1973 1.7L bucking skipping backfiring thru engine, 1973 1.7L bucking skipping backfiring thru engine Options

[johnoscar]

My guess is the condenser.
If I read the thread right, the replacement had a wire that was too short. So you didn’t replace it.(?)
Extend the wire and try it.

you are correct. the condenser wire from bosch was too short. called george at aa. the posts about the condenser wire are about 2 years oid and he didn't know anything about it. he had to ask someone in his repair garage, but did confirm,

since, i have replaced the distributor with 123ignition, without any change.

[johnoscar]

It could be a vacuum leak. You say you have had issues finding shops to look at it. Maybe snap some pics of the engine and let us take a look.

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There is a guy in the Springfield area - close to you called Hurst Injectors (https://hurstinjectorservice.com/) - GREAT GUY - GREAT WORK, knows Bosch like the back of his hand - the injectors might need a refresh - short money........

If the car sat for a while prior to this FUN - I would STRONGLY suggest starting with the vacuum circuit. Everything connected to the Plenum (box under the Throttle Body - where the throttle cable goes) must be air-tight. The Plenum itself will rust and leak........

I chased the same thing for months and finally checked the vacuum, if there are leaks the car will lose it's mind......

Oh, I am in Arlington - trailer it here and I will troubleshoot for you......N/C

ty. didn't know that. i'll follow up on what he does. your offer is more than kind and appreciated very much. i may be in contact with you....too good to pass up.

[emerygt350]

Wouldn't there be no spark if it were the condenser?

[ChrisFoley]

ctc911ctc has a 2L engine. The 1.7L plenum is different, and not prone to cracking as the 2L unit is.

[johnoscar]

i don't want to say this ........but

burnt valve?
or an exhaust valve that never sealed properly and its gotten worse and worse.

symptoms fit.

EDIT
well done for being the one and only owner.
stick with it. (IMG:style_emoticons/default/beerchug.gif)

That, sadly, was my next question as well.

Have you done a compression test?

cyl1=158 cyl2=155 cyl3=165 cyl4=154 all psi (all cold)

[emerygt350]

Those numbers are great. That really only leaves peripherals. Get on the vacuum lines. Get us pictures.

[ctc911ctc]

Chris,

Good to see your post - hope all is well - it has been a long time since I owned a 1.7, I was not aware that the plenum was different,

Thank you,

ctc911ctc has a 2L engine. The 1.7L plenum is different, and not prone to cracking as the 2L unit is.

[Highland]

Chris,

Good to see your post - hope all is well - it has been a long time since I owned a 1.7, I was not aware that the plenum was different,

Thank you,

ctc911ctc has a 2L engine. The 1.7L plenum is different, and not prone to cracking as the 2L unit is.

Is the type 4 2L bus’ plenum similar in shape to the 1.7L plenum? If so, why did they elect to use a different 2L plenum design on the 914?

[wonkipop]

Chris,

Good to see your post - hope all is well - it has been a long time since I owned a 1.7, I was not aware that the plenum was different,

Thank you,

ctc911ctc has a 2L engine. The 1.7L plenum is different, and not prone to cracking as the 2L unit is.

Is the type 4 2L bus’ plenum similar in shape to the 1.7L plenum? If so, why did they elect to use a different 2L plenum design on the 914?

i could be wrong about this -
but the bus 2.0 L was either twin carb (in most of the world except the USA) or if EFI it ran L jetronic. the VW version for the bus came a few years after the 2.0 developed by porsche for the 914 which is D jetronic. porsche designed a fairly unique intake plenum and throttle body for the 914 2.0 the one that is on the VW 2.0 is more like the intake plenum and throttle body on the 1.8 L jets or the 2.0 912E.

[johnoscar]

Check all the grounds on the engine.

TY for the reply.

That has been done. What has not been done is following ECU to all connective points.

Super important. You need to test the FI harness for continuity.

All it takes is a DVM (Digital Volt Meter).

Jeff....does your site have a diagram of what wires at the ECU go to which wires at the other end??