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Full Version: D-Jet Stalling After Overrun
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BeatNavy
Still looking to get my 2056 running like the proverbial "raped ape" (in Bleyseng's delightful wording biggrin.gif ). It shows flashes of running that way, but then something will happen and it won't consistently give the pull that I know it's capable of doing, even on the same drive (e.g., run strong cold or cool and not as strong fully warmed up). A lot of the symptoms are intermittent, and, probably like most D-Jet challenges, there may be multiple variables in play aggravating symptoms or reducing their noticeability.

In the last week I've eliminated the bucking and the idle is rock steady when it idles in the Air/Fuel range of 13 (plus or minus), although sometimes it will suddenly go very lean. When it does that it may not come back toward 13 unless I've throttled enough at some point to kick in part or full load. The last couple of days my new symptom is what I'm referring to in the title. Sometimes, not often, after overrun when I disengage the engine, the engine RPM's will drop really low. At that point the engine may actually cut out (at which point I can just pop the clutch and restart the engine and the RPM's will bounce back up fine) or after a second it will recover back up to a stable ~1000 RPM just fine by itself. It's almost like there's some intermittent problem transitioning to the idle state on the TPS. I don't see any references to this in my D-Jet gospels.

Any ideas on the cause of this symptom? If so, it might help me identify possible root cause for the other issues I've had on and off.

To recap my setup: 2056 with stock D-Jet. New wiring harness from Jeff, injectors serviced in the last few months, fuel system was pretty much completely overhauled last year, MPS rebuilt/tuned by Bleyseng, I believe valves adj/dwell/timing are right on, and I thoroughly cleaned and serviced the dizzy about two weeks ago. I also "bumped" the fuel pressure to just around 30 or 31 psi last night with no noticeable impact. At moderate or full load I consistently get good Air/Fuel ratios. I still think it often or sometimes runs too lean at light throttle.


DRPHIL914
you may still need to tweek your MPS. i dont have a 2056, but i had my 2.0 working similar and the changes i made that seemed to work to correct the issue was adjusting the MPS , and it was a very slight adjustment- but it made a huge differenced and was why i would get too lean on WOT or other times as well. , but i would recheck the CHT values whe warmed up. putting in a new CHT helped my issue. - you said timing was rechecked? if that is correct then i'm leaning toward these 2 .

Phil
BeatNavy
Hi Phil - yes, thanks, I think that's my next step. As Racer Chris says, the bench tuning only gets you so far. I am going to try to carefully tweak that over the next week or so when I have time. I think it's probably also worth going back and verifying some of the fundamentals just to make sure I'm not going crazy. I do remember you went through some D-Jet challenges a while back, and it can be a bear to track down.

Last night I took it for a spin and it ran pretty well before it fully warmed up. I've noticed this as well in the last few days. After fully warming up it may lose some power and then the engine just sounded really loud, like either I have an exhaust leak or the valve adjustment is way off. What now, right? confused24.gif

So I think my next steps are:

1. See if I do have exhaust leak
2. Probably verify/adjust valve clearance
3. Verifying dwell/timing, again
4. Start making minor adjustments to MPS

I won't have much time this weekend to look at it dry.gif
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