so my car went into limp mode the otherday. It was backfiring severly hard. I had my hood popped and my friend was looking at my engine. As soon as i went past like 1/32 gas the engine bogged, (this was at idle) and as soon as i let off it back fired very hard. from what my friend saw, he told me that the engine jerked like 2-3 inches. is this normal? it seems a little violent for a safetly measure made by mazda? thanks -alex

 

why dont you go pull you codes if you are getting any. if you are in limp mode then you SHOULD not always throw a code for the OMP. the OMP should be the only thing that will put you in limp mode.

oh yeh, post year of car when asking for help.

 

i already pulled codes and i did indeed get code 27 (omp), i was just wondering if limp mode was usualy this violent?

 

well limp mode is just fuel cut at a certin rpm, so the car will stumble and bog down. the movement of the engine the motor mounts, check to see if the mounts are any good. limp mode isnt going to cause a bad mount but it might make you notice a mount that was already on its way out.

 

Actually, my '90 GTU was in limp mode about six weeks ago and the symptoms were just as violent as you described. There was serious backfiring that just got worse as I increased the throttle, car wouldn't rev over about 2000 rpm, etc. Mine was actually caused by a short in the cable that runs from the positive battery terminal to the starter, and the car threw only code 01: "trailing coil/igniter." I also noticed that the inside of the main 100A fuse was sort of brownish in color instead of the usual bright gold, so I replaced it. After fixing everything, limp mode was gone, and the car is running strong as before. I don't think OMP failure is the only cause of limp mode.

 

That's common, all my 929 and rx-7 main fuses in the engine bay look like this. They almost look blown at first glance.