Engine Limp Mode with CEL, no stored codes
 

I have an intermittent problem. After a number of stops and starts during the day (engine is fully warmed up), upon starting the engine it goes into limp mode - it idles but there is no throttle response and the check engine light (CEL) comes on. After it sits for a few minutes with the engine off, I can try starting it again, and it eventually goes back to normal, but the CEL stays on. My scanner shows no stored codes. The car has 85,000 miles on it but the engine was replaced under warranty at about 45,000 miles. I've queried two dealers, and they say they've never seen this on an RX-8. Anyone else had this problem?

2004 GT 6MT.

What is you scanner, because you pretty much have to have a code!

bad throttle position sensor?

The scanner is a 1 year old "Innova". It hsould pick up air codes, unless the codes are factory-specific and hidden from my scanner. I woukd think that the scanner would pick up a TPS code.

Is in CANBUS II compatible?
If not, then it may get some, may not get others, and may dork some up as a third possibility.

I looked it up, it looks like it should work given the right model!

I'll check it and see.

yep--- tps or tbs?
OD

cobb ap ftw, or dash hawk

Bump. Anyone have an idea for this. Just replaced my omp for the exact same problem. Ran well for a week and she's doing it again :-(

you replaced your omp because of a cel with no code stored?

OMP is the most likely cause of a no CEL limp mode....the pump you used may be miss aligned a bit.....check out the OMP thread and see if you want to try it yourself
The dealer likely won't attempt it...so either you DIY or you will have to hope someone local will help you

but we don't replace parts with out testing them Dan ;)

LOL...The only test for this is ruling everything else out

Or a dealer visit and an iDS :)

I hate the idea of the CEL being illuminated and no code to track it. Is this truly a valid use case?

This is worse ;) Limp mode with NO CEL......

with the only outcome being bad OMP?

What about the lit CEL / no code condition mentioned above? Was it ever ruled a compatibility issue with the reader / software being used? There should at least be a pending code with the light on.

Dunno

If the CEL is lit it's due to a code, it doesn't light up for pending codes

Hello I have an update. Heres the story. The car would intermittently start up in limp home mode after she had been originally started once before. So in other words it never threw limp mode on a cold start nor would it limp in the middle of a drive.

I researched the web and these forums for two weeks and have also been working with dannobre to try and get to the bottom of my problem. The only thing I could find for limp mode was a bad omp, clogged lines, or clogged oil injectors, or all the above.

So I checked over my car by checking oil consumption (seemed normal) and trying to adjust the switch. As soon as my fingers touched the switch and we reset the ecu the car would limp right after startup; hot cold, ect..

So I thought hmm maybe the omp is not bad but the switch is shot thus throwing the car into limp mode. I bought a used OMP off of a member on here with about 45k miles and took it to Mazda to have them put it in.

The service manager came to me in the waiting room and said I had a CEL fro the OMP and that they would swap them out. Autozone and advanced auto scanners would pull my cat efficiency codes and others but no code for OMP was there at all. However Mazdas did pull it

I had since then got the car back from Mazda and the car was running pretty good. I have put about 190 miles on it since the dealer visit and it limped once since those miles were accumulated. I drove it around yesterday to various places (about 50 miles) and she ran good the whole time, and no issues have come back yet ( knock on wood ). Ill update or answer any questions I can in the meantime

Limped on me me all day today :-( in and out in and out. It goes away on startup and will come back on start up. This is extremely frustrating. I'm afraid to take it back to mazda because I wonder if they knew it was not the omp and knew I'd be back? I'm not sure but I can't even drive the car. This really sucks!!! I'm at a loss of what to do. This has been a money pit ongoing battle for the last 3-4 weeks

QUOTE=DMaverickRX8;4472294].

I researched the web and these forums for two weeks and have also been working with dannobre to try and get to the bottom of my problem. The only thing I could find for limp mode was a bad omp, clogged lines, or clogged oil injectors, or all the above.

The ECU could care less if it is pumping oil..it has no way to tell...I have mine hooked up to electrical sitting in the engine bay and it doesn't go into limp mode.

The limp mode is from the OMP positioning switch being out of spec....or the wiring is bad...or the ECU my bet would still be the positioning switch

So I checked over my car by checking oil consumption (seemed normal) and trying to adjust the switch. As soon as my fingers touched the switch and we reset the ecu the car would limp right after startup; hot cold, ect..

Did you follow my directions from the other thread? You should be able to do this yourself

So I thought hmm maybe the omp is not bad but the switch is shot thus throwing the car into limp mode. I bought a used OMP off of a member on here with about 45k miles and took it to Mazda to have them put it in.

I haven't attempted it yet for fear it won't come out of fail safe mode. The last time I attempted it it stayed stuck and wouldn't come out. I wonder if I have faulty wiring because I was underneath thecar yesterday and the harness appeared wet?

DMaverick, any luck? I am having the same issue. Going to they to have someone diagnose it.

At maztech in Tampa now. Hopefully they can get to the bottom of my problem :-(

I'll post updates

Update. Car is finally fixed. Maztech found one of my wiring harnesses was rubbing on the water pump pulley. Rubbed them bare. He took apart and repaired. Limp mode cured!