Another warm start issue

[Michael]

Quick question. Upon a warm start the engine runs a little off for a few seconds. It's not quite a dead cylinder but it's definately missing, backfiring, low on power when pulling out but just for a few seconds, then she is fine.
I was thinking maybe the begining of an injector getting clogged or a poor spray pattern?

This just started tonight so I don't know if it's the same issue on a cold engine.

[David T]

Could be an injector, a spark plug, or ignition wire. When was the last time the car was tuned up? You could try running a bottle of Techron through the fuel system.

[Michael]

Could be an injector, a spark plug, or ignition wire. When was the last time the car was tuned up? You could try running a bottle of Techron through the fuel system.

Wires plugs and cap and rotor were changed last year which doesn't mean they are bulletproof but I wouldn't look at them first either. I may go the techron/seafoam route first.

[David T]

At least check that none of the spark plug wells has any water in it and all of the ignition wire's boots seal the top of each well. Water in a spark plug well can cause a misfire.

[Michael]

At least check that none of the spark plug wells has any water in it and all of the ignition wire's boots seal the top of each well. Water in a spark plug well can cause a misfire.

Just went out and started it again and drove it up the road. Same thing. By the time I got 100' from the house it was fine. It's odd that the issue is there even after running fine just 30 minutes earlier.
No way water in the wells. It hasn't seen a drop of water in months. I will reseat the boots tomorrow after it cools down.

[Ron]

Maybe it's clearing out a cylinder with a (newly) leaking injector??

[Michael]

Maybe it's clearing out a cylinder with a (newly) leaking injector??

You know that has crossed my mind. I think it's possible that I have one injector leaking down. Yesterday it would not start until I cranked for liked 10 seconds, then when it did start there was a lot of smoke from the tail pipe for a few seconds while it idled. I attributed that to it not being started in a few weeks. This morning I decided to prime it 3 or 4 times before cranking and it fired right up but it struggled to idle while it cleared it's throat.

How can I test the injectors to see it this is a correct diagnosis? I would think I could just pull them in and place them in glass jars overnight but if I have one leaking down that fast I doubt I would get it out in time before it loses rest pressure. Is there a way to "charge" the injectors after they have been removed? Could I just crank the engine, let them spray into the jars then empty the jars and let it sit overnight like that?

[Bitsyncmaster]

You know that has crossed my mind. I think it's possible that I have one injector leaking down. Yesterday it would not start until I cranked for liked 10 seconds, then when it did start there was a lot of smoke from the tail pipe for a few seconds while it idled. I attributed that to it not being started in a few weeks. This morning I decided to prime it 3 or 4 times before cranking and it fired right up but it struggled to idle while it cleared it's throat.

How can I test the injectors to see it this is a correct diagnosis? I would think I could just pull them in and place them in glass jars overnight but if I have one leaking down that fast I doubt I would get it out in time before it loses rest pressure. Is there a way to "charge" the injectors after they have been removed? Could I just crank the engine, let them spray into the jars then empty the jars and let it sit overnight like that?

Pull the injectors and put in jar. Then jump the fuel pump via RPM relay and press the air plate down. That will fill all the injectors.

[Michael]

Pull the injectors and put in jar. Then jump the fuel pump via RPM relay and press the air plate down. That will fill all the injectors.

Thanks!

[Ron]

With what sounds like a very small leak, you might want to get it hot (to match conditions) then pull the injectors as fast as you can and hopefully catch it leaking or signs of it (w/o pressing the plate). If no luck, then put them in a jar and see what they do when you jump the relay, then after bumping the plate.

If it is an injector leak, you might catch the rest pressure falling...

[David T]

If you suspect an injector the best way to confirm is to remove them and test them. At the same time you can also clean them and maybe "fix" a leaker. You can send them to your favorite Delorean vendor or find a nearby Volvo dealer who still has a cleaner/tester.

[DMC-Ron]

If you suspect an injector the best way to confirm is to remove them and test them. At the same time you can also clean them and maybe "fix" a leaker. You can send them to your favorite Delorean vendor or find a nearby Volvo dealer who still has a cleaner/tester.

Assuming you remove the injectors and take them in or ship them, what's the typical cost for injector service by a DeLorean vendor or Volvo dealer?

Ron

[DMC1890]

Hervey will clean them, and supply new boots, for $79 or $89 (CRS). He's done mine and others that I know of, with very quick turnaround.

[Michael]

Hervey will clean them, and supply new boots, for $79 or $89 (CRS). He's done mine and others that I know of, with very quick turnaround.

Fuck Hervey
I will buy 6 brand new ones for 80 bucks each before I even think of ever doing business with that man ever again.

When I was running a Mercedes business the old cis injectors were almost identical to the Delorean Bosh units. I sent several sets off for cleaning with mixed results. I would honestly just buy new ones before risking r+r injectors twice disturbing what are already finicky fuel lines.

[Nate88]

You can get brand new injectors from RockAuto for around $38 for the exact part number of our injectors or $42 for the “DeLorean” part number (I believe it’s 62708, but I don’t remember exactly). I’m not sure the difference. If you do a search for DeLorean it will only come up with the 62708 so you have to do a search for the exact 0437502022 part number.

[bytes311]

I had all six injectors cleaned at a local Volvo shop for around $60.

[Michael]

I'm holding off on doing any tests as the issue seems to have disappeared with a very small mixture adjustment. I took a look at it on a whim and it was a touch lean. Since then it has done fine. I don't know if my climate would necessitate a mixture adjustment once or twice a year. I have the stage engine (cammed) and I live in a place that will see triple digits turn into single digits and back every 6-8 months. It could be that I have a small vacuum leak somewhere just enough to affect the mixture with drastic temp changes?

I did get a pressure test kit so if the problem resurfaces, I will have some diagnostic muscle behind me.

[Michael]

Giving proper closure to this thread. The issue resurfaced last month so I pulled the primary pressure regulator and found the rings looked OK but decided to replace them anyway. As of Sunday, she starts and idles like a champ whether hot, warm, or cold. No stumbling or hesitating. I was on the right track thinking an injector was leaking down and it was getting too much fuel after resting but my laziness of checking the easiest thing first paid off. After I cut my orings off I could see the problem. It doesn't take much deterioration to cause havoc and you can see the flat spot on the green one quite easily.

60872
60871

[Michael]

I should mention that after buttoning it all back up I warmed it up and checked the duty cycle. I had to enrichen it quite a bit. Took about 1/8 of a turn to get my mixture right.

Quick question though as I have read both. Do I shoot for a 15 to 20 degree swing on my 8cyl meter (30 to 40) or do I try and center the swing over the 20 degree mark? The book says 30 to 40 but I have read here to center the swing over the 20 degree mark which would make the cycle at about 35 to 45..or am I splitting hairs?

Mine is a stage II cammed if that makes a difference.