Hey there. Recently my bronco (excuse me) ****ed up.

After 2 weeks of trolling here and finally taking it to the mechanic, we found out that it was the computer. The ECM when we took it apart, had evidence of a fairly large fire inside there. Carbon and burnt plastic everywhere. Signs of water damage all along the outside of ECM case (Marks and rust).

Now we replaced the computer with a used 87 mercury that had a 5.0, and it fired right up.

Well some how my transmission is out of fluid, so i filled that up. The computer has to be screwing up, ive tried making it relearn it's **** about 4 times already.

Idling the needle is pegged at 2 and a half, thats nuts, I know. The transmission is completely skipping first gear, and I cannot engage the 4wd, however, its in constant low range, I can not go any faster than 40-45. Ofc, it stalls when I stop, but now it stalls as soon as i put it in reverse.

I know most of this stems from a 2wd computer going into an optional 4wd. I get that part, what I am concerned with is the fact that it wont shift.

I really need to know if my tranny is on its way to busted or its all just a computer mix up. I've tried to google that, and ive found mixed answers.

The question: Does the ECM handle the tranny, telling it when to shift?

If so then I can go get a used 87-92 bronco ecm and be done. I know new would be better, especially with a warranty. However I'm a college student, and a father so the money goes elsewhere.

Edited for clarity, and because these guys are pretty awesome. ->

 

The ECM (from the Mercury) will NEVER work in your truck. The original ECM controls the shift parameters of the E4OD (tranny) as well as the engine. You need an ECM from a vehicle that was equipped with the same engine AND transmission that your 92 has. Any F-series/Bronco with the 5.0 and an E4OD from 91+ should work. Avoid anything older if you can.

ALL of your issues stem from the wrong ECM. Since the E4OD has nothing telling it where or when to shift and the ECM you have in there is getting readings form it that it cannot use, the ECM is dropping into "limp mode" which keeps engine RPMs up to keep it from stalling because the ECM has no idea why it is getting readings from sensors that it shouldn't see. 2wd/4wd is having zero effect on it.

 

Thanks grey!

Appreciate the clarification, I didn't realize it had to be from the same tranny as well, and apparently the neither did the mechanic...or he didnt give a ****.

Glad to hear its all just the ECM and not the tranny as well.

Thanks for your time, sir.

Edit: How do i go about finding one online? Is there a name for the F-series/Bronco with the 5.0 and an E4OD from 91 ECM?

I'm looking on ebay since its the weekend and anyplace around here that may have a used ecm is closed. Does it matter to the ECM if its from an auto or a manual? or is that interchangeable?

I hate that I'm pretty clueless about everything, which one of these do i want? What does Calif, High Alt, and Fed stand for? How do i find out which i have?

Elec Cont Unit (ECU), 8-302 (5.0L), AT, E4OD, Calif
Elec Cont Unit (ECU), 8-302 (5.0L), AT, E4OD, High Altitude
Elec Cont Unit (ECU), 8-302 (5.0L), AT, E4OD, Fed

 

Well, let's see the "Calif" is the ECM used in vehicles originally produced for sale IN the state of California and if you truck was, there should be decals galore all over it indicating it as such.

The "High altitude" would be as one might assume an ECM tuned specifically for vehicles that spend most of their time above a certain elevation. I don't honestly recall what that elevation is off the top of my head.

The "Fed" designation would be the ECM that is tuned for vehicles originally old to or for the express use of the Federal Government... i.e. DEA, FBI, FEMA, etc... any Federal agency really.

 

Might be in luck, figiting with my own ECM probs. After swapping a M5OD in place of the E4OD in my 91 Bronco. ECM loaded up with tranny error codes, swapped in the ECM from my 90 donor. Still working out the bugs. If my 90 5.0, MT brain works, will sell 91, 5.0, E4OD brain box.

 

You can alleviate the fault codes related to the E4OD by running a jumper wire between the "neutral" contacts in the connector for the MLPS. You just need to tuck the harness/connector up so it doesn't get full of crud now that its not connected to the E4OD.

 

I have a 92 "Nite", it is hard to start, cranks way too much. 118,000.00 miles on it, 5.8,
E4od, new plugs, wires, cap, rotor, ignition module, fuel pump, filters (fuel, oil and air), compression 150 per cylander, no smoke, appears to be running lean, but ****ty gas milage, any help?

 

IAC, vacuum leak, starter, what's the gas mileage?

 

g_k U forgot EGR... Check your codes twbogges.

 

Codes... pull 'em... otherwise you are throwing time, money and sweat at something you may never find.

 

no abnormal codes, milage dropped from 18 to 10, exhaust is clean like tan, has power,changed out the four right side injectors, starter is new.

 

"no abnormal codes"

There is only one acceptable code. Have you done a fuel pressure check at the rail?

 

Yes, 50 psi while running and under a load. shut engine off and it creeps to zero.

 

Need new fuel pump. I just had that problem, there's a valve in the fuel pump that prevents the gas from flowing back into the tank or I should say provides a back pressure to the gas flowing back into the tank. Now this valve goes bad and the fuel doesn't get the proper back pressure even thou the pressure at the rail looks ok.

So did you replace the whole fuel pump body or just the fuel pump motor?

 

Just the pump, not the housing