86/87 ECM vs 88-92 ECM

[rusty ol ranger]

After checking wires upon wires ive decided to change the ECM in my 87 Ranger to try and get rid of the issues im having, if nothing else to rule that out as a cause for sure.

I pulled the ECM out of rusty #1, and the fuel pump wouldnt prime, then it dawned on me all those years ago around the end of clintons first term when i had a buddy help me wire the fuel pump up to run all the time it must have been the ECM that was the issue and NOT the wireing. Got a code 87 and no fuel pump. So that option is out.

So, heres my question...

I know by going to a 88-92 ECM you eliminate the knock sensor/EGR system used on the 86-87 trucks. According to what i read they ran a knock sensor and EGR to run more aggressive timing, and then in 88 did away with that.

So, would i notice a power/MPG difference (as in, less of both) going to a 88-92ecm?

Also will i get a core credit turning in a 87 ecm for an 88? I know the part numbers are different

 

[shadetreebronco]

I did the same ECM swap on my 87 BII . I didnt notice much change as far as MPG or performance.
I was thinking about installing headers and never did.
I did return the 87 ECM for the core charge . They never looked at part numbers.

 

[adsm08]

I never noticed any difference in performance/MPG. And probably 99% of the guys who look at what you turn in for a core won't know enough to know it's not the same one.

 

[Paulos]

The only issue I had swapping an '89 ECM into my '87 was a code 95 (fuel pump secondary circuit fault). Turns out the '89 has a wire coming off the load side of the fuel pump relay to pin 8 of the ECM, telling it that the relay is sending voltage to the inertia switch and the fuel pump.

 

[shadetreebronco]

The only issue I had swapping an '89 ECM into my '87 was a code 95 (fuel pump secondary circuit fault). Turns out the '89 has a wire coming off the load side of the fuel pump relay to pin 8 of the ECM, telling it that the relay is sending voltage to the inertia switch and the fuel pump.

I have to ask but do you get a check engine light when the computer throws a code.?

 

[Paulos]

I don't think the check engine light is set up to operate on my '87. If I recall correctly, there is nowhere to put a lamp in the instrument cluster where the check engine light should be.

After swapping ECMs I pulled the codes to make sure everything was good and I had a code 95. When comparing the '89 and '87 schematics there is clearly a wire going to pin 8 from the fuel pump relay on the '89, but not on the '87.

 

[bobbywalter]

I don't think the check engine light is set up to operate on my '87. If I recall correctly, there is nowhere to put a lamp in the instrument cluster where the check engine light should be.

After swapping ECMs I pulled the codes to make sure everything was good and I had a code 95. When comparing the '89 and '87 schematics there is clearly a wire going to pin 8 from the fuel pump relay on the '89, but not on the '87.

its a reporting system, it was part of the change up to single in tank fuel pumps.

as you know your 87 has a high and low pump.