7.3L Miss at Mid-RPM

[Swaan]

What does the app do that my AE software will not do? I've never heard of the Torque App before.

Nothing , AE is fine.

 

[Jessy7.3]

Also from what I understand the tps (throttle position sensor? Is what I'm assuming) has a built in fail safe for things like this. Because the diesels do not have throttle plates to limit rpm. So the engineers decided they needed a fail safe in the tps. They made it so that both sides of the tps have a 0-12 v signal. However on one side it goes from 0 to 12 and on the other it goes from 12 to 0. And when you push the throttle let's say figuratively that one side will show 2 volts and the other will show 10. And let's say you don't push the throttle one side will show 0 or near 0 and the other side should show 12. At any rate if the tps was bad, and the truck sees that the numbers are no good and don't add up or if there was a dead spot, it would make it so that the truck will only idle. Just my understanding of the tps. Go ahead and replace if you want but if you think about it, say you had a bad spot, and it messed up and said too high of a voltage, your truck would be stuck at that position say it gets stuck at full throttle, the truck would run 100% maximum power. So they have to have that fail safe.


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[Swaan]

Yeah exaclly , so if it's got a dead spot and your doing 2000 rpm is going to buck and jerk isn't it.

 

[Jessy7.3]

No the truck would see that dead spot and go into an idle only mode. It wouldn't let you rev up the truck at all regardless of park, drive, or reverse. It seems to be a common occurrence. the only way i would imagine that it would cause a buck/miss would be if there were two dead spots at exactly the same place for the opposite signals. Example if you had a 12-0 and the dead spot was at 4v and had to have an identical dead spot at 8v on the 0-12 side. therefore equalizing out to 12v again and then the would have to find the same way out the dead spot say 4.5v on one side and 7.5 on the other. I just find that it would very difficult for both signals to fail at exactly the same time and in exactly the same spot. in my opinion, it's not gonna do anything to change a tps. If you have a spare one lying around that you think will make a change then might as well try it out. I just think you'd be throwing away money if you did buy a new one. It is honestly more complicated than it needs to be but its important to have those fail safes. I know of two trucks that had bad tps sensors and they wont do anything but idle.

 

[Swaan]

Interesting, I did not realize ford operated like that.
I've had a few tps act up on class 8 trucks and the pedal never went dead it had a stumble or miss at certain rpm .
Kinda stupid on ford's part because that would leave a guy stranded on side of the road.

 

[Black 02]

I have replaced the TPS before from a similar issue where it would surge/miss at certain RPM's. I figured it out because it wouldn't do it in cruise.

For some reason my cruise isn't working to try it again. I need to try and diagnose that too.

The problem is my truck has the integrated adjustable pedal with the TPS. I think it was like $300 from NAPA and like $600 from Ford. Not a cheap fix if it doesn't work.

 

[V-Ref]

I drive around with Torque on my phone nearly 100% of the time... Just makes it convenient to monitor PIDs on your truck. AE is awesome... Just gotta boot up the laptop... Sounds like the experts have it well in hand here though!

You mentioned there's a temp/range/pressure/speed/rpm it acts right.....can you define the condition (i.e oil temp, rpm, speed, throttle position, icp, ipr, etc) that it operated correctly under? If so.....then monitor that PID(s) like a hawk for when it doesn't act right... Attempting to catch it in the act. That ought to lead you to your bad sensor/ground, bad hard part, or tuning.

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[V-Ref]

Is there ever a time in Park that you can operate in the 1750-2000 rpm range and not get the miss that's in video #2?

What are tps%, icp, ipr, pw, and mfd doing when it's doing its little miss dance between 1750-2000 rpm?

Is there any coolant or oil temp combination that it runs correctly without the miss between 1750-200 rpm?

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[dsberman94]

Is AE able to datalog whatever parameters you select? Oil temp, icp, ipr? And then can you datalog the cct over a timeframe? Never used AE which is why I'm asking.

 

[Black 02]

You mentioned there's a temp/range/pressure/speed/rpm it acts right.....can you define the condition (i.e oil temp, rpm, speed, throttle position, icp, ipr, etc) that it operated correctly under? If so.....then monitor that PID(s) like a hawk for when it doesn't act right... Attempting to catch it in the act. That ought to lead you to your bad sensor/ground, bad hard part, or tuning.

The truck acts up only when warm. Yes is smokes a little on startup, but it's been cold out here. The idle is pretty good when cold. It idles about the same with both tuners. It appears that the truck doesn't start missing until the water temperature is at operating temp and the oil temperature is above 185 degrees. That's when the hitching seems to start. Seems like it gets worse when the oil gets above 200 degrees.

