It appears that is the cause of my P0238 also. I did state in my earlier post that I saw 22.2 psi, as read by the PCM. Looks a little tweaking of my MAP regulator is in order. I'll try it today and see what happens.

 

it looks like your EBP sensor is reading low as well, it only saw 11ish PSI with 40PSi of MAP.

I do think the OCR is the source of your code.....but i am only guessing there. I hope Rolands testing proves this out.

more thoughts......is your truck defueling when you get the code? I am wondering if there is a "range" that trips the defuel...say 22+ PSI will trip the CEL and then 25+ will trip the defuel/limp mode....did the tuneing change the table for the defuel and not the CEL?

I have PHP tunes on a relatively stock truck and can hit 30PSI MGP on AE and never set a code. When my truck was running stock tuneing I could trip P0238 and defuel empty on big hills. I always figured my truck was one of the "factory hotrods" I have heard about. when the 7.3 was in production every engine was dyno tested after being built and it was not uncommon for engines to be pulled from assembly because they where making "to much power". Some engines where at the bottom of the allowable range and some where right at the top of the spec and still went in to assembly, so it was possible to get to similary equiped trucks with the same configs and have one be quite a bit more "peppy". Take that for what it is worth though...I read it on the internet.................so it must be true right?

 

Steve, EBP is hitting ~50 PSI, it uses a different scale which is on the right side of the graph.

I'm not for sure whether it is defueling but definitely not limp mode, I wonder if defueling is shown by the flatline ICP on the graph which occurs about when the code trips. Interesting that you don't trip it at 30 PSI with your PHP tunes. The plan is to call Clay and maybe then PHP depending on what Clay says.

 

lol, I'm pretty worthless before my second cup of coffee

 

"Backed off" the regulator about 1/2 turn this morning before leaving for work. I waited until I had a few miles of straight road to test it out. I set my Aeroforce Interceptor to read boost and punched it a few times. No SES light and Boost PSI, as read by the PCM, was under 22. I exceeded 25 psi on my Autometer mechanical boost gauge each time and I got a digital reading from 21.6- 21.9 on the Aeroforce. Looks like anything over 22 psi would trip the light and set the P0238 code. I think my setting is good where it's at now and I will leave well enough alone.

 

good info Roland, thanks for the follow up.

 

Yes thanks for the follow-up Roland. Clay is going to test my regulator, it is not adjustable like yours.

 

Update: Ended up testing the OCR myself, found an old pressure gauge over the weekend, that one hit 21 psi and then bled off, old leaky gauge. Pulled another gauge off of a regulator at work and that one held at 22 psi. The OCR is set correctly, which I didn't doubt but had to rule it out. Clay suspects an electrical issue or MAP is off.

Can't find anything amiss with AE, maybe picking up a new MAP sensor is the next step???

 

humm.....I have a known good MAP in my tool box, pm me if interested. I have no use for it so it's yours if you want it.

 

Thanks Steve, looking forward to testing with that MAP sensor.

 

Finally got a chance to test with the MAP sensor that Steve overnighted me. Thanks again Steve.

Still tripping the code and light....

 

Just to follow up this thread with the resolution- I swapped out the OCR with an adjustable regulator from another vendor. After reducing pressure two click from the preset the code/light is no longer tripped.

Thanks to all who posted and helped me reach this eventual resolution.

 

Glad you got it fixed. What do plan on doing with the OCR? Have you contacted Clay about it?

 

I spoke with Clay a couple times during troubleshooting but not since resolution. Due to the test I did on the OCR and the fact that I had to lower the pressure from the preset on the adjustable I believe the OCR is set properly.

The adjustable regulator is from Strictly Diesel and Dennis told me he went back to adjustables from fixed due to issues, said some trucks just require lower pressure.

I would sell the OCR if someone wants it since I don't have a use for it.