TC-88 no start, jumpy tach, TFI bad?

My 1988 Turbo Coupe isn't starting It was running fine (mostly), then about 2 minutes after I started it a couple days ago, it just died. Kaput. Nothing. It cranks, but doesn't catch or fire at all.

For a couple weeks before it died, the tach was acting funny -- jumping several hundred rpm, while the engine was running steadily. It would do this at idle, or mostly when I was accelerating. The engine never missed, the tach would just momentarily jump up to a higher rpm.

Is there any way to remove the TFI module without taking out the distributor? It seems like it should be possible, but every set of instructions I've found says to remove the distributor first....

Is there a way to test the PIP, preferrably without removing the TFI?

So, I'm pretty sure it's not the fuel pump, timing belt, or coil. I don't think it's wiring. Is there anything else besides the PIP or TFI that could be the problem?



here's what I've done so far:
- Confirmed the fuel pump runs. I can hear it cycle for a few sec when I turn the key on.
- Checked for a spark from the coil. I just unplugged the lead from the distributor and laid it up next to the alternator, and looked for a spark. (I was by myself, in a parking lot away from home.) No spark.
- I replaced the coil. A pretty easy job to do in a parking lot. I had my fingers crossed, but it didn't make any difference.
- I checked the timing belt. It's not broken.
- I had my buddy tow me home, late at night, on back streets. No lights. (My battery was dead from cranking too much.)
- Recharged the battery.
- Confirmed +12 at the coil when the key is on.
- Confirmed no ground signal to the coil while cranking, using a 12V lamp, connected between the signal wire from the TFI module at the coil connector and +12 on the battery, with the coil connector still plugged in. (When the key is off, the light comes on, and I can hear a *click* somewhere when I connect and disconnect the light. Back-feeding a relay?)
- Confirmed continuity between the coil connector and the TFI connector.
- Confirmed +12 at the TFI connector battery terminal when the key is on. (TFI connector unplugged)
- Confirmed +12 at the TFI connector Start terminal during cranking, with connector unplugged.
- With the connector still unplugged, tried to check the Gnd wire at the TFI connector, using my test light connected between it and the battery +12 lug. No response, with the key in any position. Measured 7.9 V between battery + and TFI gnd using a multimeter, with the key on. 12 V measured between batt + and TFI gnd with key off.
- Jammed a paper clip down the gnd wire of the connector and plugged it back in. Now it reads 12V when measured to batt+ with the key on!

It looks like the TFI and coil have power and are connected properly. Is there anything else I can check, or is the TFI confirmed bad?

thanks,
Eric

Just because the fuel pump runs doesnt mean it is producing adequate volume and pressure. Check fuel pressure to be sure it is in spec.

Have you run codes? Look for a CM 14 (intermittent loss of PIP signal) or 16 (intermittent loss of IDM signal. Sometimes failing PIP will set a CM 14 or failing TFI will set a CM 16, but not always.

Failing ignition switch can cause your problem and a host of other problems. Has it ever been replaced? Has the ig sw connector been checked for damage / melting?

I assume you used a DMM to check for 12 V on the TFI circuits. ALWAYS use a test light to check power circuits. The 11 megohm input resistance will cause the DMM to read system voltage even if the circuit has high resistance.

TFI can easily be removed without removing the dist. A TFI bolt removal tool ($5 at any parts store) makes it easy.

If either TFI or PIP turns out to be bad, replace both at the same time. Use ONLY Motorcraft TFI and PIP. VIrtually all aftermarket ones are junk.

ok, thanks for the tips!

I did use a test lamp checking the TFI voltages, as much as I could. The lamp didn't light at all on the ground pin, with the connector unplugged.

I did replace the ignition switch, like a dozen years ago. I never really liked the feel of the new one, but it seems to do the job. Everything stays on in the Run position, and everything that I think should get power in Start does as well.

I didn't check for codes yet.... Guess I should do that!

Since the coil doesn't seem to be responding, I'm thinking that ignition is probably the problem. Mainly I want to be sure that I'm diagnosing it correctly. I found lots of tips on replacing the TFI, but not much on troubleshooting.

-Eric

The only sure fire way to troubleshoot a TFI or PIP failure is to substitute known good components.

just to put my 2 cents in....jeff is correct about the fuel pump just because you here its running is not a correct assumption it is working!! I knew on my car something was amiss as in higher rpm`s the car seemed to starve for fuel. checking my plugs they were on the white side indicating a lean condition.it finally was getting hard to start so I dropped the tank to check the fuel pump.upon inspection the ninety degree rubber hose had cracked so it was sucking air as well as fuel.i replaced the fuel pump with a walbro 255 l.p.h. pump and my car has never run better!!it was a great upgrade and the results were worth every penny!! t`s

ok, I'll keep it in mind, but I swapped the pump just a couple years ago, so hopefully it hasn't gone bad already.

Another reason I'm inclined to think it's the ignition is the jumpiness of the tach over the last several weeks. I'm thinking the PIP might be the culprit. Which brings me to my next question --

Is it possible to change the PIP without removing the distributor? I got the vane cap off, but it looks like the shaft still has a plate pressed(?) onto the top, under which the PIP is mounted; and I can't get the PIP out without pulling the whole shaft out. Is that right?

thanks,
Eric

Distributor has to come out. For more info see: http://turbotbird.com/techinfo/TFI-PIP/TFI-PIP.htm.01

Pete, can you check your link? I got a 404 error.

Otherwise, I did take the distributor out. Curse the Ford engineer who put the clamp-down bold under the housing!

The gear was very stuck on the shaft. My first attempt to get it off was a joke. Then I tried a bearing puller, and broke a few gear teeth. Then I used a gear puller with a press, and it finally popped off, I think with a little more gear damage. I think the gear's in good enough shape to be re-used -- it doesn't take much effort to turn the distributor shaft. But it sucks that it was so hard to get off. Hopefully getting it back on will be easier, but I think my only hope will be to heat the gear and chill the shaft. Otherwise there's no way I'm going to get the roll pin holes to line up.

Is it typical that it's so hard to get off?

Now the distributor shaft doesn't want to come out of the housing, either. It seems like it should just pull out, but it's getting stuck about 1/3 of the way. I'll probably just take it back to the press and force it through. Am I missing something here?

Curse the Ford engineer who didn't make it easier to get the PIP out!!

Eric, yes, I got a 404 error using the link above. Sorry about that, I'll see about getting it fixed.
Try this one: http://turbotbird.com/techinfo/TFI-PIP/TFI-PIP.htm It works for me.

If you broke or nicked any of the gear teeth, the gear is JUNK. Get a new gear, and also replace the aux shaft, as a new gear may not mesh correctly with the drive gear on the aux shaft which has a wear pattern mated with the old gear. This can cause rapid failure of the new gear and / or aux shaft gear.

Dist shaft should slide out of the housing without too much effort.