New to the forum! Hi folks I need help!

[Cmillzz83]

Okay...so I think this is where I need to be asking a serious question about my 91 ranger sport,manual shift with the 4.0 liter engine...I have replaced the ignition lock cylinder,the ignition coil pack,the battery,the crank shaft sensor,the fuel pump and it is getting fuel pressure,and replaced the icm. The guy I got it from keeps saying something about the ecm computer and said that when he looked at it he saw corrosion in the board but I pulled it apart and the board is clean as a whistle and I'm getting no spark. There are a few questionable wires under the hood on the left side when facing the motor. They are both black with white stripes. One has a wide white stripe and the other has a thin white stripe. Not sure if those have anything to do with the issue but they are both cut and not connected and I don't know where they go. The ecm computer module does for some crazy reason have the date 2003 printed on it so I was wondering if it's possible he put a computer from a 2003 in it and it may have fit and that could be the reason for no spark or will the one from a 2003 not even fit a 1991? Please help I need to get this sucker running badddd lol. Thanks

 

[rumblecloud]

Welcome to the forum Cmill!!

I noticed you posted the same question in two spots - don't panic, someone will be along to try to help. Unfortunately I am not that someone.
It is Christmas Eve, but the people here are always ready to help, just give us a minute or two.

A couple of questions:
Did it ever run?
What made you replace all those items or did you do that to try to get it to run?
You're getting fuel, but are you getting spark?

 

[Cmillzz83]

Welcome to the forum Cmill!!

I noticed you posted the same question in two spots - don't panic, someone will be along to try to help. Unfortunately I am not that someone.
It is Christmas Eve, but the people here are always ready to help, just give us a minute or two.

A couple of questions:
Did it ever run?
What made you replace all those items or did you do that to try to get it to run?
You're getting fuel, but are you getting spark?

My buddy said he had it running and it turns over fine and has good compression and I got all the dash lights and headlights working. Just no spark. The pcm in the truck has pink colored print on the side of the pluggin tab and is dated 2003 and I was wondering if maybe it's the wrong pcm in the truck and that being why it's not getting spark.

 

[Cmillzz83]

My buddy said he had it running and it turns over fine and has good compression and I got all the dash lights and headlights working. Just no spark. The pcm in the truck has pink colored print on the side of the pluggin tab and is dated 2003 and I was wondering if maybe it's the wrong pcm in the truck and that being why it's not getting spark.

And I replaced all that trying to get spark. I'm not a mechanic and have hardly any electrical experience or knowledge but I do work on small engines some.

 

[sheep herder]

I doubt that a 2003 computer would plug into a 1991 wiring harness.

 

[Curious Hound]

I doubt that a 2003 computer would plug into a 1991 wiring harness.

Exactly. The 91 pcm would be old style OBD1. The newer 2003 would be OBD2 and would have more pins in the connector and a different way of communicating with the engine, instrument panel and transmission. Sounds like you don't have the whole story. The ignition/timing/spark system would be different between the two.

 

[Cmillzz83]

I doubt that a 2003 computer would plug into a 1991 wiring harness.

I thought the same but couldn't figure it out if it would or not.

 

[Cmillzz83]

Exactly. The 91 pcm would be old style OBD1. The newer 2003 would be OBD2 and would have more pins in the connector and a different way of communicating with the engine, instrument panel and transmission. Sounds like you don't have the whole story. The ignition/timing/spark system would be different between the two.

I agree but technically would it plug in is what I'm wondering because this one plugs in easily but is dated 2003

 

[Curious Hound]

I agree but technically would it plug in is what I'm wondering because this one plugs in easily but is dated 2003

No.

 

[Cmillzz83]

I agree but technically would it plug in is what I'm wondering because this one plugs in easily but is dated 2003

No.

 

[Cmillzz83]

This is the one plugged into my 1991 ranger

 

[Curious Hound]

Really sounds like someone swapped a newer engine/wiring harness/pcm into that truck.

 

[sheep herder]

2003 computer would have PATS so you'd also have to have a chipped ignition key. Maybe it's a remanufactured ECM done in '03?

 

[Cmillzz83]

Really sounds like someone swapped a newer engine/wiring harness/pcm into that truck.

That's what I was thinking to. Man I hope that it's just a different pcm and not the whole harness because every other plug fits my truck fine. When I looked it up it didn't say if the prong settings were the same amount and shape just that the shape of the box itself is the same

 

[Roert42]

F0AF-14A459-AA is the part number for that ecu. I did a quick search, and it looks like it is for EEC-IV. So not 2003.


Edit: this does not mean it’s for your truck.