engine misfire

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HawaiianGauer
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Re: engine misfire

Post by HawaiianGauer »

New development today:

I installed new plugs for kicks. Then moved on to another round of timing, idle, idle mixture, syncing art stuff - primarily because I failed to complete #12 & #14 above --> "confirm sync at 1500 RPM" and "confirm with timing light that Timing is advancing to max advance within 2000-2500 RPM". I also suspect it's running too lean based on conditions of plugs.

Every time I tried to confirm sync at 1500 RPM, I noticed they were NOT sync'd. The rear carb was consistently 2-4 lower than the front on the carb sync tool. I opened the idle mixture screws a bit on the rear carb, re-sync'd at idle. Same problem at 1500 RPM.

What does this mean? How do I fix?

Mahalo-
X
Mahalo for your assistance!

Harry X.
73 'Gauer 712M

check out the X-Gauer in action: https://www.youtube.com/watch?v=cYj_UNQDgpM
compunerdy
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Re: engine misfire

Post by compunerdy »

Just for kicks.. unplug all 4 solenoids and then probe one of the terminals with the key off. If you do not get 24v then something is wrong.
Tim
1975 710K
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pcolette
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Re: engine misfire

Post by pcolette »

compunerdy wrote:Just for kicks.. unplug all 4 solenoids and then probe one of the terminals with the key off. If you do not get 24v then something is wrong.
Actually with the key off there should be no reading at the terminals. Did you mean with the key on?
Paul C.
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'73 Swiss 710M
'89 Puch 230GE
compunerdy
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Re: engine misfire

Post by compunerdy »

DOH.. yes lol
Tim
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HawaiianGauer
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Re: engine misfire

Post by HawaiianGauer »

compunerdy wrote:Just for kicks.. unplug all 4 solenoids and then probe one of the terminals with the key off. If you do not get 24v then something is wrong.
with key on :oops:

#1: 18, 20; #2 22, 20; #3: 24, 20 #4: 20, 20. #1 = connection closest to front of engine & so on. 2 sets of #s equal 2 solid attempts with probe. I probed & recorded 1-4, then did it again (2nd #). I took plastic covers off female ends - no corrosion noted. Male ends on fuel cutoff valves - no corrosion noted. Despite that, I cleaned up all metal connections & re-assembled. Took probe readings again - basically similar to above - no change.

I'm thinking that's unacceptable & I need to replace that wiring harness. Can anyone confirm?

Any comments on last post - cannot sync carbs @ 1500, what does this mean? What is fix?

X
Mahalo for your assistance!

Harry X.
73 'Gauer 712M

check out the X-Gauer in action: https://www.youtube.com/watch?v=cYj_UNQDgpM
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Jimm391730
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Re: engine misfire

Post by Jimm391730 »

#1: 18, 20; #2 22, 20; #3: 24, 20 #4: 20, 20. I'm thinking that's unacceptable & I need to replace that wiring harness.
There is almost never a need to "replace" a wiring harness that has not been otherwise damaged. I suspect that your ground connection (or your probe tip connection) is faulty. Where/what are you using for your ground reference point?

I'm personally still very leery of your coil + voltage measurement, too; and that reading also depends on where your ground reference is. If you need to, ground to the battery negative terminal -- the lead terminal and/or post clamp is soft and will deform to make a good connection easier. I suspect that once you get proper connections you will see similar solenoid voltages (within a tenth of a volt) at all four; and unless someone removed or shorted out the ballast resistor you should not see ~25V at the coil positive (unless the points are open).

And all the above assumes that your meter is not faulty. Try a different meter, and see if you get the same results. If you get different readings, your readings are suspect.
Jim M.
712W and 710M
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HawaiianGauer
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Re: engine misfire

Post by HawaiianGauer »

HawaiianGauer wrote:New development today:

Every time I tried to confirm sync at 1500 RPM, I noticed they were NOT sync'd. The rear carb was consistently 2-4 lower than the front on the carb sync tool. I opened the idle mixture screws a bit on the rear carb, re-sync'd at idle. Same problem at 1500 RPM.

What does this mean? How do I fix?
any feedback on this issue?
Mahalo for your assistance!

Harry X.
73 'Gauer 712M

check out the X-Gauer in action: https://www.youtube.com/watch?v=cYj_UNQDgpM
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McCall Pinz
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Re: engine misfire

Post by McCall Pinz »

I'll have to re-read the whole thread, but are you dialing in the idle mixture screw instead of the idle adjusting screw? Take a look at the image in this link-
http://porsche356registry.org/resources ... ning-.html
eat, sleep, Pinzgauer
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edzz
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Re: engine misfire

Post by edzz »

and you are adjusting the connecting rods to attain synchronization at 1500 rpm, correct?
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krick3tt
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Re: engine misfire

Post by krick3tt »

Great link Wayne, thanks. I rebuilt both carbs and just took pictures as I disassembled them one at a time so I would know what went where.
Finished one and then did the other, syncing them as I went through the process. At this time they are doing fine... :o
Several of the guys from our local pinz club had a tech day and did them together, better to trade ideas and chat our way through it.

