ultradef

I'm having a problem with my 91 TII vert throwing a CEL (Malfunction Indicator/Engine Electrical System) and going into limp mode when I go above 1/8 throttle or so. I have gotten this same CEL twice before since doing the TII swap, but only one of these times it went into limp mode.

The first time I was sitting in traffic and the CEL went on, but it shut off after a few minutes.

The second time I was cruising on the highway at ~ 3000 rpm (80 mph) when the engine suddenly bogged, went into limp mode, and threw the CEL. That was a day or so after I installed my custom 3" T.I.D., so I just unplugged the AFM and plugged it back in and the problem was solved.

This time, I was again cruising on the highway at about 3000 rpm (80 mph) and again it bogged, went into limp mode, and threw a CEL. It was 11 pm, dark, and raining of course, so I pulled over, turned the car off, unplugged the AFM and plugged it back in again. I also noticed that the car would idle with the AFM unplugged, which I thought was impossible? I assume it was because the ECU was not receiving a signal from the AFM, so the ECU's limp mode is just a base fuel/timing map that compensates for the lack of an AFM signal? Anyway, this time as I pulled back onto the highway it immediately went back into limp mode. I tried driving it one more time after attempting to clean the connection to the AFM and it still went into limp mode if I went about 1/8 throttle or so.

Now, I know some people say that limp mode can only be triggered by the OMP, which obviously isn't true since unplugging the AFM and plugging it back in worked last time (unless that was just some coincidence and the real problem fixed itself?) So can limp mode be triggered by a bad AFM? If not, any other ideas what it can be? I have a FSM, but I'm kind of stuck at college with no tools and no garage. I either have to fix the problem here with no tools or have the car towed an hour to my rotary mechanic, so I'm at the mercy of the RX7 Forum. I'm going to try and check the codes tomorrow in between classes, but if you guys have any ideas/suggestions in the meantime I would greatly appreciate it. Sorry for writing a book, and thanks in advance.

Scott 89t2

check the codes and see what it is....
http://www.1300cc.com/howto/how2/codes.html


and just because the car runs like crap doesn't mean it's in limp mode. the OMP is the only thing that will cause the ECU to go into limp mode. this is bad running on purpose.

lot of other problems (vac leak, broken stuff etc) will also cause the car to run like crap. but these are problems themselfs that cause the bad running. and is not on purpose....

ultradef

Not to question your expertise (hell, the online FSM that I'm using was put up by you ), but in the FSM it specifically states that a bad AFM (as well as a bad OMP) will cause "basic fuel injection amount and ignition timing to be fixed". I guess my question is: Are those the conditions of the limp mode? This sounds to me like what I'm experiencing, as it definitely feels like an electronic cut off of some sort, especially because this condition always comes with the Check Engine Light (Malfunction Indicator/Engine Electrical System), which wouldn't come on if it were just a vacuum leak or something like that. I guess it could be that something broke that triggered the CEL and caused it to run like crap (not limp mode), but I was just wondering if the symptom that the FSM described (basic fuel injection amount and timing fixed) was the ECUs limp mode.

Anyway, I'll check the codes today but as I said, I was just looking for alternatives and suggestions because I'm stuck at school with very limited resources for troubleshooting and repair. Thank you for your reply, I really appreciate any help you can give me.

ultradef

OK, I checked the codes, turns out its throwing code 10 (AFM air intake thermosensor), 17 (EFI Feedback system/02 Sensor), and 27 (OMP).

Obviously, the OMP is whats throwing it into limp mode so I guess I'm gonna have to premix and drive it home in limp mode so I can either fix it or bring it to my mechanic. Is this safe, or should I just get it towed home?