4x91

thanks

24willyboy

It's not entirely necessary considering you could just use the jumper wire and watch the gauges jump, but this is much easier to use and helps you avoid misreading a code. This is what the package looks like and what's included. The book has pretty much everything you need to know to perform the KOEO and KOER tests, and has a full list of all the error codes.

ymeski56

Could not have said it better!

Additionally, you can go online & search for "MCU &/or OBD1 Code definitions". You will be hard pressed to find 2 search results that completely agree in all definitions. The definitions provided in the unit's manual, in my opinion are the most accurate you will find.

Side note: My daily driver is as 87' 302.

Chap150

As 24willyboy has mentioned, for the price of an OBD-I reader, you just can't go wrong. I lost mine when I sold my 86 Bronco a few years ago. I just ordered another from Amazon for $23.00 and change. Plus I ordered the 6' cable extension ($24.00 @ Amazon) so I can sit in the cab while doing scans.

DI1974

I have a quick question -- I have a 1994 Ford F150 and many times I have heard that because this was the beginning of codes for this truck and it is older that many times the codes are unreliable. Is this true? The first time I had issues I stopped at a auto parts store and they didn't have reader for my vehicle (in fact after calling a few stores - none did). What is the best way to diagnose this year and make of vehicle?

Chap150

DI,

I spent 25 years working Ford parts all through the phase in period of OBD systems. I never once heard a technician say that the OBD "codes" are unreliable. But even as OBD-I came of age, the biggest problem was diagnosis. Understanding that OBD was new technology, training was sketchy and application was even more sketchy.

So when looking at codes on OBD-I in today's world, you still need a working foundation of how automobile systems work and root causes of problems.

OBD-I, as with OBD-II, can indicate a false positive on a sensor because something upstream of the sensor had a voltage hiccup causing the sensor to hiccup and record a code. The OBD catches the exception because the sensor's voltage went out of range. So the OBD code is absolutely accurate and reliable that the sensor went out of range and it's telling you it did.

Diagnosis of the actual cause of the code is usually the failure, not the code itself.

OBD-I readers are fairly inexpensive and available on Amazon. I recommend copping one along with the cable extension.

Chap.

DI1974

Thank you for the clarification. I was wondering because I had the insidious fuel issue that was the result of the recall up to the '93 trucks but persisted through '94. When I took the truck to Ford, I documented all the issues from the recall, the first time the gas siphoned to the back tank so badly that it gushed out of the back cap and could not be stopped, to using the front tank only and continuously checking the back then using that gas when it was at 3/4 of a tank, and to when the pump finally died and needed to be replaced. The mechanics said they received a variety of codes and had to call Ford headquarters and guess what??? It was exactly the problem I described. This last time - they pulled codes and I guess they were all over the place (I know the O2 sensor occasionally causes issues but usually resolves almost as if its a false issue). It took the mechanics 3 weeks to diagnose! If you look at my original thread - I describe the issue pretty thoroughly (and did receive some very good advice). And I wonder if they had done more vacuum/air pressure tests if they would have been able to diagnose it better than relying on the codes? Or is it as you described....can they simply not decipher them?

https://www.f150forum.com/f10/please...2/#post5561957

I'm interested to know because although I can change my oil, radiator fluid, and some other minor issues - I do not have the experience or anyone to teach me more detailed work. I do plan on taking a basic auto maintenance class this spring but honestly - these forums have always been some of the best advice I've ever received.

Chap150

DI,

Re: your other post. Has that been resolved?

Chap

DI1974

Sadly, no. I posted a notice to my old post but also created a new thread.... https://www.f150forum.com/f10/part-2...g-once-401165/

It may be easier for you to read than for me to explain again. Also, I have a google photo link to a video I took where you can hear one of the issues, I narrate the engine light and if you look carefully, I tell you when the engine won't accelerate properly and then all of a sudden it takes off (jumps a little - not noticeable on screen) and then all of a sudden is at the correct speed.

There is also a text response from our service advisor where he states he has sent the video to several mechanics that can't diagnose the issue. (It's the same issue but worse!)

I am looking for a bit of guidance. It was mentioned that this could be a mass air flow issue and I've read that you can diagnose this with a multimeter. Also, it can be cleaned for better performance. I still need to get under the truck and clean the a/c drain (I work at a barn and there is no doubt that it has some dirt and stuff in it). Finally, again, could this could be an air pressure issue? During the summer I almost bought the compression test kit but was talked out of it and again when this issue started in Oct. Something in my gut is telling my that the mechanics are missing something right under their noses whether its a big or small problem.

CrystalLee

Please help. I got a couple different read codes P025A and U0109. It sucks I cant figure out what is wrong with it. couple times a week I will be driving and the truck and the truck loses power as Im driving. I am able to restart it after a few minutes as if nothing happened. Its not a battery issue, as I thought it was. The code says lost communication with fuel pump ctrl mod. also could be module circuit open.