Happy trails
Morris

OH, BTW.... the shirt arrived and is great. Super design.
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better take a closer look at the American Indian.---Henry Ford
Jim LaGuardia
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Re: engine misfire

Post by Jim LaGuardia »

Carbs are sync'd at idle(850-950 rpm usually around 6-9 Kg/h).
Cheers, Jim LaGuardia
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HawaiianGauer
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Re: engine misfire

Post by HawaiianGauer »

Aloha folks-
I am now absolutely certain of the diff between the idle mixture screws (4 of them) and the 2 idle adjust screws (see previous posts, pictures). Although I did screw that up earlier... :oops: ...while it confirms I'm a rookie, I also think it proves I AM trainable!! I hope you all keep the faith!!

Right now, the only issue I think I've positively ID'd is that the carb's do not remain sync'd at 1500 RPM - which was one of Scott's checklist items (go to pg 2 of this thread for Scott's checklist; see -> "7. - Re-attach linkages, adjusting lengths as necessary so that when the linkages are attached you have not changed your sync or RPM. Confirm Sync after the linkages are re-attached. Confirm sync at 1500 RPM").

Carb's are sync'd at idle. When I increase RPM to 1500 & maintain it, carb sync is off by 2-4 "marks" on the carb sync device. While at 1500 RPM, I have not touched a thing (specifically, no, I have not adjusted the linkages or anything else).

I can easily try adjusting the linkages while at 1500 RPM but it seems logical to conclude that doing so will change the carb sync at idle, no?

Are there any other thoughts about why my carb's do not remain in sync at 1500 RPMs and what to do about it?

Outside of the fact that the carb's do not stay sync'd at 1500 RPM and given all the work, etc I've done to date (which is a lot, see earlier posts in this thread), the only other thing I think I still need to do is to continue to work on the "art" of adjusting timing, mixture, and idle RPMs looking for that magic sweet spot (reconfirming carb sync along the way) as a means of returning performance back to 100% like it was back in MAR-APR time frame.

Other thoughts?
(I don't think my coil or elec fuel cutoff sensors are an issue. Coil is new & I've done a bad job grounding the volt meter, which I think is causing the reading nuances. Today I plan to make the effort today to run a wire from the meter ground probe straight to the neg term of the battery & re-do readings).
Mahalo for your assistance!

Harry X.
73 'Gauer 712M

check out the X-Gauer in action: https://www.youtube.com/watch?v=cYj_UNQDgpM
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McCall Pinz
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Re: engine misfire

Post by McCall Pinz »

I re-read the whole thread (whew) and see that you have stopped mixing up the idle speed and idle mixture screws. I'd try one more thing- With the aircleaner and intake attached, while idling, spray some starting fluid on the outside of the carb where the throttle shaft nuts are. If the engine accelerates, then you have worn throttle shafts and air is leaking around those. My guess is the rear one is bad and when you put the sync on it air is sucked in through there.

I wish I was working on your Pinz today instead of mine- we'll have a high of 29. This is actually balmy for Jan here, so I'm taking advantage of the warm weather!
eat, sleep, Pinzgauer
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HawaiianGauer
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Re: engine misfire

Post by HawaiianGauer »

McCall Pinz wrote:I wish I was working on your Pinz today instead of mine- we'll have a high of 29. This is actually balmy for Jan here, so I'm taking advantage of the warm weather!
Good reminder of how lucky I am to have nice wx year round! If it makes you feel any better, Uncle Sam will be moving us to Colorado in a few months... :wink:

Current situation: I continue to believe, after everything I've done over the months, that the single biggest CURRENT issue is the "art" of adjusting timing, mixture, and idle RPMs. I've done virtually all the other things folks have suggested in this thread (which started in NOV 13; no air leakage btw) - which I think were all valid & good suggestions as you never know what is causing or contributing to misfiring/poor engine performance. And now I have a new problem...I think my starter is toast (more on that at the very end).

Most recent work since last post: besides some checks folks suggested that were negative, I did another round of timing, mixture, and idle RPMs adjusting. I continue to be convinced it is an art form & you have to keep at at. After that round, the engine is running the best it's run - maybe since I first starting having problems last APR/MAY! I say "maybe" because I haven't had a chance to drive the highway hill that is my bench mark for engine power (more on that later). I don't think I'm at 100% but I do think I'm possibly back to the 90% or so range. I cannot explain why the carbs continue to not remain sync' d at 1500 RPMs but it appears to not be a major issue. If I'm missing something about that - PLEASE let me know! For now, I'm no longer worrying much about that as much.

