4.0 TVR Chimaera Revv imit issue

dogman · Post by **dogman** » Mon Apr 25, 2011 5:17 pm

Hi guys

I thought I should start a new thread because my old one was a dead end so seeing as I'm back to square one, may I ask any gurus out there to have a read of this one.

It's a '94 TVR Chimaera with 50k I bought it with 38k. I havent revved it hard until the last few months but I'm pretty sure it did this from day one with me. Nothing has gone wrong with it and so far I still cant find any fault yet I have this issue:

The car will revv to 6k Once only then after that, under load or revving on the spot it will only go to 5,000 sometimes near 5,500rpm. At this point it hits what feels exactly like a rev limiter. If you switch the car off and on again, back she'll go to 6k, but only once What the hell could be happening where switching off and on again lets it revv once (sometimes twice) to 6,000 RPM?

It has had new everything - Cap, Rotor, Ign Module, Coil, Leads, Distributor rebuilt/checked, ECU swapped for know good one, timing checked/changed, one way valve checked/bypassed. It has also had the diagnostics machine hooked up at The TVR Center and found no faults even when driving making it 'do' the problem - nothing came up.

Today I tried disconnecting the rev counter and checking some of the voltages at the ECU of the fuel pump, RPM input (pin 39), injector banks. All fine all be it quite rudimentary checks.

Also tested is the fuel pressure reg and the car drives perfectly all over the rest of the revv range, no flat spots and really quick.

Can anyone help?!!

ChrisJC · Post by **ChrisJC** » Mon Apr 25, 2011 6:01 pm

What does the fuel pressure do when the fault is being exhibited?

Chris.

dogman · Post by **dogman** » Mon Apr 25, 2011 6:37 pm

That I havent checked. Checked it static but not revving to 6k (didnt think it'd be this hard to diagnose back when had the pressure tested)I still have an adjustable FPR sitting around would that work to try?

dogman · Post by **dogman** » Mon Apr 25, 2011 6:40 pm

...I mean to see what the pressure is doing at 6k..

dogman · Post by **dogman** » Sat Apr 30, 2011 10:37 am

It has been cured by trying a second ECU. It's still a bit of a mystery but the theory is (offered by Mark Adams) that between 92-93 Rover changed the ECU and that TVR meanwhile may still have been fitting the older chip in the newer ECU's

This means he's saying that I've had the wrong chip from new effectively. It also suggests that the other ECU I tried had the same mismatch chip/ECU as my ECU hence it didnt cure the problem.

Thanks to Sean and Rob at V8 Developments for getting stuck in and finding a cure, although we're all still not 100% convinced what was really wrong with my ECU!