EGR questions?

[rusty ol ranger]

86 BII 2.9

Im battleing an issue where during acceleration it basically "flatspots"...athough i do feel a bit of missfiring too.

Does it worse when warm.

I had code 31 and 84 KOEO. I cant get it to communicate on a KOER for some reason.

Anyways...i pulled the EGR valve...passage was not blocked, either was the tube. Valve is opening and closing.

Im getting 12v to the vacuum solenoid, however, i dont believe its getting a signal to open the valve. I know the ECM grounds it to open it. I took a spare wire and stuck it on the ground side and while engine running could hold it to negative battery post and open/close valve at will.

However....i could get no vacuum from the solenoid on my vacuum gauge regardless of RPM...i also hooked the ground of my test light to the ground wire and held it to hot, it never blinked on.

So is it safe to say the issue is either with the yellow ground wire or ECM?

I did have the egr sensor unplugged during this test...not sure if that would of mattered.

I had a new feedback sensor laying around so i swapped it out. It did seem to have more power and code 31 went away.

Any advice?

BTW...i did check fuel pressure while warm to make sure the pump wasnt screwy...it was 38 on prime, 32 running, and would spike to 42 if i jammed throttle, but quickly returned to 32. So i dont think fuel is the issue.

The EGR pipe is intact well and everything seems to be working. So i hate to dump an 88+ ECM in it if its just a wire. Just not sure how to test the wire.

 

[franklin2]

I have a 86. I have my EGR blocked off, and it's been that way for years. Runs like a top, no problems. A couple years later the factory did away with the EGR on these engines.

 

[lil_Blue_Ford]

I’m not exactly sure how to test it either, I don’t have an EVTM book for one of those either. Personally, I’d advocate the 88+ ECM, but you’re well aware of that since you mentioned it.

Have you opened up your ECM yet to see if there’s any blown capacitors or something in there that may not be letting it do its thing? Theoretically I should have an 86 ECM out of a B2 in my shed somewhere… I don’t know where exactly though, that’s a project on my list this year, clean it out and organize it so I can find all my random auto parts.

 

[rusty ol ranger]

I’m not exactly sure how to test it either, I don’t have an EVTM book for one of those either. Personally, I’d advocate the 88+ ECM, but you’re well aware of that since you mentioned it.

Have you opened up your ECM yet to see if there’s any blown capacitors or something in there that may not be letting it do its thing? Theoretically I should have an 86 ECM out of a B2 in my shed somewhere… I don’t know where exactly though, that’s a project on my list this year, clean it out and organize it so I can find all my random auto parts.

The ECM thats in it is actually the 87 ecm out of my ranger which is running an 88 ecm, the 86 ecm was doing weird things....which the 87 took care of...but the reason i went to the 88 in the ranger was its shitty running and egr codes...so maybe it wasnt the trucks fault lol

Anyways...i found a diagram that says pin 56 is the pin that grounds that solenoid. Im going to unplug the ecm, hook a wire up to the yellow wire on the solenoid plug and put it on the battery and see if i got voltage from that pin...then ill know if the wire is good.

Then ill decide what to do for ecm's. I just rescanned it and got a VSS code which is odd cause ive never got that from the ranger and that speedo dont even turn because the drive gear on the trans is shot.

 

[franklin2]

The early trucks and BII did not have a speed sensor. Not sure what the guys do that put in the later ECM for the egr, but the early chassis does not use the speed sensor that it's looking for.

 

[rusty ol ranger]

The early trucks and BII did not have a speed sensor. Not sure what the guys do that put in the later ECM for the egr, but the early chassis does not use the speed sensor that it's looking for.

86 would qualify as early? it is an early 86, 8/85 build date iirc

I never paid attention when i was under it.

 

[franklin2]

86 was the first year for fuel injection. I say that is early.

 

[lil_Blue_Ford]

86 was the first year for fuel injection. I say that is early.

Yeah, but nothing changed by 88 that I know of… maybe 89-92 would have that issue but I don’t think? All of those used the cable for the Speedo off the transmission or transfer case…

 

[rusty ol ranger]

Yeah, but nothing changed by 88 that I know of… maybe 89-92 would have that issue but I don’t think? All of those used the cable for the Speedo off the transmission or transfer case…

I read the VSS on these older trucks was for cruise only. My bronco dont have cruise...my ranger does. I dont know

 

[rusty ol ranger]

Well i just ordered an 88 ecm. Rockauto had closeout remanned cardones for 60 bucks. Be here thursday. Hopefully that eliminates the issue...im tired of dicking with ECM'S that may or may not be good and hopefully avoid any future knock sensor or egr issues.

Also figured i was gonna buy an ecm either way, if the wire was bad i wasnt gonna hack the harness to splice a new one, and had it been good then obviously the ecm in it was junk

 

[franklin2]

Well i just ordered an 88 ecm. Rockauto had closeout remanned cardones for 60 bucks. Be here thursday. Hopefully that eliminates the issue...im tired of dicking with ECM'S that may or may not be good and hopefully avoid any future knock sensor or egr issues.

Also figured i was gonna buy an ecm either way, if the wire was bad i wasnt gonna hack the harness to splice a new one, and had it been good then obviously the ecm in it was junk

I am sure you can have full confidence in a "reman" ECM. Especially if it says "Cardone" on it. Don't get your hopes up. And just make sure you have in your mind what the truck is doing now, and what it does when you put the other ECM in place. If you have different new problems, suspect the "reman" ECM.

Fingers crossed you get a good one.

 

[rusty ol ranger]

I am sure you can have full confidence in a "reman" ECM. Especially if it says "Cardone" on it. Don't get your hopes up. And just make sure you have in your mind what the truck is doing now, and what it does when you put the other ECM in place. If you have different new problems, suspect the "reman" ECM.

Fingers crossed you get a good one.

Im not confident enough in my wiring work to trust myself to attempt to fix a factory one.

But yes...we'll see

 

[rusty ol ranger]

Well i just thought id give an update....

Got the new ECM today (88 model), spent 15 minutes swapping it out and it runs amazing now.

I still got a random missfire (just enough to feel) once in a while...but im pretty sure its plug wires...some look burnt (exhaust), atleast one is missing rubber on the outside, its a mismatched set so who knows how old they are. I stopped at napa for some injector cleaner and wiggled them and found one loose....after doing that the miss got alot better, new wires are coming tuesday i think...along with a cap. I already changed the plugs.

But yeah....60 bucks well spent.