Hello Everyone,
I have a new problem today and have two questions for you while your at halftime. First one: what is the best code reader for a '94 F/S Bronco, 5.8l, auto trans with o/d, and where do I get it. Second question: today I went to the home repair store, recently had a lot of work done on the truck as far as sensors replaced, truck has run great, but today the c/e light came on all of a sudden and the transmission started acting like it could not decide what gear to be in and rpm's seem to want to be at 1500 and surge from 1300 to 1500. The rpm's are normally at 900 witha very smooth idle. I looked briefly for a broken wire, loose connection etc., but did not see anything obvious. What has been replaced in the last 3 weeks: TPS, IAC, MAP sensors. Last three months, Ox sensor, plugs, wires, dist cap & rotor. Also in the last three weeks the base timing was set as well as the idle adjusment. The map sensor, timing and tps were done at the dealer to the tune of $500 bucks. I need to save as much cash as I can so I don't want to shoot in the dark that is why I'm asking about the code reader. I know it will tell me where to start, but I like to take advice from someone who has BTDT! Thanks, Mark

 

The best code reader would be a paperclip... well the least expensive anyway. Any short length of wire will do too. If you want to buy one, don't spend a ton of money on it. All a reader does is give you a number to read rather than making you sit and count the number of times a light flashes or a meter needle sweeps. Every reader I've ever used, I have gone back and verified the codes using the count method anyway. (No, I don't trust them).

As for the erratic idle and shifting, the first check AFTER pulling codes would be the VSS (Vehicle Speed Sensor) mounted in the top of the rear differential housing. It is held in with a single bolt. Inspect the wiring and connection to the harness then remove and wipe it off with a lint-free cloth. Replace it, clear codes, and go for a drive. If the problem still exists, pull codes again and unless codes lead you in another direction, replace the VSS.

 

All right an update,
Pulled the sensor and cleaned it. Same results. Purchased another sensor and installed same results. Now for my ignorance. All of my local auto shops did not have a reader. It would have to be ordered and be Tuesday before it arrived. The rut is on and I want my truck fixed so I can participate. I don't know where to put the paperclip that greystreak92 suggested. That is why I replaced the part before pulling codes. Today also, I disconnected the harness for the MAP sensor and could not get the truck to hardly run until it reprogrammed itself. I thought I had really screwed up again. So I am still at square one with hard upshifting and 1250 to 1500rpm idle and surging. Where do I put the paper clip to count flashes? Then where do I find what the number of flashes mean? Thank you for your patience, Mark

 

The Equus 3145 is the one that most guys use around here, costs around 30$ do a search on Amazon/Ebay or some local stores.

For the paperclip method Grey mentioned, search in this site: http://fordfuelinjection.com/

 

A Haynes service manual also explains how to pull codes using a paperclip )or a short piece of wire) and a multi-meter.

 

OBD-11 codes might help diagnose the issue with your truck but it can be done without the codes. The OBD-II system is meant to indicate when the engine is performing in a manner that would increase the expected emissions of pollutants. Secondarily the codes can indicate a malfunction in a sensor or other problem.

Troubleshoot the engine, does the issue occur when the transmission is not in O/D? in D? 1?

 

Thank you Encho, I found that site while searching the forums last night after I posted, but it was too dark to do anything.
Greystreak92, I have a Haynes manual and was actually looking at it to see about replacing the fuel pump as I thought maybe it was a fuel delivery problem when I had removed the wiring harness from the MAP sensor to verify a good connection, and could barely get the truck to run until it reprogrammed. Once it reprogrammed, fuel did not seem to be the issue. When I cleaned the speed sensor, I did not disconnect the battery, had the same symptoms, when I replaced the sensor, I did disconnect the neg. terminal. Started engine drove about 5 miles, same symtoms. I will try to read codes today. I had opted to take it back to the dealer, but would like to solve this myself for all the obvious reasons.
g_k50 to answer your suggestions, the symptoms started suddenly, one day everything was running excellent, the next just driving and suddenly the c/e light comes on and shifting is hard, like it is slamming into the next gear. The idle is high, normally it is 750 rpm's in park now at about 1250 surging to 1500. I was not working on anything as the truck has been running great. I shifted the t/m from drive to 2, rpm's go up, go back to drive and it shifts but hard. I always keep it in o/d so I can try to take it out of o/d today. The t/m was rebuilt about two years ago and has been fine, but the shop decided to put in another spring or valve or something to make the t/m last longer and it has always shifted hard from 2 to 3rd gear since doing this. I don't use the Bronco to hunt trouble, just to get out of trouble. Most use is on the road. I do travel quite a few dirt roads, which can be dusty right now since we have not had any rain. One common cause in this problem is that I had taken the truck to the car wash the day before to rinse the dust off. I used the wand and spent $2.00, so I did not try to do a thorough wash just knock the dust off. I then drove home about 4 miles and parked the truck and it ran fine. The next day was when the troubles started. This is also the reason I went with greystreak92's advice to change the speed sensor. I felt that maybe I had wet something that caused a failure. I know this long but the more info you have the better. I'll let you know, Thanks Mark

 

have you checked for any vacum leaks? is your ABS light on also by chance?

is your trans fluid full, when was it replaced last?

