ford98pony

i have a 1998 mustang gt and it starts up fine but when i turn it off to get gas or run into the store it wont start again. i have to wait like 30 mins. does anyone know why this is happening?

SilverBullet98

yo, i had/have the same issue with my 98. it will just not start sometimes. it however does not act like a bad fuel pump. i thought i had a bad CCRM(constant control relay module) but turns out it did the same thing with a new one. i bypassed my inertia switch and it hasnt done it since...so maybe that was the fix.

id start there.

ford98pony

how did you bypass it?

WhiteFoxGT

Does it crank strong when it gets hot? OR does it sound weak... I know on older cars, heat soak in the starter will keep the car from starting. A bad inertia switch switch shouldnt be a problem only when you shut the car down. It could cause th car to just die while running...or whenever its shaken over bumps.. To bypass it you just unplug it and use a jmper wire the connect the 2 pins in the plug together.

cliffyk

This is a common issue with the '99-'04 models, my '03 exhibited the same behaviour. I believe it is a heat soak issue and that fuel is vapourising in the fuel rails. Before I found the final solution (see below) I found that turning the key on and waiting a few seconds before cranking would often help, as well as letting it crank a tiny bit longer than what seems right.

The final fix that I found a month or so ago was to modify the Cranking A/F Ratio function in the tune to make the AFR while cranking, at temps of 200°+, a bit richer. The OEM setting was 13.8:1, I changed it to 13.3:1 and the problem is gone. You will need a "low-level" tuner like Sniper Commando to do this.

SilverBullet98

whitefox-remember what i tsays by the inertia switch? "if engine fails to start, reset switch" an internally shorted switch COULD exhibit this problem as well my friend. i am by no means saying youre wrong, just saying where i diagnosed and found. and not always will that "button" always pop up on the switch to show its been tripped. i just havent had a prob since i bypassed it. just my 2 pennies

also i guess the guy never said whether or not it cranked to begin with when it does this..go figure

WhiteFoxGT

True, and I wasnt trying to dis-credit your fix either. From what I have experienced, as a Ford tech, inertia switch problems are almost ALWAYS a crank/no start...most of the time being it dying on the road and being towed in. However now I think about it, you are correct too and I would check the switch or bypass it for a few days to see if that helps..

SilverBullet98

for my own curiosity, are fords the only vehicles that have an inertia switch like that in them? im a former GM tech and i never seen much like it, aside from i think the PCM shuts it down in the even of a signal from the crash sensor.

WhiteFoxGT

I couldnt answer that question. I worked at an independant shop for a little over a year before Ford and dont think I even came across one.. Until I came into the Ford world. So its possible other manufacturers have a type of fuel cut off but I have no clue..