trouble starting after a week

[John U]

I know....if I drive the DeLorean every couple of days I wouldn't have this problem...

If the car sits for a while, typically 7 days or more, I have difficulty starting it. It starts on the prime then dies. After about 4 attempts it finally runs.
Pretty much the entire fuel system has been replaced except the accumulator.
I also notice that if I shut down the car, it will restart again no problem. If it sits for an hour or two at a car show, it is difficult to start again sometimes (cranks for about 5-10 seconds then starts but doesn't run very well for about another 10 seconds)

any thoughts?

thanks
John

[WelmoedJ]

Check if your car holds rest pressure (pushing the metering plate after shut down) and if it holds rest pressure over more than one hour.
If not, you probably have a bad accumulator.

Do you start right away after turning the ignition key to on?
Try this: turn the ign key to on, then off.
Do that 2 or 3 times before actually starting the car.
Some cars love priming before staring and more than once will better build up pressure this way.

If I do that after 2 weeks (happens occacionally that the car sleeps that long :) ) the engine fires up within 2 turns.

[stevedmc]

Are you sure you are getting spark?

[Bitsyncmaster]

I have a poor running if my car sits longer than a week. What I think it is caused by are the injectors will leak down to the point the injector lines get air in them.

[David T]

Check that the Cold Start Valve system is operating. If it is not working you would have this symptom.
David Teitelbaum

[Bitsyncmaster]

Check that the Cold Start Valve system is operating. If it is not working you would have this symptom.
David Teitelbaum

The CSV only works when your cranking the engine. That is not the problem because the engine fires right off the bat but takes about 30 to 60 seconds of idle to smooth out.

[David T]

It shouldn't take that long to settle down. If it starts right up the CSV is probably OK. Next to check would be the vacuum advance and the CPR. Make sure the throttle arm is setting the idle micro. It might be sticking or there could be excessive play in the throttle linkage. Your theory about the injectors leaking would not cause this. Once the pump starts it pressurizes them quickly. The injectors could still be leaky and have a bad spray pattern though. And the seals could be hard and leaking vacuum.
David Teitelbaum

[John U]

Is there a procedure for checking the operation of the CPR and Vacuum adv?

[David T]

To check the CPR you watch the fuel pressure as the motor warms up. You compare it to the chart in the manual. To check the vacuum advance you hook up a timing light and a tachometer and watch the timing as you increase the RPM's and compare it to the specs in the manual.
David Teitelbaum

[John U]

Do you start right away after turning the ignition key to on?
Try this: turn the ign key to on, then off.
Do that 2 or 3 times before actually starting the car.
Some cars love priming before staring and more than once will better build up pressure this way.

If I do that after 2 weeks (happens occacionally that the car sleeps that long :) ) the engine fires up within 2 turns.

My car sat for about 2 weeks. I primed it 3 times and it started right away. It ran a little rough for about 2 seconds. Thanks for the advice everyone. I think I will replace the accumulator this winter since I have one sitting around anyways.

John

[DeLorean03]

Wow, dang I totally missed this thread.

I had nearly your exact same symptoms. Car went turn over on turning the key and die right away. Then I would have to keep the key turned and pump the gas pedal - soemtimes that didn't even work. I'd even have to resort to the CPR plug on CSV trick. I got to thinking about it, and all I did was very slightly enriched my car via the air mixture screw. That screw only affects that amount of fuel put into the engine in idle - thus - it will affect the amount of fuel that gets into the engine on startup.

I did it, and my car started right-up without any trouble. Of course, I only had the car for 2 more days before it went into DMCMW back in late July, so I don't have weeks and weeks of starting up to show for it. I'll bet Dave Swingle could chime in and verify if my car starts right up cold every time. Sure would make me happy :).

[DMCMW Dave]

I did it, and my car started right-up without any trouble. Of course, I only had the car for 2 more days before it went into DMCMW back in late July, so I don't have weeks and weeks of starting up to show for it. I'll bet Dave Swingle could chime in and verify if my car starts right up cold every time. Sure would make me happy :).

It's probably been sitting a week now, I just went out and it started on the first pull, I never touched the gas pedal.

[AirmanPika]

I wish my car would start like that after a week. Of course there are a lot of things I wish my car would do...like stop breaking. I'll get there some day :wink:

[DeLorean03]

It's probably been sitting a week now, I just went out and it started on the first pull, I never touched the gas pedal.

*fist pump* yes! Thanks Dave!

HEY..... wait a minute......it was 8:30pm when you did that...what are you doing at the shop that late -_o <---- "the look" ?

[John U]

Wow, dang I totally missed this thread.

