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> 1.7L still running terribly, $1800 and a month in the shop yields a barely drivable teener
BCinSC
post Sep 7 2010, 01:47 PM
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rough running
stalls at idle
backfires
0-50 takes several minutes (notice I didn't say 60 - can't hit that)
strong smell of raw gas

all speaks to at least one cylinder not firing

No visible signs of leaking fuel.
2 new injectors don't seem to have helped
Trigger and Ignition points replaced
Ignition wires checked and rechecked
Timing was supposedly set, but will check myself when I get home.

Why is this thing so cranky?
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7TPorsh
post Sep 7 2010, 01:57 PM
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Firing order?
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djm914-6
post Sep 7 2010, 01:58 PM
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All that time and money and it still isn't right??? Can you tell Autobahn to fix it once and for all and not pay anymore. This is ridiculous!
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BCinSC
post Sep 7 2010, 02:09 PM
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I called Autobahn this morning, after the white knuckle drive into work, and let Mike know how disappointed I was.
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BCinSC
post Sep 7 2010, 02:10 PM
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Thing is, initial cold start seems OK. As it warms, it gets progressively worse to the point of undrivable.
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Bartlett 914
post Sep 7 2010, 02:38 PM
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QUOTE(BCinSC @ Sep 7 2010, 02:47 PM) *

rough running
stalls at idle
backfires
0-50 takes several minutes (notice I didn't say 60 - can't hit that)
strong smell of raw gas

all speaks to at least one cylinder not firing

No visible signs of leaking fuel.
2 new injectors don't seem to have helped
Trigger and Ignition points replaced
Ignition wires checked and rechecked
Timing was supposedly set, but will check myself when I get home.

Why is this thing so cranky?

CHT could be bad. Could also be a bad ECU.
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Root_Werks
post Sep 7 2010, 03:30 PM
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Wow,

This sounds like a simple fix.

Already mentioned to check the CHT, shoot, just buy a new one and install it. Why even mess with it, cheap.

There's only a couple of things on D-Jet that cause such rich running conditions, here are a few that I can recall off the top of my big head/little brain:

CHT bad
ECU bad - I had one once that made my 914 run really, really rich.
Trigger points bad - I think I noted you already replaced those
Bad injector(s) - not closing
Cold start injector staying open

There are others, but those are usually the common ones. Make a list, go through each one at a time. You'll get it.

(IMG:style_emoticons/default/driving.gif)
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Root_Werks
post Sep 7 2010, 03:31 PM
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QUOTE(BCinSC @ Sep 7 2010, 01:10 PM) *

Thing is, initial cold start seems OK. As it warms, it gets progressively worse to the point of undrivable.


Cold start valve not closing? I can't remember, does a 73' D-Jet have one? Unplug it when it's warm, easy test.

Also screams bad AAR.
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BCinSC
post Sep 8 2010, 05:28 AM
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Work done at reputable shop

CHT - replaced <20K ago. Do they go bad often? Can I test it's functionality? Just a resistance value, correct?

Trigger points replaced last summer and again this last visit to shop - seems like they are ruled out.

Yes, '73 has cold start injector and always suspected it was malfunctioning. However, engine is rough even cold and especially under any load.

2 brand new injectors this summer and other 2 tested out of engine for spray pattern at shop and were OK

What is AAR?

Could dizzy be failing to advance? Stuck weights? It seems to move freely cold , but I've never held it hot.
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Lennies914
post Sep 8 2010, 07:20 AM
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AAR= auxilary air regulator. Open when cold, closes when hot. If stuck, it will be a huge vacuum leak. Again, easily checked. With engine warmed up, remove the AAR vacuum line from the air box side, there should be no vacuum.
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76-914
post Sep 8 2010, 08:19 AM
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QUOTE(BCinSC @ Sep 8 2010, 04:28 AM) *

Work done at reputable shop

CHT - replaced <20K ago. Do they go bad often? Can I test it's functionality? Just a resistance value, correct?

Trigger points replaced last summer and again this last visit to shop - seems like they are ruled out.

