Warm Start Problems
- Thread starter mcsc1
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What about a snap-on scanner? That’s the only one I have access to.
Originally put in a Delphi pump and now the warrantied Delphi is a carquest. Fuel pressures are fine with key on engine off and also when running. After it bled down though to 16-18 psi and then turned key on it would only reach 24-26 psi after engine had been on and “primed”.
Originally put in a Delphi pump and now the warrantied Delphi is a carquest. Fuel pressures are fine with key on engine off and also when running. After it bled down though to 16-18 psi and then turned key on it would only reach 24-26 psi after engine had been on and “primed”.
Yep that’s my dilemma. It acts like it’s flooded and it does lose pressure but everything I’ve done and looked at doesn’t show me where. I have a possible injector I want to warranty as all my plugs smelled like burnt fuel except one. That one smelled like raw gas.
you could try unplugging that injector. it will fire on 7. but also even if one of the 7 is rich should still start. might not be the smoothest thing but I'd think it would fire. there's a guy here that disconnect 2 injectors and 2 rockers I think it was and driving on 6 cyl because of a afm fault.
I may try that to see if it’s my issue but definitely not driving on that.
ya that's a method to easily detect a misfire or other isssue's by pulling the coil harness off one by one until you no longer "hear' a difference
definitely don't drive on it.. just crank and start.
since you have a scanner, if you can watch that and either cycle the key a few times or just clear flood till you have psi, and then let it crank. see what that does. I have a feeling your low pressure is throwing the whole crank routine off. I base that on nothing but a guess lol. they do sell check valves for fuel systems. normally only used for big aftermarket fuel systems using 2 or more pumps. but as far as I understand it, the pump should have a check valve in it.
the one that doesn't hold at work was from napa. we try to use oem these days.
if getting the pressure up first works, you might just have to go with a new oem from the dealer or gm parts direct. I don't trust Amazon and I kinda questioned some acdelco plug wires from Rock auto recently, they looked the same, but the oem I took off had a part number on the wire, these didn't. after getting burnt by Amazon acdelco parts twice now. I'm always worried if they are legit.
My pressure is great at cold start, running, etc. but it falls short only after it’s warm and bled down. I do agree though, it’s an issue I thought was solved by replacing the pump. Would anything else be keeping it from building pressure?
I hate you are having this problem but you just said something funny to me. You just said, "I hate throwing parts", but you initial post lists a bunch of parts. Sometimes these rigs just drain the wallet.
You’re telling me man! I thought I had the problem solved. Everything I’ve seen and videos similar to mind show the fuel pump or injectors. Replaced those and still have the issue.
Found this on another thread. Anyone think this could be an issue I should check?
Your fuel trims would show a very rich condition on both banks and it would run like poo all the time, probably. But it's not a bad idea to look at what the scanner reports and reset the alcohol content, if not using more than E10 fuel.
so you changed the injectors already? the only cheap way I can think of to check the injector is like said earlier, swap it another spot and see if that fuel smelling plug follows it.
do you have the old injectors around still? maybe could clean one and swap it in as a test? only thing I can think of to cause a injector to spray more than the ecm says to it a short to ground somewhere in a harness? I believe they are switched grounds and constant power?
do you have the old injectors around still? maybe could clean one and swap it in as a test? only thing I can think of to cause a injector to spray more than the ecm says to it a short to ground somewhere in a harness? I believe they are switched grounds and constant power?
It’s possible and I’m unsure how to go about finding the ground in the harness. But the injectors are warrantied, I can get another through that warranty.
Fuel trims might say something. You can use a noid light to see if the injectors are being pulsed. An injector balance test, using a bi-directional scanner, would show an injector that wasn't working properly (too much, too little fuel metered). Neither of those tests, however, would tell you if the ECM was pulsing them properly.
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I have a 2009 Tahoe 5.3 2wd with 189,000 and I just brought it to my mechanic to change a spark plug and he only replaced one and said the others are fine but about 2 weeks later im getting a cyl 4 misfire but engine seems to run perfectly besides a little rough at idle. I dont have a spare maf sensor but if I unplug it and the engine light disappears does that mean its the sensor?
One spark plug, really!
no telling without getting some readings on it with a scanner, when it is unplugged the vehicle runs in a default mode. I can say that after 160k the maf are known to/or can go goofy and can cause all kinds of problems. just throwing parts at it is a gamble, sometimes you win and sometimes you dont.
my thoughts exactly, who does that? unless you know the plugs are fresh and 1 happened to crop up with a problem.One spark plug, really!
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