Where did I go wrong?

[The Brad]

those numbers look spot on.. brings us to a couple things.. have you pulled rockers and pushrods to see if anything is jacked up? its now a mechanical issue or a tuning issue... whats battery voltage doing while it romps?



live life full throttle

To be clear, it's not romping, it's just rough idle. Battery voltage is at the top left of my tablet in the video. Once the GP's turn off, it's in the upper 13's. I pulled the pushrods months ago when I was originally troubleshooting this issue and they were still straight. I haven't tought about it since, since the issue comes and goes. Tuning: Jody sent me several different tunes to try, then I bought a hydra with PHP tunes, and finally had Jody live tune it. No change in roughness, or egts.

 

[lincolnlocker]

get voltage above 14v.. i have noticed many times that 7.3s like it much better when they stay around 14.2v... when they drop below 14v i notice they get finicky. more then they already are...

live life full throttle

 

[superpsd]

Have you tried another IPR?

 

[TyCorr]

Is your oil aerated Brad?

It sounds to me, wtf do I know, like there is air in the oil. The air softens the sound of the idle.

 

[mandkole]

Im pointing to tuning..490 ICP is very low at idle. In fact, Ive never had tuning that commanded just 500 psi ICP... especially with 80s or 100s. That much nozzle needs a little more pressure behind it. All trucks are different, but Bill live tuned this one and all files command 800 psi @ idle.

 

[The Brad]

Im pointing to tuning..490 ICP is very low at idle. In fact, Ive never had tuning that commanded just 500 psi ICP... especially with 80s or 100s. That much nozzle needs a little more pressure behind it. All trucks are different, but Bill live tuned this one and all files command 800 psi @ idle.

What's your inj PW at 800psi? Is that warm idle? IIRC, Docbar's truck idled at 500psi, 1.5ms pw, and he has 250/100's. Before live tuning, I idled in the 600 range and dropping it down smoothed things out a bit without hurting throttle response.

IPR was replaced 200 miles ago, and 8000 miles ago.

No signs of aeration on dipstick or in HPOP reservoir. I ran it at 3000rpm for 3 minutes and watched IPR DC after returning to idle and saw no change. That's the test procedure in my ford manual to check for LPOP pick up leak.

 

[Lethalthreat7.3]

You have an electrical issue. Whtch your tach. You can see it bounce at idle as well as when you sethigh idle.

Try holding the throttle at 1700-1800 steady for a minute. Watch your tach. If it bounces you have a signal issue from the CPS. This doesn't necessarily mean the sensor is bad tho.

Do you have ANY codes at all? Any codes, not just engine related.

I firmly believe you have a ground/interference issue. Ive been working on this exact issue.

I can go into detail but would like to know more

 

[Bustedknuckles]

Subscribing to see what you find. Been fighting this issue for a couple months on my dads 7.3. It started after FF stage 1 single shots. Rebuilt and balanced motor after cracking a piston, new swamps IDM, injectors tested, compression test, new VC harnesses, and new tunes from gearhead. The new tunes pretty much fixed it but its still rough and loud and sets random contribution codes...

 

[mandkole]

What's your inj PW at 800psi? Is that warm idle? IIRC, Docbar's truck idled at 500psi, 1.5ms pw, and he has 250/100's. Before live tuning, I idled in the 600 range and dropping it down smoothed things out a bit without hurting throttle response.

Ive run the injectors on the stock tuning for grins-- less PW (1.1), less ICP (around 500) and the motor was quieter, but fuel control got sloppy. The motor hot idles at about 800 and 1.2-1.3 pw.

Interesting thoughts on CPS..

 

[The Brad]

You have an electrical issue. Whtch your tach. You can see it bounce at idle as well as when you sethigh idle.

Try holding the throttle at 1700-1800 steady for a minute. Watch your tach. If it bounces you have a signal issue from the CPS. This doesn't necessarily mean the sensor is bad tho.

Do you have ANY codes at all? Any codes, not just engine related.

I firmly believe you have a ground/interference issue. Ive been working on this exact issue.

I can go into detail but would like to know more

I've never noticed any tach movement that didn't corrleate to rpm, but I'll try that. As far as codes, I have 1 for 4wd selenoid failure (vacuum leak), and 1 due to the chip, I think it's something like ROM internal read error.
I've swapped the CPS during my troubleshooting.

 

[gnxtc2]

You have an electrical issue. Whtch your tach. You can see it bounce at idle as well as when you sethigh idle.

I firmly believe you have a ground/interference issue. Ive been working on this exact issue.

I can go into detail but would like to know more

I remember a post that the wiper motor delay feature caused some type of electrical issue because it is on the same fuse circuit as some engine control component. I think it applies to a SD truck. Don't know if it is the same for the OBS.

Billy T.
[email protected]

 

[TyCorr]

Im pointing to tuning..490 ICP is very low at idle. In fact, Ive never had tuning that commanded just 500 psi ICP... especially with 80s or 100s. That much nozzle needs a little more pressure behind it. All trucks are different, but Bill live tuned this one and all files command 800 psi @ idle.

Bill has tuned every rendition of my 00 7.3, including the current one. Stock, stock/30, 175/80-100, 250/200 (ffd&pis). Never had icp over 600 at idle. Never. My current setup idles at 490-525 depending on the tune. The tow tune and dd idle at 525 :shrug:

I cant say about previous setups. The only setup ive used more than one tune was stock (the tune, not the truck ad's/billet 38r/fuel system/springs/prods) and the 250/200s. The 250/2 setup I use a tow tune simply because my cylinder heads arent complete. I have stock springs as the comp springs are crap and I dont have swamps springs yet. So I cant push it. Anyway, as stated there was different icp values at idle in the 250/2 set of tunes.

Stock they were all under 500 psi regardless of tune. I did have a srp1 so perhaps it was incapable of delivering 5+ at idle

The 175s and renozzled stock I dont remember simply because they were so short lived and I had new twins at the time so I dont remember shti!

But yea, there are php customers running "soft" icp values3s at idle.

 

[The Brad]

Come to think of it, I ran PHP tunes as part of my troubleshooting and my idle ICP wasn't any different .

 

[mandkole]

Hmm, it was just a thought.. carry on.

 

[The Brad]

You have an electrical issue. Whtch your tach. You can see it bounce at idle as well as when you sethigh idle.

Try holding the throttle at 1700-1800 steady for a minute. Watch your tach. If it bounces you have a signal issue from the CPS. This doesn't necessarily mean the sensor is bad tho.

Do you have ANY codes at all? Any codes, not just engine related.

I firmly believe you have a ground/interference issue. Ive been working on this exact issue.

I can go into detail but would like to know more

Here's a video of the tach movement.
http://youtu.be/-Pd6SUMpxbQ

 

[The Brad]

Hmm, it was just a thought.. carry on.

I'll take any and all ideas. Thanks!

 

[TyCorr]

Hmm, it was just a thought.. carry on.

It was worth bringing up!

 

[lariat 7.3]

my truck does the same exact tach thing at idle and when its in high idle you can notice a slight drop and raise in the RPMS. I've always had high egts.....

But the idle is smooth, sometimes you can feel a very slight miss, but i attribute that to the injectors

 

[gnxtc2]

I may be wrong but watching the needle on the tach could be misleading. The tach needle movement is generated.

I would hook up a scanner and read the rpms. The scanner will have direct connection to ECM.

I have the AIC controller in my truck. The AIC readout contradicts the tach movement.

Billy T.
[email protected]

 

[superpsd]

I'll take any and all ideas. Thanks!

Drive it to the nearest priest and ask him to perform an exorcism?