7.3L Miss at Mid-RPM

[Black 02]

Well, I got a new hydra chip from ******** and it seemed to take care of the random dying issue that my truck had. That is a good thing. Figured I'd start a new thread about my new issue.

Now, I'm dealing with a miss at mid-rpm range (1500-2500 rpm). It's most noticeable when I'm just cruising on the freeway. It starts this miss and almost bucking action where it feels like I'm losing a cylinder or something. If I stomp on it, it goes away. When it comes back to settle in at a steady RPM, it starts happening again.

Since when the RPMs are higher, the miss is less noticeable, I was driving to work this morning on cruise at about 2600 RPM. After about 5 mins of driving like this, the check engine light came on. Truck was still running funny, but the light stayed on until I shut the truck off and restarted.

I scanned the truck with my AE. Besides the codes tripped for a modded engine (EBP, intake heater, wastegate), I had a couple codes.

When I did the buzz test, everything sounded good. I got a P1298 IDM Failure code. I was told I'd get a code because I have a Swamp's IDM.

When I did the Key On Engine Running test, I got a P0269 Cylinder 3 Fault code.

Also, I got a P1211 ICP Higher/Lower than desired. I've found when I leave the truck in neutral or park and rev it up above 2500 RPM, I'll get that code also. If it is park when I rev it up above 2500 RPM and just let off the pedal, the truck will die.

I've done some data logging and the ICP is a little jumpy, but nothing crazy. Duty cycle with ICP pressures looked good.

Here is a poor video of the truck missing on the freeway. This isn't as bad as sometimes it is. You can hear the engine over my tires. Sometimes there is a more noticeable bucking going on around that speed.

https://youtu.be/kU5rmjlnI3c

Truck runs good when floored. It just runs like crap when cruising.

One person on the other thread mentioned CPS and connector. I have a new dark grey CPS from RiffRaff in the truck. Didn't check the connector. I have an old black CPS I could try.

ICP sensor is new, IPR is new......

Any help is appreciated.

 

[Black 02]

Maybe this can help. Anytime I run the truck over 2200 RPM steady, the check engine light comes on. I keep getting these codes.

P1211 ICP Higher/Lower Than Desired
U1262 SCP (J1850) Communication Bus Fault
U1027 SCP (J1850) Invalid or Missing Data for Engine RPM
B1352 Ignition Key-In Failure

Also, tonight I was data logging and noticed that the ICP would spike over 1000 psi and the injectors would start making more noise.

I got this weird anomaly after the check engine light came on. With the RPM and ICP steady, the duty cycle began climbing. It kept climbing up to almost 50% and then the ICP spiked to 3500 psi and the duty cycle dropped.

What would cause this? Bad HPOP? Leaking injectors? It seems more noticeable when the engine is warm.

Here's a chart of the ICP and duty cycle.

 

[Dmstrucks02]

What HPOP is in it? How old is the oil?
I thought you were coasting at first in that video..

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[mandkole]

Ryan, with those codes, Im not sure you still don't have a damaged pcm issue you're chasing. I don't know those codes to be typical.

What exactly were you doing with the pedal in that datalog event? A steady 2300 cruise would not cause the IPR to behave like that. Its like the power to the IPR comes/goes.

 

[Black 02]

What HPOP is in it? How old is the oil?
I thought you were coasting at first in that video..

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The oil has about 1000 miles on it. I'm using the Joe Gibbs Driven Racing Oil formulated for diesels. My engine builder requested I use that because he's had good success with it.

The HPOP is a terminator twin setup. I bought it used from Vision Diesel. They are supposedly twin 15 degree pumps, but was told by Joey and the guys at Vision that they should be plenty to supply my injectors. I don't know how many miles is on it from Vision. I have probably 5000 miles on it between two engines.

 

[Black 02]

Ryan, with those codes, Im not sure you still don't have a damaged pcm issue you're chasing. I don't know those codes to be typical.

What exactly were you doing with the pedal in that datalog event? A steady 2300 cruise would not cause the IPR to behave like that. Its like the power to the IPR comes/goes.

I was holding the pedal steady. I have the RPM data to match to prove. I just didn't plot it. I had it do it again when the cruise control was set on a flat road.

 

[Black 02]

I don't know how all of the parameters are related, but the injector PW, the ICP Voltage, and the ICP itself all have the same graph over the same timeline. During these weird spikes in the graph, the MFD is fairly steady. The plot is almost flat.

