john.r.davies Posted April 25, 2021 Report Share Posted April 25, 2021 On my Drive It Day outing, I had symptoms very like Washi's (https://www.tr-register.co.uk/forums/index.php?/topic/77015-tr6-sputtering-engine/). But he has carbs. My Vitesse has a TR6+ engine, and was running well, except when I slowed down! Then, intermittent drops in the fuel pressure, some so low that the engine dies. When stationary, I can hear the Bosch pump 'hunting' its revs going up and down. On getting home, the pump was very warm, almost hot! Is this the problem. It's mounted inside the boot, but I've never had this problem before and it's been there 5? years. Any thoughts, please? John Quote Link to post Share on other sites
Peter Cobbold Posted April 25, 2021 Report Share Posted April 25, 2021 Vapour locking when demand fro fuel drops away ? fuel pipe near hot exhaust? But why now? - winter lay up affected pump ? Does the pressure drop hunt in sync with pump noise? Peter Quote Link to post Share on other sites
Mike C Posted April 25, 2021 Report Share Posted April 25, 2021 I'd have a look at the PRV. I suspect it's sticking - changing the head and flow on the pump. If the PRV sticks and cut's off the diversion of excess fuel back to the tank on low load , the pump will be cooled by whatever fuel load the MU wants-which could be low enough to lead to pump overheating. Quote Link to post Share on other sites
Peter Cobbold Posted April 26, 2021 Report Share Posted April 26, 2021 5 hours ago, Mike C said: I'd have a look at the PRV. I suspect it's sticking - changing the head and flow on the pump. If the PRV sticks and cut's off the diversion of excess fuel back to the tank on low load , the pump will be cooled by whatever fuel load the MU wants-which could be low enough to lead to pump overheating. I buy that, scrub my suggestions. Peter Quote Link to post Share on other sites
john.r.davies Posted April 26, 2021 Author Report Share Posted April 26, 2021 Hmmmmmmmmmmmm! Yes. I bought off the Bay a non-Triumph PRV, that had a built in presure gauge, so I could adjust it in the boot, without ducking out to look at the dash gauge. After a while the Bourdon tube in the gauge failed, filling the guage with fuel and trying to fill the boot too! I 'fixed' it, by removing the guage and blocking the hole with plastic metal. "Worked" fine! But the design and workmanship of the gauge wasn't good, hence the failure. Maybe I should go back to the one I had before, a Malpassi from Malcolm at Prestige. Thanks! JOhn Quote Link to post Share on other sites
barkerwilliams Posted April 26, 2021 Report Share Posted April 26, 2021 John, If you think it is temperature related try one of these https://www.amazon.co.uk/Green-Wash-Ltd-Indoor-Outdoor-Multi-Colour/dp/B000EOQ9TS/ref=psdc_5496265031_t1_B003VNGWHS Comes with a 3m external probe drop the unit in the glove box and run the probe cable under the carpet back to the fuel pump and tape the probe to the pump. If it is fuel temperature related then next time there is a problem read off the external temperature of the fuel pump. Thereafter on hot days you have a fuel temperature readout available to warn you of impending problems, and all for the miserly sum of £7.15. Alan Quote Link to post Share on other sites
Waldi Posted April 26, 2021 Report Share Posted April 26, 2021 It could well be the PRV, or obstruction in the line from tank to pump. Can you dismantle the prv and check for sticking issues, or damage? How do you measure fuel pressure (just curious)? I ran my TR on the hottest day last year, I measured the fuel temperature in the tank, had no issues with fuel temperatures of 30-32? degrees C. Waldi Quote Link to post Share on other sites
astontr6 Posted April 26, 2021 Report Share Posted April 26, 2021 On 4/25/2021 at 5:07 PM, john.r.davies said: On my Drive It Day outing, I had symptoms very like Washi's (https://www.tr-register.co.uk/forums/index.php?/topic/77015-tr6-sputtering-engine/). But he has carbs. My Vitesse has a TR6+ engine, and was running well, except when I slowed down! Then, intermittent drops in the fuel pressure, some so low that the engine dies. When stationary, I can hear the Bosch pump 'hunting' its revs going up and down. On getting home, the pump was very warm, almost hot! Is this the problem. It's mounted inside the boot, but I've never had this problem before and it's been there 5? years. Any thoughts, please? John What size alternator have you got? In my view a TR6 engine runs best with an 18 ACR or 20 ACR alternator not the original 15 ACR. The up and down whine disappears with the larger alternators and the indicators are then also constant with out the up and down flashing from slow to normal. Plus there is more current to the pump. Bruce. Bruce. Quote Link to post Share on other sites
john.r.davies Posted April 26, 2021 Author Report Share Posted April 26, 2021 Thank you all for your opinions! Bruce, Deffo not an alternator whine! And the one I have is enormous (I know I should have one of those tiny Jap ones!) Waldi, I have a gauge sensor under the bonnet, on a spur from the line to the M/u. It reads on a dash gauge, digitally. Alan, cunning gadget, but the swirl pot supplying the pump was cool. I kicked myself after for not having used my IR temp gun! As I said, I'm going to replace it with a Malpassi from Prestige. I'll report back! JOhn Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.