Issues with 3.8L in 84 Tbird - Ignition Module?

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Issues with 3.8L in 84 Tbird - Ignition Module?

May 13, 2015, 10:52:26 AM

Hello all, been a long time fan of the fox body cars, and have owned several in the past. Last year bought an 84 tbird with 52K miles on it, and opted to sell my trailblazer and make it my daily driver (except the winter). Its now got 64K miles on it, with two issues that have come up:

- The car has started cutting out on the highway after been on road for 20 minutes. It doesnt quit, but cuts out for just a brief second, almost like a miss, but seems too sudden of a cut to be fuel deliver related. I replaced with ignition module last year, just because of all the issues they have. Could this be the "new" module failing? Distributor? Fuel pump?

- Serpentine belt chirp - When I got the car in 2014, I replaced the belt, and immediately the new belt was squeaking. I returned the belt and put a gates belt on (I had used these back in the 1990s as replacement and had good success with them), and initially it did not squeak. After a few weeks, the squeak returned. I tried playing with the belt tension, with the car running, and it made little difference. Replaced the idler pulley for heck of it, also no difference. I spun all the pulleys and they seem fine. Any ideas on how to get rid of this?

Thanks alot for your help!!

Issues with 3.8L in 84 Tbird - Ignition Module?

Reply #1 – May 13, 2015, 11:16:06 AM

Belt squeak is generally caused by slightly misaligned pulleys.

When i bought my car, it had a serpentine belt with two rips eaten away because the alt was replaced but not tightened down all the way. If you have a level or any type of straight edge, pull your fan off and lay it against the crank pulley. You could be able to spin it around and see how far off the pulleys are.

I had a belt squeal i couldn't pin down. Took the belt off a few times and everything seemed to spin fine. A few days later my smog pump locked up on me while driving on the freeway. I was able to coast to the side of the road and eventually milked the car to an auto parts store and bypassed it.

If you still can't track it down, keep the cheap belt on the car, and save the gatorback until it either gets worse and easily identified, or breaks so you still have a spare.

My car actually only squealed on start up and went away after a second or two. I was sure my ac compressor was going, but after the smog pump was bypassed all seems okay. Car does have 315k miles on it though, so it wouldn't surprise me if anything let go.

Another thing you could try, spray paint your pulley surfaces white where the belt rides. This will make worn off rubber show up well, as well as showing you which pulley might have more force on it, wearing the paint off quicker.

Issues with 3.8L in 84 Tbird - Ignition Module?

Reply #2 – May 13, 2015, 11:18:39 AM

Also from what i remember, there are two belts on a 3.8 from 84-87. If i remember right only one belt drives the water pump alt and smog pump. The other belt only hits the ac and power steering, i think. Haven't had a 3.8 for about 7 years. If it does have two belts, pull the ac/power steering on off and see if it goes away or not.

Issues with 3.8L in 84 Tbird - Ignition Module?

Reply #3 – May 13, 2015, 12:09:48 PM

For the cutting out issue, it could be a few things:

- Bad spark plug wire
- Faulty ignition switch
- Bad TFI module
- Bad inertia switch
- Bad fuel pump relay

Any of these can cause the issue you describe. There are more (bad ECU, bad ECU relay, bad coil, etc.) but concentrate on those first.

Issues with 3.8L in 84 Tbird - Ignition Module?

Reply #4 – May 13, 2015, 09:24:57 PM

Hey all. I bought a new module today and it fixed the issue. Cant believe the one i bought in 2014 lasted one year

Issues with 3.8L in 84 Tbird - Ignition Module?

Reply #5 – May 16, 2015, 10:49:44 AM

pay attention to when the squeak starts again,,

when it does make sure you have your tools to take the belt off and you gotta rush into it because,,, the smog pump may be binding up.

I threw several belts on my 3.8 before I was able to track it down to smog pump binding up when it got hot.

on the older 3.8 like you have, tension pulley removal is not fast, so I recommend you swap in a newer swing style, with a little fabrication it can be done. any ford will do as a donor.

in my diy link there are a lot of things I did to cure some common problems with off the line hesitation and carbon build up on the underside of the CFI

Issues with 3.8L in 84 Tbird - Ignition Module?

Reply #6 – May 19, 2015, 08:37:31 PM

Wonderful!! Yeah mine hesitates often on acceleration from a stop, as did my previous 2 3.8l cfis. Also, when cold the engine fast idle seems too fast and is slow to drop. What causes this?

Thanks.

Issues with 3.8L in 84 Tbird - Ignition Module?

Reply #7 – May 19, 2015, 08:39:48 PM

Alot of the links dont seem to be working. Whats up with that?