some day) but I can get a fuel pressure gauge! I have unpluged the Vacuum line to the EGR before and say no difference that I remember but I will try it again! Also when tapping on the MAF, what am i looking for? If it does change the motor behavoir, is that a good or bad sign?
Joined: Jan 2007
Posts: 236
From:
RE: Hard start when hot
if motor changes when tapping on MAF/MAS its bad.pro manuals are a must for testing as well as test equiptment . a pro manual will tell ya how to test fuel system eg if ya have to block off fuel return and how many mins. it should hold psi
Super Moderator
Joined: Jan 2006
Posts: 1,858
From: Lumberton, Texas
RE: Hard start when hot
Scan tools are really too expensive for the home user. You would need one that reports data. Do you know someone who has a repair shop that can maybe look at it for you.