Welcome everyone! Many new users popping up and its always nice to see new faces and try to assist folks. Some of us have been here a while. Some of us have been here so long, we (and I mean me) forget that some information is not necessarily "common knowledge". So, for those who might be new and for those who have been here and, like me, forget that not everyone has read the same question hundreds of times before... let me remind and inform:

If your "new to you" Bronco is fuel injected and falls into the 1986-1994 model year range, Do yourself (and those of us who can help) a favor and PULL CODES. I know this seems like a complete waste of time when you are just looking for a reason why your truck is hard to start on a cold morning. But please, please, please trust me, being armed with fault Codes, even if it is just a list of two-digit OR three-digit numbers that you don't understand, will make getting to the root of the problem much simpler, less expensive, and MUCH less time consuming.

Pulling Codes is accomplished by way of one or two self-diagnostic tests. The procedures for running these tests are written down all over the place. Haynes manuals, this site and a host of other locations. The two tests are referred to by their acronyms:

KOEO - (Key On Engine Off) is performed much as you might expect... with the engine still warm from having been run for about fifteen minutes but with the key in the ON position and the engine OFF (not running). The KOEO test is considered a "static" test and will ONLY yield information that is either stored in the on-board computer's memory and/or faults that were present within the last forty (40) operations of the engine.

KOER - (Key On Engine Running) is performed, well, the same way... but with the engine... you guessed it, Running. The KOER test is a "dynamic" test and as such allows the computer to verify certain changes that occur while the engine is actually running. The KOER test has a few more "hoops to jump through" when it is performed because of this but it will often yield tangible evidence of issues that only occur under specific operating conditions.

Please don't assume that pulling codes is the be-all and end-all answer to solving every problem. If it were, this forum wouldn't exist. However, operational issues especially in the areas of performance, idle, fuel economy, and even transmission (E4OD only 1990-1995 in the Bronco) shift points, speedometer, cruise control issues can be pinpointed through these two tests.

Code readers are not a requirement to perform these tests but they do take a healthy chunk of the guesswork out of the process of deciphering flashing lights on the dashboard. If you are going to obtain a Code reader to perform these tests, the reader must be capable of interpreting "Ford EEC-IV" faults. Some manufacturers refer to this as "OBD-I" or "OBD 1" as well. The reader can do MORE but it must be able to decipher Codes from "Ford EEC-IV" or "OBD-I" systems.

(1995 models "Originally manufactured for sale in the state of California" and all 1996 models require an "OBD-II" Code reader and there are NO shortcuts to retrieving these fault codes, the reader is a requirement unlike the older system).

 

Excellent GS. I saved this as a favorite to link to in replies when you are not available.

 

Maybe you should talk to the forum mod about making this a sticky? Might relieve the re-post/bumping that will be needed.

 

I was reading a thread where you (greystreak92) were discussing with an owner of a bronco that was shifting hard, getting terrible gas mileage and stalling out at idle.


I have a similar issue but I dont have any cats what so ever. I have manifolds to glass packs to tips. (nothing inbetween except for a small connector tube where the o2 sensor attaches) It doesn't stall out but it does get terrible gas mileage, has a rough idle (cleaned throttle body and tried raising the idle with the bolt on the TB slightly) shifts really hard when I get on it. I figure this is just from driving it hard it learns to shift faster and harder etc. My brother graduated from nascar tech as a ford technician down in north carolina but I dont like to bother him 24/7 and like to get different view points.


Now i think maybe the gas mileage is fixable but I always thought it was because of my 33" tires and 3" lift. I have a 1992 F-150 with a 5.0L V8. (sorry I forgot to mention that)


I just got inside from running codes on my truck using the lovely flash test. I recieved codes 225 (knock sensor) and 6327/6237, which doesnt show up in the code list I looked up. So I looked for all possible combinations and saw 237=IGC and 327=Electronic pressure transducer (EPT)/differential pressure feedback exhaust (DPFE) sensor/electronic vacuum regulator (EVR).


This was way more than I wanted to type but i figured I'd give you as much info as I can the first time around.


My question for you is where do I go from here. Do I lightly hit the block with a hammer (which I've seen in other threads) to test the knock sensor? If so, what do I do about the other codes. I'm clueless right now so anything would help. Or if I'm being a worry wart just tell me and I'll ignore the codes like I have been for the past however many miles.

 

This is my first posting here in years. Our son got my '94 a couple of years ago. He reported it recently passed DFW emissions with flying colors.


My suggestion, if you do not have a EEC-IV Code reader there is a good one for thirty something dollars. I was never good at the paper clip method counting flashes. Pull codes for three areas including continuous memory and correct those issues before the next topic.


I honestly don't remember if '92 has electronic odometer. If it does verify the speedometer and odometer reading are accurate as that affects shift points. If off, recalibrate.


Don't mess with the throttle body screw.

 

Since your code readout has invalid values, there is no 6327 or 6237, and no mention of during which tests they were displayed I highly suggest re-doing it. A code reader is a cheap investment.

If you did not re-calibrate the PSOM for those taller tires all your MPG calculations are also wrong.

 

Well I know my gas mileage is bad whether it's calculated wrong or not because it's about 1/4 of a tank for 25 miles @60 mph. I'll look into a code reader.