Yes, '73 has cold start injector and always suspected it was malfunctioning. However, engine is rough even cold and especially under any load.

2 brand new injectors this summer and other 2 tested out of engine for spray pattern at shop and were OK

What is AAR?

Could dizzy be failing to advance? Stuck weights? It seems to move freely cold , but I've never held it hot.

Are they reputable w/ 914 owners or the pinky rings? Sounds as if they aren't familiar w/ our 914's.
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trent1542
post Sep 8 2010, 08:50 AM
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maybe your timing is off?
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Root_Werks
post Sep 8 2010, 08:54 AM
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QUOTE(trent1542 @ Sep 8 2010, 07:50 AM) *

maybe your timing is off?


Yup, could be that, vac hose connected or disconnected when timing set?

Vac hose hooked up to correct side of can?

Those make a huge difference.
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trent1542
post Sep 8 2010, 09:50 AM
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QUOTE(Root_Werks @ Sep 8 2010, 07:54 AM) *

QUOTE(trent1542 @ Sep 8 2010, 07:50 AM) *

maybe your timing is off?


Yup, could be that, vac hose connected or disconnected when timing set?

Vac hose hooked up to correct side of can?

Those make a huge difference.

what about the timing chain?
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TheCabinetmaker
post Sep 8 2010, 10:15 AM
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QUOTE(trent1542 @ Sep 8 2010, 10:50 AM) *

QUOTE(Root_Werks @ Sep 8 2010, 07:54 AM) *

QUOTE(trent1542 @ Sep 8 2010, 07:50 AM) *

maybe your timing is off?


Yup, could be that, vac hose connected or disconnected when timing set?

Vac hose hooked up to correct side of can?

Those make a huge difference.

what about the timing chain?

(IMG:style_emoticons/default/lol-2.gif) Its a 4 cly Trent! It ain't got no stinking timing chain!
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trent1542
post Sep 8 2010, 04:57 PM
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QUOTE(vsg914 @ Sep 8 2010, 09:15 AM) *

QUOTE(trent1542 @ Sep 8 2010, 10:50 AM) *

QUOTE(Root_Werks @ Sep 8 2010, 07:54 AM) *

QUOTE(trent1542 @ Sep 8 2010, 07:50 AM) *

maybe your timing is off?


Yup, could be that, vac hose connected or disconnected when timing set?

Vac hose hooked up to correct side of can?

Those make a huge difference.

what about the timing chain?

(IMG:style_emoticons/default/lol-2.gif) Its a 4 cly Trent! It ain't got no stinking timing chain!

whoops forgot about the 4 cylinder part, just rebuilt a jeep liberty 6 cylinder and I had such a hard time with the timing chain. (IMG:style_emoticons/default/av-943.gif)
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jk76.914
post Sep 8 2010, 05:08 PM
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ruptured MPS? Have you checked to see if it holds vacuum?

Jim
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Cevan
post Sep 8 2010, 06:49 PM
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What service did the shop perform for the $1800?
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scotty b
post Sep 8 2010, 06:53 PM
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Take the intake manifold off and look for a 3 way vauum hose. It cracks, it cannot be seen with the main plenum on , and it will casue all of these issues. I know because years ago I pulled an engine to rebuild it convinced it was in need, ended up finding that piece was hard as a wedding dick and split in 2.
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scotty b
post Sep 8 2010, 07:09 PM
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QUOTE(scotty b @ Sep 8 2010, 04:53 PM) *

Take the ( " air filter " in the diagram )off and look for a 3 way vauum hose. It cracks, it cannot be seen with the main plenum on , and it will casue all of these issues. I know because years ago I pulled an engine to rebuild it convinced it was in need, ended up finding that piece was hard as a wedding dick and split in 2.


O.k. slight brain fart. It is not a 3 way vacuum line it is a 3 way metal thingy ma hooch and it has a hose that makes a awkward angle to the plenum. thereis also a line on the underside, that can't be seen. This diagram only shows the 2 on the top 13mm one to the filter housing and one to the boot. I don't recall where the one on the underside goes.


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