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Ziggy6.5
10-11-2015, 12:50
Hey guys I was currently given a 95 suburban with the infamous 6.5 turbo diesel in it. I saw a fe threads like this but nothing quite like mine
The truck has 156k on it, never abused and never towed. My dad ran an additive in the fuel which smoke the optical sensor in the IP. I replaced the optical sensor and fired it up. It didn't run in a year, the additive isn't in the tank. My dad used to start it up and just let it idle. Sooooo here's my problem. When I changed the optical sensor the truck took a couple cranks to finally run. It idled fine at 1k then kicked down a hair. Yesterday I replaced the fuel filter and now it won't idle, it starts and jumps around on the idle and it starts pretty rough.
I have a new PMD and an FSD Cooler in it as well. What could be the problem?
trbankii
10-11-2015, 16:41
Did you bleed the air out after replacing the filter?
Ziggy6.5
10-12-2015, 07:55
Did you bleed the air out after replacing the filter?

I tried to bleed it at the filter, never really worked on a diesel before so I'm not too confident I got all the bubbles out
trbankii
10-12-2015, 11:57
If you connect a clear tube to the bleeder on top of the filter housing, you can see when it runs solid without bubbles. Since the issue started after the filter change, the first thing I’d make sure of would be that there was no air in the system.
a5150nut
10-12-2015, 19:01
Did you use the lift pump to bleed filter?
Ziggy6.5
10-13-2015, 18:53
Did you use the lift pump to bleed filter?

Yes I did and I bled 5 out of 8 injectors on the motor cuz I couldn't reach the other ones.
arveetek
10-14-2015, 19:31
When you replaced the optical sensor, are you 100% sure you got it back in the same position as the original? These are very, very sensitive to improper installation. In fact, you're not supposed to change the sensor without calibrating the pump on a stand, but a lot of us do. I've done it before, and it's quite tricky to get right without making a good scribe mark to where the old one was. Just a few mm's shift to one side or the other will make a big difference in how it runs and idles. You might try shifting the sensor to one side or the other a bit and see what happens.

I got mine off one time, and it took a lot of trial and error to get it running correctly again.

Casey