idle

[Jon1971]

I have a '91 gsx with 1000cc injectors and I'm running the Maft blow, e-manage with injector and ignition. I can get it to run pretty good all except idle. I've tried setting the idle with the idle screw the Maft and the e-manage. I can not get it to idle for anything. It will not idle, it just dies when I let off the gas.

A short list of mods:
HKS 272/272
Race ported head
SCE titan .062 head gasket
2.3 stroked bottom
1000cc inj.
Slow Boy GT14 td04s turbo


If I hold the rpms to 900 I'm showing 16 on the vacuum. I've been told that's about right for the 272s I have.

Any help would be great.

Thanks
Jon

 

[ddavisaf]

Other sources of idle problems include fouled spark plugs, a defective or gunked-up idle speed control (ISC) motor, leaking injectors, a cracked vacuum hose, or a damaged intake manifold gasket.

You've probably checked these already though. Post back whether or not you have. If not, then test them and post back

 

[vr6chris]

Yeah, i would check for vaccum leakes, and also take a look at the isc

 

[Jon1971]

I've replaced the ISC with a known good unit. I put another set of new plugs in. I've checked for vacuum leaks. I can't find any. If I had a vacuum leak wouldn't I get a bad vacuum reading at 900rpms? I'm getting 16 if I hold it at 900. It has all new injectors and injector O-rings, top and bottom.

Thanks guys. If you can think of anything at all I'll give it a try. I'm just trying to get this thing to idle so that I can get it to the dyno.

 

[ddavisaf]

What kind of fuel and control are you playing with? injectors are 1000cc's... so More than likely a 255 fuel pump and a fpr right? Running a logger with mmcd (whatever it's spelled) software and tuning your fuel with a safc or with a eprom sim...?

 

[Jon1971]

I've got a Walbro 255hp -6an line from tank to rail and Aeromotive fpr. I have mmcd logger and I'm using the Maf translator and a Greddy e-manage with a lap top.

One thing I did notice is that the fuel pressure drops to 0 about 5 seconds after I cut the car off. I've got a buddy that has an Aeromotive on his without the line from the tank and his hold pressure after the car is turned off. Would this make a difference?

 

[ddavisaf]

What kind of fuel pressure are you running?
And I hate to ask but what kind of spark plugs do you have?

http://www.dsm.org/how-tos/tttt/tttt3.html
Also read over this.

How long have you had those 1000cc injectors in? Maybe one is stuck open?? 60 bucksish (yes, bucksish) for cleaning and balancing via Fuel Injector Clinic can only help, not harm.

 

[Jon1971]

The injectors are new. I thought the same thing so I pulled them out and tested them on an injector flow bench. I put about 36 psi on them and energized them; they all open and close well.

I went into the e-manage and set the anti engine stall as fallows:

600rpms 40
700rpms 45
800rpms 45
900rpms 45
1000rpms 45
1200rpms 45
1500rpms 45

The car is now idling!! A little rough but never the less it does idle!!

I took it for a ride down the road and it didn't die one time!!

I want to thank all you guys for your help.

Thanks again
Jon

 

[ddavisaf]

Glad you got her fixed...