'91 XLT Still doesn't run right.

[wes393]

I have a 1991 XLT 5.0l 5-speed with full stainless exhaust and K&N Intake, everything else is bone stock. I recently had a new clutch and ***** cylinder put in it. Before i took it to the shop it ran like a horse! However, after they (very reliable shop) replaced the clutch it magically didn't run at all. After a new distributer, plug wires, plugs, and timing adjustment it ran enough to get home. Now I've replaced the fuel filter and fuel pressure regulator, checked the pump and found it to be just fine, and have used more Injector Cleaner than id like to admit. Despite my efforts, very little power has been restored! I mean my truck used to smoke those cute little tuners all night, now it will barely climb an inclined street. Also, when I give it a couple revs it gets some pretty good combustion through the pipes. Next thing to go is the Injectors. Any thoughts? Anyone having similar problems?

 

[Seabronc]

Have you pulled the codes? They may just point you right to the problem.

Good luck,

>-

 

[BroncoJoe19]

Pull Diagnostic Trouble Codes (DTCs) From your onboard computer.

Your engine and transmission are computer controlled.

The computer uses sensors to tell it a number of different things and it controls actuators that push or pull mechanical levers (kinda). If one or more sensors aren't working properly, the computer goes "blind" and doesn't know what to do. If the computer can "see" but one of the actuators is broken and therefore can't follow the commands of the computer; the engine won't run correctly. The computer is preprogrammed with set values for each of its sensors, and each of its actuators. It will run a self check of all systems, like the space shuttle; it will compare its set value(s) to the value(s) it recieves from its sensors, and actuators. If any sensor or acutator is out of the "normal" range the computer will generate a "code." It will generate some codes on the fly, and others will be stored while you are driving. There is a simple method to "pull codes" out of the computer for one to use for diagnostic purposes.

Earlier versions of On Board Diagnostics OBD 1983-1995 can flash the error code to the dash board and can be pulled in one's driveway without any special tools.

Later versions of On Board Diagnostics OBDII some 1995, and pretty much all 1996 and newer, require one to use a code reader or scanner tool.

Some auto parts stores will scan your engine codes for FREE, you may want to call around. Some will scan OBDII but not the older (prior to 1996) OBD systems.

SO here you go...

How to scan FORD on board Diagnostic Trouble Codes (DTCs) in your driveway

HowTo Pull Codes 1983-1995 Broncos, Mustang, F series Trucks, Econolines, 302, 351 and more

 

[BroncoJoe19]

I'm thinking that the VSS in a 1991, is still in the transfer case. Make sure it is still connected. IT is important for the operation of an automatic in setting shifting poinst, but perhaps the PCM still uses that data for something in a manual.

 

[wes393]

Thanks for the advice! Ill pull the codes, Ive done it a few times before and Ill look into the VSS and give some updates. Hopefully I get this down in time for the snow!

So i pulled the codes and got an 11 which to my knowledge is a pass code. It gave me 11 twice and didnt give me any stored codes. Would a 4x4 specialty shop be any good and diagnosing this problem? Im no Supreme Commander, but if i only knew the issue i could fix it! Replacing everything in hopes of fixing it just isn't working....

 

[Seabronc]

Well in my thinking, If I took a perfectly running engine to the shop and after they got finished changing the clutch it didn't run, I'd suspect that something happened besides changing the clutch. What was physically done to change the clutch. Just maybe they disconnected something and didn't get it back together properly? Supreme Commander or not we can't see :blink: your engine and if we knew the issue someone might have the fix. Throwing parts at it didn't help :-& , so maybe you should take it to a competent mechanic so he/she can take a better look at it :-B .

Good Luck,

>-

 

[wes393]

That was my thought, and ive spent quite a bit of time looking around for anything dangling or loose but havent found anything yet. Having it looked at by a different mechanic is deffinetely an option im considering. Thanks

 

[miesk5]

yo,

Did you pull both Key On Engine Off (KOEO) and Key On Engine Running (KOER)with engine @ normal operating temp for the KOER portion?

You have the M5OD-R2 - right?

I'm figuring that "shop" may have messed up da VSS and or it's conn wiring as Joe advised.

Any signs of A SLIPPING CLUTCH?

Any problems shifitng? Especially into First?

OR AIR IN DA Concentric ***** Cylinder?

 

[wes393]

SUCCESS!

I have completely solved my issue! This is mainly the mechanics fault but mine as well. During the absolutely pointless replacement of the distributer and plug wires, the mechanic rewired my 5.0L with the firing order of the 5.7L. Then, since the truck obviously wouldnt start, he simply turned the distributor until the truck would barely run, firing at 30* BTDC. I discovered this because they also forgot to replace a few bolts in the headers causing the gasket to blow out which melted the plug wires that the mechanic just installed :angry: All together she's run perfect now! Seabronc was right, something just wasnt put back together right. The very hairy question that im going to ask them is *** were you doing touching my plug wires in the first place? Im pretty sure to replace a clutch you dont need to disconnect them. Anyhow, thanks for all the help! I was at least able to read the codes and check out some other things while she was down. Thanks again >-

 

[Seabronc]

Thanks for the follow up. It's nice to know what the problem was.

Good luck,

>-