North American Turbocoupe Organization

Engine Problem's
Ken E. Offline
Junior Member
I recently found this web site and glad I did, you guy have a lot of info that may help!
I have a 1988 Turbo Coupe that has gremlins!! The first problem is a high idle condition that has stumped me and the shops I've taken it to ( most have refused to work on it). Short history of the car- It belongs to the original owner, purchased new on December 24, 1988. It has been garage kept and is in excellent shape with only 60,000 miles. It is on it's second set on tire's and all major systems and components are factory original. I still have a couple of years supply of R12! I've known the owner for seven years and have worked on the car a few times during the first two, basic tune up, ect, then took over all maintenance over the last five. The owner complained to me, seven years ago, that the engine will occasionally go into a high idle condition. Initially this would happen once or twice a week and has become more frequent since. It will happen at any time or condition, cold motor, warmed up, and during any driving condition. It always goes to 2300 RPM, and the engine tries to adjust for accessories being turned off and on. It will start to decrease RPM then return to 2300 RPM, AC on will cause a slight increase in RPM then it will return to 2300. Anytime you turn the ignition switch off then back on(even at 35 mph) the high idle condition goes away, but will return eventually. The TPS has been changed 4 times by others and once by myself and that has not had any effect on this condition. All TCB's and recall's have been complied with. The intake has been off three times for other maintenance, valve cover caskets,ect. No known vacume leaks.

During my search for the solution to the high idle another intermittent problem has started. Engine runs rough, I'm getting the fault code 14, loss of PIP. 2 distributors, 4 TFI's and days of chasing wires and voltage have yielded nothing. All engine compartment grounds have been cleaned, reference voltage checked ok, other items replaced: coil, plugs, plug wires, distributor cap and rotor. Primary and secondary ignition circuits checked ok. I just replaced the computer after running out of other options. That didn't help either!

I have learned that this motor is very picky about settings and precision is a must! All the basic settings are dead on the spec's, and it runs great up to the point the two problems arise. I've run out of options and have gone through every trouble shooting check in the book a couple of times without success. It's to the point I'm afraid I can no longer see the problem and need a fresh approach! Any clues to where to look????

Pete D Offline
Hello and welcome.
On the idle:
* has the IAC - idle air control been cleaned?

* make sure there is no build up at the throttle plate, inside the thottle body.

* Was the idle and TPS voltage set according to this procedure:

* what brand of TPS?

* Have you gotten any other codes besides the 14, in any of the 3 parts of the code retrival?

*What does a vacuum gauge read at cold and warm idle? his is about what you want to see:

* I have heard of a high idle problem being attributed to a VAM. Have you checked it.
Quote:Measure VAM voltage between BK/W (-) and W/BK (+). KOEO should be about .25 - .3 V, hot idle @ 1000 RPM, should be around .75 - .9 V. KOEO, push door open with a screwdriver, etc and be sure the door moves smoothly, and voltage increases smoothly to 4.5+ V. Jeff K
On the code 14 -PIP and miss/rough run you might
want to peruse the following two threads:;t=019001;t=018931

This was posted by Don H in one of those threads:
Quote:Even though I bad mouthed Ford above, it doesn't seem probable that all replacement Motorcraft TFI modules are bad. There may be a problem with the connector to the TFI, maybe a loose terminal in it or a corroded wire. When I was going through this I replaced the connector, lengthened the harness about six inches and extended the grounded shield all the way to the connector. I think I may have mentioned this before, but the solution for me after at least two remanufactured distributors was a new Ford distributor with a NAPA TFI module. On my old Town Car with the 5.0 the Motorcraft module failed and was replace with a Standard TFI. The PIP never failed and the distributor lasted 320,000 miles, so go figure. It is interesting to note that the ignition module in Ford DIS systems has a microprocessor in it that recreates the PIP signal and the SPOUT signal. I hope that never goes out as they cost around $300, the same as the the complete car computer.
Also, what brand of ignition wires are you using?
Pete Dunham


firstsvo Offline
Senior Member
I had a code 14 and it was the TFI, not the PIP. My 4th Motorcraft TFI arrived today, but it's supposed to rain the rest of the week, so I probably won't get it in until Saturday. Hope this one works. I put a few thousand miles on the "borrowed" TFI with NO problems. Only problem is my SVO dist. is sitting on my tool box TFI-less. I also replaced the IRCM as my fan wouldn't come on. Did all the tests, and it was the IRCM. Put in a nice shiny new one and the fans work great. Found out the hard way that the IRCM also controls the a/c comp. New IRCM is no good. As far as I'm concerned quality control is a thing of the past.
White '88 auto mostly stock, Black '88 5 speed nowhere near stock

Ken E. Offline
Junior Member
Here is a quick update. Thanks for the info! After tweaking the TPS to .945 volts it seems the high idle is a thing of the past. I have a new TPS on order becuse there is a dead spot close to the full throttle position. The rough idle was caused by the TFI module. I replaced it for the 5th time! Test drove it about 40 miles with multiple stops for errands and no problems. Thanks again !

evintho Offline
Senior Member
Glad everything worked out! Just a quick note. Living in Vegas with July/August right around the corner, you may want to think about relocating that TFI module to a cooler and more ventilated location. TFI's + factory location + 120* ambient air temps don't mix well!
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