HELP : Oil pressure / battery / alternator problem
Discussion
Over the last couple of days, when i've started the engine in the mornings, i've noticed that applying the throttle will cause the revs to drop, splutter, rise, stick at 2000rpm for 5 secs, then fall to 0 and stall! I have to wait a good 3 to 5 minutes for the engine to warm up and the throttle to behave as one would expect!
Anyway, this morning was worse than ever - everytime i touched the throttle to see if the engine was warm enough, the revs would rise and then drop so quickly i felt it wanted to stall. Once warmed up though, it was as smooth as ever.
Now for the worrying bit...
This evening i started the engine, only to have the oil pressure light stay on, the dash illumination lights were very dim, my headlights were dimmer than usual, windows were slower than their usual slow, and the windscreen wiper was also slow. Once the engine had warmed up, it idled at about 800rpm instead of it's usual 1100rpm. There was also a whining noise from the engine bay. But the engine itself was as smooth as usual.
Earlier in the week i put this down to the cold weather. Then i thought it might be the stepper motor - i will clean it tomorrow.
However, i now think it may be battery/alternator related - i'm hoping it is oil pressure related.
A past thread stated that it the alternator isn't charging the battery, and the battery isn't producing enough power, the oil pressure gauge may not work properly - this would explain the warning light, dim lights, slower-than-slow windows etc.
I know this has been a long post, but your suggestions would be greatly appreciated
Anyway, this morning was worse than ever - everytime i touched the throttle to see if the engine was warm enough, the revs would rise and then drop so quickly i felt it wanted to stall. Once warmed up though, it was as smooth as ever.
Now for the worrying bit...
This evening i started the engine, only to have the oil pressure light stay on, the dash illumination lights were very dim, my headlights were dimmer than usual, windows were slower than their usual slow, and the windscreen wiper was also slow. Once the engine had warmed up, it idled at about 800rpm instead of it's usual 1100rpm. There was also a whining noise from the engine bay. But the engine itself was as smooth as usual.
Earlier in the week i put this down to the cold weather. Then i thought it might be the stepper motor - i will clean it tomorrow.
However, i now think it may be battery/alternator related - i'm hoping it is oil pressure related.
A past thread stated that it the alternator isn't charging the battery, and the battery isn't producing enough power, the oil pressure gauge may not work properly - this would explain the warning light, dim lights, slower-than-slow windows etc.
I know this has been a long post, but your suggestions would be greatly appreciated
no harm in cleaning your stepper,its quick and easy and from what you describe at the beginning it may well be dirty.id go with you on your diagnosis of the alternator as a good place to start looking for the main problem.if the alternator checks out ok then start checking earthing points.
>> Edited by mongoose on Friday 16th January 18:42
>> Edited by mongoose on Friday 16th January 18:42
Could be belt too. Another thing to check tomorrow.
Dont think it's fuse link as i've just read that the warning light wont illuminate if the fuse has blown.
I've had just over 2 months of trouble free ownership - i knew it would only be a matter of time before something goes wrong!
Still love my TVR though
Dont think it's fuse link as i've just read that the warning light wont illuminate if the fuse has blown.
I've had just over 2 months of trouble free ownership - i knew it would only be a matter of time before something goes wrong!
Still love my TVR though
definatly the stepper motor for the first problem as mine did exactly the same thing with the revs and it was ok once the thing was cleaned, as for the other thing check that the connections are tight on the rear of the alternator but watch that you dont short things out to earth , also check that the earth from engine to chassis is good and clean , do you have a multimeter if so check what the reading is across the battery it should read about 13.5/ 14volts when the engine is running if the alternator is producing anything, if you aint got a multimeter when its running with the lights on at idle rev it and see if they go a bit brighter, and whats the oil pressure gauge reading with the oil light on and on my 94 chim the alternator light is at the top in the middle.
>> Edited by ssc1 on Friday 16th January 21:28
>> Edited by ssc1 on Friday 16th January 21:28
anonymous said:
[redacted]
Sometimes true. My mate had a TVR for 2 years and it never ever broke down, he now has a Mitsubishi GTO, he's had it about 6 months, in that time it's been a pile of crap. It's had a major engine rebuild, and has been brought home by the AA regularly, twice in the last 4 days, and about 7 or 8 times before. OH, it's not got 150K miles.
It never rains, it just pours....
Cleaned the stepper motor this morning. Engine started and was much less lumpy when cold. Warmed up quicker too.
Red light was still on, but fuel pressure gauge was fine, so assumed this light is the ignition light.
Checked voltage across alternator, 11.6V with the engine both on and off. Checked battery, 11.7V. Diagnosed problem as "knackered alternator". Engine still running fine, and started up ok.
