Triumphant34t Posted April 9, 2020 Report Share Posted April 9, 2020 Hi there, Ive got a bit of a problem with my 2500pi. The car will crank but wont start unless the chock is on and the throttle pedal is pushed to the floor. When you release the throttle the car dies. It recently had a new fuel pump in it, im thinking its a vacuum leak somewhere in the injection system but am open to other ideas before i change all the seals. Quote Link to post Share on other sites
astontr6 Posted April 11, 2020 Report Share Posted April 11, 2020 On 4/10/2020 at 12:39 AM, Triumphant34t said: Hi there, Ive got a bit of a problem with my 2500pi. The car will crank but wont start unless the chock is on and the throttle pedal is pushed to the floor. When you release the throttle the car dies. It recently had a new fuel pump in it, im thinking its a vacuum leak somewhere in the injection system but am open to other ideas before i change all the seals. Have you done a full PI check? Pressure at the MU?, do the butterflies on the manifold open fully with the pedal to the floor? and are they all level with each other? done the suck test on the vacuum pipe to M/U? What is the history of this fault? Is there a voltage at the pump when you switch on? Bruce. Quote Link to post Share on other sites
Mike C Posted April 11, 2020 Report Share Posted April 11, 2020 (edited) Put a vacuum gauge on the brake booster connection and check the idle vacuum. My engine's PI always has to have 10 inches Hg to work properly . Some might need more. Edited April 11, 2020 by Mike C Quote Link to post Share on other sites
barkerwilliams Posted April 11, 2020 Report Share Posted April 11, 2020 (edited) Do you mean on a cold start i.e. last run a week or so ago, or last run within 24 hours, or won't restart when hot? All different problems. An engine that is not running has no vacuum, and very little whilst cranking. On a PI the reduced vacuum enriches the mixture (to accelerate), and the choke enriches it even more. Could I suggest in order of easiest first:- Check voltage preferably at fuel pump, whilst cranking - low voltage, poor fuel pressure - no fuel mist at injectors - nothing for spark to ignite. New genuine spark plugs - not cheap forgeries. Clean contacts in fuel circuit impact sensor near wiper motor. Pull all injectors and check for nice mist whilst cranking - a dribble just will not do!!! Possible really dirty air filter. Check fuel pressure 104'ish psi whilst cranking and the return pipe is clear. New battery with the highest CCA you can find to fit the space. Heavy duty wire to fuel pump; the new Bosch pumps take even more electric than the Lucas, and don't forget a heavy duty earth as well - electric needs two wires!!! You might need a fuel pump relay, but most cars have one fitted now so might not be needed. Check butterflies - not a quick job, needs a few hours and lots of patience a task with real opportunities to make it worse. It is part of the charm of a PI that it will not start instantly as if it had carburettors, it is a breed characteristic, a dawn chorus of cranking PI's at every TR event. Alan Edited April 11, 2020 by barkerwilliams Quote Link to post Share on other sites
John McCormack Posted April 12, 2020 Report Share Posted April 12, 2020 12 hours ago, barkerwilliams said: Do you mean on a cold start i.e. last run a week or so ago, or last run within 24 hours, or won't restart when hot? All different problems. An engine that is not running has no vacuum, and very little whilst cranking. On a PI the reduced vacuum enriches the mixture (to accelerate), and the choke enriches it even more. Could I suggest in order of easiest first:- Check voltage preferably at fuel pump, whilst cranking - low voltage, poor fuel pressure - no fuel mist at injectors - nothing for spark to ignite. New genuine spark plugs - not cheap forgeries. Clean contacts in fuel circuit impact sensor near wiper motor. Pull all injectors and check for nice mist whilst cranking - a dribble just will not do!!! Possible really dirty air filter. Check fuel pressure 104'ish psi whilst cranking and the return pipe is clear. New battery with the highest CCA you can find to fit the space. Heavy duty wire to fuel pump; the new Bosch pumps take even more electric than the Lucas, and don't forget a heavy duty earth as well - electric needs two wires!!! You might need a fuel pump relay, but most cars have one fitted now so might not be needed. Check butterflies - not a quick job, needs a few hours and lots of patience a task with real opportunities to make it worse. It is part of the charm of a PI that it will not start instantly as if it had carburettors, it is a breed characteristic, a dawn chorus of cranking PI's at every TR event. Alan I'm not sure that the cranking problem of PIs is uniform across them all. My 1970 PI, with Bosch pump, starts easily even when it hasn't run for a few days or weeks. I turn the ignition on as soon as I get in the car, let the pump build up pressure while I put my seat belt on, and then crank it. 4-5 seconds max, usually 1-3 seconds. Quote Link to post Share on other sites
Triumphant34t Posted April 12, 2020 Author Report Share Posted April 12, 2020 1 hour ago, John McCormack said: I'm not sure that the cranking problem of PIs is uniform across them all. My 1970 PI, with Bosch pump, starts easily even when it hasn't run for a few days or weeks. I turn the ignition on as soon as I get in the car, let the pump build up pressure while I put my seat belt on, and then crank it. 4-5 seconds max, usually 1-3 seconds. When the car was running sweet one turn of the key and it would start pretty much straight away, i did the same with the pump allowing it to build up pressure. Quote Link to post Share on other sites
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