Start Valve Problems
Discussion
Hi I'm trying to sort out an ongoing issue with my TVR S1 which is with me in the Netherlands. The car starts and runs fine but only with the start valve electrically disconnected (I found this out just by pure accident). If you attach the electrics the car runs rough and will die if you don't manually keep the revs up and if it does die it is impossible to re-start. This makes for frustrating driving as either you are gunning the engine when in neutral with a risk it will conk out or, if the start valve is disconnected, runs fine but ticks over at about 2000 RPM which is irritating as heck and then the car gets super hot when static which is a whole other saga! Anyway I'm looking for any advice to help diagnose the issue and help me find a solution. I'm relatively handy but this is beyond my experience and capability. It might just be a cabling fault or doggy connection as the car is from 1988 so not unexpected for a failed component or cable problem just need some ideas of what continuity/resistance levels I should expect across components to see what is kaput. Any support and advice gratefully received or if somebody knows somebody in Netherlands who is Cologne savvy I more than willing to go to a garage.
Hi Pete, I don't know the direct answer to your question but I can relate my experience with the start-up valve in case that helps.
My 2.8i S1 behaved itself fine, starting from cold to rev around 1600rpm then gradually dropping to about 800rpm over the next 1-2 minutes. One day it changed to starting OK but then the idle rising gradually to around 2000rpm and staying there. I eventually traced this to a broken wire that meant the auxiliary air valve was not powered - I assume this is the valve you're talking about. First, I removed the valve to check it.
When cold the valve is open and you can see light through the inlet and outlet pipes. I put it in the oven, increased the temperature and at somewhere around 50'C it closed. After it had cooled down I checked it had opened again, then connected a power supply (13.8V) to the socket and watched the valve close. So the valve itself was OK. It was then that I checked the plug in the car and found no voltage when there should have been, i.e. when the ignition was on.
A few thoughts on your fault:
If connecting or disconnecting the cable makes the difference you describe then it suggests the valve is opening and closing. So maybe the fault is something else, meaning that the engine won't run/idle when the valve is closed?
Does it start OK from cold with the cable connected, then become rough as it warms up, or is it rough from cold?
When it is warm, will it idle at ~800rpm if you press the throttle? Or does it need more rpm to keep going?
Simon
My 2.8i S1 behaved itself fine, starting from cold to rev around 1600rpm then gradually dropping to about 800rpm over the next 1-2 minutes. One day it changed to starting OK but then the idle rising gradually to around 2000rpm and staying there. I eventually traced this to a broken wire that meant the auxiliary air valve was not powered - I assume this is the valve you're talking about. First, I removed the valve to check it.
When cold the valve is open and you can see light through the inlet and outlet pipes. I put it in the oven, increased the temperature and at somewhere around 50'C it closed. After it had cooled down I checked it had opened again, then connected a power supply (13.8V) to the socket and watched the valve close. So the valve itself was OK. It was then that I checked the plug in the car and found no voltage when there should have been, i.e. when the ignition was on.
A few thoughts on your fault:
If connecting or disconnecting the cable makes the difference you describe then it suggests the valve is opening and closing. So maybe the fault is something else, meaning that the engine won't run/idle when the valve is closed?
Does it start OK from cold with the cable connected, then become rough as it warms up, or is it rough from cold?
When it is warm, will it idle at ~800rpm if you press the throttle? Or does it need more rpm to keep going?
Simon
Try the Wedge Forum as well. That engine was fitted to more Wedges than S's. Also see here....
https://www.pistonheads.com/gassing/topic.asp?h=0&...
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Simon and V8s4me,
Thanks for assistance, re Simon’s question the car is virtual impossible to start with cable connected. I think I’m going to swing through the cabling to see is the is a fault and then play with the components of the fuel management. What could possibly go wrong.🙀😹
Thanks for assistance, re Simon’s question the car is virtual impossible to start with cable connected. I think I’m going to swing through the cabling to see is the is a fault and then play with the components of the fuel management. What could possibly go wrong.🙀😹
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