99 7.3l intermittent SES light
 

Hey everyone! I'm brand new here. Live in Alaska. Bought a 99 7.3l a few weeks go. 250k miles. Buyers inspection from reputable shop found cyl #5 & 8 high low open. Cleared codes and passed run ability test. Could not replicate. So I bought the truck. Paid $6k for it which was a steal. SES light comes on intermittently for a few seconds and goes back off. Mainly when I'm just leaving the house. Once it's fully warm the SES light mainly stays off. Snap On reader today says bad ICP. Checked icp and no oil in connector. What do u guys think?

Nothing?

Maybe the ICP is just bad? I had basically the same issue on my 01, no oil in the connector or anything. Turned out to be a bad ICP and CPS sensor.

That's what I originally thought so I unplugged the icp and ran it and it seemed to run a little worse. Not a huge difference. Mainly just a little more of a miss on idle with it unplugged. Could it be ipr?

Do you have a way to test your dusty cycle?

450-500 PSI of ICP to start, 550-750 to idle, and should ramp up into the 2,000's when getting on it.

IPR DC should be around 11 or 12% at idle and ramp up as well into the 20's or 30's as you get on it.

If you have the capability to do that and pull some codes with a reader we can go from there.

I don't. I wish I had an AE scanner. There's a local guy I found but we were having problems with his computer. I've found a correlation, it's been around 0 degrees to 20 above here and the SES light only comes on during warmup and the first few miles of driving. Not affecting run ability whatsoever. Truck starts perfectly fine. Once I'm down the road the SES light will stay off. When it does come on it only stays on for a few seconds and turns off. I don't know if it's just coincidence but during warmup and idling I can slowly press on the gas pedal and bring the RPM's up to around 1k-1.5k and the light will come on. Usually as soon as I let off it turn off. Sometimes it stays on for about 10 seconds after. I can hear the ebpv close as well. I really wish I had someone local here that had a scanner that worked. I did pull the 42 pin connector and checked resistance of a the injectors. They were all around 5 ohms.

Icp on startup was into the 600's, idling was around 480-500, stepping on it it reached 2900. Ipr duty cycle was 12 idling, highest it went while getting on it was 39. When I really stepped on it the icp voltage went up to around 3.8 and on the live data stream it flashed yellow and my ses light came on briefly.

Buzz test revealed p1275 cyl 5 high/low open, p1278 cyl 8 high/low open.

Cylinder contribution test showed:

p0263 cyl 1 inj circuit cont/balance fault

p0284 cyl 8 inj circuit cont/balance fault.

I'm no expert by any means, but I have had my truck pulls those codes and as far as I know it could be 1 of three things I think, Cylinder issue, most likely rings going bad in which case you'll have a lot of crankcase blow by. Valves. Or injectors.

How often do you add treatment to your fuel?
I would run some good diesel injector cleaner through it and see what happens.

Since you say its intermittent it could be just a couple of gummed injectors.

I wish I could help you out more, But without being there its difficult for me.

I'm not having a bunch of blow by. I can do the oil cap trick and it will stay on no problem. I try and put treatment in at every fill up. Right now I'm using Howes. What do you suggest to clean the injectors?

I also tore apart both valve covers today and both harnesses looked good. I re checked resistance at the both valve cover harness' and the 42 pin. Everything was within specs. I pulled the idm as well just to inspect and everything looked good.