That's weird - rev limiter

[oldtin]

Put in a new (to me) DME, swapped in my dinan chip. Now I seem to have a 5500 rpm rev limit. Before the coil ate the old DME it would spin well beyond. Any ideas what's going on here?

Anyone have a JC/Turner chip laying around?

[zoner]

I don't remember having that issue with the Dinan chip in my '95. The chip should raise the rev limit, not lower it. IIRC, my M42 (non-DISA) with the Dinan chip had noticeably better pull throughout the entire RPM range than my M44.

[oldtin]

With the previous DME before it toasted, it would rev to at least 7k with the same dinan chip. I would have thought if I toasted the chip too it would be a work/no work thing. It sounds/feels like a rev limiter kind of thing - bouncing off the revs. It's not consistent at 5500 - ranges from about 4700-5500. Anything else it could be? Fuel starvation? Runs perfectly normal before the upper revs.

[bmwconnect]

Originally Posted by oldtin

With the previous DME before it toasted, it would rev to at least 7k with the same dinan chip. I would have thought if I toasted the chip too it would be a work/no work thing. It sounds/feels like a rev limiter kind of thing - bouncing off the revs. It's not consistent at 5500 - ranges from about 4700-5500. Anything else it could be? Fuel starvation? Runs perfectly normal before the upper revs.

I would look past the DME and check fuel injectors, fuel pump or ign coils

[oldtin]

At this point I don't think it's DME related. It was a bad coil pack that took out the previous DME - so that was replaced, along with plugs/wires. Would have thought fuel starvation would have been more of a gradual loss of power, but poking around on the interwebs there are other instances of failing fuel pumps acting like this or AFM-related issues. At nearly 220k on mileage and original fuel system, I think I'll start with a filter and take a look at fuel pressure. I would expect the AFM to act up more at lower/commuting revs where the contacts would wear more...

[oldtin]

hmm. working ok in the upper revs tonight. Hating intermittent stuff. Will have to give the harness a good going over.