Hi,
I have a 92 5.0L V8 EFI....... It has run perfectly for the longest of time. On Sunday night, I drove it in my driveway, and on Monday morning it wouldnt start when I went to fire it up. The motor Cranks but it wont even act like it wants to catch (run).

Here is what I have replaced, as of Monday:

-NEW TFI Module
-New Spark Plug..gap set
-New Spark Plug wires 8mm.
-New Fuel Filter
-New Fuel Pump
-Cleaned Contacts on cap and rotor
-Checked for spark, I have spark at each end of the splug wires....on all 8 wires!! I have plenty of spark.
-I have fuel pressure.... new fuel pump
-The fuel rails, injectors and Regulator have 56K miles on them
-All Vaccum lines are connected
-The battery is full charged.
-It doesnt want to start even after spraying a little starting fluid, in the intake.
-My computer seems to be working, becuse it runs the fuel pump 2-3 second test when I turn the key on. (and I have pressure)

At this point I am baffled, What could it be? Its a relatively low mileage engine....... (75K miles)

Any Ideas??????? I'm desperate !!!

Thanks,
Al on AIM @ Mr Asp84
or e-mail @ asp84@earthlink.net

For a motor to run you gotta have 3 things, compression, fuel and spark. You say you have spark i figure you got compression..... i'd make a run down to make sure your getting fuel. Is their gas in the gas tank? (might be a dumb question but???????) just a couple of thoughts.

Well, I have fuel pressure, and I have spark.....I dont know if I want to know if I have correct compression or not...... :( It scares me to even think of the word....... It's not as if I have overheated it.......and it only has 75K miles)

Since, I have an EFI system ,I am going to check my (elecrtic PWR Ground activated) fuel injectors, to check for an injector pulse.

you say you have spark and you hear the fuel pump turnin check the timing maybe your distributor is loose .

if ya got spark , and fuel that leaves timing :eek:

Perhaps your injectors aren't firing. Take the two plugs that go from your injector harness to your main harness and throw some dielectric grease in there. Could be a loos altenator as well (could have just gotten too far out of time) but it seems like it'd be running really bad before that happened.

For the 5.0 motors, you don't have to have any of the sensors to run, so I wouldn't waste time there. Are you sure the vacuum line off the back of the intake didn't fall off? It isn't the best of connectors and without vaccum there you have no fuel pressure regulator.

Good luck

-Jack

Since you've checked everything else...it's the modual.

Need a special tool to remove/replace it to.
It's on the side of the dist and has a small harness coming out of it.

Have you checked the codes? :rolleyes:

Could be a bad coil (spark doesn't necessarily mean strong spark)

Could be the dizzy (Hall Effect)

Could be the TFI (most are on fender in '92)

Could be a bad EEC relay (no injector pulses)

But checking the codes would have been step #1 -- long before all that other crap you replaced.

Edit:
If you've been cranking the hell out of it, it can also be flooded. Does depressing the accelerator make a difference? It will shut off the injectors and help clear the flooding. It will also ensure that it is getting air, in case your IAB isn't opening.

sounds like the ECU to me. mine has recently done similar stuff but after sitting for a while it fires back up. it died on the freeway once and did not start till the next day after towing it home. then it started right up. after the third time it did this i ordered a new ECU. problem solved....

Thanks for all the comments, I havent been able to play around with it the last two days, so I have no new news to report.

HIP: I am interested in hearing more about your ECU failure! Were you using a Ford Motorsport ECU, or a used one from a stang?


Also, I should note: ( I first noted the problem)Two days prior on Saturday, after leaving it sit overnight, when I went to start it, It would barely fire up, it took a lot of cranking to get it fired up. But once I got it running, It ran like a champ, and started up quickly the rest of the day!! The next day seemed worse, but still, once I got it started it ran like normal, and when I went to start it on Monday..........It Just wouldnt start! :(

another note, I have a code scanner computer, but for some reason it wont initiate the test. Now, remember, this is a 5.0 conversion vehicle.......I used a 1990 computer harness. (the odd year) So I assume I dont have the switch hooked up right.

Thanks,
Al

I have had a 90 5.0 in a 4Runner and had a few problems that might help.
-Once, while on the beach in Pismo, the engine just died and would not re-start. Engine would crank over, and I had spark, good fuel pressure and fuel pump.... (I was running a independent fuel pump relay at that time, so there was plenty of fuel pressure.)
I found that the ECU Relay failed. I didn't have my schematics with me, but I noticed that the ECU Relay was not switching when the key was turned on.
It may have no relation to your problem, but just my $.02

B

If what BBrian said is true then backfeeding power to the system should work. Run a line from the battery to the positive side of the coil. That will power everything (including the ECU).

You did however say that your fuel pump was coming on so I don't think this is the problem. But it is a quick test anyway.

Did you check your crank and run source? Your fuel pump will come on and your motor will crank and will be very difficult (if not impossible) to start in the morning. However it will crank nicely when warmed up.

I had my crank and run running to the post behind the ignition in my EB without a solenoid. It just didn't have enough juice. It would be a bitch to start in the morning but once warmed up it would be fine. Put a solenoid in and beauty. She was running. Try the battery to the coil thing and tell me the result.

Also, do you have the Probst book? Good book to have for SEFI.

-Jack

Well,
The EEC relay is working........... The Crank and Run Source is derived from the old explorer power Distribution box, so I know its getting good clean power.

I gonna try and see if I can get a new ECU. and see if that works.... its wierd though, my computer is still running the 2-3 second fuel pump self test.

I'll be working this weekend, so stay tuned.

Thanks,
Al

Well, I replaced the TFI module on the Distributor, and still no luck. After that, I roughly checked my timing by doing a Top Dead Center (TDC) test on my #1 cyclinder. Timimg is right on. or I guess not far out enough to make it not run


Anyway, after all that, It still will not fire(run)! Well, I gues it might be time for a new EEC-IV next!

anymore input appreciated.

Thanks,
Al

Have you ever replaced the starter solenoid with an aftermarket one? Not many people know this but the EFI rigs use a starter solenoid with a built-in diode to prevent frying the ECM. I do know someone who constantly kept frying ECMs on his Bronco during startup and only recently found out that the PO of the rig replaced the solenoid with a model for an older rig, had no diode.

Its the original Ford EFI starter solenoid, (1994 solenoid) Dustball, What were the symptoms of you friend's EEC problems?
Did it just die? or did it run improperly for a couple of days?

Thanks,
Al

It'd be just fine for any amount of time then when he'd go start it, it'd crank and crank but would not fire, burnt out the ECM from a power surge. Since your fuel pump is priming and you're getting spark, that leads me to believe your ECM is fine.

The EEC-IV Computer may be fine...... but my questions are:
1) Are the injectors firing in the wrong order??? (they still work) The computer needs input from the distributor to confirm when to fire the injectors.....since its sequential EFI.

2.)Could it be something in the distributor assembly? ie: stator? (I have already replaced the TFI.)

3.) What other type of timing issue could it be? (I have done a T.D.C. test, and the rotor points to #1.

4.) Lastly, Why wont it start w/ starting fluid?
You would think that a good shot of etyhl would give it that extra punch. But, you guessed it, it has no effect. It acutally bogs the engine down more than help it.

This is a mystery............can you solve it?????

(check above, for a more in depth analysis of the probelm)

Thanks,
Al

ok so here is what i am claiming, is that his cam shaft has skipped a gear...... he has gas-spark-compression so it has to be the timing of the spark or gas, and the gas is computer contrulled, so if the comuter were to mallfunction it wouldn't spray fual at all,it has to be timing of spark.

what do you guys think??