Help my Cerbera only has 4 Cylinders

[Katanarog]

Have had Cerbera 4.5 since December and this is first problem so not too bad. I used car all weekend no problems until this evening. I parked it up for about 10 minutes, when I restarted it and drove away I noticed a 'pinking' noise also increased popping on the overrun. When the car is on a slight throttle oopening it feels like its only running on 4 cylinders then it feels like the others come in once the throttle opening is increased. I have checked the linkage but that seems ok. Any ideas would be appreciatd.

[cinman]

For what it's worth, replacing the coil helped similar prob with my 4.2

[HarryW]

Not much help at all, but I can't resist, with the flat plane crank surely they all sound like they're running on 4 cylinders .
Sorry about that

Harry

[Grey42Cerbie]

Have had Cerbera 4.5 since December and this is first problem so not too bad. I used car all weekend no problems until this evening. I parked it up for about 10 minutes, when I restarted it and drove away I noticed a 'pinking' noise also increased popping on the overrun. When the car is on a slight throttle oopening it feels like its only running on 4 cylinders then it feels like the others come in once the throttle opening is increased. I have checked the linkage but that seems ok. Any ideas would be appreciatd.

Sounds like it could be throttle pots. Which is the cheapest place to start, then leads, then coils then maybe Lambda sensor. If you take it into your dealer they should be able to hook it up to a PC and let you know.

Steve
Grey 4.2 Cerbie

[ChrisI]

It's a funny ol' game with the throttle/response on these things, as it's becoming very plain to me with my 4.2 nowadays. I've just replaced the coil for right-bank of enging (there's one coil per 4 cylinders see), all leads and plugs (which isn't as simple as it sounds - be sure you've some time and all the right fitting tools before you do THAT yourself!) It now ticks over a beauty, and is firing on all 8 (use the cable tie thing to work out which ones' its firing on - let the engine run for a few mins to get warm, then dangle a plastic cable tie down the side so it touches the exhaust manifold - if that cylinders firing, it will leave a tiny smudge of melted plastic - if not, it won't).
Now, however, the throttle seems a tiny bit "woolly". Ticks over good, accelerates good, but when ticking over and I lightly touch the throttle to get a tiny increase in revs, the revs actually "drop" - I have to apply slightly more pressure on accelerator before revs pickup -weird?
Sorry mate -- did any of that help?

[mudstud]

Had exactly the same problem, turned out one of the throttle pots was way behind the other. Joolz sorted it pdq.

[Katanarog]

Thanks for your suggestions. Ive tried a few things but no joy. I suspect it may be throttle pot. The resistance across one is less than the other. How this could fail god only knows and perhaps Peter Wheeler.Have booked it in to TVR Centre for diagnostic check fingers crossed not too expensive. haha

[Big T]

I've been having the same problem, 'big delay in delivery of power' 'Alot of lag' 'Feels like I've been running on half an engine' etc etc...,I thought that the stuttering was normal but was told it wasn't. Via PC to ECU from Andy (APM) the other day (top man BTW), found out that the throttle for one bank of cylinders was basically doing the work for both, (along those lines anyway) Would explain for the low BHP & torque reading I had from the RR.

Could be Coils, throttle linkage, pots, sensors switches. Getting it resolved ASAP with dealer cos I'm p****d off with doing a couple thousand miles on half an engine!!! Or there abouts.

P.S. ChrisI, I saw Andy doing the cable tie thingy to my motor and was wondering what that was all about, thanks!!




>> Edited by Big T on Wednesday 7th May 23:34

[dannylt]

The throttle pots are cheap crappy things and they fail all the bloody time. If one fails, the other will be used. This won't really cost too much power, but it can certainly cause lagginess and stuttering at low to mid revs on part throttle.

danny

[gazzab]

Danny - did you get the joolz fixes to your throttle pots to stop the 2000 rpm stutters?
I would like to get mine to run smoother at those revs and am hoping to understand these little secret mods and see if I can get APM to do them as I need a service soon.

[ChrisI]

One of my pot retaining screws seems to have burred itself and I cannot get a flat-blade enough grip to undo it now. Anyone got any suggestions that don't involve me drilling it out?

[darreni]

does anyone know what these mods to the throttle are?
mine is running like a bag of shite, i emailed jools a few days ago to see if he could shed any light, but no reply yet.
I set up the pots on saturday & the car ran like a dream for the rest of the day, but sunday it was back to its bad old self.
I'm fairly sure its not plugs/leads/coil/lambada, but the day it started playing up again the temp gauge did not register until it hit 90 & then swung round.
if the temp sender is iffy, would this affect the fueling ( i'm sure the ecu uses the temp for fueling or something)?
The car hesitates & jerks around the 2000- 2300 rpm in any gear & is truly horrible to drive, to the extent i'm now driving the wifes mk1 golf until this is sorted.

any ideas?

Darren.

[vroom]

A good test is with the car stationary and engine nice & warm. Lift the revs to about 1500RPM. Do the revs blip transiently to 2000 + RPM???

If so you need the Joolz mod...

[markoso]

Sounds like someone should come up with a conversion involving large numbers of huge weber carbs...