Tvr Tasmin 400se will not rev when hot
Discussion
Hi - first post here. Trying to sort out a problem. The car revs freely until it really heats up - say five miles or more and then it will not rev above around 4,000 rpm.
When I bought the car a while back it was not running right so took it to a rover specialist, they swapped a lot of bits to test them. The ECU was okay, the air flow meter okay and most other things are nearly new as the last owner spent a lot on the car. When I got the car back it ran better in some ways but they blamed the injectors for it not revving.
There has been a delay as I have had to take the body off the chassis as the chassis had rotted out at the side rail and front rail. Now all replaced and lots of other jobs done. Back to the engine - the injectors have been rebuilt, a new throttle pot fitted but the problem still exists. I do not want to go crazy chucking loads of bits on that have been done in the past. I tested the Bosch coil - not two years old yet - does anyone know what the readings should be when testing it terminal to terminal, the result is one ohm and terminal to coil hole, 11,300 ohms. It gets very hot but what doesn't under the bonnet. As I said, it runs well until it gets really hot, temperature gauge is okay though.
When I bought the car a while back it was not running right so took it to a rover specialist, they swapped a lot of bits to test them. The ECU was okay, the air flow meter okay and most other things are nearly new as the last owner spent a lot on the car. When I got the car back it ran better in some ways but they blamed the injectors for it not revving.
There has been a delay as I have had to take the body off the chassis as the chassis had rotted out at the side rail and front rail. Now all replaced and lots of other jobs done. Back to the engine - the injectors have been rebuilt, a new throttle pot fitted but the problem still exists. I do not want to go crazy chucking loads of bits on that have been done in the past. I tested the Bosch coil - not two years old yet - does anyone know what the readings should be when testing it terminal to terminal, the result is one ohm and terminal to coil hole, 11,300 ohms. It gets very hot but what doesn't under the bonnet. As I said, it runs well until it gets really hot, temperature gauge is okay though.
Could possibly be one of the HT components breaking down when hot, either leads or coil, but they usually cause a misfire rather than stopping the revs. Can you get the car into a dark garage and run the engine in the pitch black - if the HT is breaking down then you may well see blue sparks, especially across the top of the coil and from the king lead (coil to dissy) where it rests on any of the metallic engine components. other cause could be the coolant temperature sensor?
Do you have an adjustable fuel regulator? Do you have any way of checking the fuel rail pressure (i.e, is there a built in fuel pressure gauge on the rail?). What colour are the spark plugs when you pull them out? If very lean then it could be a fueling problem. Cheers.
Do you have an adjustable fuel regulator? Do you have any way of checking the fuel rail pressure (i.e, is there a built in fuel pressure gauge on the rail?). What colour are the spark plugs when you pull them out? If very lean then it could be a fueling problem. Cheers.
Hi not tested it in the dark yet but did test the newish leads on a meter and all around the same resistance wise the coolant sensor has been replaced as the car was fouling the plugs big time now they are a good colour have tried adjusting the fuel pressure but still the same when warm thinking about changing the coil but not sure what it should read test wise
burnsdavies said:
Hi not tested it in the dark yet but did test the newish leads on a meter and all around the same resistance wise the coolant sensor has been replaced as the car was fouling the plugs big time now they are a good colour have tried adjusting the fuel pressure but still the same when warm thinking about changing the coil but not sure what it should read test wise
I'll probably bore people to death with this but the other year I bought a new coil, dissy and HT leads and all three failed within 7 weeks so just because it's new doesn't mean it's good. Re the HT leads - the new set I had all measured fine and identical resistances. It was only when the engine bay warmed up that the insulation broke down. In the dark about 2" of king lead glowed blue (like a faint fluorescent tube) where it rested on the edge of the rocker cover. It was very obvious in the dark.I've a Bosch unit on one of mine. I can check the resistance tomorrow when I get a few minutes.
