Ok, I have recently had problems with my 1992 F150 4X4 5.8L E4OD Extended cab. After fixing vacume leaks and eliminating the EGR everything ran better than ever. After just a few months the tranny would shift real hard. Usually not when I first started it up but after driving a few minutes it seemed like the computer would recalculate and the truck would jerk once or twice, then shift real hard and idle a little higher. Well, I had replaced the TPS a few months earlier and thought that it was out of adjustment or bad. But I did not have time to fix it so I just drove it when needed (it does not get drove much anymore because of gas prices).

The last couple of times of driving it, it would idle real low and stall when it was cold. After warming up it wouldn't stall anymore but shift real hard. Well today I started it up to go to the dump and it stalled three times. After reving it up to keep it running I backed down in front of my driveway to load the garbage and left it idling. After a couple of minutes it stalled and won't start again. I immediatley smelled "burnt electronics" smell in the cab. It will crank but not start and the fuel pumps will not run when I turn the key on. After doing several checks I open up my brand new code scanner (my old when quit and I just bought this one a few days ago) and connected it to the truck. NOTHING! It will not run any of the sensors or make any noises what so ever when I switch it to the test position with the key on. The manual that came with it said the ECU or circuits may be at fault.

Any suggestions? This thing is sitting in front of my house right now halfway blocking the road.

 

You could start by by checking your fuses.

 

Pull the ECU out and then take the cover off it, see if its all burnt up on the circuit board at all.

If it was what you could smell burning, you will see evidence of it when you look at it. It will smell burnt inside as well.

If not search the wiring harness for signs of burnt areas, you should have some fuses or fuseable links burnt out too.
Be sure the check the wiring harness leading down and over the tranny. You will have to open or remove the plastic covering to see the wires good. If it burnt bad enough the cover may be melted as well.

Either way I'd disconnect the battery until you find out what did burn.

From what you said you should have got a CEL at some point, did it ever come on? Did it or does it now when you turn the key to "run" without starting it?

 

I have not found any fuses blown in the fuse panel on the lower driver dash or the panel on the driver inner fender well. The burnt smell seems to be on the driver side and not the passenger side where the ecu is.

 

the ecu is on the drivers side on a 92.

look below the brake booster in the engine compartment.

that is the ecu.

 

Thanks for all the help. The ecu is fried. I finally found it on the drivers side just like you said quicklook. I don't know what that box is on the passenger side below the glove box.

Anyway, now I need a computer.

EEC-IV EFI-SD48B
A2Z
F2TF-12A650-CA G
61ES58BM01 28117-185 1G12

Where is a good place to get one? Ebay? junkyard? rebuilt?

Thanks for all your help.

 

junkyard is where most go.

if i remember napa has them.

glad you found it.

 

Before you put another ECM in there check the wiring going to it so you don't potentially fry another ECM.

 

I would also pull the alternator and have it tested, just to be sure you don't have a overvolt problem.

 

IIRC The box on the passenger side is the antilock for the rear wheels.
regards
rikard

 

Thanks for the comments and information. I did not see anything wrong with the wiring anywhere. That is why I was having a problem finding what was burnt up because the smell was so strong, I just knew there would be melted wires or something obvious under the dash.

I have always thought I had a problem with my alternator. I have had it tested a couple of times but the volt meter on the dash drops pretty low when a/c is on with lights and wipers. I believe I have a 70 amp and I think it is suppose to be a 80 amp. So I will probably change it anyway.

Thanks again for all the help.

 

Now I need to know which computers will work and which ones will not. For example: which years are compatable? does it have to be the same 5.8L engine? same e4od tranny? speed density? etc. I doubt I am going to find an exact match so I just need to know which trucks to look for that will work.

Also what is a fair price for one? Thanks for all your help.

 

Has anyone every heard anything from this company?
Auto Computer Exchange

So far I have not located a computer from any local junk yards.
Also, my truck is a 1992 built in August 91. A few of the junk yards I have talked to said it is coming up a 1991 model from the numbers off of the computer. Is this normal or do I have a 91 ecu instead of a 92 that I should have?

Thanks for the help.

 

Well I just recieved and installed my rebuilt ecu from autocomputerexchange.com. The truck started right up and idled smooth and relatively low (700 rpm or so). I drive it for about a mile or so then it starts. The same problem I was having before, shifting real hard. While it was idling in front of my house, it abrutly jerks as if the computer just reset something then it starts idling higher (1100 rpm or so). When I put it in gear it instantly engages with a big clunk. As I drive it changes gears very soon and jerks each time. The only difference with the new computer is that it seems to lobe along after changing to second gear. Once it even seemed like it jumped from first to third because I pulled up a steep hill and it just about would not go because it was lugging. I have not pulled codes yet because I simply have not had time to do anything. I had the transmission completley rebuilt about 18K miles ago.

I don't know is it is possibly the tps (which I have replaced just recently) or the vss (I don't know anything about the vss), or something wrong with the tranny. I was hoping that my old computer was acting up and replacing it would fix this problem as well.

Any thoughts would be greatly appreciated. Thanks.

 

The best test for the VSS or Differential Speed Sensor (DSS) as it was called in 1992 is to watch your speedometer. If it is steady and gives a good indication of the speed then your sensor in the rear end is OK.
Sounds like it could be the TPS sensor, check it with a DVM to see if it is in the ball park range of voltages and then with an analog meter as you slowly move it to see if it is smooth over its range.