92 stock- need help please

[clearwtrbeach]

Ok, I'm trying to limp this 92 through until taxes. I have a new innova 3140b diagnostic machine. ( I used one from the auto store 2 yrs ago on my 94 w/ no problems). No check engine light, no codes, KEO ran and no codes. Trying to do the engine running test (like i said no problems before) now it won't get pass the beginning recognizing cylinders to go through the rest of the test. Tried several times and on my other vehicles - those worked fine-95 and newer.
Here's the problem: Hard starts, new battery, not cold out and isn't the major problem. Oil, air filter change a wk ago. Last several weeks, first it seemed intermittent then more noticeable, particularly under a load. At one point felt like the OD was going back and forth-but I think it's more like it's not getting fuel and cutting out/chugging kind of. sorry not great but it's the best way i can explain it. Fuel pump was replaced 4 yrs ago.
Like I said I can't get the diag. to get pass the first part to continue engine running to check things like o2 etc.
I can't trust driving it at this point.

 

[MrShorty]

1st thing I would probably try is to try running the test with a jumper wire. If the test runs with a jumper wire, then the problem is likely in your code reader. If the KOER test still won't run, then there is possibly something wrong in the PCM.

 

[clearwtrbeach]

We did try the jumper wire, as well as trying it on the other pick up -95' and my honda and it worked. Pcm is kind of what I was afraid of, although at least I know how to change it since i did my 94 a few yrs ago.
How would I test the PCM with out replacing it??
I can't say as I trust the advice of the parts store. I have to say the mgr and the auto parts store- previous ford dealership mechanic freaked out when I used the store one (trying to see if it was my code reader) telling me I can't have my car running while using the machine or I'd 'fry' it ! Really?? did you not know it's a engine running, and the machine clearly tells you that.

 

[awood]

If you decide to replace the PCM, you might consider trying a used one. I'm not endorsing the one in the link below - I just googled an image and that's what I came up with - But you need to match the part number (the long number starting with "F") and the calibration code (the 4 digit alpha/numeric number in the largest size font - T2Z1).

This is just an example that is likely different from yours, but if you match both of these to YOUR PCM, you should be good to go.

http://www.ebay.com/itm/92-MAZDA-NA...MPUTER-ECM-ECU-PCM-F27F12A650YB-/370702780138