I have a tired 90 bronco with a 351. It has always been a slug. Motor needs a rebuild. anyhoo. But I have a few problems. Firtly to confirm my guesses at highway speeds if you let off the throttle there is a shudder. the faster your going the more it is. It is not the driveshaft. I put a brand new one in and it didnt change that. I believe (since it throws the code) that it is the tourqe converter clutch(E4OD). The tranny will after a 30 miles trip on the highway in the summer stop shifting until it cools down. you have 2nd and 4th manually shifting it otherwise it doesnt shift. The top speed is about 75mph with the accelerator to the floor on level ground. I assuming that it has to do witht he tranny.

Now onto a bigger problem. The truck is not a daily driver. at 11 to 12 mpg its not feasible for my 500+ mile a week commute. But I did start it up every couple of weeks to keep it going although not for awhile since this new problem. The problem the last few times I ran it is that it willstart, it will idle, but it will not accelerate. If you accelerate ever so slowly it does so ok but it pops a little. If you nail it it really pops and stutters. And just about stalls. From the reading on here I'm guessing it has something to do with the TFI/Hall Effect sensor. Or a bad ECM. The truck never was a power house. Like I said previously it topped out at maybe 75 and with 265/75-15 and 3.55 gears with limited slip it would barely spin the tires on dirt when you goosed the throttle. It seems like a timing problem to me and something that must've been bad that got worse. Also I swapped a TPS sensor from a known working vehicle and that changed nothing so I'm fairly certain its not that. Any help is greatly appreciated.

 

First, you probably know this, but your E4OD is shot and probably needs a rebuild. You might get by with just changing the fluid, but it won't help for long.

The other problem could be a lot of things. Pull the codes and let us know what the computer says. Also, a tuneup wouldn't be a bad thing to try.

I don't think it's either the TFI or the hall effect sensor. The TFI usually acts up when it gets hot, and the hall effect sensor will usually result in the truck not starting at all.

Timing is a good guess what is it set to?

 

i pulled the codes awhile back and as i remember the tcc, i beleive somehting relative to the egr and maybe an o2 sensor. i know the egr's are notorious on fords for going bad but i dont know what symptoms or effects that presents. and ive had o2 sensors unplugged on vehicles that ran relatively ok. i tried to put everything i remember into the post. it idles all day just doesnt like acceleration. also it has no cats so they are not plugged up. also it occurs to me that it could a fuel filter. i bought the truck back from my dad not long after he put a fuel pump in it. i assumed he wouldve changed teh filter but i dont know.

also timing has never been touched on it so i would assume its close to stock.

 

ok first this truck wont run properly with a bad o2 sensor or 1 not being hooked up so replace that and keep it plugged in. your timing should be checked, stock is 10btdc with the spout connector removed. change the fuel filter as well its good insurance along with a tune up. use motorcraft or autolite copper plugs, none of that fancy platinum crap. also do a compression test and report the numbers back here. I would also start to look for another tranny at this time.

 

well i'll check the timing then. where is the spout connector? and what is it im looking for? also in reference to o2 sensor its my understanding that when the motor is cold its running in closed loop operation and its not using the o2 sensor at all. its not until the engine is warm that the 02 sensor data is relevant. ive had cars that ran great until warm and then ran like poo. i don't mean to sound like i don't appreciate your insights cause if i knew it all i wouldnt have to ask for help. i do appreciate your help and thanks again.

when i first got the truck it had been sittin for a year or so so i did a full tune up and it was still a dog and the tranny was supposed to have been rebuilt not too long ago. but witihin a year the tranny started doin all kinds of dumb stuff. would a funked up tranny make it feel like the motor has no guts. as far as a compression test i could do it but i know the motor is in need of an overhaul. it doesnt use oil but its tired and it does puff a touch of white smoke if its been sittin more than a couple days between starts. i guess i got a lot of little stuff ahead of me here. im hopin it warms up a little soon so i can get crackin.

also i have access to a 79 f250 with a built 460 and a c6 for real cheap. i thought i read that the front straight axle off of these is a fairly easy swap but is the motor an easy swap? thanks again.

 

you say it's always been a slug i seriosly wonder what you have for compression. I've owned two bronco's with wheezers now and have been impressed with both. I put 180k on the 89 and it was running well when i sold it. I have a '83 currently and did a basic rebuild (non egr) but with better heads...and it's powerful and getting over 15mpg. Got 16 mixed driving with the efi 89. I'd really look into a rebuild and tranny...i think you will be impressed with the W.

I've also owned two older bronco's ('79's)with 429's...one built with c6 and current one just about used up with a bw t-19 4speed.. The power is incredible no doubt but nothing i need to have fun.

I've even been considering using a stroked wheezer (408) with about 9.3:1 cr and a 212/218 retro roller cam or roller block in my heavy '75 crew cab 4x4.

I'd put closed chamber 2v oz cleveland heads on it and have a 4" stroke, great torque curve and decent mileage. Add the weight savings and you'd have a much better package with far less hassle. The W is a great block and add cleveland heads and you have a great package that can be ***** to the wall performance or designed for torque and economy.

The big advantage of the big block IMO is it's ability to handle the rigors of huge power... a lot of metal and strength. If i wanted over 400hp and 500 ft lbs in a working rig i'd always take the 460.


BTW folks I finally found a top for my '79 for $100 and a near perfect tailgate for another 50....pumped and will be driving the beast before long. Might keep the 429 in it or?? I'll own it forever though and have time.... got my '79.

 

The first thing you do is check fuel pump pressure, because if it is low the motor will do what you desribed should be at least 35 psi ,43psi at best. I helped a friend that was having the same problems with his truck ,he had 10 psi, we changed the fuel filter psi jumped to 39 psi motor would rev up good enough to squeck one tire. Check it out ,let us know what you found.


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