Andy1966 Posted May 16, 2015 Report Share Posted May 16, 2015 Guys Need your help my PI CR Car starts from cold with little fuss, but i cannot seem to find happy setting to start when hot if left for 1/2 - 1 hour. My cold start as follows (no problems) 1. Bosch pump let run for 30 seconds 2. Full choke 3. usually starts after a couple of turns of keys whether left for 1 week or 1 month. My Hot Start 1. Bosch pump 30 seconds 2. Half choke 3. Starts but clearly over chocked and i quickly have to reduce choke to minimal to maintain reasonable revs, then completely off. Am i doing something wrong ? What do you guys do to start yours when hot. Car CR Pi Car, running Bosch pump with electronic ignition (Accu Spark). Choke connected in both positions (metering unit & throttle body) Andy Quote Link to post Share on other sites
peejay4A Posted May 16, 2015 Report Share Posted May 16, 2015 When I had my 6 the hot start procedure was no choke, half throttle. Quote Link to post Share on other sites
Andy1966 Posted May 16, 2015 Author Report Share Posted May 16, 2015 Yep agreed thats what i would expect but it won't start without choke ? Cant believe this is right way to start car from Hot Quote Link to post Share on other sites
aardvark Posted May 16, 2015 Report Share Posted May 16, 2015 +1 for Pete's way - no choke, half throttle. CP car on olde points. Cheers Dave Quote Link to post Share on other sites
peejay4A Posted May 16, 2015 Report Share Posted May 16, 2015 In which case the first port of call for me would be to check fuel pressure at the MU. Quote Link to post Share on other sites
orangen_haut Posted May 17, 2015 Report Share Posted May 17, 2015 Hi Andy, 30 seconds is -in my opinion- a very long Time to run the pump, 10 seconds is enough, also when the car is cold. If the car is warm, dont use the Choke... This is my very first post in this Forum and my english isnt very good...., but i try to do my very best...:-) Best wishes from Munich Michael Quote Link to post Share on other sites
Andy1966 Posted May 17, 2015 Author Report Share Posted May 17, 2015 Guys Thanks very much for all your help, i will give the advice a go and let you know how i get on. Andy Quote Link to post Share on other sites
Graze Posted May 17, 2015 Report Share Posted May 17, 2015 Hi Andy, 30 seconds is -in my opinion- a very long Time to run the pump, 10 seconds is enough, also when the car is cold. If the car is warm, dont use the Choke... This is my very first post in this Forum and my english isnt very good...., but i try to do my very best...:-) Best wishes from Munich Michael Micheal Welcome I've been speaking English for 57 years and your 1st post is word perfect Well done Please contribute as often as you can Graze Quote Link to post Share on other sites
Peter Cobbold Posted May 17, 2015 Report Share Posted May 17, 2015 Hi Andy, 30 seconds is -in my opinion- a very long Time to run the pump, 10 seconds is enough, also when the car is cold. If the car is warm, dont use the Choke... This is my very first post in this Forum and my english isnt very good...., but i try to do my very best...:-) Best wishes from Munich Michael Michael, Greetings from North Wales, and welcome to the forum. Peter Quote Link to post Share on other sites
mike3739 Posted May 17, 2015 Report Share Posted May 17, 2015 Michael Your English is word perfect Welcome to the forum, happy TRing Cheers Mike Quote Link to post Share on other sites
Steves_TR6 Posted May 17, 2015 Report Share Posted May 17, 2015 I go with the consensus of no choke and some throttle for hot starting. This has worked on both my tr6s , with a variety of fuel pump arrangements! Presently on a Bosch 996 pump with an inline pre filter, which seems totally reliable right down to an empty tank in a hot day in traffic! Steve Quote Link to post Share on other sites
Denis Posted May 17, 2015 Report Share Posted May 17, 2015 Strange...my car has always been the total opposite...it's always started first turn from hot or warm...but has always needed lots of cranking & chasing on the starter to catch from cold, plus lots of Cold start and subtle little dabs of throttle, especially when it catches! Quote Link to post Share on other sites