I had nearly your exact same symptoms. Car went turn over on turning the key and die right away. Then I would have to keep the key turned and pump the gas pedal - soemtimes that didn't even work. I'd even have to resort to the CPR plug on CSV trick. I got to thinking about it, and all I did was very slightly enriched my car via the air mixture screw. That screw only affects that amount of fuel put into the engine in idle - thus - it will affect the amount of fuel that gets into the engine on startup.

I did it, and my car started right-up without any trouble. Of course, I only had the car for 2 more days before it went into DMCMW back in late July, so I don't have weeks and weeks of starting up to show for it. I'll bet Dave Swingle could chime in and verify if my car starts right up cold every time. Sure would make me happy :).

Where is the screw, how much do you turn it, and does it affect idle rpm at all?

thanks
John

[DeLorean03]

Where is the screw, how much do you turn it, and does it affect idle rpm at all?

thanks
John


Screw is where John Hervey labeled: "Air Flow Meter Adjustment" - takes a 3mm wrench. Turning clockwise enrichens, counterclockwise leans the engine out.
12588


As far as how much - it varies from one car to another. Turn it at most an 1/8 of a turn, let the car get completely cold (wait a day) unless you already haven't started your car before you adjusted the idle screw, and see what happens. It worked for me with no issues. It should not affect idle RPM.

[jawn101]

Screw is where John Hervey labeled: "Air Flow Meter Adjustment" - takes a 3mm wrench. Turning clockwise enrichens, counterclockwise leans the engine out.
12588


As far as how much - it varies from one car to another. Turn it at most an 1/8 of a turn, let the car get completely cold (wait a day) unless you already haven't started your car before you adjusted the idle screw, and see what happens. It worked for me with no issues. It should not affect idle RPM.

Not the greatest idea to just go attack this with a wrench.... identify if you have a problem that actually requires adjustment here first, then do so only with a dwell meter probing your FV duty cycle...

[DeLorean03]

Not the greatest idea to just go attack this with a wrench.... identify if you have a problem that actually requires adjustment here first, then do so only with a dwell meter probing your FV duty cycle...

He asked the question. I provided him the answer to his question.

Also, just to note, I run my system open loop. I can't stand that lambda system.

[John U]

Not the greatest idea to just go attack this with a wrench.... identify if you have a problem that actually requires adjustment here first, then do so only with a dwell meter probing your FV duty cycle...

Any detailed instructions on how to do this? :blush:

[jawn101]

Any detailed instructions on how to do this? :blush:

It is probably beyond my actual skill level to write one up, but it's not hard. I was able to do it very easily under the tutelage of Dave S. Perhaps he or one of our other seasoned tech vets can write something up in the 'how-to' section. You know, in all their spare time :lol:

[DMCMW Dave]

Any detailed instructions on how to do this? :blush:


It is probably beyond my actual skill level to write one up, but it's not hard. I was able to do it very easily under the tutelage of Dave S. Perhaps he or one of our other seasoned tech vets can write something up in the 'how-to' section. You know, in all their spare time :lol:

I'll see if I can find some time to make a public writeup on this. In the mean time, believe it or not, it is covered (in non-detailed instructions) IN THE SERVICE MANUAL. The major error in the service manual is how they tell you to remove the OEM plug over the adjustment. Not really an error, but an overly-complex procedure.

[82DMC12]

Also, just to note, I run my system open loop. I can't stand that lambda system.

What's wrong with it?

[John U]

I'll see if I can find some time to make a public writeup on this. In the mean time, believe it or not, it is covered (in non-detailed instructions) IN THE SERVICE MANUAL. The major error in the service manual is how they tell you to remove the OEM plug over the adjustment. Not really an error, but an overly-complex procedure.

Is this the procedure that involved drilling the cap out?

[DeLorean03]

What's wrong with it?

There's nothing "wrong" with it - I just don't like it. I like my idle nice, solid, and steady.

[82DMC12]

There's nothing "wrong" with it - I just don't like it. I like my idle nice, solid, and steady.

My lambda works perfectly and I have a nice, solid, steady idle?

[jawn101]

My lambda works perfectly and I have a nice, solid, steady idle?

+1... 750 all day long...

[DeLorean03]

Ok dok - glad to hear you guys have a solid lambda system. I guess you're trying to say something is wrong with mine...?

Bottom line - I run closed loop and it runs just like I want it to run.

[82DMC12]

Ok dok - glad to hear you guys have a solid lambda system. I guess you're trying to say something is wrong with mine...

Yup. A working Lambda system is steady at warm idle. It works great.