I guess my question would be..... What would cause the ICP to remain constant at a constant RPM, but cause the duty cycle to steadily increase until it hits a point and causes the PW, the ICP, and the ICP voltage to make a drastic spike?:shrug::shrug:

 

[secondarychaos]

I don't know how all of the parameters are related, but the injector PW, the ICP Voltage, and the ICP itself all have the same graph over the same timeline. During these weird spikes in the graph, the MFD is fairly steady. The plot is almost flat.

I guess my question would be..... What would cause the ICP to remain constant at a constant RPM, but cause the duty cycle to steadily increase until it hits a point and causes the PW, the ICP, and the ICP voltage to make a drastic spike?:shrug::shrug:

Silly as it sounds, I had some similar symptoms (although not a complete match) when I had a loose IPR nut.


But I'll assume you've checked all your basics and not suggest anything

 

[Black 02]

Silly as it sounds, I had some similar symptoms (although not a complete match) when I had a loose IPR nut.


But I'll assume you've checked all your basics and not suggest anything

I know where you're coming from....

The issue was happening with the old IPR and I put a new one on and it still does it. The nut was tight on both IPR.

 

[secondarychaos]

I know where you're coming from....

The issue was happening with the old IPR and I put a new one on and it still does it. The nut was tight on both IPR.

hmm... alright.

So, the computer is seeing a flat ICP, but Duty Cycle is climbing.

Duty Cycle reaches either a time or energy saturation, and the ICP spikes.

Computer sees high ICP and drops Duty Cycle, ICP follows.

Under the assumption that the computer wants more ICP than it's getting during the flat-ICP time, my first question is whether or not the ICP is actually flat during the climbing duty cycle.

Have a spare ICP sensor to try? Check the wiring around the ICP sensor? Can you get a gauge on the HPO line?

Can you reproduce this code/ICP issue with the truck in park?

Is there a miss at other rpms? Oil leak? Extended crank to start? Low oil pressure?

Literally anything odd could help us help you.

Edit: Check your engine ground to make sure you're not getting screwy signals

 

[psduser1]

Your problem sounds like it's on the electronic sise, but just for s&g, have you actually seen an icp spike by mechanical gauge? Only a few minutes to check that.

 

[Black 02]

hmm... alright.

So, the computer is seeing a flat ICP, but Duty Cycle is climbing.

Duty Cycle reaches either a time or energy saturation, and the ICP spikes.

Computer sees high ICP and drops Duty Cycle, ICP follows.

Under the assumption that the computer wants more ICP than it's getting during the flat-ICP time, my first question is whether or not the ICP is actually flat during the climbing duty cycle.

Have a spare ICP sensor to try? Check the wiring around the ICP sensor? Can you get a gauge on the HPO line?

Can you reproduce this code/ICP issue with the truck in park?

Is there a miss at other rpms? Oil leak? Extended crank to start? Low oil pressure?

Literally anything odd could help us help you.

Edit: Check your engine ground to make sure you're not getting screwy signals

I had an OBS ICP sensor and it immediately threw a check engine light and didn't seem to work. I know they are expensive, but I'm gonna order a new one I think.

I'm also gonna change the wiring plugs for the IPR, the ICP, and maybe the cam sensor. I'm gonna change the UVC gaskets and wiring too. I've talked to a couple people and they said all of that can't hurt. The IPR is Ford and literally has maybe 200 miles on it. It's expensive, but it's the only way to eliminate these electrical gremlins.

I spoke with Dave at Swamp's and after listening to my video, he thought it sounded less like a "miss" and more of what he calls "trailer hitching".

The truck doesn't seem to miss at idle and it seems to miss less when the engine is cold. When the operating temp reaches normal, it seems like the miss starts occurring. It does hiccup a little when cold though. Just gets more pronounced when warm.

In park, if I rev the truck up to 2500 RPM or so, it will throw a P1211 code every time. I haven't data logged the ICP while doing this yet. I can.

The truck cranks normal on startup, but it is smokey. When warm it's clear. If I plug the truck in, it has very little if any haze.

I've wiggled all of the plugs on the engine and it doesn't make any difference.

I unplugged the ICP sensor and drove it and it still does it. The "miss" doesn't seem as aggressive when the ICP sensor is unhooked.

I removed the Hydra and drove it and it still does it.

That's all I can think of.

Dave thought maybe one of my injector poppets wasn't working correctly allowing a bleed off until it snaps shut and seals.