Andy1966 Posted May 18, 2015 Author Report Share Posted May 18, 2015 Yes agree. I attended a Lea valley group run last year and was pleasantly supprized about how easy other PI TR s started after each of the stages, my car always needed choke and was clearly coughing and spluttering before it cleared its self and the choke was switched off. My car has the Bosch 996 pump also mounted outside boot under rear near side arch, over the weekend i took the car for a run as only just got refurbished diff back in place and pump was noisy at end of 30 min run but not hot to touch, any ideas ? I would like to check my fuel pressure and have 3/8 bsp T Piece to fit, but would like your advise on pipework and gauge to make meter. Question : do you guys fit meter and leave in place or fit and simply place threaded bung in T Piece when not in place ? Thanks Andy Quote Link to post Share on other sites
mike barrett Posted May 18, 2015 Report Share Posted May 18, 2015 Yes agree. I attended a Lea valley group run last year and was pleasantly supprized about how easy other PI TR s started after each of the stages, my car always needed choke and was clearly coughing and spluttering before it cleared its self and the choke was switched off. My car has the Bosch 996 pump also mounted outside boot under rear near side arch, over the weekend i took the car for a run as only just got refurbished diff back in place and pump was noisy at end of 30 min run but not hot to touch, any ideas ? I would like to check my fuel pressure and have 3/8 bsp T Piece to fit, but would like your advise on pipework and gauge to make meter. Question : do you guys fit meter and leave in place or fit and simply place threaded bung in T Piece when not in place ? Thanks Andy Andy just fitted a pressure transducer to mine (4-20mA 150psi transducer feeding a loop powered gauge). I used a 3/8 BSP T piece, the one available from RS, and removed the test point and fitted a 1/4 BSP adapter with a Dowty washer, to take the pressure transducer. I plan to leave the pressure transducer in place and will fit the gauge in the car. I have just fitted a new MU and had awful problems undoing the flexible pipe going to the MU, had to cut it and then replace it when I replaced the MU. New MU in place and no leaks! Back to the original topic.... My TR6 has always been a pain to start, lots of cranking, lots of choke when cold and half throttle but no choke when hot. Monitoring the pressure at the MU shows its only just 100psi and drops to 65 psi when cranking, I have a Bosch pump and some strange wiring, including a switch under the seat to turn off the pump, and some sort of alarm box under the dash. Before I start to fiddle with the pressure relieve valve I plan to measure the voltage at the pump I have a feeling there is a significant volt drop thru the cables. mike Quote Link to post Share on other sites
peejay4A Posted May 18, 2015 Report Share Posted May 18, 2015 (edited) Volt drop is your problem Mike. Beefier live cable to the pump is needed then use the existing one to operate a relay. Also your battery and/or its cabling might be tired. Edited May 18, 2015 by peejay4A Quote Link to post Share on other sites
mike barrett Posted May 18, 2015 Report Share Posted May 18, 2015 Volt drop is your problem Mike. Beefier live cable to the pump is needed then use the existing one to operate a relay. Also your battery and/or its cabling might be tired. I think you are correct. Need to check battery voltage as well when cranking. Yes plan is to run new cable and use the original cable to switch a local relay. While I have the car in the garage I am tempted to borrow 20A PSU from work and see what pressure the pump generates at different voltages. Just out of interest. cheers mike Quote Link to post Share on other sites
john.r.davies Posted May 18, 2015 Report Share Posted May 18, 2015 No argument with the electrical theory. If you want to check pressure temporarily , and oil pressure gauge will do, but it must be damped or the oscillation of pressure as the shuttle - er - oscillates will shake the needle off the gauge. Make up a pierced metal disc - I used some copper C/ heating pipe - to place inthe connection to the M/u. The hole should be as small as possible. John Quote Link to post Share on other sites
Andy1966 Posted May 19, 2015 Author Report Share Posted May 19, 2015 Hi Mike Voltage : I know my car has had a new feed wire installed to Bosch pump, i measured voltage at pump recently and seemed ok about 13-14 volts. However i have never completed this when cranking, I have always had a suspicion my battery is too small so i guess this would prove theory as looks lost in battery tray. what battery power should i have ? Fuel Pressure : Yet to complete this, i have the 3/8 BSP T Piece, can you take image your set up, to give me some guidance please as never done this to date. You Guys still Meet at Plough ? I saw Tom & Tim at Barrington last year just after your Italy trip, I should pop down and get some advice Andy Quote Link to post Share on other sites
