BroncoII4x4.com

I posted about my engine erratic idling problem and that I wanting to check for any stored error codes. I also mentioned I've never seen the engine trouble light come on. What I did'nt notice before is the fact that when turning the key to on, before turning further to crank it over, I guess all the dash lights should come on.... as a bulb test.... and I see no "engine trouble" light. So, I'm thinking it may be it's burned out.

I don't have a owners manual to verify, so can anyone tell me if I should be seeing this light. Also, where should it come-up on the dash? Dead center between speedo and tach... where there's other lights? Or to the left, near the tach.
Thanks, dave

Check engine light, according to my 88 manual, is in the lower left of the center indicator light display.

Thanks Steve,
and since you referred to your owners manual for that info, can I assume you do not see the "check engine light" when you first turn your key to the on position? dave.

I can't say right off, my son-in-law has had my Bronco II for a month now. and I could not check it uot...

Got the BII back. It does come on in the first key power position...Just checked it...

Thanks Steve G.... you the man.

Guess I better pull the dash apart and check the bulb.

p.s.

the BII is still running a bit odd. Now, only once in a great while does the idle fall off to under 750 and nearly die and it always recovers itself just before it stalls. But now on cold start-ups, it idles at 1500 and "roams' up and down a bit. After about a minute it drops to 1000 and another minute, to 750.

In so much as I've:
1.cleaned/decarboned and tested the function of the IAC valve ... it's fine,
2. did the same for the throttle body butterfly valve itself ... (took it completely off the intake manifold),
3. re-newed the plugs, cap and rotor ... wires looked to be clean and plyable rubber... no dryness or cracking.
4. looked over the vacuum hoses for splitting or sloppy loose fit at their connections,
I'm not sure whats the next most likely possible cause.

This same truck started and ran better back in the colder months of Jan,Feb and March. Problems started with warmer days AND right after I did the 3" body lift. dave.

what do you mean by erratic idling problem??? you checked the iac with pwr and the solinoid is working properly? the reason i ask is i had a similar problem and i had to clean mine a couple of time before it finally worked right. im not sure if the TPS would cause this but you can always check it...

Yeah FatMan,
The IAC valve: I scrubbed the little plunger and the bore with a aerosol degreaser and a stiff little brush... it really was not gummed up...just a black sooty coating. Came real clean. Then I bench tested it ...( instrument testing room at work),applied 0 to 12 volts dc to the two connector prongs in the plug. It stroked smoothly as I ramped the voltage up and down. No hanging up.

I DID'NT do the test from the book, where you run the truck and when disconnecting the wire to the IAC the RPM's are suposed to go up about 1000.(Did'nt see the need).

I don't have a test,( or should I say any ressistance values to go by for checking the TBP), but I did check for a change as I worked it open and closed....like you would check a potentiometer. Oh, and IIRC the ressistance was something like 1k ohms at idle position and increased when I opened it up.It's gotta be good or the truck would'nt run at all... prolly.

I'm wondering... there is a air inlet temp. ( AIT ? ? ), sensor somewhere too I think. Truck IS running worse with warm weather now... Is that what the Thermostatic valve is? And is that the thing in the air filter box that two vacuum hoses go to? Does it matter which hose goes on which fitting on that little guy?

Anyone can chime in if they have a suggestion, dave.

you know i just read your first post and i had a problem with my 79 that it would'nt barely start and when it did it would idle like crap i didn't notice but my neighbor being the FORD guru he is said that i wasn't getting any pwr when i turned the key in the on possision. anyway it turned out to be my ECM but the fuelys dont have ecm module i think instead they have the TFI module. im not sure if that would cause your problem but i do know it would cause it to run sluggish...


have you tried to run codes anyway??? if not i would try you dont really need a code checker. you can jumper points on the connector and watch the engine check light flash to get codes. i will look through the FORD trouble shooting manuels i have to see what i can find.

oh yeah check out www.fordfuelinjection.com lots of good info and the guy knows his shit...

will get back with ya tonight

Wow, hey thanks. Thats the kind of info I need! What pins to jump out to get a light on the dash to flash and what the flashes represent. I did this years back when I had a Mustang but don't remember how exactly and the dumb Chilton manual does not go into that...a most basic engine systems thing! The book does have a extensive list of codes and they're descriptions...just no explanation of how to retreive them... other than get a code scanner. dave.

i have a code scanner and book so when you find out what codes it pulls let me know. im not sure which pens but let me do some searching. the site i posted may have it it's been a while sense i've done it as well.

okay found it try this and see if you get codes... http://fordfuelinjection.com/?p=13 ...i've looking through my books and damn there detailed alot of it calls for using multimeters and anolog meters and different test equipment i know i dont have. but i'll see if i can find something as far as trouble shooting for rough idle..

oh yeah does it drive like it idles or does it drive fine?

BII drives fine although it's not the peppiest truck on the road.

Mayby I'm repeating myself from another post, but I did get the "check engine" light to work now and since then it's not come on while driving. (Still gonna check for any codes. ) It's nice to have $hit working on your truck, you know what I mean.

I'm getting alot of little nagging things fixed like to sloppy loose steering wheel. Just a couple loose bolts under the steering coumn cover. Noisy speedo cable... lubed and good to go. later dave

so, what happened? I am having this same exact issue myself. what is that thermometric valve all about, and what does it do? man i miss my volkswagen - mechanical fuel injection, no computer! It also does the weird thing idling, if I ever so slightly depress the gas pedal, the idle drops to about 250 rpm, and then recovers to accellerate. I will probe my o2 sensors to test resistors & such. should check my vacuum lines too.

Nate

Nate,
The Bronco just started running pretty much back to normal as of my last post about this. I did pull access tyhe stored comuter codes by doiung the jump pins thing and there were no problem codes in the comuter.

It's not perfect...a bit hard to start...but it does have 180k on it. If I found time to spend on it, I'd change the fuel filters and get the injectors cleaned or replaced because I just think these things have probably been ignored by the previous owner,( and me since my 1 year of ownership).

dave