Rough start after letting the car sit for a few days

[vps3922]

Hi all,

I decided to post a thread about my issue. You are all a great resource and I love to be able to leverage that.

Here is the gist: My friend Dave (sdg3205) and I replaced the fuel lines with the set of stainless steel braided fuel lines a few weeks ago. The car was always starting fine up to then, had no issues, primed and “waroom”, there it was with a great idle.

$hit started happening right after replacing the lines. I brought the car home and let it sit for a week. I then tried to start and I could hear Dave McKeen's RPM relay to prime the fuel line and the engine fired once and died right away. I could repeat that. I thought that I should maybe help the engine to pump fuel and did the "Marty McFly accelerator pedal pump" during cranking. It took a few attempts and the engine started and turned but really rough. I had to keep pumping gas in order to keep it running. It stalled right away after I took my foot off the gas. This went on for a few engine turns until it leveled out.
I had to keep my foot on the gas slightly to let it run on a good RPM and could then take it off. It would run fine afterwards.
I went for a drive. The car always started up fine when sitting anywhere during the drive.
I noticed that the start-up will get rougher as longer as the car sits in the garage. It is ok after a day. It maybe blubbers once after two or three, etc.
I have the feeling that we caused a vacuum leak somewhere when installing the fuel lines. I know that we mixed up two connectors the first time we tried a startup after the replacement, but I am not sure which ones they were.
I am open for any tip you might have and where to look first. I doubt that it is the classic cold start issue, as it is working fine even if the car sits in a driveway for a few hours after driving it.

Thank you all!

Let me know if I can provide any more information.

[DMC5180]

Classic symptom of a leaking injector(s). Air in the injector lines after sitting. Priming the FP doesn't help this beyond pressurizing the system for the CS injector. (pumping the pedal doesn't really do anything for you) Holding the pedal down while cranking will aid you in clearing a flooded engine.

Once the car has started and running smooth, If you shut it down and come back in a hour does fire right up just by turning the key?

[David T]

Hi all,

I decided to post a thread about my issue. You are all a great resource and I love to be able to leverage that.

Here is the gist: My friend Dave (sdg3205) and I replaced the fuel lines with the set of stainless steel braided fuel lines a few weeks ago. The car was always starting fine up to then, had no issues, primed and “waroom”, there it was with a great idle.

$hit started happening right after replacing the lines. I brought the car home and let it sit for a week. I then tried to start and I could hear Dave McKeen's RPM relay to prime the fuel line and the engine fired once and died right away. I could repeat that. I thought that I should maybe help the engine to pump fuel and did the "Marty McFly accelerator pedal pump" during cranking. It took a few attempts and the engine started and turned but really rough. I had to keep pumping gas in order to keep it running. It stalled right away after I took my foot off the gas. This went on for a few engine turns until it leveled out.
I had to keep my foot on the gas slightly to let it run on a good RPM and could then take it off. It would run fine afterwards.
I went for a drive. The car always started up fine when sitting anywhere during the drive.
I noticed that the start-up will get rougher as longer as the car sits in the garage. It is ok after a day. It maybe blubbers once after two or three, etc.
I have the feeling that we caused a vacuum leak somewhere when installing the fuel lines. I know that we mixed up two connectors the first time we tried a startup after the replacement, but I am not sure which ones they were.
I am open for any tip you might have and where to look first. I doubt that it is the classic cold start issue, as it is working fine even if the car sits in a driveway for a few hours after driving it.

Thank you all!

Let me know if I can provide any more information.

This may have nothing to do with the recent work. The symptom is similar to what happens if the frequency valve is not working. See if it is buzzing when the motor is running. Sometimes all it is is a dirty connection at the plug to the valve. Disconnect and reconnect the plug several times. Also the cold start valve may not be operating to get you started. Pull the valve and see if it is spraying during cold cranking.

[vps3922]

Once the car has started and running smooth, If you shut it down and come back in a hour does fire right up just by turning the key?

Yes, it does.

Thank you for your remote disgnostic. I know that it is hard to do this through the internet, but I have at least a few pointers to start and that is all I wanted.

[vps3922]

This may have nothing to do with the recent work. The symptom is similar to what happens if the frequency valve is not working. See if it is buzzing when the motor is running. Sometimes all it is is a dirty connection at the plug to the valve. Disconnect and reconnect the plug several times. Also the cold start valve may not be operating to get you started. Pull the valve and see if it is spraying during cold cranking.

Good ones. I will have a look.

Thank you for these tips!

[Kozmatic]

This may have nothing to do with the recent work. The symptom is similar to what happens if the frequency valve is not working. See if it is buzzing when the motor is running. Sometimes all it is is a dirty connection at the plug to the valve. Disconnect and reconnect the plug several times. Also the cold start valve may not be operating to get you started. Pull the valve and see if it is spraying during cold cranking.

+1 check all the electrical connections. Something may have been knocked loose during the work.

[Bitsyncmaster]

My car will start harder if it sits about one week. I do think it is the injectors leak down and get some air in the lines if left that long.

But my CSV starts to fire after one second (my hot start relay) and it fires right up. It does take a few seconds to start idling normally. It seem like that CSV just puts out enough to get it started.

My guess with your problem is the CSV is not working. You can check for voltage on it when cranking a cold engine or put it in a jar and disconnect the ignition to test it.

[DMC5180]

I wanted to edit the previous post but it timed out on me.

My car does the same thing after sitting several weeks. The interesting part was that it started doing it after I had replaced all the injectors with NEW ones a few years ago. Since it was just a minor nuisance, I did not go back to figure out which ones were leaking. If I drove the car more frequently I'd probably never notice it.

[sdg3205]

Just a few notes:

The connectors Volker noted that we "mixed up" was actually just the WUR/CSV plug swap to get the car running again after the line swap (engine was still warm).

He's running a new O2 sensor given he just upgraded to Stage 1. I trust DMCNW would have checked the mixture - Volker - is your tamper proof plug still in place? I don't recall.

We verified mixture (and thus FV function) recently because i couldn't hear the FV oscillating - it sounded like 50% and was in fact 50% until we blipped the throttle, at which point it ran a proper duty cycle IIRC.

We can easily run a leaky injector test if need be.

[vps3922]

Just a few notes:

The connectors Volker noted that we "mixed up" was actually just the WUR/CSV plug swap to get the car running again after the line swap (engine was still warm).

He's running a new O2 sensor given he just upgraded to Stage 1. I trust DMCNW would have checked the mixture - Volker - is your tamper proof plug still in place? I don't recall.

We verified mixture (and thus FV function) recently because i couldn't hear the FV oscillating - it sounded like 50% and was in fact 50% until we blipped the throttle, at which point it ran a proper duty cycle IIRC.

We can easily run a leaky injector test if need be.

Hi Dave,

I do not have a tamper plug. The distributor head has never been drilled and I am proud of that. I will check for the contacts to the WUR and CSV next week (will head out for camping this weekend after work) and we can definiteley do a injector test. I do not think that we actually broke anything. I think it is just something not sitting properly. I do not have any fuel leaks (or at least not at the rate that I would see it before it evaporates). You did a great job on that.

Well, a good few starting points in this thread. Thank you all!

[Bitsyncmaster]

There are a lot of wires getting that CSV to work. Mine never worked when I got the car and I had to unwrap the harness because the schematic was not showing the correct wiring. Mine turned out to be a jumper on the back side of the bulkhead connectors. It went from one connector to the other and had 70 ohms in that connection. I never pulled the connectors so I just rewired it not to use that jumper.