I am looking into replacing the computer in the GF's 90 Ranger. I am looking for recommendations on what brand and where is the best place to buy one. I would rather pay a little more for a product that is going to work how it's supposed to than a cheap one that's going to give me more headaches. Any and all suggestions are appreciated, thanks in advance!
John

 

This question is best answered with another question. Why are you replacing the computer? Not to say it doesn't happen, but computer failure is rare, and many computer replacements are due to other problems being misdiagnosed. So by what means did you determine that the computer needs to be replaced?

 

I'll try to make a long story short. This truck sat in the woods for three or four years and had never been run, before we got ahold of it. It had belonged to a friend of mines sister, she parked the truck shortly after the transmission started slipping. Anyway since then we have done a ton of work to this vehicle: rebuilt engine and trans, freshened up the t-case and axles, rebuilt the front end and the list goes on. One problem we fought with for the first couple years was water leaking in when it rains. Apparently the cowl area at the base of the windsheald was leaking into the interior anytime it rained, we discovered the drains were clogged with debris from sitting under the trees. One area inside the cab that was heavily affected was the passenger sider kick panel area. In the process of repairing the cowl, I noticed the computer had been getting wet; the outer casing had a fairly heavy layer of rust on it. I am aware that these things are very sensitive to moisture and corrosion.
I have replaced every sensor, valve, and sending unit on this thing and it still doesn't run right. Some of the issues are intermittant, they really like to come out either when it's wet, cold or both. Some of the symptoms have been hard starting, back firing, rough lopey idle, underpowered, and poor fuel economy. I am at a loss here, I've replaced everything else I can on this thing and it's still not coming around. Any other info is greatly appreciated, thanks again

 

Pkupman82, try to make sure all your ground connections are clean and tight. Especially from the cab to the engine and engine to battery. Might be best to get another OEM computer from a wrecking yard. 1990 to 1992 Ranger will be the same. You can also ask the yard if one from an Explorer will work too. They should have an interchange manual that will tell them.

 

I have gone through all the grounds on this thing, they seem okay. I suppose being it's a "rust belt" rig it might not hurt to add a few more grounds. I have been sceptical on using a junkyard computer, I suppose it would be a cheaper alternative to buying a new one. I would have no problem with buying a new unit, except I keep running into bulletins on problems with the reman computers. It's the most trouble and frustration I have ever had with a Ford truck, being a "true blue" Ford man I still have faith we can beat this one. Thanx again!
John

 

Have you checked the connector to the computer/ECM? You could easily have dirty or corroded terminals on the computer or the connector or both.

Does the check engine come on momentarily when the ignition is turned on? If so, does it stay on when the engine starts - in other words, have you checked for trouble codes? If so, get the code numbers and post them here so we can give you more help.

 

Haven't gotten any C.E.L. ever that I can recall. She is very good about letting me know if something is wrong with her truck. When I was doing the repair work to the cowl/firewall area I removed the entire dash and steering column... as well as the computer. That is when I noticed the outer casing of the computer was covered in rust and corrosion. I went through and cleaned and secured every ground connection I came across. Like I said the time when this thing really throws a fit is when it's wet and or cold outside. Something is wrong because this thing is gutless, slow, and only gets around 10-12 mpg... like I said though I can't seem to get any codes from it. I know a few other people who own 4.0 powered Rangers and Explorers and every one of them will dust this thing. I'm at a loss I don't know what else it could be.