mint875000cstq

Hello all,

I have a strange problem. When I start my car, it starts and idles at about 100-150 rpm and chugs and wont idle correctly for about 10-30 secs. then magically jumps up to correct idle speed (without any pedal) and performs like a beauty. What's up? I have a new throttle switch, newer fuel pump and filter and my ISV is buzzing during this short startup ordeal. It is so strange because after the 10-30 secs., all is normal and all systems function properly.

Thanks ,

Aaron
1987 5000 csqt ALL ORIGINAL 278,000 miles.

SteveAngry

Leaky injectors?

CARSNPLANES

Does this happen all the time or just sometimes or just first start in the morning? The 10 - 30 sec is the engine running on the cold start injector. (at least you now that works). That means for those few seconds, the regular inj don't have fuel coming out of them, hence the low idle. You said you just replaced the filter and some items. Did you make sure you tightened all the connections? The highest point is the filter (5000,200)and if any hose comnnection is loose, you could be breaking vacuum and losing fuel pressure. (should be leaking somewhee too) Otherwise it could be leaky injectors and it's trying to clear out the excess fuel during those few seconds in addition to the extra fuel provided by the CSV. However, the CSV is inoperative above 90c.

mint875000cstq

Happens when I start the car in the morning and when I start it after work. The fuel filter is actually 'new' as in about a year old. Maybe I am a victim of the 'tank lining deterioration' problem? But wouldn't I have other problems other than just starting ones? hmmmmm.

CARSNPLANES

To troubleshoot, lets make an assumption and go from there. Lets assume you're fuel starved during these times(early morn, after work)because the 30 psi pressure at the fuel dist is lost. Happens sometimes when the checkvalve doesn't hold. All that will happen is that you have to crank longer before it starts. The pump is trying to make up the loss of fuel pressure where normally it wouldn't have to if the pressure was right there to begin with. So assunuming this is happening, try making the pump run a few seconds before you begin cranking the starter. Do this by inserting a fuse in the pump relay located in the main fuse box. Are you familiar with this procedure? Ign off, insert the fuse in the slot on the pump relay, turn to ign only don't start yet. You should hear the pump running as long as the fuse is in. Turn off the key, remove the fuse. Now go ahead and try starting the engine. if it starts first time and runs normally with normal idle, then we've tested for the correct assumption, which is a loss of system pressure overnite. If it got worse, then we've introduced more fuel than we've needed and we can assume that the cylinders were already full of fuel, possibly due to leaky injectors (injectors that release fuel too early due to weak spring or worn seat).
Lets see what you have first.
Jody

whitacre

I seem to have the same problem, and i thought it was my CSV or a leaky injector as well...

Heres something to throw out there though....when i put in plus or much better yet, premium gas (i filled my tank up on my V8Q for 27 bucks, premium gas...i almost had an orgasm)

anyway when i fill it with plus or premium, i notice it starts right up no issue idling or anything...its quite odd.

mint875000cstq

One can of Techron - 12 gal. of fuel.....Problem vanished! :-)