[Catori]

Have a '93 GT that will not start. Have sought help before and nothing seems to work.

The problem: car will not start - turns over very strong - the electricity pulse to the fuel injectors is being cut out by something - confirmed by noid light. This is why the car won't start - no pulse to the injectors to put in fuel - car will briefly fire up on starter fluid - but will not run because of injector deficit.

What usually works is to cut the electricity to the car by pulling the battery for a period of time. If it chooses to start after this fix, then it will cut back out after idling for about 3 minutes - then it will not start again. You can also pull the ECU for a bit and it might work - but again, only for a short time.

What's been tried: has a new fuel pump, new pump relay, new MSD distributer, new fusable link that runs in the electrical line for the fuel system, new throttle position sensor, new tfi coil - none of these worked - replaced the ECU/computer and this fixed it for a about a day - then the problem re-occured.

Someone suggested that it may be a ground that is kicking the injectors off - anyone have a diagram of the location of the engine and harness grounding points?

ANY IDEAS APPRECIATED!!!

I have over $9500 invested in this car and am about to trash it.

Thanks for the help.

David

[dr.gonzo!]

Have you pulled the codes with this test or is that the noid light you talked about?

DIY KOEO/KOER/Cylinder Balance Self-Test Procedure

[Catori]

Pulled codes just about every time - reason for replacing the throttle position sensor and I replaced the air intake temp sensor due to a code.

The electrical cut out for the injectors does not show up as a code.

Thanks for asking - greatly appreciate the help.

David

[wraitherx]

im thinking that you have an intermittent short somewhere. You should try doing a continuity test from each of the wires on each of the injectors and to the ecu.

[fl4321]

i need 1/4 windows

[superbean]

sounds like a bad ecu to me...

Had similar problems with nissan ecu's crapping out with lousy injector pulse

[wraitherx]

yeah ECU sounds right but he mentioned that he replaced it which leads me to think that it is an intermittent short. I mean, even if it is a used ECU whats the chances of the same problem occuring on a different ECU not to mention that he said it fixed it for a day and then it came back.

[1fst5.0]

check all your grounds, and youre probably gonna have to go through the wiring. also, the hall effect sensor in the distributor needs to be checked too, not just the module.

[94bonestocker]

Possibly the Fuel Pump Cutoff Switch is intermittent? You know the one that trips in an accident. Try Tapping on it and see if it trips.

Whats your fuel pressure?


Edit: Nevermind, just re-read your post stating the power to the injectors is dropping.

[94bonestocker]

Ok, So after looking at the wiring diagram that TMoss has on a different website, it shows that the + side of the circuit comes right off of your ignition switch via the Red wire. The - side (or the Ground if you wish) is coming from the ECU which it looks like it just gives the injector when it wants it to squirt. From the diagram it shows that the ground for the ECU comes from several pins, Black wires 20, 40, 60, and an Orange wire on pin 49. Which one is for the injectors is anyones best wag.

So this is what I would do to narrow the possible problems.

1. Check that power is coming into the injector harness with the key in the on position via the red wire. It shold be powered at all times when the key is on. Check it either with a multi-meter or a "probe" style checker light thingie. I can't for the life of me remember what they call it.


2. Measure the ohms from the pins (disconnect the main ecu plug and measure the plug side, not the computer side) I stated in my main post (20, 40, 60 and 49) to ground. I can't believe the reading would be over 1 ohm. If any of the readings are higher, trace the wire to where it attaches to the chassis and see if it's heavily corroded or a broken wire. Fix any if the readings are to high. Of course if you found a bad ground try seeing if that fixed it before continuing on with the next step.

3. Connect a jumper in line from the + side of the battery to the Red wire feeding the injector harness. Make sure to connect it in parallel with the existing harness. What this does is tell you if it's a + power issue, or a ground issue. If you get this far and this jumper fixes it you have a bad power wire and more than likely it's heating up after a few minutes and killing the + to your injectors.


Of course this is all going on the fact that the Wiring Diagram that I'm quoting is correct.


As always if you find the problem please post back as to what it was for the future people searching this thread looking for an answer.


Good Luck!!!

[Catori]

To all that have replied - THANKS for the thoughts/ideas. Will try these things tomorrow and see what I can find.

Bonestocker - thanks for the detail in your post - helps a lot to narrow the focus.

Will post results once I have tested these ideas.

Take care.

David

[2002BLGT]

ignition starter switch is probably less than 20 bucks , take probably less than an hour to install it on the column , Id try that before I even broke out the test light , if that doesnt fix it , take that crap MSD distributor out and put in an OEM replacement one and try that next ....the MSD dizzys have a high failure rate to say the least

[94bonestocker]

Please report back on the fuel pressure as well. If the injectors don't have enough fuel pressure they won't fire.

[86er]

TFI? module

[scottmach]

Originally Posted by 2002BLGT take that crap MSD distributor out and put in an OEM replacement one and try that next ....the MSD dizzys have a high failure rate to say the least

Mine lasted all of 200 miles before I put the stock one back in today. That wasn't too bad though as my Summit one never worked out of the box. Back to the stocker and lesson learned.

[e3sean]

the ecu ground is right where the harness plugs into the computer there is a ground then the fuel injector harness has a ground that should be going to the block and there is a grounding strap that goes from block to firewall.

also try a new ecu relay and maybe bypass the inertia switch for the time being.

just hook up a fuel pressure gauge and if u have good fuel pressure and you have spark when it dies then its a short in the harness.

[PONYMAN]

Went through that with my Fox.
Turned out it was a bad fuel pump & the mechanic was at it ,he cleaned out the tank.

[BoostFiend]

Originally Posted by PONYMAN Went through that with my Fox. Turned out it was a bad fuel pump & the mechanic was at it ,he cleaned out the tank.

+1 although not on a Fox, I had a brand new Walboro 255 that would cut out as soon as the car warmed up. If I waited a few hours i could get it to fire up but it wouldnt' stay running.

[superbean]

Just fyi when testing injectors.. it's a continuity test, not voltage test. The ecu controls the ground circuit (-) and when the 'pulse' is sent, the solenoid (injector) fires

[Catori]

Sorry for the long delay in getting back with results.

So - took the MSD module off of the distributer, tested at Advance and was bad. Bought a new Ford module and put it on MSD distibuter. Car fired right up - drove it for a bit and parked it. Went back about two weeks later - started right up and warmed up fine. Two weeks more - drove it onto a trailer - brought it home. Started it up to back off of trailer - car died when idling - would not restart. Obviously frustrated - backed it off trailer using starter motor - using clutch to control speed - car refired and I backed it off trailer. When pulling forward onto pavement - car died again - would not refire. Used clutch and starter to move to driveway - car wanted to restart and did. Drove it down road and back. Parked it. Went back two weeks later to start and warm up - would not start. Went back today - turned over slowly - fired up and ran. Let it warm up and idle for a while - car died once again - will not restart.

Thought it might be the clutch switch -was going to change - but I do not see how that would cause it to die when it is idling in neutral with the clutch pedal out.

Thought I had it fixed by replacing the module on the front of the distributer, no luck. Just an FYI - it first went out with the Ford distributer installed.

Ideas?