Is this the dreaded 914 vapor lock?, Asking for your ideas and thoughts Options

[Artfrombama]

Drove my 914 to a PCA function yesterday morning, 93f and humid.
After driving on the interstate at 70-75mph for around 45 miles I exited and the motor died. I had enough momentum and coasted into a gas station/convenience store where I topped off the tank and tried to restart the car, no luck. The car would fire, run a few seconds and die then refused to re-start for another 10-15 minutes then the same scenario again. No tools to diagnose or repair.
While waiting on AAA for three hours (another story) I would occasionally try to start the car with the same results.

Today, car started normally, runs normally.

1974 L-jet, original three bung fuel pump, original location.
500 miles on new tank, sock, filter, ss lines.

[Artfrombama]

Discovered the temp sensor in the RH head became disconnected.

[wonkipop]

Discovered the temp sensor in the RH head became disconnected.

(IMG:style_emoticons/default/beerchug.gif)

by the way thats great you have reported back art.
if someone else gets into a similar problem they can tick that off their list of probable cause. good on you.

[emerygt350]

Discovered the temp sensor in the RH head became disconnected.

(IMG:style_emoticons/default/beerchug.gif)

by the way thats great you have reported back art.
if someone else gets into a similar problem they can tick that off their list of probable cause. good on you.

And that was all it was?

[Artfrombama]

Discovered the temp sensor in the RH head became disconnected.

(IMG:style_emoticons/default/beerchug.gif)

by the way thats great you have reported back art.
if someone else gets into a similar problem they can tick that off their list of probable cause. good on you.

And that was all it was?

Yes, no one to blame but myself.
Spade terminal inside a plastic sleeve. Difficult area to get to, difficult terminals to connect properly.

[emerygt350]

Discovered the temp sensor in the RH head became disconnected.

(IMG:style_emoticons/default/beerchug.gif)

by the way thats great you have reported back art.
if someone else gets into a similar problem they can tick that off their list of probable cause. good on you.

And that was all it was?

Yes, no one to blame but myself.
Spade terminal inside a plastic sleeve. Difficult area to get to, difficult terminals to connect properly.

Well, thank goodness you found it.

[Artfrombama]

Discovered the temp sensor in the RH head became disconnected.

(IMG:style_emoticons/default/beerchug.gif)

by the way thats great you have reported back art.
if someone else gets into a similar problem they can tick that off their list of probable cause. good on you.

And that was all it was?

Yes, no one to blame but myself.
Spade terminal inside a plastic sleeve. Difficult area to get to, difficult terminals to connect properly.

Well, thank goodness you found it.

Yes, a pair of Webers were starting to look good!

[ClayPerrine]

Yes, a pair of Webers were starting to look good!

Please don't put webers on it. The stock injections is far better than webers, and modern EFI has them both beat hands down.

[wonkipop]

Yes, a pair of Webers were starting to look good!

Please don't put webers on it. The stock injections is far better than webers, and modern EFI has them both beat hands down.

@ClayPerrine

art is still having problems with it.
got a PM. ran fine yesterday. so he buttoned it up after attending to temp sensor 2 plug.
but today problem is right back. fires then dies i believe. same problem.

art was asking for the full pin out test.
i know its not really there in the factory manual and i swear i have seen it posted here.
i cannot dig it up in my files. i have put it somewhere but now i cannot find it.

i sent him the link to the 912E L jet troubleshooting guide i had which jeff bowlsby has on his site.

he needs to test the EFI loom from AFM to ECU.

@JeffBowlsby
i don't believe art has a vapor lock problem.
its doing the same thing intermittently parked stone cold in his garage.
one day it runs. the next it doesn't. always the same symptom he had when it first popped up out on the highway. see his first post.

really feels like an intermittent electrical connection or component fault.

he has swapped out dual relays to test. etc.
he can give you the full list of things he has done.

its an interesting problem.
i figure clay perrine might have the insight to get to the bottom of it.

he has the link to the full set of factory manuals i sent to him.
so he can go back to fully testing his fuel system with both pressure and flow.
but i don't think its that.

[Artfrombama]

Yes, a pair of Webers were starting to look good!

Please don't put webers on it. The stock injections is far better than webers, and modern EFI has them both beat hands down.

@ClayPerrine

art is still having problems with it.
got a PM. ran fine yesterday. so he buttoned it up after attending to temp sensor 2 plug.
but today problem is right back. fires then dies i believe. same problem.

art was asking for the full pin out test.
i know its not really there in the factory manual and i swear i have seen it posted here.
i cannot dig it up in my files. i have put it somewhere but now i cannot find it.

i sent him the link to the 912E L jet troubleshooting guide i had which jeff bowlsby has on his site.

he needs to test the EFI loom from AFM to ECU.

@JeffBowlsby
i don't believe art has a vapor lock problem.
its doing the same thing intermittently parked stone cold in his garage.
one day it runs. the next it doesn't. always the same symptom he had when it first popped up out on the highway. see his first post.

really feels like an intermittent electrical connection or component fault.

he has swapped out dual relays to test. etc.
he can give you the full list of things he has done.

its an interesting problem.
i figure clay perrine might have the insight to get to the bottom of it.

he has the link to the full set of factory manuals i sent to him.
so he can go back to fully testing his fuel system with both pressure and flow.
but i don't think its that.

Non not a vapor lock problem, I thought the fuel pump was the problem because I was getting erratic fuel pressures. I have replaced the original (rebuilt) fuel pump with a replacement from the jungle site, replaced the fuel pressure regulator.
Occasionally I can hit the key and the car will start normally and idle great for a few seconds but most of the time the motor will crank, crank, crank and occasionally “hit”.

Even though the units are quite robust I’m starting to suspect the ECM.

Things I have checked;
Super white hot spark, plugs firing normally
Tried another (new) dual relay
Thermal switch II (In RS head)=14K ohms
12V power to injectors=yes
Good grounds=yes
Pulse from -coil to pin 1 on ECM-yes
Fuel pressure=yes
Fuel pump runs from AFM

A pin-out diagram would be helpful in eliminating broken wiring.