Runs on 4,5,6 cylinders

[88 Red Ranger]

P R O B L E M........S O L V E D.....---.....C L O S E........T H R E A D



I'm sorry for the length of this but I hope the info helps. Thanks for help.

I have an 88 ranger 2.9l, 5 speed, manual tcase, 235/70r15 with stock gears. I notice that it is missing some because I can feel when it fires on all 6. Even driving down hill in 5th gear, tach @ 2400 I LOOSE SPEED. I can not maintain 65mph down hill, let only uphill I slow down to 3rd gear 3500rpm and 46mph.

I know it is not gas quality. I am blowing black smoke bad. Running to rich. Sometimes it will only run on 4 cylinders. I changed the cap/rotor, wires, coil all with no change. Uphill/downhill or flat ground it might run on 6 cylinders, 5 or 4. The GPS shows I am averging 41 on the express way. How do I know if the FPR or TPS are working correctly?

The vacuum line from the FPR to vacuum port is dry. It does smell like gas. Some one local suggested either the ACT or MAP. I know the MAP should test out to 156MHZ but I do not have a tester to check MHZ. What are some of the symtems of a bad MAP or bad ACT?

I hooked a fuel pressure gauge to the schrader valve on the fuel rail. Turn the key on, not start, holds 30-32psi. I know the haynes says 40. It will run fine at that pressure on 6 or 5 cylinders but when it really starts to cough and bog down the pressure RISES to 40-42. When it settles out and runs correctly it is back down to 30-32psi. I have now changed the ACT sensor and the MAP. Both of these helped alot but it still does not run properly. It will run longer on 6 cylinders now, but every 2-5 minutes it will still drop one or two cylinders then go back to 6. It does not run good enough that I would feel comfortable driving back to MI from SC.
So far I have replaced the ACT,MAP, cap, rotor, wires, plugs, cleaned the iac and TB.
I think either a bad signal to the injectors or clogged injector. I have looked at the wiring diagram in the tech section and see that 361/r goes to all the injectors and 3 have LG/W and 3 have T/R. ???? Which wires would be getting the bad signal -- the common red to all OR the others??? Did I see on this site a place to rebuild the injector?? If so, I do not remember under which forum.

 

[cavedweller]

Well a Tfi is only about $40 bucks a NAPA,I forgot how much the wrench is ....The reason I'm saying the ignition module is that when they start to go bad ,they and warm/hot weather do not get along and your engine can act like yours is ....I mean unless you have replaced it already

 

[88 Red Ranger]

I found the thread about rebuilding the injectors for RJM for $20,

 

[jhammel85]

Definitely too much fuel getting dumped in or maybe a few cyls are firing, judging by the black smoke.

The FPR sounds fine since those readings are normal. I think you are on the right track in checking out those injectors in one way or another.

Have you run codes yet? Definitely do so to hopefully find a code telling you about whats happening. Don't go throwing any more parts at it until you do.

 

[88 Red Ranger]

ACTRON scanner for OBD1.
KOEO 11
Continous Memory 18 & 41

The scan book and Haynes manual do not agree on what these codes mean.
Scan book 18 -- bad tach siganl to ECA
Scan book 41 -- bad EGO Haynes 41 bad HEGO.
I can not find either EGO or HEGO. Where is it. The only fitting I find in the exhaust system is the O2. RIght now I am using public internet and I do not remember what the haynes says 18 is.

 

[Twizzler09]

HEGO/EGO is the O2 sensor. HEGO = Heated Exhaust Gas Oxygen or something like that. Here is a link that defines the different acronyms, they all mean the same thing. Well, close enough for your purposes. http://fordfuelinjection.com/?p=31

I googled code 18 and got.....

18 ignition diagnostic monitor (IDM) circuit failure

So I would imagine that the computer isn't getting a proper ignition signal. Might want to look up the IDM and see what its for.

 

[88 Red Ranger]

When we bought the truck the O2 was not hooked up and has not been for the 2-1/2 years we have owned it. It did not start acting up until June 14 this year.

 

[Twizzler09]

Well the computer uses the O2 sensors to help it determine the proper air/fuel mixture it needs to be running. Without it, your probably confusing the hell out of it. It can compensate on its own to a certain degree by using a factory-set default mixture, but over time the engine deviates from that "fail-safe" setting a little bit. It will run on it but not at its peak efficiency.

If its been running for 2 1/2 years without acting up though, I'd be willing to bet your problem lies with the IDM circuit. Try to find a reference for an IDM circuit online. Google it or something.