Hello all! I have a 90 F150 5.0L and would like to rebuild the engine but convert it to an OBD 2 system instead so I can have better monitoring of the systems. The truck is currently wasting away in my backyard and would like to know if it is do-able with the original block or should I just get a junker block of a newer model with wiring harness and rebuild and use that one.


Thank you!

 

Its not the engine so much that is the problem - it is all of the other wiring in the truck you will have to replace. For starters, all of the dash and speedometer wiring....and it has to come from a 96 donor truck because that is the only year they did OBD2 on these types of trucks before the body style changed over.

So I would not recommend it. Analog gauges are cool too.

 

I was actually trying to keep the dash the same, and just wire in the other lights with the pcm mil circuit, that way it wouldnt matter what fault there was it would still light the check engine light.

 

I guess what I was saying is that you don't have a choice - you have to change it. The 92-96 body style uses a programmable speedometer and odometer which is computer controlled. So the cable controlled unit in your 90 would have to be re-worked somehow. It gets even more complicated if you have an automatic transmission, because those are computer controlled in the 92-96 as well, but not in the 90.

When you say you want "better monitoring of the systems," what are you going for exactly?

 

Last time I encountered this discussion was when I was on a BMW forum. The gist was that the next model ('95 & up) had the good engine, and the 82 to 94 had the looks and the light weight. Folks were converting the engines back to OBD1, because the bringing the body up to OBD2 was a full on nightmare. That was at the expense of VANOS, (variable valve timing) which would have been desirable. I think you'll find it the same in any brand, the line in the sand is just too broad.

 

What I mean by better monitoring is that if/when the check engine light comes on, i can have more information about what has failed. OBD 1 monitoring systems follow the 90-10 rule (if the input is between 10-90% of operation voltage the ecu thinks its working as it should). Where as OBD 2 can detect an input that is degrading over time and stricter tolerences.

 

I think you are wasting your time. I'll let others chime in and give their opinion, but to me it would just not be worth it. It CAN be done but as I stated above, its a lot more than just the engine.

If you are serious about doing it I would also start researching mass air conversions, because you will inevitably have to do that to move to ODB2 as well. If you wind a donor truck with everything you need that would be the ideal situation.

But still....your money and time would best be spent elsewhere....my $.02.

 

waste of time unless you are really wanting to do modifications to it, which for the work involved it may be wiser to megasquirt it.
if you are going to do it, you need a donor truck. there are TONS of things to swap over.

 

For what $$ a nice example can be found, it would be easier and better to just find and buy a '96.

 

And the big kicker is that you will have to change your camshaft to an HO firing order.
What you're talking about is possible and some people have done it, not for "monitoring" but to get the MAF system.
But you would have to change over pretty much the entire wiring system on the truck, all the engine management sensors, intake, vibration damper and the list goes on and on.
It's do-able but it's a ton of work, you would really have to know A LOT about the trucks and it would be a waste of time as someone pointed out just to be able to monitor your motor a little better.