D-Jet Problems, Stalls when hot, misses at med. rpms Options

[john_g]

I'm having problems that I'm pretty sure come from somewhere in the D-jet system. I have a '74 914, bored to 2056. Here are my symptoms:

It idles okay. It's a bit rough when cold, but it doesn't cut out on me and warms up to a steady idle quickly (1200 when cool, 800-900 when warm), but when it's been run for a longer time and is good and hot, the idle drops well below 800 and it stalls. It'll start back up right away but only if I treat it as if it's flooded - I have to put the accelerator to the floor as I restart it. Secondly, at mid rpm's, between 2200 and 2800, it hesitates, sputters, misses, and occasionally backfires - this happens whether it's cold or warm.

What I've done or have had done:
usual tuning routine
replaced the CHT sensor
replaced the MPS
replaced the distributor
cleaned the PVC valve
checked for vacuum leaks
checked the TPS, it seems good

Two air-cooled mechanics with good reputations have worked on it and haven't been able to solve the problem fully. All the above helped a bit, but the situation is still there. There has to be some sensor that isn't reading the situation correctly. Any ideas, or ... has anyone had a similar problem? (IMG:style_emoticons/default/confused24.gif)

[Old Yella]

Hi
I don't usually give advice but as I have had the same shit happening I have sought advice and got some excellent advice from the forum. Thanks Tom.

Mine car now runs great when hot but has cold temp problems as some components are just worn out. I'm working on those slowly.

My car was doing exactly the same thing as yours

1 check for air leaks

2 check your fuel pressure is correct, mine went up to 70 psi. pressure regulator failed.

3 timing is critical.

4 Check the TPS with the ohm meter. I got a replacement that checked out and then it caused bucking so it was back to the old worn one which worked a bit better

5 Don't adjust anything till the motor is absolutely at operating temp

6 Try and use an fuel air ration gauge if you can because without it you may be too rich. I'm now about 6 clicks leaner and haven't broken down for weeks

7 check that your throttle plate isn't binding also, the shafts may be so worn lots of air is getting past there.

Good luck

[john_g]

Hi
I don't usually give advice but as I have had the same shit happening I have sought advice and got some excellent advice from the forum. Thanks Tom.

Mine car now runs great when hot but has cold temp problems as some components are just worn out. I'm working on those slowly.

My car was doing exactly the same thing as yours

1 check for air leaks

2 check your fuel pressure is correct, mine went up to 70 psi. pressure regulator failed.

3 timing is critical.

4 Check the TPS with the ohm meter. I got a replacement that checked out and then it caused bucking so it was back to the old worn one which worked a bit better

5 Don't adjust anything till the motor is absolutely at operating temp

6 Try and use an fuel air ration gauge if you can because without it you may be too rich. I'm now about 6 clicks leaner and haven't broken down for weeks

7 check that your throttle plate isn't binding also, the shafts may be so worn lots of air is getting past there.

Good luck

Thanks for the advice. Some of the checks you've mentioned have been done, but not others, so I've got somewhere to go.