[DeLorean03]

Then there are a good number of DeLoreans with lambda systems out of tune. A good number of them I see will idle fine, then the fuel-to-air ratio starts to get finicky (which is evidenced by watching the needle dip on a analog dwellmeter), you'll hear the rpms start to drop a tad, and then after a bit, the needle will swing rich again - and this cycle will repeat over and over again. This should not be confused with "hunting idle" - those are two separate beasts.

I won't try to act like I know how the lambda system works and what is causing this - all I know is I've seen this behavior on at least 5 different DeLoreans. I'm not saying I'm right and you're wrong or vice versa - I'm simply explaining the behavior I noticed on my car and multiple other DeLoreans. At the advice of other owners, I was informed I could run an open-loop system and experience the idle I am accustomed to from more modern vehicles. I did just that back in 2004, and I have enjoyed my car the way it is.

It's kind of like installing a "hot start relay" in that open female plug in the electrical compartment. Technically, the fuel accumulator should just be replaced, but why not install the relay and call it a day. It's all about preference.

I have been told that the strain of the automatic transmission idling can make the idling on a DeLorean a bit more "off-kilter" or "unsmooth." I don't claim this; it's just "what I've heard."

Don't get me wrong - if I could get my DeLorean to run absolutely perfectly smooth with no oscillations or altering idle at all whatsoever with a closed loop system - I'd be all for it. For now, either way, we all have smooth idling cars.

[82DMC12]

Then there are a good number of DeLoreans with lambda systems out of tune. A good number of them I see will idle fine, then the fuel-to-air ratio starts to get finicky (which is evidenced by watching the needle dip on a analog dwellmeter), you'll hear the rpms start to drop a tad, and then after a bit, the needle will swing rich again - and this cycle will repeat over and over again. This should not be confused with "hunting idle" - those are two separate beasts.

I won't try to act like I know how the lambda system works and what is causing this - all I know is I've seen this behavior on at least 5 different DeLoreans. I'm not saying I'm right and you're wrong or vice versa - I'm simply explaining the behavior I noticed on my car and multiple other DeLoreans. At the advice of other owners, I was informed I could run an open-loop system and experience the idle I am accustomed to from more modern vehicles. I did just that back in 2004, and I have enjoyed my car the way it is.

It's kind of like installing a "hot start relay" in that open female plug in the electrical compartment. Technically, the fuel accumulator should just be replaced, but why not install the relay and call it a day. It's all about preference.

I have been told that the strain of the automatic transmission idling can make the idling on a DeLorean a bit more "off-kilter" or "unsmooth." I don't claim this; it's just "what I've heard."

Don't get me wrong - if I could get my DeLorean to run absolutely perfectly smooth with no oscillations or altering idle at all whatsoever with a closed loop system - I'd be all for it. For now, either way, we all have smooth idling cars.

I hear ya, but a cycling idle when the engine is warm is due to mixture off-adjustment, such as a leaky injector, vacuum leaks, bad timing, or poor CO adj. Remember - lambda is reactionary, it simply tries to correct what has ready happened (by reading the exhaust). When the inputs are so far off, the idle runs up and down.

I just restored 11114, sitting since 1990. Proper tuning and it also idles at 750 smooth and steady.

Andy

[DeLorean03]

I hear ya, but a cycling idle when the engine is warm is due to mixture off-adjustment, such as a leaky injector, vacuum leaks, bad timing, or poor CO adj. Remember - lambda is reactionary, it simply tries to correct what has ready happened (by reading the exhaust). When the inputs are so far off, the idle runs up and down.

I just restored 11114, sitting since 1990. Proper tuning and it also idles at 750 smooth and steady.

Andy


In that case, my bet is my vacuum leak at my mode switch. Every time I flip it to anything on the dash, big ol' SWOOSH starts - the mod diaphragm need to be replaced. Got a spare one ready - just need to get the car back from DMCMW and do it over the winter or at on of Ken's Thursday tech sessions.

Now that I think about it, my idle was like that when I had a faulty FD. I might be able to tune it right now that my fuel system is pretty solid. Ken also has a ultrasonic cleaner for the injectors I could use just to b safe. Mine are only 8 years old with consistent MARVEL Mystery Oil run through the fuel system.

Maybe hooking the lambda system back up is not too bad an idea. Of course, I'll need to buy a new O2 sensor as mine would be long done after 8 years of open loop.

Something to consider doing once I get at back from DMCMW :D.

[82DMC12]

In that case, my bet is my vacuum leak at my mode switch. Every time I flip it to anything on the dash, big ol' SWOOSH starts - the mod diaphragm need to be replaced.

That would probably do it, if the revving only happens while the switch is leaking.

You could plug the hose going to the mode switch and if you can get it to work closed loop that way, it just needs a switch rebuild.

Andy