intermittent power, lots of idle noise

Copracr · Dec 24, 2012

I'm pretty sure this just started 2 days ago when it got cold.

On cold startup idling in the driveway the idle will randomly bump up for a moment. When it idles up for that moment there is increased noise that sounds like my motor is eating gravel. Still runs smooth, but its loud as hell. At just off idle it's gone, but then when I get under way the power will randomly kick in, and with it comes that louder diesel crackle sound. I'll go to accelerate from a stop and it will be down on power and quiet then suddenly it wants to run great. It starts cutting in and out noticeably. When the power cuts in, my ICP value goes from 6000kpa (870 psi) right to 16000 (2320 psi) instantly.

Codes stored are P0113 (IAT stuck at -40), P1140 (water in fuel?), and p1211 which says ICP high/low.

I'm not sure whats the chicken and the egg without some better diagnostic tools so I recorded some ICP values while driving. On a full throttle run it will spike up to 19000Kpa (2755psi) then settle down to a little over 16000 (2320 psi). At idle it flutuates from 2800-3600 Kpa (377-522psi).

I'm just guessing the IPR is getting stuck at low pressures? This all just started 3 days ago when it got cold out. Any better suggestions for testing or repairing outright?

Sorry about the Kpa, that's what my snap on scanner reads out. I went through and converted to psi since thats what everyone seems to be using.

mclean · Dec 24, 2012

EBP stuck?

Copracr · Dec 24, 2012

mclean said:
EBP stuck?

I know thats the one thing it can't be. I deleted that whole ebpv system. The only thing left is a soft code in the PCM

Copracr · Dec 25, 2012

I had an old Hpop and IPR in the garage so I cleaned up the IPR and installed it. It's definetly worse now, lol. I'm having trouble maintaining speed on inclines on the highway and it runs much rougher. I did a buzz test and everything sounded good and no codes come back. A contribution test showed P0284 cyl 8 (I have 8 AB injectors in there).
When driving down the highway my IPR % was pegged at 65, and the pressure was right around 6000 Kpa (870 psi).

I'm now assuming the IPR I put in was garbage, but I'm not sure about the cyl contribution test results. I had an injector go bad on me once and the rough idle/acceleration seems similar but this noise sounds like my flexplate/TC is bad (I pulled the inspection cover off just to be sure it wasnt).

I forgot to mention - before the IPR was swapped out I could unplug the ICP and it would change when the noise occurs. Now if I unplug the ICP since swapping the IPR it gets a real lopey idle and wont accelerate at all.

Whytry · Dec 25, 2012

Try an ipr I had this same problem thought it might have been tuning and it was just the ipr, I would go get a new one or get one that you know is good and try it

POWER-STRUCK · Dec 25, 2012

sounds more like you have a bad icp sensor or high resistance in the wiring harness, pcm is seeing lower than expected signal voltage from the icp sensor and pushes the ipr% up trying to achieve proper pressure, my guess is that the icp pressure is much higher than the sensor is reading

Copracr · Dec 25, 2012

POWER-STRUCK said:
sounds more like you have a bad icp sensor or high resistance in the wiring harness, pcm is seeing lower than expected signal voltage from the icp sensor and pushes the ipr% up trying to achieve proper pressure, my guess is that the icp pressure is much higher than the sensor is reading

If I had a bad ICP sensor, would it run better with the ICP unplugged? Right now it wont do more than lopey idle unplugged.

POWER-STRUCK · Dec 25, 2012

what do your PIDS read with the icp unplugged koeo and koer

Copracr · Dec 25, 2012

POWER-STRUCK said:
what do your PIDS read with the icp unplugged koeo and koer

KOEO= 0v / 0kpa

KOER= 0v / 4999Kpa (725psi)

Very rough idle, that intermittent gravel chewing noise, very snappy throttle response though. The engine has been shut down for 4 hours so its not fully warmed up.

POWER-STRUCK · Dec 25, 2012

whats the ipr%

Copracr · Dec 25, 2012

i think it was 10-15% running at idle.

POWER-STRUCK · Dec 25, 2012

did you get any recordings with the sensor plugged in?

Copracr · Dec 25, 2012

yes, I just drove it home from work and it was running a lot better. Its still down on power and its not running smooth, but it was a lot smoother. Here's what I got:

Idle warm - 2.8-3v, 5%, and 2030 psi
Running down the road on level ground- 2.8-3v, 5%, 1740-2030psi
Trying to maintain 70 on a 5% uphill grade - 65%, 1300-1450psi and 3/4 throttle

I'm thinking new IPR and ICP in the morning.

Copracr · Dec 25, 2012

Whoa, ICP is $180 at NAPA!

yzrmbsg · Dec 26, 2012

Copracr said:
Whoa, ICP is $180 at NAPA!

43.60 for the brand new one I got on ebay 2 weeks ago. And none of that needing an adapter bull**** either. Made my truck happy

Copracr · Dec 26, 2012

I swapped in a new IPR and now it runs pretty good, I found some specs on IPR and ICP values and everything looks good there now. But the noise is still present.

Mostly, it does it at idle and light throttle, and will cut in and out under medium throttle. Never does it on decel. When the noise kicks in I can feel a vibration/miss and less power. I started thinking it might be the flexplate, but maybe its an injector?

The buzz test was normal, but the cylinder contribution test found cylinder 8 bad. I drove it around a while and re-did the test but still cyl 8 bad.

I have some old AD injectors in the garage but I've never seen them run. Should I install one and see what I get?

POWER-STRUCK · Dec 26, 2012

might be a loose gasket wiring harness on drivers side and check this post for injector inspection pre install
http://powerstrokearmy.com/forums/showthread.php?t=25776&page=4

Copracr · Dec 27, 2012

POWER-STRUCK said:
might be a loose gasket wiring harness on drivers side and check this post for injector inspection pre install
http://powerstrokearmy.com/forums/showthread.php?t=25776&page=4

OK, besides new o rings and checking their clearance is there anything else I can do to the injectors before install?