Starting Problems, Starting with Throttle but Won't Idle Options

[nmkimosabe]

My 1974 1.8 with fuel injection will only start by manually opening the throttle but I can't get it idle and thus run properly. I recently had the AFM rebuilt and replaced the points, plugs, condenser and replaced the CHT sensor but the problem continues as it did before. I've looked for vacuum leaks to no avail with starter fluid. I now seek the expertise of the members of this forum for additional suggestions.

[Superhawk996]

Given you had a worn distributor is there a reason you wanted to stay with rebuilt stock instead of going to a new 123 distributor?

The thing that bothers me here is your last update was
UPDATE: Well, the car finally was running better in the shop but then died when the car was taken for a test drive

This really doesn’t align with the bad distributor theory as a bad distributor doesn’t usually work then stop during a test drive. Usually when you get those kind of died instantly while driving failures, it’s electrical in nature.

As Wonki suggested, that could extend all the way into the ECU not failing until hot. You may want to reach out to @jeffbowlsby - at one time he was offering a test service of ECU’s in car and with the ECU test equipment but that may have been D-jet only ?

You’ve had a lot of parts swapped but I’m still not getting the sense that you have a mechanic that really understands L-jet. Could just be that you’ve had multiple problems masking other problems. (IMG:style_emoticons/default/confused24.gif)

I wish I had a better suggestion for you but there’s just too many questions I have that can’t easily be answered 2nd hand not knowing what he’s tested electrically and how he tested it.

Maybe Wonkipop has better suggestions - I’m not an L-jet guy and he is.

[nmkimosabe]

Given you had a worn distributor is there a reason you wanted to stay with rebuilt stock instead of going to a new 123 distributor?

The thing that bothers me here is your last update was
UPDATE: Well, the car finally was running better in the shop but then died when the car was taken for a test drive

This really doesn’t align with the bad distributor theory as a bad distributor doesn’t usually work then stop during a test drive. Usually when you get those kind of died instantly while driving failures, it’s electrical in nature.

As Wonki suggested, that could extend all the way into the ECU not failing until hot. You may want to reach out to @jeffbowlsby - at one time he was offering a test service of ECU’s in car and with the ECU test equipment but that may have been D-jet only ?

You’ve had a lot of parts swapped but I’m still not getting the sense that you have a mechanic that really understands L-jet. Could just be that you’ve had multiple problems masking other problems. (IMG:style_emoticons/default/confused24.gif)

I wish I had a better suggestion for you but there’s just too many questions I have that can’t easily be answered 2nd hand not knowing what he’s tested electrically and how he tested it.

Maybe Wonkipop has better suggestions - I’m not an L-jet guy and he is.

I appreciate you taking the time to respond. The mechanic now believes the electrical issue when the car died was possibly the burnt 88Y pin on the dual relay which was later switched. I've been as methodical and thorough throughout this process, and it has been quite aggravating. I've had many vintage Porsche's and never experienced this level of frustration. Stay tuned for an update this week.

[wonkipop]

Given you had a worn distributor is there a reason you wanted to stay with rebuilt stock instead of going to a new 123 distributor?

The thing that bothers me here is your last update was
UPDATE: Well, the car finally was running better in the shop but then died when the car was taken for a test drive

This really doesn’t align with the bad distributor theory as a bad distributor doesn’t usually work then stop during a test drive. Usually when you get those kind of died instantly while driving failures, it’s electrical in nature.

As Wonki suggested, that could extend all the way into the ECU not failing until hot. You may want to reach out to @jeffbowlsby - at one time he was offering a test service of ECU’s in car and with the ECU test equipment but that may have been D-jet only ?

You’ve had a lot of parts swapped but I’m still not getting the sense that you have a mechanic that really understands L-jet. Could just be that you’ve had multiple problems masking other problems. (IMG:style_emoticons/default/confused24.gif)

I wish I had a better suggestion for you but there’s just too many questions I have that can’t easily be answered 2nd hand not knowing what he’s tested electrically and how he tested it.

Maybe Wonkipop has better suggestions - I’m not an L-jet guy and he is.