 

Hi All,
Another update! First to answer kemicalburns, yes I have checked for vacuum leaks, no the ABS light is not on, and I checked t/m fluid first when the shifting got hard. I believe the hard shifting is due to the high rpm's. Anyway, went out this morning to do the tests and collect codes as we had been instructed to do. Started truck, and it cranked right up, idled at 900rpm's for 30 to 45 seconds and slowed back to 600 - 700 rpm's like it has done since the day I bought it. Decided to go for a ride and warm it up good before getting codes. T/m shift was smooth, idle was good shifted to 2, shifted to drive, all smooth. Ran the crap out of it, slowed it down to a crawl. Came to a stop sign, put it neutral rpm's fine. Now I am stumped and mad, these gremlins don't just go away and if they do they will resurface at the most in-opertune times. This is where it gets fun. Okay truck is running good, let's go get the tires rotated! Well that just screwed up the world! Not really, the original problem came back after shutting off the truck at the tire store, and cranking it to move into the bay. Well these folks are friends of mine since I have purchased quite a few tires over the years, so after rotating, they put their super duper scanner on my truck to read codes. Came up with 126 and 998. Okay. They said according to Haynes that the MAP sensor voltage was higher than expected and that hard fault present-FMEM mode activated.
I decided that fmem meant to f#$k me every monday! It actually means failure mode effects management, an alternative computer mode that maintains vehicle driveability in the event of an EEC-IV component malfunction. Yes this is quoted from the Haynes manual which I now posses with my greasy little hands! These guys suggested that the engine control module may be or is about to fail. My local auto parts shop had one! I replaced it! started the truck with the exact same symptoms. Son of a oooo bummer. Decided at that moment to go see Mr. "I am gonna take your money". On the way to the dealer, the c/e light clears, shifting returns to normal, truck is running great! Now I think okay did the computer have to recalibrate itself after replacing the engine control module or what? In any case it is at the dealer to look into the problem further especially since I may have a bad MAP sensor which would be covered under warranty since it has only been three weeks since replacement. I'll keep you posted on the results, Mark

 

Perhaps you have a bad ground some place. i really hate problems like this.

 

His 94 is not OBD-II. It is still EEC-IV. Either way, the E4OD transmission is controlled by the ECM and as such all of the 600-series codes generated by the ECM are indications of problems within the E4OD and there are a host of other codes that when they rear their ugly heads, will affect transmission performance. The E4OD is fully electronic in its shift functions and as such is integral in its functions with every other parameter of the EEC-IV AND OBD-II systems.

With the issues you are having, the signal return wiring back to the computer should be checked from any sensor that any of the codes returned are related to. Signal return is critical with the EEC-IV and OBD-II since this is what the computer "reads" or interprets to maintain engine/transmission control. If there is erratic signal coming back from a particular sensor and the sensor is not the problem, the wiring is the next check. The system sends the same voltage to all sensors... the voltage or changes to it that come BACK from any given sensor tell the computer what is going on.

 

Hello Everyone,
Sorry for not having updates. We have had a medical emergency in the family, and I don't have anything to report for two reasons. Reason one has already been stated. Reason two is because the dealer "did not get to my truck" before the emergency. So I don't know what is going on. This is why I would rather have an enema than going to Mr. "I'm gonna take your money". If these people put as much effort into fixing things as they do advertising, I don't see how they could not be the top dogs! Please understand that I am being as politcally correct as I can be. Because I am mad. This is why this forum is so important. If you have a problem, post it. If you have a solution, post it! If you have knowledge share it by posting! Above all keep your posts up to date! And special thanks to those that post and communicate regularly, you are saints without getting credit, and I will try to fix that. Okay I'm through venting. I will let ya'll know what "we" find as soon as I have time to get back to the dealer. Right now I am doing five hour one way overnighters till our issue is resolved. Thank you for your patience. Mark

 

I hope the medical issue gets solved soon and all your family members become healthy again (Bronco included), keep us posted.