Kevo_6 Posted May 19, 2015 Report Share Posted May 19, 2015 Hi Andy I have this set up G3/8" bspp test coupler with test point, 200mm g1/4" microbore hose test point ( but you can choose any length you like), 10 bar glycerine pressure gauge 1/4" bspp bottom entry. I don’t have a permanent gauge in the car as I don’t fancy 106psi of fuel going everywhere but that’s just my personal preference. Quote Link to post Share on other sites
Andy1966 Posted May 19, 2015 Author Report Share Posted May 19, 2015 Kevo I like that set up ! i have started to look into this already. Thank you Andy Quote Link to post Share on other sites
mike barrett Posted May 19, 2015 Report Share Posted May 19, 2015 Hi Mike Voltage : I know my car has had a new feed wire installed to Bosch pump, i measured voltage at pump recently and seemed ok about 13-14 volts. However i have never completed this when cranking, I have always had a suspicion my battery is too small so i guess this would prove theory as looks lost in battery tray. what battery power should i have ? Fuel Pressure : Yet to complete this, i have the 3/8 BSP T Piece, can you take image your set up, to give me some guidance please as never done this to date. You Guys still Meet at Plough ? I saw Tom & Tim at Barrington last year just after your Italy trip, I should pop down and get some advice Andy Andy yes still meet up at the Plough at Fen Ditton, first Monday evening of the month, unless its a bank holiday. Mix of TR reg, CT and TSSC members in fact anyone is welcome! At the last meeting there were 3 TR6, spitfire, GT6 and a proper Mini... + a couple of moderns. Will take some pics of my pressure transducer etc and try to post them. On my car I have just measured the voltage at the pump and battery. Battery voltage with no load 12.55V. Ign on and only pump running: Voltage at battery = 12.25V, Voltage at pump 10.27V, pressure 100psi Cranking: Voltage at battery = 9V !!, Voltage at pump = 6.9V, pressure ~70psi. The pump is drawing 9.9A when battery voltage is 12.25V. So one of the weekend jobs is to rewire the pump (its still has the original Lucas wiring...) and buy a new battery... Will have a look on the forum to see what battery people recommend. At the moment it has Bosch Silver battery 12V 55Ah, 420A, part No 555 059 042 regards mike Quote Link to post Share on other sites
mike barrett Posted June 2, 2015 Report Share Posted June 2, 2015 Just coming back to an old topic as I have completed some work on the car... I have replaced the battery, ran a new fused lead to the pump, replaced the MU (with one from Niel set so that I can easily weaken the mixure when going over the alps...) and have adjusted the fuel pressure to 110 psi **. I have also added a wide band lambda sensor and readout so I can see what the mixture is doing. She now starts much much easier and seems to run better. Pleased with my efforts so far Mike ** I realise it should be 105psi does it matter if its a bit high? I could tweak it back down again as I now have a pressure readout (feed from a pressure transducer) by the dashboard so its easy to check. Quote Link to post Share on other sites
stuart Posted June 2, 2015 Report Share Posted June 2, 2015 It can make them run rich with too much pressure. Stuart. Quote Link to post Share on other sites
Andy1966 Posted June 4, 2015 Author Report Share Posted June 4, 2015 Mike Many thanks for the update, sounds like you have cracked it. I am yet to check the fuel pressure at MU as have not got all the equipment organised, only recently got car back together after Diff refurbishment and Lubrication of all UJs + got Car MOT'd. Can you advise on the following 1. Battery type you have fitted (amps) 2. I have heard the upgraded power cable for pump should be via relay, is this correct and if so how can i identify if i have one in place already as cannot find anything as of yet. Andy Quote Link to post Share on other sites
JohnG Posted June 5, 2015 Report Share Posted June 5, 2015 Andy I asked a similar question regarding best fit battery Th consensus was biggest cold crank amperage (cca) you can get, Ah not so important I went with that and have a 620cca and 75Ah battery, bought from Tayna on fleabay It was, in the end, physical size and terminal configuration that were the limiting factors Quote Link to post Share on other sites
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