I appreciate you taking the time to respond. The mechanic now believes the electrical issue when the car died was possibly the burnt 88Y pin on the dual relay which was later switched. I've been as methodical and thorough throughout this process, and it has been quite aggravating. I've had many vintage Porsche's and never experienced this level of frustration. Stay tuned for an update this week.

yeah well, the dual relay is real important for having the fuel pump work in an L jet.
so........
lets see.

i can tell you another interesting story about "ECU"s.
going back 25+ years ago, and being an early adopter of CAD (thanks to my time in chicago, (IMG:style_emoticons/default/beerchug.gif) thank you america) i had a hot rodded 486 i ran my drafting and modelling software on. and one day it (IMG:style_emoticons/default/stromberg.gif) itself. i came in the office and fired it up and it ran for about 10 minutes. then kaput. if i remember right i went out for a coffee and cig or three and came back and switched it back on. fired up. ran for 10 minutes. kaput again. sat down and thought about it. right. somethings getting hot and when its up to temp is when if fails. rang my computer tach man nerd at that time. the late 90s were great. nerds door to door. he came and picked up the box and threw it in his ute and took it home. ripped it apart. found the crack in the circuit board. i said great. i have forgotten to back up for a fortnight or two and i have a masterpiece or three on it i need to retrieve. "no worries". he set the box up on his back verandah outside over night with a hard drive to down load all the data and fired it up first thing the next morning and before it could get hot enough to die he managed to get all the data off it. saved our arses. but not our bank account as we had to get a new machine. forced us to get a pentium. (IMG:style_emoticons/default/biggrin.gif)

moral of the story. if it runs and idles well etc but then when you head out the door and get 10 minutes down the road and it dies well.............and its an EFI system from half a century ago, you got to suspect some thing electrical.

and start testing and diagnosing. and resist spraying it with parts machine gun.

i hope this is the end of your troubles.
very frustrating as you say.

however - i would say this, L jet is very very simple and honestly not hard to get to the bottom of, if you get your brain into what it is. its a fairly limited set of things that can go wrong.

[nmkimosabe]

Given you had a worn distributor is there a reason you wanted to stay with rebuilt stock instead of going to a new 123 distributor?

The thing that bothers me here is your last update was
UPDATE: Well, the car finally was running better in the shop but then died when the car was taken for a test drive

This really doesn’t align with the bad distributor theory as a bad distributor doesn’t usually work then stop during a test drive. Usually when you get those kind of died instantly while driving failures, it’s electrical in nature.

As Wonki suggested, that could extend all the way into the ECU not failing until hot. You may want to reach out to @jeffbowlsby - at one time he was offering a test service of ECU’s in car and with the ECU test equipment but that may have been D-jet only ?

You’ve had a lot of parts swapped but I’m still not getting the sense that you have a mechanic that really understands L-jet. Could just be that you’ve had multiple problems masking other problems. (IMG:style_emoticons/default/confused24.gif)

I wish I had a better suggestion for you but there’s just too many questions I have that can’t easily be answered 2nd hand not knowing what he’s tested electrically and how he tested it.

Maybe Wonkipop has better suggestions - I’m not an L-jet guy and he is.

I appreciate you taking the time to respond. The mechanic now believes the electrical issue when the car died was possibly the burnt 88Y pin on the dual relay which was later switched. I've been as methodical and thorough throughout this process, and it has been quite aggravating. I've had many vintage Porsche's and never experienced this level of frustration. Stay tuned for an update this week.

yeah well, the dual relay is real important for having the fuel pump work in an L jet.
so........
lets see.

i can tell you another interesting story about "ECU"s.
going back 25+ years ago, and being an early adopter of CAD (thanks to my time in chicago, (IMG:style_emoticons/default/beerchug.gif) thank you america) i had a hot rodded 486 i ran my drafting and modelling software on. and one day it (IMG:style_emoticons/default/stromberg.gif) itself. i came in the office and fired it up and it ran for about 10 minutes. then kaput. if i remember right i went out for a coffee and cig or three and came back and switched it back on. fired up. ran for 10 minutes. kaput again. sat down and thought about it. right. somethings getting hot and when its up to temp is when if fails. rang my computer tach man nerd at that time. the late 90s were great. nerds door to door. he came and picked up the box and threw it in his ute and took it home. ripped it apart. found the crack in the circuit board. i said great. i have forgotten to back up for a fortnight or two and i have a masterpiece or three on it i need to retrieve. "no worries". he set the box up on his back verandah outside over night with a hard drive to down load all the data and fired it up first thing the next morning and before it could get hot enough to die he managed to get all the data off it. saved our arses. but not our bank account as we had to get a new machine. forced us to get a pentium. (IMG:style_emoticons/default/biggrin.gif)

moral of the story. if it runs and idles well etc but then when you head out the door and get 10 minutes down the road and it dies well.............and its an EFI system from half a century ago, you got to suspect some thing electrical.

and start testing and diagnosing. and resist spraying it with parts machine gun.

i hope this is the end of your troubles.
very frustrating as you say.

however - i would say this, L jet is very very simple and honestly not hard to get to the bottom of, if you get your brain into what it is. its a fairly limited set of things that can go wrong.

I love your story about the hot -rodded 486 and I have similar memories of those and the IT nerds running around the company offices. I would agree that L-jet seems like a simple system once you figure it out, but it does require a learning curve to understand it fully and how all the components work together. Of course, what doesn't.
I'm curious as to why you live in Antartica?