PGB BME Posted July 8, 2016 Report Share Posted July 8, 2016 Hi My TR7 V8 wont idle without some choke and below 2000rpm. At 2000rpm and the choke a quarter of the way out it then drops to 500rpm and surges back above 2000rpm and keeps doing this. At steady rpm above 2000rpm and with choke still on if I put my foot to increase revs it stalls. The car has electronic ignition, new plugs, (old one looked ok colour wise). In 2005 it has £13k spent on the conversion by S&S and has only done 4k miles since. Oh the carbs are SU, it had new fuel pump at IWE last year. I've checked for air leaks everything appears ok Any ideas? Phil Quote Link to post Share on other sites
David James Posted July 9, 2016 Report Share Posted July 9, 2016 Phil Fuel, electrics? The new fuel pump might be intermittent? It is possible there is an intermittent blockage of some sort in your fuel supply at the tank, pump end? Isolate by rigging up a temporary supply to the carbs from a can/tank held above the engine. Alternately try disconnecting the fuel line at the carb supply and run fuel into a can. Check for steady flow when ignition switched on. It does sound like it could be an air leak but electrics and dicky fuel supply can do funny things. Looking at the possibility of air leaks disconnect and blank off all connections to the inlet manifold not required for the engine to run. Brake servo, engine breather, etc. A vacuum gauge might be useful to ascertain leaking. Run engine. Failing no obvious problems with the inlet manifolds I would remove the carb dash pots and check the jet assemblies look to be in the correct position and the choke moves them up and down ok. Whilst the dash pots are off blow down towards the jet tops and check you can see the fuel bobs up to near the top of the jet. This is a good check to see if the fuel levels are about right. Switch fuel pump on and observe all is well at the jet tops. float valves working ok? With the engine running it might help to have a second body to look at the position of the dash pots, filters removed. to see if they are in a similar position when the engine is running. This is all only a start, but good luck. David Quote Link to post Share on other sites
acaie Posted July 9, 2016 Report Share Posted July 9, 2016 (edited) Did it come on suddenly or gradually? Can help when thinking about it. I had something similar come on suddenly, when the oil breather hose came off one of the carbs, creating an air leak into the inlet manifold. An air leak would be the top of my list, followed by some other fuel problem, but you never know. Good luck Al Edited July 9, 2016 by acaie Quote Link to post Share on other sites
PGB BME Posted July 10, 2016 Author Report Share Posted July 10, 2016 Hi Guys Just finished stripping the carbs down and giving them a clean all put back together, bit of tweaking and hey presto running smooth, will give her a good run tomorrow just to be certain but looks like the issue is sorted. Carbs had a bit of debris in the bowls and one of the needle wasn't seating correctly. Many thanks for you comments Phil Quote Link to post Share on other sites
David James Posted July 11, 2016 Report Share Posted July 11, 2016 Sounds good. Well done Phil. Happy V8 driving. Nothing quite like it. David Quote Link to post Share on other sites
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