Attempted to drive 1/4 mile down road to an alternator specialist. Almost there when TVR decides to die - no power, throttle has no effect, engine running at just lower than idle, oil pressure gauge reading just und 5psi (had been fine - 30ish). Also heard a quiet-ish pop from the engine bay.
Pulled over immediately and turned off engine. Would not restart - now diagnosed problem as flat battery (or at least, not enough juice to turn engine). Prayed that problem is not oil pressure related and that i had actually just destroyed the engine. Had to call my Dad to give me a tow back home.
Been looking everywhere for an alternator, but no one ahs them in stock. Getting one for monday - only £69. Won't take long to fit, but will then have to try and start the car - and hope this cures the problem.
Deeply annoyed though as i was due to have driver tuition on Tuesday 20th. Turns out i wont get a refund and can only re-book if some else takes my place, so that looks like £235 wasted
Poxy TVR
Cleaned the stepper motor this morning. Engine started and was much less lumpy when cold. Warmed up quicker too.
Red light was still on, but fuel pressure gauge was fine, so assumed this light is the ignition light.
Checked voltage across alternator, 11.6V with the engine both on and off. Checked battery, 11.7V. Diagnosed problem as "knackered alternator". Engine still running fine, and started up ok.
Attempted to drive 1/4 mile down road to an alternator specialist. Almost there when TVR decides to die - no power, throttle has no effect, engine running at just lower than idle, oil pressure gauge reading just und 5psi (had been fine - 30ish). Also heard a quiet-ish pop from the engine bay.
Pulled over immediately and turned off engine. Would not restart - now diagnosed problem as flat battery (or at least, not enough juice to turn engine). Prayed that problem is not oil pressure related and that i had actually just destroyed the engine. Had to call my Dad to give me a tow back home.
Been looking everywhere for an alternator, but no one ahs them in stock. Getting one for monday - only £69. Won't take long to fit, but will then have to try and start the car - and hope this cures the problem.
Deeply annoyed though as i was due to have driver tuition on Tuesday 20th. Turns out i wont get a refund and can only re-book if some else takes my place, so that looks like £235 wasted
Poxy TVR
You sure it's the alternator? Could be the 100A fuse between the alternator and chassis. Check it and change it (70p) before spending mucho dosh on an alternator.
Do a search - lots of people have thought they had duff alternators but it was the fuse which they found out after 2-3 alternators and more head scratching.
Of course, it could be the alternator!
T/.
Do a search - lots of people have thought they had duff alternators but it was the fuse which they found out after 2-3 alternators and more head scratching.
Of course, it could be the alternator!
T/.
jsr said:
Did check past threads and thought it might be the fuse link, but then the warning light wouldn't come on.
Is the fuse a specialist part, or just a standard 100A fuse that can be found in an electrical shop?
Like I said, might not be the fuse, TVR warning lights have been know to be telling lies or be wired, er, differently.
The fuse is kind of specialist (you just knew that didn't you!). I got 2 from TMS (www.tvrgear.com) for 70oddp each. Someone said once it was the same as used in a Jaguar, but I might have been dreaming ... It's a flat bit of metal with 2 'hooks' where you tighten screws up and it creates a link. So it's a fused link, not a fuse like wot you're used to.
FWIW the symptoms I had with two occasions of broken/blown 100A fuse were: slow cranking of engine (owing to flattish batttery); alternator light stays on, but then might go off if the engine is revved; low indicated oil pressure on the gauge (maybe 0-5psi); and misfire/loss of power over 3000rpm.
The alternator light (the one with the battery on it!) was the only light to stay on. The oil pressure gauge now permanently under-reads by 5-10psi - I've had the oil pressure checked by my local independant.
On both occasions, replacing the £1 fuse under the car has fixed the problem. It's located on the main chassis rail behind the driver side front wheel.
The alternator light (the one with the battery on it!) was the only light to stay on. The oil pressure gauge now permanently under-reads by 5-10psi - I've had the oil pressure checked by my local independant.
On both occasions, replacing the £1 fuse under the car has fixed the problem. It's located on the main chassis rail behind the driver side front wheel.
Update:
Got a replacement alternator today, and my Dad kindly fitted it for me while i was at work! Engine turned over straight away!
Car now feels better than ever! Probably because it getting a full helping of volts.
Was a bit lumpy initially with what i thought were deadspots in the rev range, but within a few miles, everything was smooth again. Must be the ECU re-learning certain parameters.
Anyway, i'm well chuffed and can now do my driving course!
Got a replacement alternator today, and my Dad kindly fitted it for me while i was at work! Engine turned over straight away!
Car now feels better than ever! Probably because it getting a full helping of volts.
Was a bit lumpy initially with what i thought were deadspots in the rev range, but within a few miles, everything was smooth again. Must be the ECU re-learning certain parameters.
Anyway, i'm well chuffed and can now do my driving course!
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