Hard to start when warm
Thread Starter
3rd Gear
Joined: Mar 2009
Posts: 3
Likes: 0
Hard to start when warm
I have an '88, stock, with 4+3 trans. When it's completely cold (as in having sat for 2 days), it fires up immediately, no problem. After having warmed up the engine, if I let it sit for approximately 5 minutes or less, it'll start right up again. If I let it sit for any longer (10 minutes to a day and a half), it takes 5-10 seconds and a little coaxing with the throttle to get it to fire up.
It also has a little bit of an erratic idle (wavers between 500-700 rpms), Idk if that is related or not.
I have replaced:
-fuel filter (problem went away for 1 day)
-plugs
-wires
-cap
-rotor
-pcv valve
-checked K&N air filter, barely dirty
Any help or advice will be greatly appreciated. TIA!
It also has a little bit of an erratic idle (wavers between 500-700 rpms), Idk if that is related or not.
I have replaced:
-fuel filter (problem went away for 1 day)
-plugs
-wires
-cap
-rotor
-pcv valve
-checked K&N air filter, barely dirty
Any help or advice will be greatly appreciated. TIA!
Pro
Joined: Mar 2006
Posts: 576
Likes: 0
Service Engine Soon light? Try disconnecting the MAF sensor and see if it acts better. If it starts easier, there's your problem.
The reason I am suspicious of this is because you mention the K&N filter. K&N filter oil can make it's way into the MAF. If that is the problem you can try cleaning the MAF. Do a search on it here, it's been discussed. I tried it, it didn't go well for me. Others have had different results.
This is a shot in the dark, but you're not out much effort or dollars for disconnecting a sensor.
The reason I am suspicious of this is because you mention the K&N filter. K&N filter oil can make it's way into the MAF. If that is the problem you can try cleaning the MAF. Do a search on it here, it's been discussed. I tried it, it didn't go well for me. Others have had different results.
This is a shot in the dark, but you're not out much effort or dollars for disconnecting a sensor.
Racer
Joined: Aug 2008
Posts: 444
Likes: 0
From: Fort Madison Iowa
St. Jude Donor '11
maybe try your fuel filter again. if you had alot of crap in your gas tank for some reason, and you cahanged your filter once and it alleviated your problem for a while it could have very easily just plugged up again. maybe even try draining your gas tank first.
Team Owner
Joined: Jul 2004
Posts: 28,432
Likes: 3,285
From: Hartford WI
Check the ignition system. I don't care what you have done before. Lets not rule things out before we test them. Your thing sounds like a heat soak issue.
Crank the car cold and see if you get a blue flame. Then go driving the car around and come home and try the same thing. Best done in the dark
Crank the car cold and see if you get a blue flame. Then go driving the car around and come home and try the same thing. Best done in the dark
Thread Starter
3rd Gear
Joined: Mar 2009
Posts: 3
Likes: 0
Thanks for the replies! I will try the MAF disconnect and spark test as soon as possible, seeing as they are completely free. I'm sure the MAF could use a good cleaning anyway, I'm sure it's never been done. The fuel filter being clogged again is also a very logical conclusion IMO, especially since it seemed to work for a bit the first time. I've been meaning to check the timing also, but haven't gotten around to it yet. Suppose that could have anything to do with it?
Pro
Joined: Oct 2005
Posts: 721
Likes: 1
From: Charlotte NC, behind someone going 10 under the speed limit
I have an '88, stock, with 4+3 trans. When it's completely cold (as in having sat for 2 days), it fires up immediately, no problem. After having warmed up the engine, if I let it sit for approximately 5 minutes or less, it'll start right up again. If I let it sit for any longer (10 minutes to a day and a half), it takes 5-10 seconds and a little coaxing with the throttle to get it to fire up.
It also has a little bit of an erratic idle (wavers between 500-700 rpms), Idk if that is related or not.
I have replaced:
-fuel filter (problem went away for 1 day)
-plugs
-wires
-cap
-rotor
-pcv valve
-checked K&N air filter, barely dirty
Any help or advice will be greatly appreciated. TIA!
It also has a little bit of an erratic idle (wavers between 500-700 rpms), Idk if that is related or not.
I have replaced:
-fuel filter (problem went away for 1 day)
-plugs
-wires
-cap
-rotor
-pcv valve
-checked K&N air filter, barely dirty
Any help or advice will be greatly appreciated. TIA!
Same thing though, stop for gas, it fires up perfect. Stop to eat lunch, cranks about 6-8 seconds.
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Team Owner
Joined: Jul 2004
Posts: 28,432
Likes: 3,285
From: Hartford WI
Other than the wavering/erratic idle I have the SAME EXACT problem with my 88. Sent out injectors for cleaning/testing, fuel pumps, good regulator, holds pressure, I have no %#@$ing clue what it is. Leaking Cold Start injector?
Same thing though, stop for gas, it fires up perfect. Stop to eat lunch, cranks about 6-8 seconds.
Same thing though, stop for gas, it fires up perfect. Stop to eat lunch, cranks about 6-8 seconds.
I think my L98 in my 91 Firebird when new was just like that. My hunch is that when cold, it puts more fuel for the startup but I might be wrong.
Pro
Joined: Oct 2005
Posts: 721
Likes: 1
From: Charlotte NC, behind someone going 10 under the speed limit
Just the 8 main injectors. Your 91 didn't have a cold start injector. I don't think it's supposed to be like this, it's not hurting anything it's just kind of embarrasing having to crank it so long and bystanders think your car is broke down.
Team Owner
Joined: Jul 2004
Posts: 28,432
Likes: 3,285
From: Hartford WI
Then try send the cold start one off and see what happens.