Chimeara misfire combined with dash clicking
Discussion
Hello all. First TVR, purchased unseen entirely because it has a new chassis and was a bit of a bargain despite what problems I might find.
I'm very happy with the chassis - i.e. perfect, and the bodywork. Of course being a TVR it does have a couple of electrical gremlins, which a test drive wouldn't probably have spotted.
The first question I have is misfire/loss of power. Every so often it seems to just drop onto 4 cylinders, or lose power completely. It will still 'drive' but slows down and stops. A couple of key cycles and its fine again.
Tonight I noticed this happen at a T junction - the car was very low on power, HOWEVER, I realised at the same time there was a distinct clicking coming from behind the dash (at least it sounds like from behind the dash). Clicking sort of at what I'd expect firing frequency to be, and the clicking frequency rose and dropped with engine rpm's (I'm thinking injector or. I cycled the key a few times and the noise as well as the low power was there. Third or fourth key cycle, clicking gone, power back again! Definitely related. I'd say it sounded like an injector firing, but I can't hear the others firing so why would I hear this one?, possibly arcing but then why would it stop with a key cycle. Maybe a relay right up behind the dash somewhere but then why would it click at firing frequency?
The clicking absolutely must be related to the low power - too much of a coincidence. Maybe fuel starvation and the injector at the far end of the rail gets noisy? I'm clutching at straws I guess.
If it helps it seemed to do it a few days ago when I bumped over a drain cover (but this might be a big coincidence but it was at that exact moment).
Suggestions please. Kudos to the responder who gets it right first time!........
I'm very happy with the chassis - i.e. perfect, and the bodywork. Of course being a TVR it does have a couple of electrical gremlins, which a test drive wouldn't probably have spotted.
The first question I have is misfire/loss of power. Every so often it seems to just drop onto 4 cylinders, or lose power completely. It will still 'drive' but slows down and stops. A couple of key cycles and its fine again.
Tonight I noticed this happen at a T junction - the car was very low on power, HOWEVER, I realised at the same time there was a distinct clicking coming from behind the dash (at least it sounds like from behind the dash). Clicking sort of at what I'd expect firing frequency to be, and the clicking frequency rose and dropped with engine rpm's (I'm thinking injector or. I cycled the key a few times and the noise as well as the low power was there. Third or fourth key cycle, clicking gone, power back again! Definitely related. I'd say it sounded like an injector firing, but I can't hear the others firing so why would I hear this one?, possibly arcing but then why would it stop with a key cycle. Maybe a relay right up behind the dash somewhere but then why would it click at firing frequency?
The clicking absolutely must be related to the low power - too much of a coincidence. Maybe fuel starvation and the injector at the far end of the rail gets noisy? I'm clutching at straws I guess.
If it helps it seemed to do it a few days ago when I bumped over a drain cover (but this might be a big coincidence but it was at that exact moment).
Suggestions please. Kudos to the responder who gets it right first time!........
It fires up instantly every time (or so it seems, I've only done a couple of trips in it and it's done it on both trips)
If it's 'running fine' when I fire it back up it just pulls away fine.
If it's still 'running' bad' when I fire it back up it idles OK (but lumpy) but when I pull away it just dies (i.e. no power)
When i'm driving and it starts misbehaving, if I pull over and park up it continues to idle (but won't rev as readily / llumpy) but has no power to pul away agin.
If it's 'running fine' when I fire it back up it just pulls away fine.
If it's still 'running' bad' when I fire it back up it idles OK (but lumpy) but when I pull away it just dies (i.e. no power)
When i'm driving and it starts misbehaving, if I pull over and park up it continues to idle (but won't rev as readily / llumpy) but has no power to pul away agin.
Great suggestions guys - This morning I went out and tried to locate the earth straps under the handbrake, and couldn't find them easily. So I pulled the wiring out of the footwell - Crikey what a birds nest! Original metal bodied relays are still there. I also pulled out the ECU and gave the whole lot a good shake. I drove down to the local factors to get some new relays , they don't have any in stock, so I picked up some gear oil, rotor cap and a couple of other bits and pieces. Ive since done about 30 miles over 5 journeys and it's not done it again. I have the wiring loom sitting in the footwell ready to give it a shake and see if that helps, for next time it does iit (Which I'm sure it will!)
I'm also going to replace the king lead even though it is new - Couldn't get one this morning but will do some more miles later and try somewhere else.
The spark plug extensions also look quite old - potential source of the fault?
Big beaming smile on my face though, love the noise :-))
I'm also going to replace the king lead even though it is new - Couldn't get one this morning but will do some more miles later and try somewhere else.
The spark plug extensions also look quite old - potential source of the fault?
Big beaming smile on my face though, love the noise :-))
Another two trips and still no issues, mind you only a few miles each. Confidence builds and then you get knocked back again eh?!?
I like the look of the boots - I'm going to order a set anyway and try them out. I have a Mastercraft Ski boat with a Ford 351 that suffers from the leads degrading due to the very high temps under the hood - these look like a great solution.
Just used an infrared thermometer on the top hose and with the car sat after a run the temp reading is 85 - 90C. Guess the gauge is out by 30C and I should stop worrying about it!
I like the look of the boots - I'm going to order a set anyway and try them out. I have a Mastercraft Ski boat with a Ford 351 that suffers from the leads degrading due to the very high temps under the hood - these look like a great solution.
Just used an infrared thermometer on the top hose and with the car sat after a run the temp reading is 85 - 90C. Guess the gauge is out by 30C and I should stop worrying about it!
Well, I've done a hundred miles or so this weekend, and it's done it only once, on the same left hand bend/bump/drain cover again. Looking at the loom it might be one of the relays tapping against the positive terminal of the battery???
I wasn't able to ge relays but have ordered a couple for collection onTuesday and we'll go from there. Intermittent every 100 miles or so I can live with, but I'll probably strip back the first portion of the loom, check terminals and give a good clean etc. etc. while I'm doing the relays.
I wasn't able to ge relays but have ordered a couple for collection onTuesday and we'll go from there. Intermittent every 100 miles or so I can live with, but I'll probably strip back the first portion of the loom, check terminals and give a good clean etc. etc. while I'm doing the relays.
I've changed the relays tonight and swapped the stepper motor for a new one. Seems to fire and idle much better from cold. Still around 1000 rpm but the rev counter is a little random anyway.
Changed both relays and given the wiring a god look over, battery terminals a good clean etc. I also found one of the HT leads wasn't perfect - repaired it but I'll probably get some replacements made up and see how it goes. Hopefully I haven't made it any worse!!
Changed both relays and given the wiring a god look over, battery terminals a good clean etc. I also found one of the HT leads wasn't perfect - repaired it but I'll probably get some replacements made up and see how it goes. Hopefully I haven't made it any worse!!
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