94 mustang 5.0 cranks/no start

STROKER_T · June 15, 2011

Mornin everyone,gotta '94 stang convertible 5.0 that cranks,but wont start unless u shoot ether to it...found water in the gas,replaced fuel pump with a bosch and cleaned tank....NOW i got good fuel and pressure,spark is ok and i have power to injectors...now here's the kicker: the check engine does NOT prove out,self test or whatever the reference is....i pulled every connector i could find to eliminate the possibility of a bias sensor...no go still...

Just wanted to verify that indeed the check engine light should come on with key in run position,then go out after engine starts...this thing is kickin my ass,anybody have an idea of what i'm missing here...? THANKS Posted Image

Mbl35 · June 16, 2011

Any codes, do you have spark? Inector pulse?

Jim Warman · June 16, 2011

Like Mike asked... Injector pulse? Use a noid light to check - make sure to check as many as you can get to (all would be ideal).

Where are you checking for spark? What kind of spark tester? This kind is about the best. Check right at the spark plug boot.

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Got any intake vacuum while cranking? 3 or 4 inches would be pretty comfortable and would indicate that the exhaust isn't plugged.

Try turning the key from off to run a few times before initiating the starter... some of these older cars would grow carbon deposits on the back side of the intake valve and this would soak up much of the initial fuel delivery.

STROKER_T · June 16, 2011

Thanx guys I'll check that....used your typical spark light and getting good spark from coil wire...gonna check for pulse at injectors,it makes sense that just because u have power to injectors doesnt mean there's pulse...which brings me back to whether check engine light should self check or not...this is my uncle dennis's car,sure would like to hear this thing run....

if no pulse and no check engine light,sounds like breakout box time...good times Posted Image

mrbudge · June 17, 2011

You say it will start with ether? Does it stay running, if so you may have a TP sensor stuck at WOT. On the old OBD1 Fords the check engine light goes on with the key and goes out as soon as the pcm sees a PIP signal. Now someone may have yanked the bulb for whatever reason. Check at any sensor for vref with the key on. The old tfi cars would spark even if the pcm was not powered up. VREF is a good way to determine if the pcm is alive or not.