My car had been sitting for a couple of weeks, and a minute or two after I started it up the check engine light came on.

Obviously, I'm going to have to pull the codes and try to find out what's going on, but I figured I'd throw this out there to see if anyone can help guide me in the right direction.

The car seems to run fine until the check engine light comes on, and then it won't allow you to accelerate at all. Is this limp mode or something?

You can't get into boost at all, and if you try to accelerate too much it just stumbles all over itself and gargles at the tailpipe. The engine will rev just fine when parked, but not at all when it has a load.

The strange thing is, that it takes a few moments for the check engine light to come on. If you start the car up and take off immediately, the problem won't start as long as you can stay on it. It only starts when you come back down to cruising RPM or let it idle for a few moments.

If anyone has any advice on which way to point me, I'd appreciate it.

I should mention that my seven is all stock with 67K on it.

 

i had some issue one time with it stumbling and didnt want to accelerate, and i got a check engine light like a year ago it happened, seemed to be one of my secondary injectors failed. but it drives normal aslong as you didnt go over a certain rpm

 

check your hose to the map sensor, it my have blown off at some point, always check the most simplest explanation

 

Best thing to do right now is just pull the code. Otherwise you'll just go crazy. Problems like these on our cars could be ANYTHING.

 

Well, I pulled the codes yesterday morning, and I got a 27 and 50, which is double throttle and metering oil pump.

Then I got to thinking that the engine should probably be warm before I check the codes, so I took it out for a quick drive, and surprisingly, my car ran fine. I ran several errands, came back, cleared the codes and checked again, and all I got was the 50 code (double throttle).

So, I have to assume that the main problem had to to with the metering oil pump. (code 27) I think I've read somewhere that the MOP code will put the car into "limp mode", so that would make sense.

Unfortunately, after tinkering around for an hour or two, I started my car back up, and the check engine light and both codes were back.





So, I guess, I'm going to have to start checking my wiring to the MOP. It looks like it's going to be easiest to get to from underneath. Am I right?

 

Yes, 27, or the other codes (IIRC 3 total) related to the MOP/OMP will put you in limp. As for fixing it, I did it from underneath...
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/changing-oil-metering-pump-omp-while-car-my-how-675341/
Mine was a transient initially too. But it came back and stayed.

 

Is it normal that when I can start the car and take off immediately, I don't get any check engine light or limp mode?

It only falls back into check engine / limp mode after I've slowed down to idle/cruse speed.

As long as the engine is under load, everything runs fine.

 

Normal? I don't know. You might be (hopefully) suffering from some weird continuity issue that's easy to fix. But as I said earlier, mine was intermittent at first too. I'd re-set and for brief periods, maybe as long as a day or two, everything would be good. But eventually it came on and stayed...even after clearing the codes it would return almost as soon as the car started. Though it didn't seem to have anything to do with slowing down or idling. Mine first appeared after a hard WOT run onto the freeway.

 

So, I guess my next question is,

If the MOP is bad, and I don't want to shell you the dough and time to fix it at the moment, then how do I bypass the electronics?

I've been pre-mixing anyways, so couldn't I do a hot-wire job and get my car back on the road for the time being?




I know I've seen guys on here talk about using a resistor to fool the computer and not get sent to limp mode. Can someone tell the specifics of how to do this?

 

Don't know how you would "fool" the ECU. Probably a much better alternative is to move to a PFC. If you can't do that right now, a decent used OMP isn't much. While not a walk in the park, it can be changed without much overall cost.

 

Anybody got a used OMP?

 

Me I got afew.

 

I'll send you a PM