Engine problem driving me crazy, nothing I try seems to be working, please advise!!!

[dragnazz5.0]

talk about stuff being hard to diagnos over the internet....and than throw something like no o2 sensors from the factory into the equation. whats the point in having a fuel injected or a computer controlled car in the first place if youre not going to have o2 sensors? i think the best bet would be to put a mid pipe on that had provisions for o2 sensors and than see what happens. the a9p is definetly an american mustang computer and needs the feedback from the o2 sensors. maybe im wrong, but it seems really wierd that any company would use a computer without o2 sensors in a certain location and than use the same computer with o2 sensors in a different location.

i dont think the leaded fuel is even a problem, if it is leaded fuel at all. ive never owned a car that requires leaded fuel since im only 22 but cars that were once required to run leaded fuel can run unleaded with no ill effects so why would it be any different going the other way.

 

[86bluecobra]

i dont think the leaded fuel is even a problem, if it is leaded fuel at all. ive never owned a car that requires leaded fuel since im only 22 but cars that were once required to run leaded fuel can run unleaded with no ill effects so why would it be any different going the other way.

This is not altogether a true statement. The valve seats are different leaded to non leaded engines.

 

[dragnazz5.0]

yeah, i know the valve seats are different. thats the only thing different from a leaded to a unleaded engine. if im correct the leaded engines have softer valve seats? maybe they are harder valve seats? not really sure since ive never dealt with them. but anyways, i dont think the leaded gas would cause a driveability issue at all unless the octane rating was close to that of the gas they used back in the 30's.

im thinking the main problem has to do with the o2 sensors.

 

[86bluecobra]

I would think that the computer you installed now would need o2 sensors. The old computer was obviously tuned to run without them. As for your fuel pump not working i wonder if your spare computer needs to be wired different. i.e. the pin conectors for the one computer now need to be swapped some for the spare.

 

[dragnazz5.0]

http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

maybe that will help out a little in the diagnosis if its a pin problem or a wiring problem.

 

[hydra]

First off, I appreciate your patience with me trying to learn about your setup. I know it can be frustrating to have someone questioning you especially the way I have been. Hope it doesn't come out rude.
From what I found with Google...
Many cars are setup this way, no cats and no O2s. The reason seemed to be leaded fuel that is still used overseas, which would render these 2 things useless in short order. Is leaded fuel availalble in your area? Where did the Explorer motor come from? Are the valves in the Explorer motor appropriate for leaded fuel?

The reason I am so fixated on the O2s is that they are the only feedback to the computer on what the a/f ratio is. With out O2s the computer has no idea what is actually happening in the motor. The computer will just follow the pre-programmed tables, and think all is well. Even if the ECT/ACT are providing crazy signals.

If Ford knew there was not going to be any input from the O2 sensors on these cars, they may have changed some of the program. It is concievable that your open loop settings are a comprimise between OL and CL from a US puter. This is just speculation on my part though, but I am curious about the tune.

On a side note, having or not having cats does not influence whether or not you need O2s. The primary function of the O2 is to provide feedback to the computer on a/f ratio. If 2 sets of O2s are used (similar to OBD2 cars) you can use the O2s to check the effectiveness of the cats. Single O2s (like the A9* puters) are mounted before the cat and are not used for the cats in any way.
Probably trivial at this point.

Let me know what you think about the leaded fuel question I posed.

This is a pretty interesting thread

jason

Jason,
Leaded fuel was available in the middle east up to around 4 years ago. It is no longer available now. The explorer motor originated from Canada, and has always run on unleaded. Once again I don't think that it would have returned 17/22mpg (and we have LOTS of elevation changes here) if everything wasn't 100%

 

[hydra]

talk about stuff being hard to diagnos over the internet....and than throw something like no o2 sensors from the factory into the equation. whats the point in having a fuel injected or a computer controlled car in the first place if youre not going to have o2 sensors? i think the best bet would be to put a mid pipe on that had provisions for o2 sensors and than see what happens. the a9p is definetly an american mustang computer and needs the feedback from the o2 sensors. maybe im wrong, but it seems really wierd that any company would use a computer without o2 sensors in a certain location and than use the same computer with o2 sensors in a different location.

i dont think the leaded fuel is even a problem, if it is leaded fuel at all. ive never owned a car that requires leaded fuel since im only 22 but cars that were once required to run leaded fuel can run unleaded with no ill effects so why would it be any different going the other way.

Both the old computer and the new one are A9Ps. Both of them are off a local, running car. Both cars lack provisions for O2 sensors and appear never to have been fitted with cats. Finally, both cars have their speedos in km/h and their temp gauges in degrees C.

 

[hydra]

I would think that the computer you installed now would need o2 sensors. The old computer was obviously tuned to run without them. As for your fuel pump not working i wonder if your spare computer needs to be wired different. i.e. the pin conectors for the one computer now need to be swapped some for the spare.

Read what I wrote above. What bothers me about the fuel pump not working is that it didn't work either when I swapped back the original ECU...