Maddogron

Hello, I'm new here but I thought I'd get right to it !!!
I have a 1987 Bronco II and here's what I've got going on;

Starts fine every time,
I can go for miles around town with no problems and it runs like it new,
BUT, as soon as I get on the Freeway It takes about 1/2 mile and it
starts bucking and I get black smoke. This will go on timed at about 8 sec and run fine and start it over again.But now if i go back to town driving
it will run bad with black smoke about every 8 sec. and it I stop
and do some shopping it runs fine again ( until I use the Freeway )

I've changed o2 sen, TPS, Plugs, air filter, Fuel Reg.

Any one have an idea where to look next.
Thanks
Ron

 

'92BigBronco

I would put my money on your TFI(thick film ignition) module. It should be mounted on the distributor on the earlier EFI models. They're notorious for causing the problem you're describing.

Be sure to use the dielectric grease included with the new module.

__________________
1992 Ford Bronco
351W
E4OD- B&M Stage 2 shift kit
Full 3" stainless Bassani Exhaust
32" BFG's/stock suspension

"No replacement for displacement."

"Our lugnuts require more torque than most Honda's produce!"

HeyU

You'd loose your money. It's most likely the MAP sensor getting screwed up. Never heard of a TFI going bad and causing those symptoms.

Could ask what these guys think though http://broncoii.org/b2forum/index.php

'92BigBronco

LOL, There has been many a lawsuit regarding the TFI module causing such problems to the extent of engine stalls in freeway traffic. There are numerous things that could cause the problems described. The fact that it runs well on a cold start or after being parked for awhile is what hints at the TFI module.....a part most definitely sensitive to heat.

However, I do agree that the manifold absolute pressure sensor could also be the manifold absolute pressure sensor as it could also cause an overly rich mixture.

Good luck with the forum pushing! One post with the forum's name is more than enough.

__________________
1992 Ford Bronco
351W
E4OD- B&M Stage 2 shift kit
Full 3" stainless Bassani Exhaust
32" BFG's/stock suspension

"No replacement for displacement."

"Our lugnuts require more torque than most Honda's produce!"

ds1919

so did that fix the issue?

ds1919

HeyU

The TFI module going bad will not cause a rich mixture at all ever. Will simply not happen ever. They TFI is indeed is indeed heat sensitive or at least the originals were. Anyways when the TFI modual gets hot the ignition simply fails it does not tell the EEC-IV to run rich. The spark will get weak then it'll die completely. Best thing you can do is pull codes from the computer.