hi guys,
i'm new to this forum and am hoping someone can help me. i am also new to broncos and have a problem with mine. i've had it about 4 months and haven't had a problem with it until the other day...i was traveling down the road and noticed that the throttle would not go to the floor. i pulled over and checked the cable and noticed that the plastic housing was broke and causing the cable to bind. i managed to get home. i had to drive it before ordering another cable and now another problem has surfaced. it cranks and runs fine for a short ways and then it starts skipping and popping back into the airfilter box? while in park if you press the gas very much it acts like something is retarding the fuel,air,timing and it starts popping back but if you let of the gas it revs just a little and then returns back to idle? i did change the tps sensor yesterday but no luck. i still have to put on the new cable due to having to order it. any help would be appreciated!! oh! i also forgot while going down the road if i shift into nuetral and cut it off and then crank it back up it runs fine for about a half mile and then starts skipping and missing again. it acts like the ecm resets and then happens again?????

 

Ok, first off, welcome to FTE and the Big Bronco Forum. We will do our best to get you the most accurate info we can.

You say you are new to the Bronco. Are you new to Fords in general? I ask because the first thing you will want to do is run a KOEO (Key On Engine Off) test and if that doesn't yield fault codes either in continuous memory or sustained faults then you will want to try to run a KOER (Key On Engine Running) test. However, given the nature of the problems you described, you will most likely get answers from the KOEO test.

There a several ways to go about this. Each has its advantages and disadvantages. The least expensive involves making jumper wire for the EEC-IV test connector (near the firewall under the hood on the driver's side of the truck) and putting the key int he ignition and counting the flashing "check engine" light. The more expensive but worth the investment in the long run is to get a code reader for EEC-IV equipped Fords and run the test with it connected to the EEC-IV test connector. The last (and least convenient for you in your situation) is to take the truck somewhere and have the codes pulled.

Check this link for more information about Ford EFI systems than you could ever want/need.

 

thanks greystreak,

i am familiar with fords but not that familiar....i replaced the throttle cable yesterday and planned on taking it to advance to get them to hook a tester up but no luck there! i went and bought a ford code reader and ran the test (keo??) and got 85(canister purge circuit failure), 96(fuel pump secondary circuit fault) 33 egr valve fault). i planned on cleaning or replacing the egr just as good measure. as far as the fuel pump relay being open any suggestions?

 

Intriguing... there should be no secondary fuel pump circuit in a 91. By 91 Ford had gone to a single high-pressure in-tank pump and dropped the one on the frame rail under the driver's seat.

I'll look into that more closely as soon as I can get home to my references.

Make certain there are no electrical connections hanging loose under the hood. The CANP circuit is a small solenoid up near the passenger side of the throttle body. Make sure the connection is good. Clean the contacts if necessary.

You are on the right track with Code 33.

Let me do some digging on the fuel pump circuit and I'll be back. In the meantime others may chime in with suggestions.

 

Maybe he isn't getting the proper code guide for his model-year?.

 

thanks guys,
now that you mention "loose conections", i did find a connector coming from the egr connector harness that is dangling but i can't find anywhere that it goes? it has a white wire and red wire and y's off of the connnector going to the top of the egr valve. it comes from the front of the motor and is lying on the top of the alternator. just a quick question...with the motor running fine for a few mins until it starts acting up, as soon as you switch the key of and back on it runs fine until it does it again. wouldn't this be something "electronic"? would it be a good idea to check the fuel rail pressure also? if it is loosing pressure while running it doesn't seem that it would recover pressure just by cutting the key off and back on? just a suggestion from a friend of mine as well as a ignition coil going bad? thanks for any input....encho i did run the koeo test according to the manual that came with the code reader i bought, is there something i'm missing?

 

That's the CANP circuit. You are looking for a small cylindrical solenoid with a vacuum line going in/out of it. It is usually zip tied to something near that side of the engine closer to the throttle body.

 

thanks guys for the input, i gave up and took it to the ford dealership today. i talked with the mechanic who is working on it and so far it has all of them scratching their heads!! they do agree that it's electronic (problem) but so far they are not sure what it is!! just my luck....

 

fuel pump needs replacing.

 

I wonder...while they were scratching their heads, did they hook up your CANP circuit?

 

i did tell him about the loose connector. he also said that he checked the pressure at the fuel rail and when it acts up after running for a min that it was between 25-30 psi. i'm not sure what its supposed to be but he didn't act as if that was out of range? i will double check and make sure that they do find where that connector goes. he did say that they were going to hook another ecm if they had one on the shelf just to rule it out. im my opinion it acts as if something is retarding the timing after it runs for a minute or so. i'm just curious as to what is could be!

 

It should be nearing 40, so yes, the pressure seems low.

 

thanks everyone for the tips! encho you nailed it! it was the fuel pump. after looking further the mechanic told me the pressure was actually dropping as you accelerated. just picked up the bronco and its running great. i hate i had to take it to a mechanic but at least it's fixed. of course i couldn't have dropped the tank and replaced the pump myself due to a very recent back surgery anyway. at least it was a lesson learned for future reference. thanks again guys!