Have taken the revs up to 5500 after a short run a few times but after some more miles its like hitting the rev limiter as for fuel pressure it's a rising rate one when I got it back from the experts it was over 50 and fouled the plugs on the way home have tried 38 but now on 44 it's a high Comp engine and feels better at 44 and the plugs look ok
Couple of thoughts:
I assume this is a 3.9 Range Rover engine. Quite a number of us Chimaera owners run our cars on BPR6ES or BPR6EIX plugs to reduce the fouling. My TVR guy now fits the former on all RV8 cars having seen the results on my car. The latter are the more expensive iridium plugs, which last longer between changes.
Coil - I have a good spare i could post to you to try without the expense of buying a new one. Ditto a set of leads, though as said above, it's really only the king lead you should be looking at. I may still have an ignition amplifier (cannot remember if I sold it recently) - they can give trouble, particularly if they get too hot, which is the risk on the earlier Chims - TVR moved the thing away from the coil on the later cars I read.
There are a couple of current threads on the Chimaera forums, both here and on FB, with cars suffering from "rev limiter" issues when hot. Worth watching those threads to see what happens.
https://www.pistonheads.com/gassing/topic.asp?h=0&... is one of them, there are others
I assume this is a 3.9 Range Rover engine. Quite a number of us Chimaera owners run our cars on BPR6ES or BPR6EIX plugs to reduce the fouling. My TVR guy now fits the former on all RV8 cars having seen the results on my car. The latter are the more expensive iridium plugs, which last longer between changes.
Coil - I have a good spare i could post to you to try without the expense of buying a new one. Ditto a set of leads, though as said above, it's really only the king lead you should be looking at. I may still have an ignition amplifier (cannot remember if I sold it recently) - they can give trouble, particularly if they get too hot, which is the risk on the earlier Chims - TVR moved the thing away from the coil on the later cars I read.
There are a couple of current threads on the Chimaera forums, both here and on FB, with cars suffering from "rev limiter" issues when hot. Worth watching those threads to see what happens.
https://www.pistonheads.com/gassing/topic.asp?h=0&... is one of them, there are others
Edited by QBee on Tuesday 29th August 06:26
I've recently been through similar problems with my 390 and having replaced temp sensor, airflow meter, etc I was told it was the injectors by the 'specialist' I took it to. Like yours they wound up the pressure to around 50psi which didn't actually help and made the car stink of fuel. Not happy I took it to a Land Rover garage who said firstly the new set of plugs had been ruined by the poor running so they were replaced, then the ecu was found to be a problem with dry joints, which has now been sorted out, but the very poor running when hot was down to an inferior rotor arm, a genuine old style Lucas item with the name moulders into the plastic was fitted and it now runs perfectly. Make sure you have a decent rotor arm from a Landie specialist not one of the cheap ones from regular parts suppliers. Even the new Lucas boxed ones aren't much good and it's only the box that shows you it's a Lucas, the rotor arm could b from anywhere....
Cheers, Al.
Cheers, Al.
burnsdavies said:
Have taken the revs up to 5500 after a short run a few times but after some more miles its like hitting the rev limiter as for fuel pressure it's a rising rate one when I got it back from the experts it was over 50 and fouled the plugs on the way home have tried 38 but now on 44 it's a high Comp engine and feels better at 44 and the plugs look ok
If it was 50psi then you would not be able to go over 50-60mph!....38psi is way too low...42-44psi @ WOT is about right, I would be dubious as regards to "Experts" especially ones that set the fuel pressure that high..
So do you still have the issue now your fuel pressure is correct?
Cheers
Ziga
You could have a failing Coolant Temperature Sender...(CTS)...
I forgot to ask, is the car a flapper or a hotwire?....Like Tweety said..some of these new so called genuine parts can fail almost straight away, the RV8 is sensitive to inferior parts..especially around the ignition.
This issue does also sound like a broken wire, when it gets hot it opens the gap...
What is your timing set to?
What plugs are you using?
Have you checked all the earth points? (3 main ones)
Is the distributor cap seated properly?
If parts are changed then you need to be methodical or it can just be a waste of time and money...If you change the plug leads..test...No difference put the old ones back on...Change the rotor arm...test..no change...re-fit old one....etc
When you say cannot rev past 4000rpm what is the car doing...i;e misfiring...pinking...popping...feels like the accelerator is back to front...?
