PDA

View Full Version : hard start delema



freidfocus
03-23-2011, 12:17 PM
I have recently acquired a 1993 SC that has a re-man long block in it from Ford that was installed about 20,000 miles ago I am told. The car has had a ton of upgrade done to it *ie performance mods to the engine FMIC s-trim blower raised top BBK headers full exhaust suspension mods and a Lentech trans. the cars runs like a raped ape and will pass everything but a gas station but it has a little quirk that I have not been able to resolve,.... after the car has run for 15-20 min. if you shut it off the car will not restart. Car will crank crank and then crank some more, but will not fire. If you let the car sit for about and hour it will fire right off and run like there is no tomorrow.. I have recently replace the fuel pump module and the FPR due to another drive-ability issue and that has now been resolved. I have checked to see if there were any codes in the PCM but found none, KOEO nor in KOER. There is no check engine light on and I have checked several things in a data stream function of my scan tool and all seems to be normal other then the fuel pulse width, under cranking the fuel pulse width reads 0.00ms, but when the car is running the pulse width reads with in spec. Through all of the research I've done I cant find weather or not there is supposed to be a pulse width count on cranking do to the fact that the "a typical" IDM readings do not display with out the car running... any help or ideas on this would be greatly appreciated..:confused::confused::confused:

David Neibert
03-23-2011, 12:34 PM
Try holding the gas pedal to the floor, to shut off the injectors. I had a similar problem several years ago, that we were able to correct with tuning. What are you using to tune the car ?

David

freidfocus
03-23-2011, 12:51 PM
there has been no tuning done to the car up and too this point, as far as i know there wast much info given to me when i acquired the car. I have tried the "clear flood" mode as they call it by depressing the throttle to the floor and I have the exact same results,... crank crank crank no start. every one in a while it will attempt to start after a long crank but wont

freidfocus
03-25-2011, 10:11 AM
I know there is someone out there that has had a similar problem,... It just seems as if everyone I talk too has no idea as to where to begin,....

David Neibert
03-25-2011, 01:00 PM
I know there is someone out there that has had a similar problem,... It just seems as if everyone I talk too has no idea as to where to begin,....

Are you still using the stock injectors ? If larger than stock what MAF are you using ? I'm asking because I'm pretty much amazed you are still using the stock tune for the number of mods you have listed.

For example: On my car, just changing from medium length to long tube headers and a less restrictive exhaust required some major changes to the tune. It wouldn't harldy idle and the headers were glowing orange.

I think the short answer to your question is this. Get a QH chip, download Binary editor, buy a def file and a base tune from either Dave Dalke or Fraser, because you have too many mods for running a stock tune.

David

freidfocus
03-25-2011, 01:43 PM
It does have a lager tb on it it is a bbk 70mm.. The car has been set up this way and run this way for several years now with no issues. I mean i have talked to the guy that I got this car from and there has never been any driveability issues up until now.. I about ready to pull my hair out on this one because no has any clue as to where to go....

fasterthanyou
03-25-2011, 01:45 PM
well you need to start somewhere... when this issue is happening, pull the spark plug wire off and see if you have spark. hook up a fuel pressure gauge and see if you have fuel pressure. use a noid light and see if your injectors are firing.. that is exactly what should be done when trying to diagnose a no-start issue.

fasterthanyou
03-25-2011, 01:47 PM
if you have fuel, spark, compression, it will run. so find out which one is missing and there you go. if its spark, its probably the ignition module, if its fuel, check your fuel pump relay, fuel pump, power and ground for your fuel electrical system. if its compression, which I doubt it is, then its pretty obvious what to do from there.

fasterthanyou
03-25-2011, 01:49 PM
my posts were overly simplified, it could be anything, im just trying to help.

freidfocus
03-25-2011, 03:46 PM
fuel sys has been checked. fuel pump and regulator have been replaced, spark has been verified so i guess i'm gonna have to run a noid light on the injectors at this point and see whats going on. but does anyone out there know if it is normal to see no pulse width modulation on the scan tool during cranking? Because the cross counts show 0.00ms in modulation!

mywhite89
03-26-2011, 07:59 PM
I have seen on many gm vehicles, the igniton modules will cause starting issues on warm starts when they go bad. Doesn't seem to be the most common thing on our cars. If it was me, I might try a DIS module. You don't have the equipment to properly test ignition problems as they occur and our cars wont throw codes for them lot of times either.

Like david N said, you might just have a tuning issue. You would be amazed how the change in weather will make my car idle and run differently. These cars modified do not adapt well to anything different then the climate they were tuned in! I don't like to have to say that, but it is true.

Chris

frdlvr30
03-26-2011, 08:41 PM
My educated guess would be IAT sensor or ECT sensor. Either of these will cause hard starting if the incorrect Intake Air temperature or Engine coolant Temperature Input is being given. That being said, as long as you have fuel and spark. Both of these effect fuel control for starting. You really should take David N's advice and think about tuning it with that many modifications.

decipha
03-27-2011, 01:03 AM
sounds like your issues are due to an intermittently faulty crank sensor

judging by your responses i've narrowed down that its a 94-95

thus in which case you won't have a DIS module

David Neibert
03-27-2011, 10:29 AM
sounds like your issues are due to an intermittently faulty crank sensor

judging by your responses i've narrowed down that its a 94-95

thus in which case you won't have a DIS module

:confused:

94-95 SCs have DIS modules too.

David

decipha
03-27-2011, 12:23 PM
no they have edis

only the 89-93 have the external tfi "dis module"

the 94-95 have a true edis setup with a missing tooth reluctor wheel

slowpoke
03-27-2011, 03:27 PM
sounds like your issues are due to an intermittently faulty crank sensor

judging by your responses i've narrowed down that its a 94-95

thus in which case you won't have a DIS module

this is exactly what i started thinking once i began reading this thread. when my crank sensor(pip circuit failure) was on its way out i remember it being real hard to start once it was warmed up. not saying this is your problem but its worth looking into.

decipha
03-27-2011, 06:33 PM
that and the fact that he's not logging any pw indicated that hes missing the pip, i'd almost bet my left that the its an ignition related issue and can be easily discovered by testing for spark once warmed