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Tom Powell Samba Member
Joined: December 01, 2005 Posts: 4855 Location: Kaneohe
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Posted: Thu Jan 11, 2018 5:34 pm Post subject: engine dies on turns after going downhill |
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With my '87 automatic tintop, if I'm on a long downhill stretch of road at idle and make a turn at the bottom the engine sometimes dies. This seems to happen regularly at times and then does not happen again for several months.
My theory is that the plugs may be slightly fouled by the long idle and the power steering pump overloads the idling engine and kills it. The fact that it happens in bunches, but only periodically may be due to fuel fill ups from different sources.
Armstrong steering and shifting to neutral for restarts are no problem. I don't know if there is a relationship between the engine dieing and the use of slight braking for the turn and drawing a vacuum for the brake booster.
Aloha
tp |
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Jake de Villiers Samba Member
Joined: October 24, 2007 Posts: 5911 Location: Tsawwassen, BC
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Posted: Thu Jan 11, 2018 6:50 pm Post subject: Re: engine dies on turns after going downhill |
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Tom Powell wrote: |
With my '87 automatic tintop, if I'm on a long downhill stretch of road at idle and make a turn at the bottom the engine sometimes dies. This seems to happen regularly at times and then does not happen again for several months.
My theory is that the plugs may be slightly fouled by the long idle and the power steering pump overloads the idling engine and kills it. The fact that it happens in bunches, but only periodically may be due to fuel fill ups from different sources.
Armstrong steering and shifting to neutral for restarts are no problem. I don't know if there is a relationship between the engine dieing and the use of slight braking for the turn and drawing a vacuum for the brake booster.
Aloha
tp |
Huh. On over-run, the ECU shuts off the fuel, so it isn't the plugs loading up - unless its with oil? _________________ '84 Vanagon GL 1.9 WBX
'86 Westy Weekender Poptop/2.5 Subaru/5 Speed Posi/Audi Front Brakes/16 x 7 Mercedes Wheels - answers to 'Dixie'
@jakedevilliersmusic1
http://sites.google.com/site/subyjake/mydixiedarlin%27
www.crescentbeachguitar.com
www.thebassspa.com |
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Tom Powell Samba Member
Joined: December 01, 2005 Posts: 4855 Location: Kaneohe
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Posted: Thu Jan 11, 2018 8:27 pm Post subject: Re: engine dies on turns after going downhill |
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The engine doesn't die until I start the turn so I suspect the steering pump is killing it while it's at idle. But that doesn't happen during idling around a parking lot and making turns. I suspect braking and using vacuum for the booster might be a contributor, but that doesn't happen in the parking lot either. I watch the tach before the turn and it indicates an idling engine. I don't have enough eyes to see if/when the tachometer drops. The fact that it happens in bunches separated by months of normalcy makes me suspect fuel from different gas stations might be a contributor.
Aloha
tp |
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E1 Samba Member
Joined: January 21, 2013 Posts: 6376 Location: Westfalia, Earth
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Posted: Thu Jan 11, 2018 9:59 pm Post subject: Re: engine dies on turns after going downhill |
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Hi, Tom:
Has it ever blown out oil smoke when this happens?
Mine did exactly as yours for three years. I thought it was a vacuum leak or air leaking in somehow, telling the ecu to pump fuel to match the excess air. I'd get to the bottom of a hill and it acted like the plugs had fouled, if coming to a stop at the bottom I had to rev it up as if the plugs were soaking wet with unburned gas.
Then at the end of the three years, on two big downgrades, it blew out gobs of blue oil smoke. I was, Um, concerned. It turned out to be a clogged oil breather.
I'm not entirely sure the two conditions were from the clogged breather, but save for the smoke the running condition was identical. Turns were not involved as in your case, though.
But I'd bet a burger -- or in your case, a nice Mahi-Mahi sammy -- that it's your oil breather. _________________ 84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
Colin Chapman |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50257
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Posted: Fri Jan 12, 2018 6:26 am Post subject: Re: engine dies on turns after going downhill |
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When I first got my 83 1/2 POS, it would do something similar. The rings were totally shot giving zero compression and for reasons I no longer remember the decel fuel cut off didn't work, so by the time I would reach the bottom of a long hill the engine would barely run. Getting the throttle position switch adjusted and otherwise fixing the decel fuel cut off cured the problem. |
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Jon_slider Samba Member
Joined: April 11, 2007 Posts: 5091 Location: Santa Cruz, Crowdifornia
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E1 Samba Member
Joined: January 21, 2013 Posts: 6376 Location: Westfalia, Earth
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Posted: Fri Jan 12, 2018 12:35 pm Post subject: Re: engine dies on turns after going downhill |
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It seems part of this mystery depends on whether turning the wheel is indeed a factor.