When the ICP spikes, I can hear for the lack of a better term a "clatter" in the engine. I'm guessing it's the injectors making noise. When the ICP is jumping around, that clatter stops and starts like a switch. You can hear it in the video of mine if you listen closely.

 

[Black 02]

I forgot to mention the engine has about 40-50 PSI oil pressure when warm at about 2000 RPM. I have a Melling LPOP.

Here is a graph of ICP and Duty Cycle while the truck was sitting in park and it threw the P1211 code. When the ICP went to zero, I let off the throttle and the truck died. I revved the truck up to almost 3000 RPM when the ICP spiked up and held it steady.

Here is a graph of the Duty Cycle and RPM over the same time. The duty cycle climbs and then drops to 4.69% while holding that high RPM (over 2500). When I let off, the truck died and the duty cycle went up to 14% give or take. These two graphs are over the same timeline.

I'm pretty good with excel, but I'm not sure how to graph 3 parameters over time and give a vertical scale with each, so that's why I graphed the data on two different charts.

I noticed the ICP dropped to 0 on the graph. I'm guessing that's why the P1211 code threw.

I'm confused as to why the Duty Cycle dropped to 4.69%. Very odd......

Could a bad cam sensor cause the issue of giving poor data at a higher RPM???

 

[Black 02]

Ok, so I've replaced the ICP sensor and plug, the cam sensor, the IPR and plug, the UVC harness and gasket and the issue still occurs.

The spikes in the ICP graph don't occur when the ICP sensor is unhooked, but the miss still occurs.

The issue of the P1211 code throwing when revving the truck above 2500 rpm is still happening. I've also added two videos of the miss. These are when the truck is in park. It seems electrical to me. I don't know what else to check. I'm at a loss right now.

The truck runs great when accelerating. I did the Swamp's test on the pump and it held 3000 psi at 40% duty cycle on my highest tune. It's just running like a$$ when holding the throttle steady at about 1750 to 2000 rpm.

Here are the two videos. Sorry about the video quality, but the audio is clear enough to hear the issue. The 2nd video is probably more indicative of the problem.

https://youtu.be/oRzmTtS_f4E

https://youtu.be/TyYB_kHsq7w

 

[golfer]

sounds like the tuning has the ICP pressure pretty high at low MFD.

email me your Hydra S/N...for a tester tune...

 

[Black 02]

I want to thank golfer with helping me try to diagnose this problem. It's been frustrating and it's still happening.

There is something going on related to temperature of the engine or engine oil. The truck runs great when it's cold. It smokes a little when really cold but clears up and has just a subtle haze when warmed up idling. I drove almost 20 miles today and there was no miss or hitch throughout the RPM band. Very smooth. Then, all of a sudden, like a switch was flipped, the truck started missing/hitching. It's most noticeable at like 1750 RPM. After it started doing it, it got progressively worse as I continued to drive it. I drove another 15 miles and it was even doing it from stoplight to stop light as I'd accelerate easily as it came through the 1250 to 2250 RPM range.

I'm gonna keep data logging this thing to see if I can figure it out. I just don't want to damage my new engine, but I have to figure it out.

ICP, IPR, UVCH and gasket, and connectors have all been replaced with Ford replacements. Miss occurs with ******** tuning and with Swamp's tuning. It idles smooth when cold, but idles somewhat rough when warm. Almost sounds like it has a cam.

I wondering if its:
TPS
Injectors worn
Engine oil.... gonna change this soon.
?????

Damn cornbinder!!!!!

 

[V-Ref]

Torque App... Catch it in the act... May help you see if there's a specific oil/coolant temp that this happens at

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[Black 02]

Torque App... Catch it in the act... May help you see if there's a specific oil/coolant temp that this happens at

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

 

[Swaan]

I would replace the tps. You could have a bad spot in that range you were talking about. If the ecm gets a wacky signal from tps it's going to do things like you describe.
Worn inj or engine oil will not cause your symptoms but a tps will.

 

[Jessy7.3]

The torque app is just a monitoring system. It shouldn't have any bidirectional control over the pcm. Like for example a scan tool could activate computer controlled stuff such as turning on a horn or activation of a relay. The torque app and its hardware will only let you view certain engine perimeters but should not be able to activate or change anything the computer is doing. You will have to buy hardware, (recommend elm 327 or whatever and you'll see those models when start searching). It just plugs into the obdII port and will be about 30$. And also the torque app has a free version and a full version that I think is like 5$. Its basically like adding an advanced trip computer and using your Bluetooth device as a monitor. If you don't like torque then there are lots of other apps that let you use the same hardware.


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