I forgot to ask, is the car a flapper or a hotwire?....Like Tweety said..some of these new so called genuine parts can fail almost straight away, the RV8 is sensitive to inferior parts..especially around the ignition.
This issue does also sound like a broken wire, when it gets hot it opens the gap...
What is your timing set to?
What plugs are you using?
Have you checked all the earth points? (3 main ones)
Is the distributor cap seated properly?
If parts are changed then you need to be methodical or it can just be a waste of time and money...If you change the plug leads..test...No difference put the old ones back on...Change the rotor arm...test..no change...re-fit old one....etc
When you say cannot rev past 4000rpm what is the car doing...i;e misfiring...pinking...popping...feels like the accelerator is back to front...?
Sounds like a failing ignition amplifier to me. I had exactly the same issue twice due to a cheap replacement part. Car would start hesitating when hot, then wouldn't rev over 4k. Eventually it stalled at traffic lights and wouldn't idle. Let it cool down and it would start and get me home. Eventually I opted for the Lucas re-location kit which takes it away from the side of the dizzy and put it by the coil.It's been fine ever since.
Thanks for checking your coil as you say about the same readings wise the car is a flapper system its had a new dissy, vacuum and the Bob weights are doing there job
I replaced the coolant temp sender it was dud
the car had pinking problems the experts put a delay in the vacuum pipe to the dissy not so much a delay more of a stop you could suck on the pipe as much as you like but no action in dissy what I did check was the tdc on pully with the piston it's a good way out not sure how accurate as I put a Vernier gauge down the spark plug hole it is at least 5 deg out its set now to 2 reg on pully
I hear it's not uncommon for the key way to be out. can someone answer this for me please is the pully key way the same one as the cam chain runs on ?
When the car hits its missfire point it's not just the odd missfire seems like most cylinders sometime it can be made to rev higher but missing all the way
I replaced the coolant temp sender it was dud
the car had pinking problems the experts put a delay in the vacuum pipe to the dissy not so much a delay more of a stop you could suck on the pipe as much as you like but no action in dissy what I did check was the tdc on pully with the piston it's a good way out not sure how accurate as I put a Vernier gauge down the spark plug hole it is at least 5 deg out its set now to 2 reg on pully
I hear it's not uncommon for the key way to be out. can someone answer this for me please is the pully key way the same one as the cam chain runs on ?
When the car hits its missfire point it's not just the odd missfire seems like most cylinders sometime it can be made to rev higher but missing all the way
I've heard that the crank timing marks can be out but both of mine are spot on when cylinder 1 is at TDC. Could it just be timing? I'd take out the bloody silly vacuum stop thing and let the vacuum advance do its thing. The issue is many of the newer dissies have a different advance curve than the originals. Originally the setting was 8 degrees BTDC. If I set my 350i to this then when I accelerate it pinks it's head off. I've tweaked and tweaked the timing so at static it now runs about 2 degrees BTDC but under full load it pulls like a train. I started at the 8 BTDC and then slowly slowly crept it back a degree at a time over a number of runs until the pinking just stopped.
Have you tried slackening off the dissy and rotating it round a little either way, when warm obviously, to see if a different timing position helps it rev freely?
Have you tried slackening off the dissy and rotating it round a little either way, when warm obviously, to see if a different timing position helps it rev freely?
Yes I tried road-test with the dissy loose and armed with my timing light tried many settings and ended up at the setting I have now. I did dump the delay thing I was hoping to take it out tonight but it's raining at the moment no fun in the wet what I was thinking of doing was putting an ice pack on the coil and see if it still does it then try the same on the RPI power amplifier might have to wait till tomorrow for that as only just put them in the freezer .
Thought I would try simple things before I start to replace things any way going away next week so don't want to order anything yet and if I can borrow things to try then even better I am based on the Essex Suffolk border
Thought I would try simple things before I start to replace things any way going away next week so don't want to order anything yet and if I can borrow things to try then even better I am based on the Essex Suffolk border
Gassing Station | Wedges | Top of Page | What's New | My Stuff