1988 Ford Ranger 2.9 - o2 sensor issue ?

[jmiedzinski]

Hi Guys,

So, I bought another Ranger, this time it's 1988 2.9L extended cab. It was running extra rich, so I replaced ECT sensor which solved the issue. Then, I replaced few other parts: spark plugs, MAP sensor, TPS, Intake air temp sensor, IAC valve to sort out rough idle. This also helped a lot. Now I have another issue. After short drive truck starts to misfire heavily like it's loosing spark on several cylinders. It stumbles and sputters and then it goes away and it's running fine again. This may take few seconds to few minutes. This is also intermittent. My truck has the exhaust butchered, no Y pipe and straight pipes to sides. Since Y pipe is the place where o2 sensor resides (al least that's my understanding) I suppose I don't have one installed. However EEC doesn't give me any codes about missing/faulty o2 sensor. Do you think this heavy misfire issue may be related to missing o2 sensor ? How come the EEC doesn't give me any codes about missing o2 ?

Rgds,
Jerry.

 

[rusty ol ranger]

Hi Guys,

So, I bought another Ranger, this time it's 1988 2.9L extended cab. It was running extra rich, so I replaced ECT sensor which solved the issue. Then, I replaced few other parts: spark plugs, MAP sensor, TPS, Intake air temp sensor, IAC valve to sort out rough idle. This also helped a lot. Now I have another issue. After short drive truck starts to misfire heavily like it's loosing spark on several cylinders. It stumbles and sputters and then it goes away and it's running fine again. This may take few seconds to few minutes. This is also intermittent. My truck has the exhaust butchered, no Y pipe and straight pipes to sides. Since Y pipe is the place where o2 sensor resides (al least that's my understanding) I suppose I don't have one installed. However EEC doesn't give me any codes about missing/faulty o2 sensor. Do you think this heavy misfire issue may be related to missing o2 sensor ? How come the EEC doesn't give me any codes about missing o2 ?

Rgds,
Jerry.

I doubt the O2 is causing that.

Crawl under it someone might have put an O2 in the different pipes.

Your problem sounds more ignition related

 

[jmiedzinski]

Your problem sounds more ignition related

Do you think I should replace ICM or try something else first ?

 

[rusty ol ranger]

Do you think I should replace ICM or try something else first ?

You said its not throwing O2 codes....what codes, if any, is it throwing?


The ignition module might be a good place to start depending on what codes its throwing.

 

[jmiedzinski]

Initially it was complaining about ECT, EGR and fuel pump, now only fuel pump code persisted after I replaced all the mentioned sensors. Fuel pump code makes sense because somebody rewired the pump and now its running all the time. I think the fuel pump relay is missing and its hardwired to something that is hot when the key is on. No more codes reported.

 

[rusty ol ranger]

Initially it was complaining about ECT, EGR and fuel pump, now only fuel pump code persisted after I replaced all the mentioned sensors. Fuel pump code makes sense because somebody rewired the pump and now its running all the time. I think the fuel pump relay is missing and its hardwired to something that is hot when the key is on. No more codes reported.

Check your fuel pressure.

There possibly could be a short in the wiring job thats letting the pump drop power for a second.

Id try the ignition module first (buy a motorcraft) but if that fails to fix it (which, seeing as how you have no ignition codes its a long shot) youre probably going to have to start tracing fuel pump wiring

 

[jmiedzinski]

Thanks, I will do that, but I think I should test it while driving. This also makes sense if there is some poor connection that is shorting the pump it will likely happen when truck is moving.

Id try the ignition module first (buy a motorcraft)

I wish I could, but since I'm in Poland I'm only limited to rockauto as a parts source (they ship internationally with decent delivery time) and currently they don't have motorcraft ICM in stock.
Anyway, many thanks for all the advice!

Best regards,
Jerry.

 

[rusty ol ranger]

Thanks, I will do that, but I think I should test it while driving. This also makes sense if there is some poor connection that is shorting the pump it will likely happen when truck is moving.

I wish I could, but since I'm in Poland I'm only limited to rockauto as a parts source (they ship internationally with decent delivery time) and currently they don't have motorcraft ICM in stock.
Anyway, many thanks for all the advice!

Best regards,
Jerry.

Oh i didnt realize you were overseas.

Good luck!