Rev limit at 3400 revs??
Discussion
This is the second time that these symptoms have happened to me for no apparent reason. The recent saga goes like this:
I had just travelled back from Europe (1Hr at 70-80MPH), gone through the EuroTunnel and was merrily making my way along the M25 when I noticed a bit of lumpy and rough running from the Chimp (96 500HC). The engine temp was about 80 on the gauge, oil pressure was about 35-40, fuel was about 1/3 tank - all other indications were normal (do I have any other indications????). Accelerating under (minimal) load would cause the engine to run rough, the harder the acceleration (or lack of it!) or more pressing of the pedal made the symptoms worse.
Under no load (ie coasting or stationary) the engine would not rev over 3400 revs. It appeared to cut out at 3400, drop to about 3300 then rise slowly to 3400 again where it would cut out thus repeating the cycle. It would also do this under load.
A few miles further down the road (30-40 mins) the engine would go above 3400 revs but was noticeably less powerful above 3400. Drove her the next day (and all the way back to Europe 250 miles) and all was well.
This happened once before when I was on my way to the launch of the T350 at Kerridges back in Feb with exactly the same symptoms.
Any ideas anyone?
I had just travelled back from Europe (1Hr at 70-80MPH), gone through the EuroTunnel and was merrily making my way along the M25 when I noticed a bit of lumpy and rough running from the Chimp (96 500HC). The engine temp was about 80 on the gauge, oil pressure was about 35-40, fuel was about 1/3 tank - all other indications were normal (do I have any other indications????). Accelerating under (minimal) load would cause the engine to run rough, the harder the acceleration (or lack of it!) or more pressing of the pedal made the symptoms worse.
Under no load (ie coasting or stationary) the engine would not rev over 3400 revs. It appeared to cut out at 3400, drop to about 3300 then rise slowly to 3400 again where it would cut out thus repeating the cycle. It would also do this under load.
A few miles further down the road (30-40 mins) the engine would go above 3400 revs but was noticeably less powerful above 3400. Drove her the next day (and all the way back to Europe 250 miles) and all was well.
This happened once before when I was on my way to the launch of the T350 at Kerridges back in Feb with exactly the same symptoms.
Any ideas anyone?
Thanks Ivan, I've also heard that and so I tried it but there was no under or over pressure when I released the cap. I also have a clean stepper motor (looked at other threads earlier) and no other 'strange' anomolies that I can think off. I checked all the ignition leads (all firmly attached), vacuum pipe attached and clear (I can suck/blow through it).
So as you can see, I've tried and checked a few things so far!! Frustrated or what???
So as you can see, I've tried and checked a few things so far!! Frustrated or what???
If it was after long runs, why doesn't it do it after ALL long runs. I wasn't pushing the car hard, steady driving, cool conditions outside, plenty of cooling in the front of the car. I would expect it do it more if I was pushing the car hard (as I was the other weekend whilst playing with a lot of Belgian TRs - That's TRs not TVRs - TR3,4,5&6s).
It is something I have considered though. I will be changing the coil (once I have found out which one to change it with!) very soon though.
If the symptoms happened more regularly, I could try to isolate the condition/try different things - but twice in nearly 2.5 months??? Not exactly regular yet!
Thanks for the advice - keep it coming.
It is something I have considered though. I will be changing the coil (once I have found out which one to change it with!) very soon though.
If the symptoms happened more regularly, I could try to isolate the condition/try different things - but twice in nearly 2.5 months??? Not exactly regular yet!
Thanks for the advice - keep it coming.
If it makes you feel any better the TR6s you play with are probably even less reliable than your TVR, mine drove me up the wall.
