Let me start with saying I need to go through the system in more detail soon. I am collecting vacuum hoses, will get injectors tested, and so on.
Meanwhile, the car runs very fast and strong. The two symptoms I have are odd, and seem contradictory to me.
First, the car wants to idle high when warm. I can adjust that out mostly with the idle speed screw on the throttle body, but there is a tipping point there where the idle speed becomes very sensitive, up to that point large changes in screw setting do little to nothing.
Second, the ECU idle mixture screw needs to be full CCW to idle. If I move the setting off of full CCW it starts to stall and die.
Third, maybe unrelated, is a puff of blackish smoke on decel. (is that over run?). Not sure if this is related, or just some wear showing.
The car runs smooth and strong under throttle, will smoke the tires off the line if asked, and starts easily both cold and warm. It actually does run pretty well with the above considered, but it doesn't seem like these conditions are normal.
Still a learner on D-Jet here, reading and understanding as I go... Having fun, not frustrated.
Thanks guys!
Morrie
So...I agree that these things potentially seem to be contradictory, at least the way you've described them. Likely more than one thing going on.
I do think you're running too rich. That would explain the idle knob having to be full CCW on ECU, the "puff of smoke" on decal, and very sensitive idle bypass screw. Verify if this is the case: pull the plugs and check to see if they are dark and sooty. (I assume you don't have a wideband sensor?)
The following are some possible causes of running too rich:
-Fuel pressure too high (should be approx 28-29 psi)
-MPS not holding vacuum
-Leaking CSV (disconnect fuel line to see if that makes a difference)
-Failing CHT (check resistance both warm and cold)
-Leaking injectors
The fact that you have a high idle even though I think you're running rich would suggest you may have vacuum leak and/or timing too far advanced. The latter is easy to check. The former takes some real hunting.
If you haven't already, read this a few times and give us some more info: https://members.rennlist.com/pbanders/djetparts.htm#troubleshoot
Hi, Rob,
Your advice was just what I needed- somewhere to start. I was in a state of analysis paralysis.
I have the WB O2 setup I used to tune my 912 that is going into the 914. That will be one of the first things I do.
I'm getting some help from my friend Jason at Paragon who just did the vacuum line replacement on his bee- he is putting together a set of new lines for me.
I will start by validating the timing is set properly, recheck breaker points, and ignition points, and then do a check to make sure there are no obvious vacuum leaks. While I am at it I will pull the plugs and check condition, though I expect soot as you commented. From there I will use my CIS kit to check fuel pressure, and go to the other items.
Thanks for your advice, and patience...
Awesome, all good steps to take. D-Jet can be simple to troubleshoot - unless more than one thing is wrong (which is often the case, especially for those souls trying to revive a car that hasn't been given TLC in a long while). That WB 02 will help definitively answer at least one question. If you get info that validates running rich, make sure to check your MPS as a possible suspect, too.
Good luck!
Morrie,
Going to need a little more info about your engine and D-Jet set up.
Engine mods?
Sounds like your TPS is adjusted but your MPS might be an issue.
Black smoke not good, check the condition of the plugs.
All of the items mentioned are important to a good running engine.
A bit of advice, 914's were not built to smoke the tires, major stress on the stock drive train.
Mike
I'm in the middle of a similar situation.
My problem is the vacuum canister on the distributor...
Hope this helps a little bit.
Is the MPS calibrated for 2056???
Your signature says a 76, does it have all the emissions plumbing?
Ok, what exhaust set up are you using?
Are all of the FI components '76? Is there any mix and matching?
Miles since 2056 update? Any other mods? ie: cam, lightened flywheel?
Mike
So non working vac diaphram on the dizzy....unknown MPS on a 2056 which may or may not have been claibrated....hasn.t checked the valves...points....timing.....ect.
And it won.t idle because.....?
Start with all the mechanicals first and make sure what parts you have...first or you will be chasing your tail for some time.
My .02
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