Help! 2.8 engine that doesnt rev above 5k

[TMC Motorsport]

Hi all,
Need some help if possible please. The last time we raced the Zed at Donington it ran fine in qualifying, then when it came to the race it wouldnt rev above about 5k rpm. It also ran very hot, sticking at around 102 degrees.

The car now has no catalytic converters, no abs unit and no asc. All the wheel speed sensors are still connected, as is the sensor on the diff. We tried having it remapped as thought it might have been running lean, but that hasnt stopped it happening.
It also now has a digital dash board so the speedo feed is no longer connected. Could this have an effect?
It seems fine out of gear, and will happily rev to 6k when not under load (dont panic, we only did that briefly!) so this makes me think its a clutch or gearbox sensor?

Has anyone come across this? Any ideas? We're testing next weekend and racing at silverstone the week after so it needs to be sorted!

Many thanks in advance.

Matt

 

[zedonist]

Could it be an induction air leak, need to check all rubber boots and hoses, or it could possibly be a faulty MAF.

You do not mention if you have put it on a code reader, it may throw some codes that will help.

As a off beat solution what fuel are you running, too high or ow may cause timing to be scewed and the knock sensors are restricting use under load?

Hope it is really simple for you, but one way of tracing a fault is to say when did the fault first appear, and what did I change on the car just prior, may lead you in the right direction.

 

[zedonist]

Just as an a side, having piqued my interest, the rear right wheel sensor also acts as a speed sensor, and will limit the car to just over 5000k whilst under load, but you should get a code when reading the ECU for wheel sensor or such like.

 

[TMC Motorsport]

Turns out it has been throwing a wheel speed code when weve had it on the dyno.
Apparently its likely to be because we've removed the ABS/ASC control unit. We either need to put that back in, or modify the ECU to ignore the lack of signal. Will try putting it back in to start with and go from there.

 

[zedonist]

Keep us posted, always good to finish a thread with the solution, quite a few people are now tracking the Z3 on here, so it may potentially help them when stripping the cars down.

 

[TMC Motorsport]

So we reconnected the ABS/ASC unit, ran it up on the dyno and all seems to be well. We still have the brakes bypassing the unit, but the ECU seems happy to let it rev now.
Not only this, we are now showing a very healthy 233bhp, still on a standard map. Further gains to be made when we eventually get the remap done in the next couple of weeks.
Thanks for the help and suggestions!
If anyone is near Silverstone on Saturday 24th August, drop in and say hi!

Matt

 

[zedonist]

Glad you resolved it so quickly, hopefully the extra weight wont slow you down!

 

[bruce&kim]

Hi Matt is that the http://www.silverstone.co.uk/events/750-motor-club-august/ event? have the long weekend off then quite fancy a blast up to Silverstone

 

[TMC Motorsport]

That is indeed that weekend. We're racing in the Roadsports on Saturday.

 

[bruce&kim]

Looks good mate only £15 for the weekend look forward to watching you tickets booked &room @ Days Inn Milton Keynes booked for two nights for £52.00 !!!for 2 !!

 

[zedonist]

I am away that week, would have been nice to go.......i expect there are other events in the calendar?

 

[TMC Motorsport]

One left after this, at Donington on the 21st September.
We might be planning others but that is the next definite one for us.

 

[zedonist]

I could make Donington, will bring my spanners!

 

[TMC Motorsport]

Update on this one, although the car ran well,unfortunately the feed from the power steering pump to the rack sheared and dumped all its fluid so we had to retire the car. We were 2nd in class and 4th overall at the time.
Onwards and upwards to Donington though, hopefully with an M3 brake conversion and possibly a remap.

 

[Brian H]

Shame about the power steering issue, I take it was a hose/pipe that sheared? Be interested to see what is involved in the brake upgrade.

 

[GazHyde]

Ouch! Sods law it happens when you are doing well...

 

[hard top]

Sorry to hear that, let us all know how you guys get on.

 

[zedonist]

shame, bad luck and all.....................there is always Donnington!