had17462 Posted November 8, 2012 Report Share Posted November 8, 2012 Hi all, friend of mine has been driving his car and hes only getting 16-18 mpg, hes asked me to ask would the expence of a efi conversion be worth it or would su carbs be better,he dont want to sell it and get a diesel before someone suggests it, had a recon metering unit and runs a bosch fuel pump regards nick. Quote Link to post Share on other sites
Andy Clarke Posted November 8, 2012 Report Share Posted November 8, 2012 Nick, If mine was an original TR5, I wouldn't dream of removing the PI setup. But my 250, fitted with rebuilt SUs and a Chris witor cam, along with his recommended needles and airbox setup pulls like a train and returned 30.6 mpg on a tank full, to tank refilled test over a 320 mile run last month. It drinks more on short journeys, but that may be down to my heavy right foot and the fact that I love the exhaust note. Andy Clarke. Quote Link to post Share on other sites
had17462 Posted November 9, 2012 Author Report Share Posted November 9, 2012 thanks Andy I will tell him,hes willing to take the injection off and keep it just in case he does sell it when he rebuilds his 4. Nick Quote Link to post Share on other sites
Jersey Royal Posted November 9, 2012 Report Share Posted November 9, 2012 I would think the Pi system needs tunning on a rolling road. On a 2000 mile trip my Pi system returned the average of 29.5 mpg. Yours must be running rich. Cheers Guy Quote Link to post Share on other sites
AndyGT6 Posted November 9, 2012 Report Share Posted November 9, 2012 Nick, But my 250, fitted with rebuilt SUs and a Chris witor cam, along with his recommended needles and airbox setup pulls like a train and returned 30.6 mpg Andy Clarke. Hi Andy, Purely out of curiosity, which Chris Witor cam and what needles are you using. Andy Quote Link to post Share on other sites
Peter Cobbold Posted November 9, 2012 Report Share Posted November 9, 2012 Running rich could be due to nothing more than a leaking metering unit diaphragm. Easy to check, easy and cheap to replace. Search on TR6 forum for 'tongue test' Quote Link to post Share on other sites
Andy Clarke Posted November 10, 2012 Report Share Posted November 10, 2012 Andy, The cam fitted to my 250 is the CW30210T (actually produced by Kent Cams) and the needles are BFZ with new, non waxstat jets. Chris was also quite specific about using the original 2500S airbox (which needed a little fettling) to avoid turbulent airflow. If you are passing Glastonbury, you (or anybody else with an interest) are welcome to give it a thrashing. Nick, apologies for diverting the thread. Andy Quote Link to post Share on other sites
had17462 Posted November 10, 2012 Author Report Share Posted November 10, 2012 no worries ,what about efi mpg, nick Quote Link to post Share on other sites
AndyGT6 Posted November 10, 2012 Report Share Posted November 10, 2012 Thank you Andy for the cam & needle info, I'm running the same cam in my 2.5L GT6 but currently trying a couple of different needles to improve the fueling. I have a home made airbox with K&N filters. One last question if possible as this is another persons thread, are you running the standard cast iron exhaust manifold, and has the cylinder head had any work to improve flow. I'd love to see how well your TR runs sometime, but I'm up in Cheshire and don't often travel near Glastonbury. Andy Quote Link to post Share on other sites
Andy Clarke Posted November 10, 2012 Report Share Posted November 10, 2012 Andy, The head is a mildly cleaned up and unleaded 219016 and the exhaust manifold is standard cast UK TR6. Quote Link to post Share on other sites
AndyGT6 Posted November 10, 2012 Report Share Posted November 10, 2012 Thank you for the above info. My head has been lightly ported also, but I run the single outlet cast iron manifold. Space constraints mean I can't really use the saloon air box as the inlet would hit the suspension turret on a GT6. I also run the standard GT6 inlet manifold which has been cleaned up inside. I'll definetly put the BFZ needle on the list of possible needles to try if the ones I've got are not suitable. Andy Quote Link to post Share on other sites
Dave Dawson Posted November 11, 2012 Report Share Posted November 11, 2012 hi nick I had tr6 that was running rich at idle there was black smoke. after i had checked out the igntion i fitted a colour tune plug to no 3 cylinder which had an orange flame i then took off the metering unit's side cover, with the engine idling i inserted a feeler gauge between the rollers and follower i i found that a .006 thou made the idle smoother and the colour-tune showed a blue flame i then made up a L shaped .006 shim (search old threads) and fitted it between the rollers. I ran the car with this mod for about a 1000 miles returning 28/ 29 MPG. This car a CR series had only done 56000 miles had very noisey valve gear also the compression in no 1 2 3 cylinders was slightly lower than the others,when i removed the rocker shaft i found it heavly grooved under nos 1 to 6 rockers the plug at the end of the shaft near the oil feed had a hole punched thru it so very little oil was getting to the front rockers. after i had replaced the assembley the engine would not idle and was running weak so i removed the the shim from the metering unit, the engine would now idle smoothly later i found that the compression was equal on all cylinders also i found the MPG had improved to around 30. In conculsion i now always check the vacum level at the metering unit is with in spec and at m.o.t.time have the co checked (my current tr5 is between 2.9 to 3.5%) Dave Quote Link to post Share on other sites