Using either tuner's tunes, the truck hitches the worst at about 1750 RPM and holding steady. That corresponds to about 1/4 throttle at most. Stand on the throttle and it typically takes off like a bat out of hell and smooth. Pulse width seems to be between 1.3 and 1.7. MFD seems to be between 13 and 18.

Today, I data logged my drive to work again. I noticed that the graph shows the ICP moving up and down when the hitching occurs, but it's not as rapid as the hitching. Maybe the AE doesn't record that quickly either. Either way, the ICP is dancing around with a fairly pedal. The oil temperature was about 200 degrees here.

After I got on the freeway, I switched to G-head's tune. Within 30 seconds of doing this, the duty cycle started climbing until it got to 88% and then the ICP spiked from like 1200 psi to 3800 psi instantly. I know this isn't "ghost" data because the injectors hammered incredibly hard when the spike occurred. It was an extremely noticeable sound change when the clattering occurred. This doesn't happen on Swamp's tune. When this happened, the P1211 code threw (ICP +/- expected). This graph was while holding the pedal steady at about 2300 RPM on the freeway with OD off.

When I got to work, I let the truck idle for a little bit. It idles a lot rougher when warm then cold. I did 4 different CCT tests at this time.
First time 5,6, and 8 failed.
Second time, 1 and 8 failed.
Third time 1, 2, 7, and 8 failed.
Fourth time was just cylinder 8.

When I'm driving on Swamp's trial tune holding steady at like 2300 RPM, the truck is fairly smooth. When I stand on it from there, the truck almost bogs down then accelerates slowly. The ICP doesn't climb above 2300 psi, but the duty cycle stays down under 20%. May just be the tune.

I'm at a loss. I've changed every typical sensor I can think of.

Now I'm down to....

Bad Injectors
IDM Issue
PCM Issue
Bad Throttle Peadal Signal
Engine Oil.

I'm gonna change the oil and just put some Delo in it and try it.

Otherwise, I'm losing my mind trying to diagnose this thing. I need to get Dave or Matt out here and live tune this damn thing!

 

[golfer]

..with what and where are you dumping the IPR 'drain'?

had a truck come here with Termies on it..(OBS truck w/ twins and 300/200s).

acted very similar until he dicked around with the IPR drain.

got a stock HPOP you can toss on?

bet ya dollars to doughnuts it fixes it.

 

[Layson]

Are you dumping the IPR drain back into the reservoir and not into the crankcase?

Have you ever monitored your engine oil temp in AE?

 

[superpsd]

Watching to see how you fix this one. Very interesting. If the IPR drain is good. I would possibly find a PCM to try. I would also use a multimeter and ohm the harness out and solenoids just to rule a few things out. Intermittent issues are not fun. Hope you nail it down.

 

[Black 02]

I have the Riffraff HPOP reservoir spacer and the twin feed line and IPR drain both go back to the spacer.

Where should they be ran to?

I monitored them today, Layson. On the freeway, the ranged from 190 to 215 degrees with the AE. They changed fairly quickly, so maybe the IPR dump is heating the oil up too quickly?

It appears that Joey's website is gone now and he hasn't returned an e-mail from me in over a month.

 

[psduser1]

Try swapping the drain to the fuel pump opening in the valley.

 

[superpsd]

I keep hearing about how Term hasn't been responding?

 

[mandkole]

Yeah, I haven't been in contact with Joey in years, but it appears that he's been moving away from this business. He's got a day job and does not seem to play with 7.3s much anymore. Its certainly a business that could be sold, so hopefully he doesn't just let it run itself into the ground. It happens...

 

[Layson]

I doubt it but it isn't his day job. My twin pumps have been at his shop for over a year now.

Black 02 your oil temps look great and you gor the spacer. I originally routed my ipr dump back in the reservoir and I was seeing 265 degree oil temps.

 

[Black 02]

Try swapping the drain to the fuel pump opening in the valley.

I have my S468 drain there. I guess I can try to modify the fitting or something......

 

[Black 02]

..with what and where are you dumping the IPR 'drain'?

had a truck come here with Termies on it..(OBS truck w/ twins and 300/200s).

acted very similar until he dicked around with the IPR drain.

got a stock HPOP you can toss on?

bet ya dollars to doughnuts it fixes it.

I can try to move it somewhere else.

I do not have a stock HPOP anymore. Went as a core....

I need to try to find one because I need to figure out this issue.