What did I do? Before I started another round of timing, mixture, and idle RPM adjusting (which now ALWAYS includes using the carb sync device - a MUST), I pulled & inspected the spark plugs (remember, I installed brand-new ones during the last weekend of major work). Despite setting the idle mixture screws the same, sure enough plugs 3 & 4 clearly appeared to be running too lean. 1 & 2 looked normal. So I focused on tweaking the idle mixture screws on the rear carb to run more rich as I fiddled with timing, mixture, and idle RPMs over the next couple of hrs. Current end state right now is rear carb idle mixture screws are turned out more than the front; timing is 8 BTDC; carbs sync at 6; RPMs ~930~980.

After these most recent rounds of adjustments, I took a long drive (1.75hrs each way) around the island but on roads where I never exceeded ~45mph. At the end of the drive, we spent a couple of hrs off-roading in some massive mud, etc. Drove home. Engine ran GREAT!

Some notes I think may be interesting to others after many, many hours over many, many months of playing with timing, idle mixture, and RPM adjustments:
1. Timing. I've read where people suggest timing should be at 12 BTDC at sea level (which is me). I tried hard working different combinations of adjustments to get to 12 but the engine just did not run as well as it did at 8. BTW, I marked where the distrib psn was when I first bought the 'Gauer - when it ran its best since I've owned the vehicle. So I've also tried hard to work adjustment combo's with the distrib set at that "orig" psn thinking "well it ran great when the distrib was at that psn". Turns out that psn was at a much lower BTDC (3? I think?) and despite many adjustment combo's, I just could not get the engine to run as well as where the distrib is set now.
2. RPMs. Many recommend between 700~900. Despite my efforts to get my RPM down into that range, I could not find an adjustment combo that resulted in smooth, consistent idle below 900. It's as low as I've been able to get it where engine perf is not neg impacted.

My current timing, mixture, and idle RPM adjustment conclusions after this long journey are:
1. The experts in this forum provide good baselines to start from (turn out screws xx; target BTDC to yy; etc etc) BUT, in the end, there are other factors impacting performance of YOUR engine resulting in final settings that work best for YOUR engine but aren't exactly in line with expert guidance. And that's OK.
2. timing, mixture, and idle RPM adjustments (particularly for those without diagnostic tools like a tail pipe sniffer) IS an art form, meaning, be prepared to play, tweak, play, test, tweak again...it's probably gonna take a while to find the magic combination that works best for your engine.
3. You MUST do the prep & verification steps Scott (in this thread) and others tell us to do...or else chances are you are truly wasting your time & spinning your wheels.
4. Buy the damned cab sync tool (see #3...).

If the experts disagree with my conclusions, or see need to temper some of my concluding comments - pls set me (and other rookies) straight!

Unless others weigh in, I think this thread (which is mainly about timing, mixture, and idle RPMs adjustments) is about done.

So on to my next problem: after that last long drive & fun in the mud, I had to go away for a few weeks. Got home a couple of days ago...and immediately discovered it would not start. The starter is whining but clearly NOT turning the motor so I think the starter has died. What ticks me off is the fact that there were ZERO signs/symptoms of starter problems. None. If anyone thinks that sounds very suspicious and therefore thinks it may be something else, pls let me know (I did disconnect all the wires to the starter solenoid, cleaned them up despite none looking corroded, added some dielectric grease, reassembled - no change; I also confirmed with volt meter both batteries at 12 volts).

Aloha-
X
Mahalo for your assistance!

Harry X.
73 'Gauer 712M

check out the X-Gauer in action: https://www.youtube.com/watch?v=cYj_UNQDgpM
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pcolette
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Re: engine misfire

Post by pcolette »

After reading the whole thread and particularly your most recent post, I have 2 suggestions:

1- there is an intake balancing hose that connects the front and rear intake manifolds. It is hidden under the 2 sections of engine tin under the carbs. It's my understanding that if this hose develops a leak it could affect your ability to sync the carbs or at the very least affect the mixture. Not positive about this but maybe someone else will chime in. The part number is 9000916/07 (01-35-60) and runs about $4.00 plus new clamps.

2- your starter problem sounds like it may be either a bad solenoid which is available as a separate part (7121095900) or the starter pinion gear is sticking and needs to be cleaned and lubricated. You'll probably have to pull the starter which can be a bit of a PITA.
If you've been considering buying the gear reduction starter from Expedition Imports I give it a big thumbs up.

Hope this helps....
Paul C.
_________
'73 Swiss 710M
'89 Puch 230GE
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