So my I've spent the last 2-3ish months doing body work on my bronco, during that time it really just drove in and out of my garage. And it ran fine before that. Now it sputters and shakes when accelerating with more than about 1/4 throttle. It revs up fine when in neutral, but gets worse when going up hill, which points me towards a fuel pressure issue. The threads on the fuel rail schrader valve are stripped, but ill be getting a new one in tomorrow, so I can test for proper pressure. And when it is missing, the o/d light flashes on and off, which is funny since I did a trans swap to a manual earlier this year, and it also wasn't doing that before. I haven't gone into any real diagnostics yet, But upon visual inspection, nothing seems out of place, although the distributor cap does seem to have a little bit of play rocking back and forth. The timing is properly set, and when driving with the SPOUT connector unhooked, it runs ever so slightly worse.
I pulled codes with a jumper wire and got 636, 654, 621, 622, 629, 627, and 624. All of which are trans codes, which I would expect since my ecu is trying to communicate with all of the e4od's sensors and switches that are no longer there. Using a scan tool gave me all of the same codes, plus one more, 212 "Loss of ignition diagnostic monitor signal/SPOUT circuit gronded" although I doubt the accuracy of the scanner on that.
The issue seems to happen regardless of operating temp, speed, and gear. just seems to be engine load. Like I said, it revs up fine in neutral, and I can take it to highish rpms as long as I accelerate very slowly, but any more than 1/4 throttle and the motor basically has an aneurysm.
Tomorrow night I will check out the fuel system and probably look at the tps with a multimeter and see what I can find, just looking for any ideas until then.

 

If the cap rocks, something is wrong. The snap clips should hold it hard against the flat bowl.

The 212 code is from driving without the SPOUT connector. I doubt the problem is related to the fuel system, but it never hurts to check fuel pressure. Testing the TPS & other sensors/actuators also doesn't hurt, so check everything. I'd guess you'll find a fault in the TPS or MAP vacuum line (assuming it has a MAP - you should put that & the E4OD-to-ZF swap into your signature).

(click this text)


(click this text)

 

Alright, so I got to starting my diagnostics process. First thing I checked was the TPS, had 5 volts at the power wire, and 0 volts at the signal wire, replaced the sensor with one made by Standard Ignition, it now has proper signal voltage, but the bronco still runs the same. To test the MAP sensor, I just traded sensors with my '89, and inspected the vacuum line. Both trucks drove the same with the sensors swapped.
Testing fuel pressure was where things started getting weird. Turning the key on with engine off, I got 18lbs of pressure, which is way too low. I unplugged the FPR vacuum line and tried again, then it went to 30psi. With the engine running, it stays at 35psi during idle, neutral revving, and light acceleration. But when it starts sputtering and shaking (during mid to high throttle acceleration) fuel pressure rises to 40psi.
Another thing that I noticed that maybe is irrelevant is that all three of my trucks of course have loud fuel pumps, you can hear the humming if you walk near the rear of vehicle while it is running. On both f150s it is a constant hum, but on the bronco, the humming changes in tone, going up and down.
And the last thing for now is that I pulled codes once again, KOEO a had the same several trans codes as before, with the addition of 452: Vehicle speed sensor signal fault. Although I dont have any abs light on and the speedo works fine, but that could be related to my flashing o/d light. When attempting to pull KOER codes, with a jumper wire, I got no codes, the light would just stay on for a minute or two and then stay off. I tried using my code scanner, and it was unable to retrieve code 111, which it needs in order to properly communicate.

 

No, a scanner doesn't need a code to communicate. Code 111 is only there if there are no other codes to read, so that would be useless. And an '89 is incapable of producing any 3-digit code. A scanner needs to communicate to find out what codes are there, but they're NOT reliable on these old trucks. You should only use a jumper wire to read codes.

 

The '89 isnt the truck I'm trying to diagnose, the '94 is(sorry I should have been more clear on that), and the only reason I tried using the scanner is because I couldn't get any koer codes with a jumper wire, even though it was working for koeo a minute earlier.

 

Getting spurious codes is worse than getting no codes. But if you read that page carefully, you can probably figure out why it's not delivering KOER codes with the jumper. And the '89 comment was only to illustrate that a scanner CANNOT wait for that code because it would never read anything on your '89. The jumper wire always works when done right and the preparatory conditions are met.

 

So today I was messing with the bronco again, and I pulled the ecu out, it seems like water has been getting into it, as there was corrosion on both sides of the case and a little bit on the inside of t as well. I'm not going to say that it is bad yet.
The ecu is not the original, it's manufactured and the part number from the manufacturer comes back to fit my bronco, but on the other side it has a number starting with e9af printed on it, which should be an '89 crown vic? And under that it has a number starting with f0af, which would be a 1990 crown vic. That stuff might not mean anything, but it's kind of weird.


rust on the outside of the case.


there is a little bit of corrosion on the outer edges, but everything further inside looks fine.




The numbers stamped on the bottom side.

 

ECUs can be tricky to understand. I started using a Quarterhorse and the EEC software (to tune the ECU I got out of the JY for my351 swap +MAF upgrade). from http://moates.net/ It is possible that the EEC came out of a Crown Vic but there is enough similar specs that it will work fairly well with your Bronco.
At one point several years ago, I was having similar sounding issues with my 93 F150 and it turned out to be a plug wire had melted against the Exhaust, Just a thought.

 

I wanted to get the bronco up and running before I was hit with a snow storm, so I replaced the ecu with one that came out of a '94 f150 with the same motor, but a c6 trans. My issue mostly went away, but I still had a harsh hesitation under heavy throttle. But it was still drive able, so I drove it fine for a few days, and then on this Saturday it died. The bronco just stalled out and still wont start back up, I checked for spark and have none. I borrowed the ignition coil from one of my f150s and still no change, I also have a spare tfi module(verified working after I pulled it from a junkyard) that I plugged in and still nothing. I popped the distributor cap off and the rotor had soot on it, seems like the same stuff you find on a spark plug from a vehicle running rich. Tomorrow I will be checking out the PIP and the ignition switch, will update with what I find.