Not a ride I was planning to take, need diagnosis help please

[MPTech]

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Was heading to a Friday night open Car Show after work, driving along, no warning, and car completely dies. Pushed in the clutch and coasted into a church parking lot. Did some roadside diagnosis. Had spark and engine would turnover but no attempt to start. After a couple attempts, I believe I smelled gas from the exhaust. Amp meter still showed a good charge. I let the engine cool down considerably and tried again, still nothing.
At that point I called AAA and had it tow'd home.

At this point, the only thing I can think of and a friend thinks so too, is the TFI. Any way to check / test?
Never had an issue with the car for 16k miles and no warnings.

Also, I looked online and saw them at O'Reilys (just trying to get an idea of price and availability), they were anywhere from $39 to $150!! That's a pretty big range. Any suggestions?

Also considering going to a remote unit, looking at this one, after i get it running again: McCully Racing Motors - TFI Relocation Kits for V8, Ford TFI Engines (http://www.mccullyracingmotors.com/index_files/tfikits.htm)

[Svtfreak]

If you have spark, then TFI should be good I think. But most auto parts stores have a tester for it. Especially older places. Last time I needed one, I had to figure out how to use it as no one there knew how.

Fuel pump still running? If it has fuel, compression and spark, it should run considering it was. Personally, I would check pump function (hear it running and good pressure), double check spark and test TFI, then look to the ecu.

[DaleG]

I'm betting on something like a loose/shorted wire at the ignition switch. Hope its an easy fix.

[Carlos C]

If you're absolutely sure you have spark, then it is not your TFI. The rest of the symptoms you described typically pinpoint a burned-out TFI module (engine suddenly dies, strong smell of gas in exhaust, engine turning over with no attempt to start, etc). These modules are known to burn out, and sometimes they actually give you warning that they're going bad by overheating. The engine will shut off, and once the module cools off, the engine will start again.

A module/sensor tester will tell you if it's bad, but as I mentioned, if you checked that you had spark and it's still not starting, it's not it. You didn't describe the type of induction, electronic, spark, and fuel management systems you're running. Maybe you could give us more info on your engine, so we can help you troubleshoot better.

Carlos

[Joe Campbell]

Agree those are bad TFI symptoms. Had similar issues when I ran a massflo system. The McCully relocation kit will help. Eventually my ECU died too. Eventually I switched to FiTech and couldn't be happier. The old Ford EFI, trusty as it was in stock form, is now well beyond antiquated and completely reliant on chinese-made crap imitation modules. Not sure there are any makers of quality units left.

[MPTech]

Sorry for neglecting details, let me know if I missed anything:
'93 Mustang GT 302 roller rocker EFI
GT-40P ported heads
GT-40 intake
FMS F-cam
Ford Racing Blue 9MM Ignition Wire set + new plugs
OEM distributor
MSD cap and rotor
Mallory Promaster E Series Ignition Coil / heatsink
O2 sensors (Bosch #13942)

Painless wiring harness
OEM style (in-tank) fuel pump (new when I built the car, 4 years old & 16k miles)

I can't think of anything else, but let me know if I missed something.


I did try it again today (didn't change anything), but no improvement. Still cranks, but doesn't even try to start.
I tried to listen for fuel pump running, but didn't hear anything (I never heard it running before either, would I if the system is already pressurized?)

Let me clarify the spark, the tow truck guy remove the coil wire at the coil, when I cranked it, he said I have spark at the coil, so I don't know if I have spark at the plug, didn't check that.

[MPTech]

Joe Campbell, yeah I've been eyeing the FiTech since they came on the scene, thinking about it, but not in the budget at the moment (son got married a little over a month ago and pretty sure the daughter is going to be next year).

For right now, I just want to get it running for this year. It's been very reliable up to this point.

[bobl]

It's possible for the TFI to be bad and still have spark. As the engine cranks the TFI sends an rpm signal to the ECU which then triggers the injectors and such. The ecu then sends the Spout signal back to the tfi to control spark. However, if the ecu does not get a signal it cannot trigger the injectors or send a spout signal to the tfi. TFI failing to see a spout will take over spark control and still fire the coil, just like you are setting you timing with spout disconnected. So I'd look at the TFI first.

Bob

[Svtfreak]

When you turn the key on, before cranking, you should hear the pump run for a couple seconds then shut off. It restarts when cranking and running.

[Carlos C]

Just like "Svtfreak" stated, follow his instructions to hear the fuel pump. If you don't hear it, check the fuse for it and also the emergency shut-off switch, to make sure it didn't pop. If it did, just reset it.

But considering that you noticed a strong fuel smell coming from the exhaust, let's re-visit the ignition system. Since you have an OEM distributor and EFI, the TFI module is attached to the distributor. Even if the TFI module is bad, you will still get a spark from your coil to your distributor - just as Bob stated. What you need to check is if you have spark from the distributor to your spark plugs. You can do this by purchasing a spark plug tester, or by disconnecting one of your spark plug wires, attach a spark plug to it (preferably not one currently used on the engine; otherwise, disconnect the fuel pump fuse and relief fuel system pressure), and ground the spark plug body to somewhere electrically conductive while cranking over the engine. If there's no spark, the module is dead. Try this test with a couple of spark plug wires to verify your results. While you're at it, inspect your distributor cap and rotor for damage, dirt, and/or excessive wear.

You can purchase the spark plug tester and an electronic sensor/module tester from auto parts stores. Try these simple troubleshooting steps first, and let us know what you find. Good luck.

Carlos

[MPTech]

Didn't think about the emergency shut-off (you're talking about the Inertia Switch, correct?). I'll check that too.
I checked the fuses, everything seemed good.

I'll check the spark at the plugs too.

