Hard to Start LT1
Thread Starter
Intermediate
Joined: Jan 2005
Posts: 37
Likes: 0
Hard to Start LT1
Have a '93 that's hard to start. Worse when hot and sits a while. Had the injectors cleaned and tested OK. Holds fuel pressure. 40 psi when the key is on and 38 when running. Takes about 20 minutes to bleed down. Still suspected an injector so ran a boroscope down the intake and visualized all the injectors while under pressure. No leakage seen. Has new plugs and wires. No check engine light. Recently changed the O2 sensors and they were black. See black smoke when it first starts but runs fine and gas mileage is good. Saw some threads about the pulsation damper and press regulator. No sign of gas when the vacuum line is pulled. The pressure rises to 45 psi when the vac line is removed. One odd thing is when the vac line is reconnected, the pressure jumps quickly from 45 to 38. Also when reved up the pressure has about a +/- 1 psi swing at high frequency. Don't know if the pulsation damper will cause the hard start and if it was bad, would the system hold pressure? Any help appreciated!
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Sounds like you have done the proper fuel testing and it is all good.Yes if the pulsator was bad it would leak down it connects after the fuel pump it is a bladder in a block it simply slides on the lines.Even if the bladder broke as long as the seal at both ends hold it will not leak down plus I doubt it would cause starting issues as long as you have pressure at key on holding.
Your no gas smell at FPR says it is ok and what you did shows it is working right.
All in all it does not sound like a fuel issue based on your tests. Time to look else where.Have you tried pulling the codes? They don't always set the SES light.
Another thing to check is the TB has it been cleaned lately? There are a lot of good threads on TB cleaning in the archive.At the least shoot some cleaner through the passage in the middle of the TB to the IAC. There is a hole between the blades in front. You know the adage fuel+air+ spark= ignition
Your no gas smell at FPR says it is ok and what you did shows it is working right.
All in all it does not sound like a fuel issue based on your tests. Time to look else where.Have you tried pulling the codes? They don't always set the SES light.
Another thing to check is the TB has it been cleaned lately? There are a lot of good threads on TB cleaning in the archive.At the least shoot some cleaner through the passage in the middle of the TB to the IAC. There is a hole between the blades in front. You know the adage fuel+air+ spark= ignition
Last edited by Redeasysport; Aug 20, 2008 at 10:56 PM.