If it is, it's neither oil breather, nor throttle body. _________________ 84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
Colin Chapman |
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Tom Powell Samba Member
Joined: December 01, 2005 Posts: 4855 Location: Kaneohe
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Posted: Fri Jan 12, 2018 12:58 pm Post subject: Re: engine dies on turns after going downhill |
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E1 wrote: |
It seems part of this mystery depends on whether turning the wheel is indeed a factor.
If it is, it's neither oil breather, nor throttle body. |
That's exactly where my thoughts are. The engine runs fine all the way down the hill, but dies when i start the turn at the bottom. Additionally I've sometimes had a "weakness" while backing out of the driveway after starting the engine. Sometimes the engine would die during this "weakness" and that might be associated with turning the steering wheel, but It hasn't happened often enough to collect any meaningful data.
I doubt there are seasonal gas formula change here in Hawaii, but I will assume that some fuels/brands are better or weaker than others. Next fill up I'm going to try the cheapest fuel I can find and see if the problem occurs more regularly. Next fill up after that I might try some non ethanol fuel to see if the problem disappears.
Aloha
tp |
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E1 Samba Member
Joined: January 21, 2013 Posts: 6376 Location: Westfalia, Earth
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Posted: Fri Jan 12, 2018 1:03 pm Post subject: Re: engine dies on turns after going downhill |
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Are there any equally-long or longer hills without turns that you can test on? _________________ 84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
Colin Chapman |
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bobbyblack Samba Member
Joined: May 21, 2015 Posts: 4333 Location: United States, Iowa
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Posted: Fri Jan 12, 2018 1:13 pm Post subject: Re: engine dies on turns after going downhill |
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Well... I'd start by reducing the one thing you know for sure: turning+power steering... Take off the PS belt. I know you'd be driving for 4+ months without it, and that would SUCk0rZ, but.. then you'd know.
BTW, it would be good to know what your idle RPMs are, and if they are higher/lower on that decent.
Could be as easy as upping the idle with the set screw.
Also, ever try flipping to neutral for that long decent? Still dying on that turn?
Good luck! _________________ '87 Westy 'Flossie','86 Westy 'R1','86 tintop GL - Subi2.2 'J2','83.5 stock tintop L 'ZoomBus','74 Karmann Ghia, '63 Notch |
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Tom Powell Samba Member
Joined: December 01, 2005 Posts: 4855 Location: Kaneohe
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Posted: Fri Jan 12, 2018 1:28 pm Post subject: Re: engine dies on turns after going downhill |
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E1 wrote: |
Any hills without turns you can test on? |
Up and down hills and driving and stopping at the bottom no problem. The common denominator is coasting downhill then turning or backing up at idle after start.
Aloha
tp |
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Tom Powell Samba Member
Joined: December 01, 2005 Posts: 4855 Location: Kaneohe
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Posted: Fri Jan 12, 2018 1:33 pm Post subject: Re: engine dies on turns after going downhill |
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bobbyblack wrote: |
... Also, ever try flipping to neutral for that long decent? Still dying on that turn? ... |
OK
I'm going to try slipping it into neutral as I slow down for the turn and collect some data.
Aloha
tp |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50257
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Posted: Fri Jan 12, 2018 1:53 pm Post subject: Re: engine dies on turns after going downhill |
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Tom Powell wrote: |
bobbyblack wrote: |
... Also, ever try flipping to neutral for that long decent? Still dying on that turn? ... |
OK
I'm going to try slipping it into neutral as I slow down for the turn and collect some data.
Aloha
tp |
Unless you want to foot the bill for a rebuild of your automatic don't do this. There are reports of people killing their auto boxes this way. |
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Tom Powell Samba Member
Joined: December 01, 2005 Posts: 4855 Location: Kaneohe
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Posted: Fri Jan 12, 2018 2:20 pm Post subject: Re: engine dies on turns after going downhill |
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Wildthings wrote: |
Tom Powell wrote: |
bobbyblack wrote: |
... Also, ever try flipping to neutral for that long decent? Still dying on that turn? ... |
OK
I'm going to try slipping it into neutral as I slow down for the turn and collect some data.
Aloha
tp |
Unless you want to foot the bill for a rebuild of your automatic don't do this. There are reports of people killing their auto boxes this way. |
The owner's manual recommends towing with dollies under the rear wheels or on a flat bed truck to avoid damage to automatic transmissions. For front hook-up it states towing speed/distance for automatic transmissions - 30 mph/30 miles. I'll assume that means rear wheels on the ground and in neutral.