So, assuming that it is the TFI, can anyone recommend a good one or a good brand? I've heard AVOID the China crap, but hard to tell online or ordering.

[Norm B]

If you have, or can get, an automotive stethoscope, listen to the injectors while turning the engine over. Should here them clicking if the computer is receiving the timing signal and working properly. You can sometimes get away with a dry piece of doweling instead of the stethoscope if your hearing is good enough. Don't use anything metal! You will quickly and uncomfortably find a bad plug wire if you have one.

Good Luck
Norm

[Carlos C]

Didn't think about the emergency shut-off (you're talking about the Inertia Switch, correct?). I'll check that too.
I checked the fuses, everything seemed good.

I'll check the spark at the plugs too.

So, assuming that it is the TFI, can anyone recommend a good one or a good brand? I've heard AVOID the China crap, but hard to tell online or ordering.

Yes, the inertia switch. Accel and MSD, among others, make quality distributors with TFI modules. You can try them for just the module, but they would be more expensive just because of the brand-name. You didn't specify if your distributor was new or if came from a donor. If it was from a donor and had many miles on it, it would be expected to fail at some point. If that's the case, you can go to an auto parts store and purchase a new one. The key when installing one is to make sure that you use enough of the paste that comes with the module. It serves as a heat sink. Otherwise, it will overheat and burn out prematurely, regardless of the brand or where it came from.

I've owned four Fox-bodied Mustangs, and had to change the module on three of them - all three had a lot of mileage on them. Only one new module went out on me soon after I installed it (defective item), and the auto parts store replaced it for free. To give you an idea, I owned my last two '87 (street) and '88 (race) Mustangs simultaneously. The '87 had a stock motor with 175,000+ miles (before I re-built it), with an OEM distributor/module, and only had to replace the module once. The '88 had 195,000+ miles as a street car with an OEM motor/distributor/module, and only had to replace the module once. When I converted the '88 to a race car, I switched to a 351 Windsor with an Accel distributor/module. And although I only put about 3,000 miles on it, it was driven very hard, and never had a problem with it. It is now the set-up I'm installing in my Coupe.

Carlos

[CraigS]

Can you get your wife to help w/ testing. Next you need to confirm spark at the plug and that is a LOT easier to do if someone else is turning the key. Also you can check for fuel pressure at the shrader valve on the rail that is there to connect a pressure gauge to. A quick check is cover it w/ a rag in one hand while you press the center plunger just as if you were letting air out of a tire. A gauge would be better but at least you will know if you have some fuel to the engine. BTW, do the spark check BEFORE the fuel check.

[JIMOCO]

When I don't have help I attach a jumper cable to the base of the spark plug and the other end to ground. This way I can position the plug in a spot where I can see it and turn the key.

[MPTech]

Disappointment, finally got around to replacing the TFI module (kind of a pain and I had to pick up a special small, deep socket). When I removed the TFI, I noticed that the top/front screw was not tight at all and the TFI module had NO paste at all and none on the distributor surface either. Given these conditions, I assumed replacing the TFI would fix the problem.
NO improvement.

Also checked the Inertia Switch, looked fine.
And the ECU ground looks good too.

I think I need to get someone to check the fuelpump, to tell you the truth, I don't remember hearing it when it did run.

[AC Bill]

You can usually hear it before you crank the starter, with the key in the on position. Once you start cranking it or the engine starts, the sound of it is drowned out.
As mentioned, it only runs for about 2-3 seconds in the on position, before it goes quiet. If you don't hear anything, that could be the issue.

[FFRSpec72]

Can you put a fuel pressure gauge on the fuel rail and see if you have pressure ?

[MPTech]

My Cobra Club buddies came through for me!
We had a little cruise through the backroads planned for this morning, so I had to Txt them to tell them I'm out and couldn't get it started this yesterday. They asked if I was going to be home this morning and the gang stopped by.
First we checked the fuel pump at startup, it is quiet and hard to hear from the drivers seat, but the fuel pump was running.
They could also smell fuel, so that wasn't the problem.
Then took the Dist Cap off and checked it, also looked ok.
Next we checked spark at the plug. No Spark. (I had checked the spark at the coil with the tow truck driver and he said I was getting spark.
Since we had a spare ECU (thanks Rich), we tried that first, so I unplugged mine and tried the spare ECU. No improvement.
The guys also brought a spare Coil (thanks Keith), so we swapped that out and tried again.
SUCCESS!!!! Fired right up!
My coil was a New Mallory Coil when I built my roadster, so it had 16k miles on it.
I'll be buying a new one, but I'll think twice about the Mallory.

THANKS Guys!!

Oh, and we went on the cruise! BEST Part of my morning.

http://i9.photobucket.com/albums/a78/MPTech/Mobile%20Uploads/2016-07/75EF5958-504C-4FBB-8F3F-F35ED6879091_zpsupstkaed.jpg

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[Garry Bopp]

Now that's a happy ending!

Garry

[AZPete]

What a family!

[Carlos C]

Great pictures! For future reference, when the ignition system is suspect, always troubleshoot from the spark plugs back. It makes it easier to isolate each component and find out the culprit. And don't feel bad about having replaced the TFI module. If the paste was dried up or non-existent, and the module already had a lot of miles on it, it was a matter of time before it failed on you, as it had most likely been taken heat damage. Glad you got it running.

Carlos

[MPTech]

Carlos, thanks for the tip. As for the TFI module, I will use the old one for a spare (keep it and the new deep socket in the car, just case mine fails again of another Cobra owner). Also found out the old one was an off-brand after-market unit, so like you said, probably better that it was replaced with a Motorcraft unit.

I was happy we found it and it was a simple Coil issue.