87 BII 2.9L

I recently cleaned the IAC and since then, my problem has worsened a bit.
I took some advice from a previous post about high idle, cleared that up
but now there's an
extreme amount of stumbling/ hesitation when I first start the BII, once it warms a bit everything is fine.

how do you test the throttle sensor or better yet what voltage changes occur
when your trying to test it?

Anyone ever come across this problem, or know a good reference post to search for ?

Thanks

 

1) Make sure there is no binding in your throttle linkage. If it sticks when you go to give it gas, then the idle stop needs to be turned in a turn or two (This also affects cold idle, if I remember right).

2) Your IAC (and maybe EGR) may need to be replaced (cleaning only does so much, and can also cause more problems in the future), or you may have other sensor problems. Pull codes / test sensors and see what comes up.

3) You may also want to check all of your vacuum lines, as well as your PCV valve / breather. Could be bad / dirty. You may also want to check / clean your throttle body / upper intake plenum.

I believe that's about all of the answers I've seen for this problem throughout this forum. I'm sure others might have some suggestions as well. Hope this helps

 

My BII once had a cold stumble. PUlled codes and had KOER 41 & CM 41 come up. Tested and replaced O2 sensor and cold stumble was gone. As noted, the first step would be to pull codes from the computer. See Ken00's tech info post for instructions.

I once saw a TSB pertaining to an '87 that suggested another possible cause was a dirty throttle body & upper intake.

 

I guess this is one of my "problems" too, but I don't pay much attention to it. I just write it off as "a cold-natured Ford thing" I plan on cleaning my intake, etc. and porting out the upper/lower intake and throttle body flange(s). I think this is why the 2nd gen trucks with the 2.9 *don't* have EGR systems? That's the only place I can think of that dirt would come in, other than vacuum / PCV.

 

Where is the O2 sensor located ?
I might check that out next.

 

The sensor itself is in the exhaust upstream of the cat.

As noted, the first step in "checking out the O2 sensor" is to pull codes from the computer.

 

I pulled the codes and got a 33 and 63

I checked the tps and checked the voltage. I can kepp it at about 1.0v at idle, any more and I'm reving to high, way to high.

I'm assuming that it's working.

EGR - I'm open to suggestions on this one, all my vac lines are in good shape, some I have recently replaced.

Thanks for the input.

 

Were those KOEO codes (before the separator pulse) or CM codes (after the separator)? KOEO codes are almost always electrical in nature, because they are set with the engine off. So a KOEO 33 would have to be something in the PFE sensor circuit.

CM codes, without accompanying KOEO/KOER codes are likely intermittent faults.

 

Sorry, same codes for both KOER & KOEO -after pulse - repeat

 

When the code shows up in all "sets," then focus on treating it as a KOEO (hard fault) code. Which means it is almost certainly electrical in nature, which means you need to start by carefully checking the PFE sensor circuit. Is the PFE seeing Vref? Is the PFE generating any kind of signal (mine would output a little less than 3V KOEO)?

 

ok, I'll check that next.
Is the pfe on the firewall, or down wind of the egr tube?

Not sure I've ever looked for it before.

 

does it look anything like this and sit right behind the throtttle??

 

It's attached to the throttle body/upper intake with a vacuum tube going to the EGR valve. That looks like the animal.

 

I may re-pull codes this week and see if there are any problems on mine. I plan on doing a port / polish on the TB and upper/lower intake as well as cleaning all of that stuff up, among many many other things... whenever I get around to 'em. Hope you get your problem(s) fixed... let us know what's up

 

Man, I've changed the
MAP sensor
Idle Air Control
Throttle Position Sensor
PFE

Nothing has changed, still runs like harley when it's cold.
Should I unplug the neg cable to let the eec adjust ?

I did not mess with the o2 sensor, will the eec spit a code or will it
just be part of the general egr spacific codes?

Thanks for the help, panic