Anyway, back to the plot, I was working on the heating up thing, if it was cool and you were not caning it than obviously that one is out the window. The Lamba sensor side of things is also a regular one on here, but that seems to be all the time not intermitent once it starts happening. I also remember something similar on here which someone fixed by unplugging the ECU and leaving it off for a while. Disconnecting the battery is NOT the same, some ECUs have a capacitors inside to keep the settings which are looped by the plug (don't know if TVR has this) whilst you change a battery. Would cost nothing to unplug it one night, put back in the morning car fixed - how nice would that be
Ivan
Anyway, back to the plot, I was working on the heating up thing, if it was cool and you were not caning it than obviously that one is out the window. The Lamba sensor side of things is also a regular one on here, but that seems to be all the time not intermitent once it starts happening. I also remember something similar on here which someone fixed by unplugging the ECU and leaving it off for a while. Disconnecting the battery is NOT the same, some ECUs have a capacitors inside to keep the settings which are looped by the plug (don't know if TVR has this) whilst you change a battery. Would cost nothing to unplug it one night, put back in the morning car fixed - how nice would that be
Ivan
My old Integra did this once when a hole appeared in the radiator and all teh coolant leaked out. It seemed to be linked to the fact that the engine wasn't running the way the ECU thought it should. given the coolant temp. :-)
Anyway, more water cured that. I've heard another car do the same thing and I wonder whether is could be some sensor somewhere that's gone iffy. One of the temp sensors for example.
Anyway, more water cured that. I've heard another car do the same thing and I wonder whether is could be some sensor somewhere that's gone iffy. One of the temp sensors for example.
The problem has happened twice in as many months. You could waste thousands of pounds replacing bits with no idea what so ever of what the problem actually is. You will also not have any idea of changing a bit is the cure.
Right now I would wait until the problem either comes back or never happens again rather than start changing bits which will quickly mount up in cost.
It could be almost anything.
Right now I would wait until the problem either comes back or never happens again rather than start changing bits which will quickly mount up in cost.
It could be almost anything.
david beer said: I remember a while back my Griff began to behave most odd, flat spots hesitation and would not rev above 4500, i have a code reader, plug in, tune resistor out of spec. Check and sure enough, in two pieces. It seems my passenger was pressing a little hard on the foot board!!
Where did you get the code reader from? Would be very helpful to have one aswell. Do you remember the price?
Thanks for the info.
The standard code reader is around £4000 and you need to be a bona fide motor engineer to get it. There is a simpler one that is from a Range Rover but it is not intelligent or that useful I would say. It may indicate a code but that doesn't necessarily give a direct indication of the cause.
Details pages 93 to 95 in bible 2. I have annotated the codes with the common causes where applicable.
The professional systems can actually perform diagnostics which is much more useful.
>> Edited by shpub on Wednesday 23 April 16:10
Details pages 93 to 95 in bible 2. I have annotated the codes with the common causes where applicable.
The professional systems can actually perform diagnostics which is much more useful.
>> Edited by shpub on Wednesday 23 April 16:10
david beer said: 3400 rpm is where the ecu doesnt use the lamda sensors and very often there is a hesitation around this point. Maybe something strange around this department, fault code reader needed i think.
David this is a new one to me does this apply to all tivs or just V8s I have a misfire on my tuscan at about 3500rpm you have got me thinking. steve H have you got any thoughts on this?? cheers TONY
The Tuscan is a totally different fuel injection system and is several light years more advanced than that of the rover system as it also handles all the ignition timing and has the barin the size of a planet compared to the one of a stuffed bear that the Rover system uses...
Misfires etc are notoriously difficult to cure if they are not obvious. Full diagnostic and rolling road investigatuion is often the best way forward.
Steve
Misfires etc are notoriously difficult to cure if they are not obvious. Full diagnostic and rolling road investigatuion is often the best way forward.
Steve
Had the same problem with my 500HC but cut out at about 5000 rpm.as if rev limiter cutting in.
I'm not really a petrol head but I changed the fuel pump relays, small square Bosch ones that cost about £8 from the right place (£18 from TVR dealer). Seems to have done the trick. Let me know if you want supplier details.
I'm not really a petrol head but I changed the fuel pump relays, small square Bosch ones that cost about £8 from the right place (£18 from TVR dealer). Seems to have done the trick. Let me know if you want supplier details.
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