Gentlemen
Now that cold weather has arrived an odd engine problem developed when out for a recent evening blat (~30 F), not wanting to run above 3200 rpm.
This started shortly after startup and lasting beyond coolant temp reaching running temp, but resolved ~30 minutes later.
Beyond 3200 RPM the engine/ECU jumps to thinking the engine is at 16,000 rpm. After the rpm spike the speed drops (I suspect the rev-limiter is activated until the ecu thinks the engine has slowed down and the engine re-engages). This cycle continues if i maintain the throttle position: there is a loss of power and the RPM fluctuates between too fast and too slow. If i let up on the accelerator to re-establish an RPM below 3K everything is normal until i reach 3200 again (regardless of whether i do so quickly or gradually).
Once well beyond full warmup this problem goes away.
I don't think the issue is with the sensors because they both give similar voltage readings with data logging and think it less likely both would go bad at the same time. The fact that this issue resolves AFTER warm up leads me to believe it is not likely related to the air temp/coolant temp correction tables in the ECU setup.
I am not sure if this issue is caused by a deficiency in my engine tune, cam/crank shaft sensor error, or wiring harness/connection/ground error?
I suspect there must be a slightly off connection in the harness resolving once everything beneath the bonnet is hot. Any ideas (other than every connection) as to likely places to check?
Duratec 2L Birkin, Haltech Sport 1000 ECU, ITBs, street use only
Cheers
P.