250 HPDI Idling issue.

[magwart]

250 HPDI will not idle. It chucks a little, spits, stalls etc. If you pop it in gear it will run fine. The motor will run at 5800 rpm's with no problems. But as soon as you put it in neutral it will stall. Almost like it's starving for fuel, but it will run run at max rpm's. I've checked every thing. Fuel is fine etc. I've read this is common on other boards recently as today. Any thoughts other than bringing it to the dealer? Thanks

[F150owner]

Does the HPDI idle on 4 cylinders??

[SEAHORSE]

IF the throttle position sensor is not adjusted per the service bulletin, you can have a very bad idle on an HPDI engine. Also the synch of all the throttle plates should be checked out. Unless you have the knowledge, the service bulletin, and the correct tools, it is best left to a trained tech.

This is assuming that engine condition, state of tune, and the spark plugs are all in good shape. You can always check these items before having to take it to a dealer.

[522Ed]

A friend of mine who works on yamaha engines told me it does drop down on cylinders when on idle from 6 to 4 or 3. I had notice that on mine. But it does not stall. I could be wrong but so far he has been a great help to me when I have questions about my motor.

[5 keepers]

Anyone have a pic of the TPS?

[Hamfisted]

5 Keepers here's a generic HPDI Throttle Position Sensor.... Item #10 is the TPS.
But yes, when the gear selector is in the neutral position the HPDI motors kill the middle cylinder on each bank.





Mike

[5 keepers]

Thanks Hamfisted.

[rudetech1]

It does drop cylinders but should not stall. Get it checked out by a tech.

[5 keepers]

One thing I noticed on mine was that the foot throttle was out of adjustment and once I made the adjustment, it made a world of difference. If you have one, you may want to check that.

[magwart]

Well,,,,,,,,,After checking everything under the sun and still getting no where with a bad idle and stalling issue's the motor finally paid a visit to the dealer. And guess what????????? No compression in one of the cylinders. New Block and head are on the way. I for the life of me can not understand how a motor will not idle worth a hoot but can run at 5700 rpm's wide open and have a bad cylinder?. Thanks for all your help fellas.