2LT Misfire on Cold Starts after IP rebuild/injector cleaning

[dpiedade]

Hello!

I've been reading a lot recently about all the 2LT misfires on cold starts, but I haven't found a case quite like mine.

I just had my IP rebuilt along with injectors cleaned and tuned. The injector guy told me one of the injectors wasn't misting the fuel as well as it should, so I should be replacing the injector nozzles soon.

What is currently happening is that on cold mornings, the car starts rought, lots of white smoke and misfiring (it seams misfiring from just one cylinder but I'm not 100% sure). Sometimes I have to give it some gas for a couple seconds as it seems to die if I don't. After that, it continues to misfire at idle up to 1000 rpm, above that it sounds perfectly fine.

Also, the white smoke (after the initial cloud) only comes out the exhaust when the engine misfires, its not continuous.

After driving it for a bit, if I let it idle, its just fine, I don't recall it ever misfiring. If I park it and let it sit for a couple of hours, it misfires again (not nearly as bad as on the first start of the day) and it goes away again after a bit.

The temps here overnight should be about -1 to 0 degrees celsius and about 6/7 when I'm starting the car.

It never misfires above 1000 rpm.

I made this video that didn't turn out as good as I would like, but it shows the misfiring (not that noticeable on the tachometer but clearly noticeable when the gear shift lever vibrates).



Thank you very much for any help!!

 

[GTSSportCoupe]

Make sure there is no air getting into the fuel supply. Also, make sure your glow system is working properly with good connections etc. Maybe you disconnected something while swapping the injection pump? When it's that cold, I usually have to cycle my glow 3 times to get a perfect clean start, otherwise I get misfire and smoke too. The factory glow is way too short on these things.

 

[roscoFJ73]

The 1st thing you need to do is make sure the glow system is working correctly. If that doesn't fix it you should have the compression tested.
It is also kind of pointless rebuilding an injector pump and not doing the injectors. One complements the other ,neither can reach its full potential without both items working correctly.
Did the shop know about the cold start problem before they decided to rebuild the pump? Did they say what parts on the pump needed replacing?

 

[dpiedade]

GTS, I'm checkingy plugs asap. I'm also going to try and check for air getting into the fuel lines, could be my oem primer.

Rosco, the cold start problem wasn't there before tge rebuild, at least it wasn't noticeable. The only time I had a start problem was in the summer when I parked the car on a steep incline overnight (front up), but filters and oils hadn't been changed at that time, it ran overall rougher.
I guess I should've changed the injectors while doing the pump, but wasn't sure if I wanted to keep the engine. The IP had all the seals changed, should be like new.

Thanks for the input guys, all help is really appreciated!

 

[roscoFJ73]

He must have pulled the injectors out to be able to tell you one had a bad spray pattern. Maybe one of the injector gaskets or seats is now allowing some air into that cylinder.
When it starts and warms up , the expansion maybe taking up the slack and sealing it. They can be fickle things.
A bad spray pattern doesn't usually give you white smoke and a miss fire on cold starts , although it wont help the situation.
Have you consulted the shop about your problem?

 

[dpiedade]

Yeah, he did pull the injectors and had them cleaned and calibrated, but he told me I should change the nozzles and I didn't. I'll check plugs + IP timing + fuel lines before checking the injector gaskets.

The mechanic says its either glow plugs or compression, thats the most likely in his opinion. I'm finding both this options a bit of a coincidence since it started when he worked on the car.