I wouldn't coast downhill in neutral, but for dieing in the turn I'm moving at about 10-15 mph and shift into neutral for the restart.
I plan on trying neutral at about 10-15 mph before the turn and see what data I can collect. Tweaking the idle a bit sounds like a good idea also.
Aloha
tp |
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E1 Samba Member
Joined: January 21, 2013 Posts: 6376 Location: Westfalia, Earth
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Posted: Fri Jan 12, 2018 2:21 pm Post subject: Re: engine dies on turns after going downhill |
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Hope Tom hasn't already left for that drive... _________________ 84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
Colin Chapman |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50257
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Posted: Fri Jan 12, 2018 3:48 pm Post subject: Re: engine dies on turns after going downhill |
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Tom Powell wrote: |
Wildthings wrote: |
Tom Powell wrote: |
bobbyblack wrote: |
... Also, ever try flipping to neutral for that long decent? Still dying on that turn? ... |
OK
I'm going to try slipping it into neutral as I slow down for the turn and collect some data.
Aloha
tp |
Unless you want to foot the bill for a rebuild of your automatic don't do this. There are reports of people killing their auto boxes this way. |
The owner's manual recommends towing with dollies under the rear wheels or on a flat bed truck to avoid damage to automatic transmissions. For front hook-up it states towing speed/distance for automatic transmissions - 30 mph/30 miles. I'll assume that means rear wheels on the ground and in neutral.
I wouldn't coast downhill in neutral, but for dieing in the turn I'm moving at about 10-15 mph and shift into neutral for the restart.
I plan on trying neutral at about 10-15 mph before the turn and see what data I can collect. Tweaking the idle a bit sounds like a good idea also.
Aloha
tp |
I believe people have killed their autoboxes by coasting in neutral down a long grade at highway speeds, just for kicks. This was with the engine running from what I can remember. If the manual says 30 mph max then do that or less. You should be able to feel when the fuel cut off occurs on decel, plus the fuel cut off can cause surging at idle. If you are never experiencing either of these, then I would suspect your decel cut off isn't working. |
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Tom Powell Samba Member
Joined: December 01, 2005 Posts: 4855 Location: Kaneohe
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Posted: Tue Jan 23, 2018 5:27 am Post subject: Re: engine dies on turns after going downhill |
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This problem occurs so seldom that it hard to pinpoint exactly when the engine dies. But, this evening it occurred again and the dieing seemed to occur slightly before the turn was initiated. Not sure if it was related to braking and using vacuum for the booster. I'll have to collect more data, but the problem happens so infrequently that it will probably take months before I find the exact relationship between braking, turning and dieing.
I'm headed to the mainland for a few months and when I get back I'll bust out my ECU monitor, hook that up, and see if it will tell me anything.
Aloha
tp |
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danfromsyr Samba Member
Joined: March 01, 2004 Posts: 15129 Location: Syracuse, NY
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Posted: Tue Jan 23, 2018 7:06 am Post subject: Re: engine dies on turns after going downhill |
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we had a air cooled that had the same/similiar symptoms..
in the end it was the 3 little thin wires in the distributor for the HALL sensor.
would on occasion get just enough G force to touch and ground out the ign signal. _________________
Abscate wrote: |
These are the reasons we have words like wanker |
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E1 Samba Member
Joined: January 21, 2013 Posts: 6376 Location: Westfalia, Earth
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Posted: Tue Jan 23, 2018 9:19 am Post subject: Re: engine dies on turns after going downhill |
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That's really interesting, Dan, as the collector on ours that keeps the wires from getting trapped under the cap on ours was broken. Last summer one of the wires broke for good when swapping in a rotor.
I don't think the wire had to do with our issues prior to the clogged oil breather incidents, but worth a check by Tom for sure. _________________ 84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
Colin Chapman |
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17009 Location: Retired South Florida
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Posted: Tue Jan 23, 2018 11:49 am Post subject: Re: engine dies on turns after going downhill |
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Going down hill, all of the fuel in the tank is at the front of the tank opposite of the outlets. Does it seem to happen regardless of how much fuel is in the tank? Old tanks can starve the engine for fuel in some rare cases. It is usually aggravated by a low fuel level.
Interesting points about coasting with an automatic. If the engine is running, the transmission pump is circulating fluid. Not sure how that is leading to an early demise. Engine off, that's a different story. _________________ ☮️ |
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