Need help with a romping start up

[zilla68]

Hot or cold, it randomly does this.

Start it up, motor sounds like a huge azz cam is in it, romping like crazy. The first time I shut it down thought something major was wrong, started back up and it still did it. Gave it a little throttle and it cleared up.

Plugged in or not, doesn't matter, doesn't do it all the time, but did it 2 times this weekend, 1 time today.

Any ideas??

oil change has about 3k on it, still full and clear as a bell.

I have a scanner, but no idea what to start looking at.

 

[David N]

What brand oil, and weight are you using?

 

[ghohouston]

Pull the chip and see if it still happens. You being in oklahoma, I doubt its very cold and causing issues. Check your icp sensor for oil. Scan it for codes. Sometimes 7.3's Will just randomly do it... I had my 2002 do it on a warm day on the first start once, and it did it for like a minute straight, never had that happen again.

 

[ghohouston]

And the oil viscosity is def another thing, if you're running 15w40, cold starts wil be rougher

 

[thuglike]

Chris,

Usually 1 of 2 culprits when it does this hot or cold and randomly.

Injectors or your ICP sensor. Are either new or originals?

If you can monitor ICP and IPR Duty Cycle at start up...It would help you out.

 

[thuglike]

What brand oil, and weight are you using?

Good suggestion as well!!!!!

 

[markfuga]

I remember reading a thread recently with this exact same problem. Looking for it now, but of course can't find it. Problem turned out to be the nuetral saftey switch on the transmission. Probably the last thing you'd think to check for a rough idling engine so just throwing it out there.

 

[zilla68]

What brand oil, and weight are you using?

delvac 15-40

 

[zilla68]

Pull the chip and see if it still happens. You being in oklahoma, I doubt its very cold and causing issues. Check your icp sensor for oil. Scan it for codes. Sometimes 7.3's Will just randomly do it... I had my 2002 do it on a warm day on the first start once, and it did it for like a minute straight, never had that happen again.

I will check the icp this weekend. It's not near as cold as it has been in the past month, so I'm doubting cold is the culprit, its pretty decent right now.
It sat all day, oil temp was 50 ish, unplugged, fired up no romp,

 

[zilla68]

Chris,

Usually 1 of 2 culprits when it does this hot or cold and randomly.

Injectors or your ICP sensor. Are either new or originals?

If you can monitor ICP and IPR Duty Cycle at start up...It would help you out.

both are originals, 187k on the clock.
I have new pis 230/100's to go in, haven't had time to get them in, the thing holding me back is losing the ability to keep both tanks and run e fuel to fuel the injectors. Trying to decide what to do.

 

[zilla68]

Good suggestion as well!!!!!

oil is fresh on the stick, looks brand new, has about 1800 miles on the last change.

 

[lincolnlocker]

delvac 15-40

When I tried that in my dually it woukd start doing that same thing between 1500 to 2000 miles...

oil is fresh on the stick, looks brand new, has about 1800 miles on the last change.

Your first post says 3k on oil... id change the oil first.. then see what it should do.


live life full throttle

 

[OldschoolPSD]

Unplug the icp sensor and look for oil in the connection. I've put icp sensors in all my 7.3s at one time or another and romping is usually a good indicator.

I run DELO in all my junk and always have (except for way way back when you could still buy Drydene... But I think my OBS still had a warranty back then lol) so I can't comment on oil.

 

[markfuga]

Try starting the truck in Nuetral. Could be the nss.

 

[lincolnlocker]

Unplug the icp sensor and look for oil in the connection. I've put icp sensors in all my 7.3s at one time or another and romping is usually a good indicator.

I run DELO in all my junk and always have (except for way way back when you could still buy Drydene... But I think my OBS still had a warranty back then lol) so I can't comment on oil.

Good call. Try that. After you post that I thought back and ive done 2 trucks like that.

live life full throttle

 

[zilla68]

ok, I'll give the icp a look this weekend if we don't get the ice storm they are saying might be coming, lol.

 

[zilla68]

is there any other signs the icp gives when its on its way out?

 

[ghohouston]

Throwing codes, they can cause a no start, rough idle, etc

 

[zilla68]

Throwing codes, they can cause a no start, rough idle, etc

ok, then that is probably my issue, idle seems different than before, almost like air is in the system when I ran my tank out before switching over.

what am I looking for when I'm watching the icp% on my scan gauge?
is there somewhere that will list this info?

 

[OBS-Addiction97]

If it clears up after you hit the throttle it could very well be the mlps. I have seen this before.