1999 f250 7.3 misfire after sitting over night

I’ve been dealing with an early 1999 7.3 powerstroke having a miss fire on startup after sitting overnight. It recently had all new motorcraft glow plugs and relay put in it also has all new injectors and injector cups and under valve cover harnesses. Oil level and condition is good has delo 15-40 diesel oil in it. Icp reading at an idle is 500-600 psi wot it will reach around 2500 psi ipr percentage at a hot idle is 4-6%. It will set a p1211 code on a long hard wot pull. Any thoughts?

I'll give you all the thoughts I have. :lol:

2500 PSI during a long pull sounds good to me. Maybe a smidge low? This is a known good capture I took off an '02 F-250 for reference:

www.scanshare.io/share/VGE3ean5SEO6_m2TZ5aEXw#0,1,23,24,26

Two most common reasons I've seen for P1211 are an aftermarket tune, and low fuel pressure due to the tank lining coming apart and plugging the in-tank strainer. Tuners for these trucks are easy to install and extremely common.

4-6% IPR at hot idle sounds too low. Most I've seen are at 7-12%. May or may not be related to your issue.

You can try to use the PERDEL% PIDs during a cold start to see if one cylinder or another stands out. Keep in mind that, depending on the color of CMP sensor installed, you may see 'ghost' readings on #3 and #8.

I'd also check the IPC sensor connector for oil intrusion, and replace the sensor/connector if you find any.

Also, do you have an amp clamp? You can verify the glow plug operation KOEO while cold. I like to see at least 180A on the glow plug relay feed cable, engine cold, first key-on of the day. Less than that can indicate an inop plug.

I saw that the glow plugs just got replaced, but that doesn't mean they're working electrically.

It does have a tuner on guess I didn’t even consider that could cause that code makes sense though. Ipc connector is dry. I thought the ipr percentage was a little low too and my thought was that maybe it is sticking a little causing abnormal icp pressures or possibly an oil drain back issue?

I will have to check on this in a few days once I can grab my amp clamp. I did go though with a test light hooked to battery positive and checked to make sure the glow plugs had a good connection.

I redid my numbers today and for icp I did reach 2700 psi wot. Another thing to note is the pickup has no trouble starting it was about 40 degrees F today and had been sitting all weekend and fired up easily. I’m guessing the code just has to do with the tuner so I’m with my original problem the misfire after sitting over night. One thing I do notice is my oil pressure gauge doesn’t come up until about 2 seconds after it starts.

one thing with the hard start after sitting overnight is did this happen immediately after plugs and injectors replaced? if so it might be oil that drained into cylinder/s when doing the injectors. if it subsides after running for a while that should resolve itself. but if not and you have a borescope that will fit through the hole stick one through glow plug hole and check for oil on pistons. the injector cup may not have been seated right or the oring was damaged on injector/tube

It isn’t hard starting and it had been a month or so since I put the injectors in that I made this post and it is daily driven so any oil or air in the system should have been gone. I did notice on a start up it lets out a cloud of smoke which smells like oil and it has been using oil so I’m thinking it’s the o rings on the new injectors that are leaking oil into the cylinder causing air in the high pressure oil system. I don't believe it is the injector cups because I had ran it for a few months after that no issues it wasn’t until I put new injectors in did I start noticing issues.

ok I would say to look at the o rings and see though it is a pain getting back to them. the other thing to look at would be the turbo for oil seepage past the inducer and exducer fins and bearing. that is a known issue with the turbo depending on if it has been rebuilt recently or not.

I did look at the turbo took the down pipe off and took the plenum off to look for signs of oil and didn’t see anything.
I took both valve covers off and removed the glow plugs and had oil in cylinder 2 after sitting so I Got injector o rings on the way and I’ll update once they are installed.