Can anyone with a 2.9 please help with my query?
Discussion
The latest on the jerking when the engine is under a light load.
No apparent problems with any connections having given them all a good wiggle.
New cap, rotor and brake servo hose fitted as they all looked past their best.
So I disconnected the TP and it may have idled slightly more smoothly for a half a second but I think I just imagined it. Anyway, it didn't drive any differently (still jerky on load).
So once home and standing with the engine running on the drive, I disconnected each air flow meter. The new one first (lower one) and the revs dropped and the engine nearly stalled. I reconnected the new one then tried the other and there was a slight hesitation in idling speed as I unplugged it but other than that it still ran about the same. Surely that can't be right?
What would be really helpful would be if someone with a 2.9 could also unplug their connectors from each airflow meter, in particular the top one and see if it changes the running of the engine.
In my opinion, it should have some impact on how the car runs.
Your help is very much appreciated.
Cheers,
KS2
No apparent problems with any connections having given them all a good wiggle.
New cap, rotor and brake servo hose fitted as they all looked past their best.
So I disconnected the TP and it may have idled slightly more smoothly for a half a second but I think I just imagined it. Anyway, it didn't drive any differently (still jerky on load).
So once home and standing with the engine running on the drive, I disconnected each air flow meter. The new one first (lower one) and the revs dropped and the engine nearly stalled. I reconnected the new one then tried the other and there was a slight hesitation in idling speed as I unplugged it but other than that it still ran about the same. Surely that can't be right?
What would be really helpful would be if someone with a 2.9 could also unplug their connectors from each airflow meter, in particular the top one and see if it changes the running of the engine.
In my opinion, it should have some impact on how the car runs.
Your help is very much appreciated.
Cheers,
KS2
Have you tried new HT leads? On my old S it was always the throttle pot (every 6 months until I got a Cerbera one which seems to last ages even though it costs less) or the HT leads (always used ford ones as others seemed a bit dodgy).
From memory the airflow meters behave exactly as you describe. Only one is used for air temperature measurement I think. If in doubt switch the connections over and see what happens?
Chris
From memory the airflow meters behave exactly as you describe. Only one is used for air temperature measurement I think. If in doubt switch the connections over and see what happens?
Chris
chris_chim said:
Have you tried new HT leads? On my old S it was always the throttle pot (every 6 months until I got a Cerbera one which seems to last ages even though it costs less) or the HT leads (always used ford ones as others seemed a bit dodgy).
From memory the airflow meters behave exactly as you describe. Only one is used for air temperature measurement I think. If in doubt switch the connections over and see what happens?
Chris
Hi Chris,
Many thanks for the advice, I'm going to swap the airflow meter connections around later and see what happens.
The TP seems OK at the moment but no doubt it will fail at some point as they always do!
Do you have a part number for the Cerbie TP?
Cheers,
Kevin
Just call a TVR dealer and they will know what you mean, I used TVR Centre at Barnet (part numbers don't seem to mean much to TVR dealers). They initially gave me the wrong one (one turns one way (straight6?) and one the other (V8?) although both fit mechanically) but swapped for right one. So check before fitting.
Chris
Chris
kentish - i use www.tvrgear.com to order any TVR parts. Its the spares side of TMS in melton mowbray and i find them very good
Actually having checked my receipts (I am a bit of a hoarder) the correct part number (from TVR Centre at least) is E1586 (Throttle Pot Cerb 4.2). The incorrect part number is E2936 (Throttle Pot 4.5 Cerbera) and this one costs almost twice as much even though it looks identical! Purchased in March 2002 for the grand sum of £17.60+VAT and lasted until my car got rear-ended in January 2004. That was a record for throttle pots on my S!
Thanks folks, your help's much appreciated.
I took your advice and really took a good look at the TP and there seems to be a problem with it, at least there is when it's idling. If you wiggle the TP and connector the revs rise and fall, even by just moving the cables next to the TP connector. I also held the loom firmly at the connector and wiggled it further back to see if there was a connection fault in the loom. Didn't seem to make a difference, so hoping backwards from the TP is all OK.
I couldn't believe that my TP has probably only been on the car for 600 miles (maybe less) and has failed again.
However, I'm not sure it's the only problem as I disconnected it and the car didn't really run any better. Perhaps that's because it isn't doing ought anyway!
It's a starting point!
Thank you for the part numbers, I'll go for one of these instead and the gold conectors that have been mentioned.
Cheers folks!
KS2
I took your advice and really took a good look at the TP and there seems to be a problem with it, at least there is when it's idling. If you wiggle the TP and connector the revs rise and fall, even by just moving the cables next to the TP connector. I also held the loom firmly at the connector and wiggled it further back to see if there was a connection fault in the loom. Didn't seem to make a difference, so hoping backwards from the TP is all OK.
I couldn't believe that my TP has probably only been on the car for 600 miles (maybe less) and has failed again.
However, I'm not sure it's the only problem as I disconnected it and the car didn't really run any better. Perhaps that's because it isn't doing ought anyway!
It's a starting point!
Thank you for the part numbers, I'll go for one of these instead and the gold conectors that have been mentioned.
Cheers folks!
KS2
Read with interest and tests are exactly the same as I did...Yep, its the TP OK. I have kept the part no on this threat too as it could be v handy!
Mine turned into a non starting problem and only got to the bottom of it by changing the TP and airflow meters at the same time which sorted it...though when I put the old meters back on again as I could not believe they were the problem,they worker just as well and it still started OK! Very strange!
My TP is directly under the bonnet inlet opening in the hump and when I washed the car or it rained it used to get damp inside and guess that led to corrosion, so have temporarily knocked up a roof that fits over the top of it to keep the water off and it seems to work until I get time to make something better.Just a bit of thick house damp proof course cut to shape,but does the trick.Some might say it was a damn silly place to position the bonnet vent in the first place!
Cheers all. Tim.
Mine turned into a non starting problem and only got to the bottom of it by changing the TP and airflow meters at the same time which sorted it...though when I put the old meters back on again as I could not believe they were the problem,they worker just as well and it still started OK! Very strange!
My TP is directly under the bonnet inlet opening in the hump and when I washed the car or it rained it used to get damp inside and guess that led to corrosion, so have temporarily knocked up a roof that fits over the top of it to keep the water off and it seems to work until I get time to make something better.Just a bit of thick house damp proof course cut to shape,but does the trick.Some might say it was a damn silly place to position the bonnet vent in the first place!
Cheers all. Tim.
I thought the TP problem could be water as well but after I while I concluded it was temperature. If you take a problematic TP apart you cannot see anything wrong with it (no evidence of water ingress and no corrosion) and if you test it on a meter it appears to work fine but on the car it gives problems.
Not sure how the Cerbera pot is different (except its blue rather than black!) but it does seem to solve the problem. It never went wrong so I never took it to bits! Don't somehow think its anything to do with gold contacts though.
Not sure how the Cerbera pot is different (except its blue rather than black!) but it does seem to solve the problem. It never went wrong so I never took it to bits! Don't somehow think its anything to do with gold contacts though.
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