had17462 Posted November 11, 2012 Author Report Share Posted November 11, 2012 Dave many thanks for that ,i will pass on the info nick Quote Link to post Share on other sites
Peter Cobbold Posted November 11, 2012 Report Share Posted November 11, 2012 Dave many thanks for that ,i will pass on the info nick pass on this too: My first suspect would be the MU diaphragm - if punctured it gives an excessively rich mixture which wont burn well. Do the 'tongue test': with engine off! suck on the hose that connects MU to inlet manifold, while sucking close the bore of the tube with tongue tip and stop sucking. If the low pressure in the hose persists for a couple of seconds the MU is OK, if it wont hold the suction replace the diaphragm. Or the choke control not returning on the MU. Quote Link to post Share on other sites
Damson6 Posted November 20, 2012 Report Share Posted November 20, 2012 (edited) The PI system will not run well unless everything else is spot on. Check valve clearances compressions ignition plugs etc and vacuum to make sure engine is right, then start on the fuel system! PS I got 29mpg over a 1000miles in September Edited November 20, 2012 by Damson6 Quote Link to post Share on other sites
KiwiTR5 Posted November 26, 2012 Report Share Posted November 26, 2012 One of the basic "litmus" tests around any of the PI TRs is a casual check of the fuel consumption. As a guide I would expect a TR5 or TR6 PI to return somewhere around 25-28mpg in normal use (excluding excessive citybound stop-start situations). Quite a few of the issues around the PI systems lead to an over-rich mixture and consequent excessive fuel consumption. If the consumption is around 20mpg or worse it indicates a problem which is often related to overall engine tuning (not forgetting the air filter) or something has gone wrong with the metering unit ...either by its own accord or by someone "improving" it. Why does the fuel consumption increase with an engine that is badly tuned or has other problems? ...A typical senario: The PI metering unit senses manifold vacuum (not airflow) as its reference for how much fuel to deliver. If an engine is in a bad state of tune and consequently not delivering the power demanded of it you, the driver, will respond with your right foot but the engine is not able to deliver. However this action opens the throttles further and consequently decreases the vacuum sensed by the metering unit. The metering unit then delivers more fuel, mixture is over rich, engine probably delivers no more or even less power, more right foot... and,as a result, black smoke and money pouring out of the exhaust pipe! Robert Johnston Auckland, New Zealand Quote Link to post Share on other sites
had17462 Posted December 5, 2012 Author Report Share Posted December 5, 2012 Hi all , does anyone run a tr5 with carbs ? Nick Quote Link to post Share on other sites
ianhoward Posted December 5, 2012 Report Share Posted December 5, 2012 Hi all , does anyone run a tr5 with carbs ? Nick That's a TR250!!! Cheers Ian Quote Link to post Share on other sites
Guest ntc Posted December 5, 2012 Report Share Posted December 5, 2012 That's a TR250!!! Cheers Ian Now now Ian It would be interesting to find out how many proper 5's run Weber's? I think it may surprise you Quote Link to post Share on other sites
Tom Fremont Posted December 5, 2012 Report Share Posted December 5, 2012 Precious few '250s have Webers - a handful nationwide I reckon. Here's what I call mine: Quote Link to post Share on other sites
littlejim Posted December 6, 2012 Report Share Posted December 6, 2012 Watch it Tom, an OZ dyslexic will think you live here. Quote Link to post Share on other sites
Peter Cobbold Posted December 9, 2012 Report Share Posted December 9, 2012 Precious few '250s have Webers - a handful nationwide I reckon. Here's what I call mine: ============================================================================================== Oh dear, this side of the Atlantic "US" can mean something else: unserviceable. "" We have everything in common with America nowadays, except of course, language." Oscar Wilde Quote Link to post Share on other sites
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