reduced engine power after 3bar install

[9secVette]

Wondering if anyone can help me out here,
I have had this car tuned with a maf for some time without a problem(1514 values raised to 1200) after installing the 3 bar map set up everything is fine untill I hit boost. I then raised the values to max,(4580) just to see, but it still goes into reduced engine power. Any tips??

Thanks :cheers:

[GMPX]

I have a feeling you need to go higher in the C6101 table.

Cheers,
Ross

[Highlander]

Make sure that there are no codes present. Verify that you have set correctly the scalar on the map sensor. If you get any single problem from any map calculation it will set the reduced engine power.

[9secVette]

Thanks guys! I'll check both your ideas and post results. :cheers:

[9secVette]

That took care of it! Thank you very much, on to the dyno. :master: :cheers:

[Highlander]

what took care of it?

[Redline Motorsports]

Raising the 6101 table so it is higher then the predicted airflow usually solves this problem.

[9secVette]

Make sure that there are no codes present. Verify that you have set correctly the scalar on the map sensor. If you get any single problem from any map calculation it will set the reduced engine power.


Highlander, thanks for responding.
I thought I had this taken care of but once I went to the track it went back to reduced engine power again setting a P0068

I have the C6101 table maxed to 4095.9 across the board, so I guess I must be doing something incorrect for the map calculation.

The predicted map max is all at 105 (C3003) Minimum is set at 0 accross the board.

I have switched to a two bar map to give that a try and changed my map scaler (C6301) to 190, C6302 map sensor offset is at 10.3 Rationality tests are 600 &400 for high and low.

When I used the three bar sensor I had it set at 288

any info would be great! thanks in advance.

[9secVette]

Make sure that there are no codes present. Verify that you have set correctly the scalar on the map sensor. If you get any single problem from any map calculation it will set the reduced engine power.


I do get a 102 code that is turned off, but I do not think that is it. Of course I still have the problem so....:)

[Highlander]

You will have the 103 and sometimes 102 codes present. that is necessary for the Speed density...

You should get some codes when the reduced engine power appears. You might be getting a p0106 which is a map sensor codes.. please resport the codes you get.

[9secVette]

You will have the 103 and sometimes 102 codes present. that is necessary for the Speed density...

You should get some codes when the reduced engine power appears. You might be getting a p0106 which is a map sensor codes.. please resport the codes you get.

Thanks for the quick response!
Just the p0102 and p0068, I am assuming it's the p0068 that is causing the issue. This is in an 04 Vette, I have raised the tables I have listed a few posts up. Can you think of anything I can be missing? Keep in mind the car was fine with a few less pounds of boost, 12-raised to 15.5. on a 427 engine.


Thanks for the help:cheers:

[DrX]

There is a disagreement between the SD calculated and MAF airflows.
Assuming correct MAF sensor calibration and MAP sensor scalar value, could the MAF be still active but maxed out, or not fully disabled?


DTC P0068

Circuit Description

The powertrain control module (PCM) uses the throttle position (TP), barometric pressure (BARO), intake air temperature (IAT), and engine RPM in order to calculate the predicted mass airflow rate. The PCM compares the predicted mass air flow (MAF) value to the actual mass airflow value and the speed density calculation in order to verify the proper throttle operation. If the PCM detects that the difference between the actual air flow (MAF) and the speed density calculated air flow is greater than expected, DTC P0068 sets.

[ringram]

Did this get sorted out?
Got a similar issue here.

[9secVette]

Did this get sorted out?
Got a similar issue here.


No not yet, Thanks DRX!

The maf has been removed and the operating system has been installed for 3 bar map s/d use. I have also tried a two bar map and scaled it for both 2 and 3 bar each time. Maf has been set to max value also. I'm not sure what else I could be missing here, but I'm sure it's just one simple thing. A friend of mine is going to pull the program with HP tuners, according to him they have a section where he can raise the minimum rpm to set the p0068 code to 8149. I looked all through EFI and could not find that. I am going to meet up with him this week, I'll post up how it went. If anyone knows where this can be found in EFI please let me know.

thanks! :cheers:

[DrX]

What is your B0120 set to? Try maxing it out as you have no MAF anyway. Looks like that was the only change I made when I was having this problem.

[9secVette]

What is your B0120 set to? Try maxing it out as you have no MAF anyway. Looks like that was the only change I made when I was having this problem.


Thanks again DrX,
I checked B0120 table, I got all excited because it was at 8888.1 and max is 12,xxxx. I maxed the table but have the same results.:nixweiss:
Since this is an RPM based table it seams odd that max is 12k, but maybe this is the table my friend with HP was talking about?
the operating system I using is 12587603--04073003, which show to be a match. I'm really at a loss, anyone please!!

btw, this was with the two bar in place, I am technically just over that at 16lbs, I have had a three bar in there (both scaled) but was told that might be the problem so I switched it. Am I correct that if the two bar is maxed it will still work fine just not show the pcm the additional lb of boost, or can that be a problem I introduced on top of the B0120 problem?

Thanks

[DrX]

I checked B0120 table, I got all excited because it was at 8888.1 and max is 12,xxxx. I maxed the table but have the same results.

8888 should have been good enough. Don't think you will be revving that high. Must be another issue.

[9secVette]

8888 should have been good enough. Don't think you will be revving that high. Must be another issue.


Thanks anyway :beer:

Anyone? can someone maybe look at the file? pleeaase :help2:

[joecar]

Post your .tun file in this thread (go Post Reply, and then go Manage Attachments, browse to your file, and upload it);

there's quite a few people here that will view it. :cheers:

[9secVette]

This is the file prior to raising the B0120 table, it is now maxed, there are some minor idle issues that I have not bothered fixing yet till this problem was taken care of, but any help would be greatly apprieciated.
:cheers:
I guess while your looking, I noticed when the car starts cold, it runs for a few seconds then dies, this will happen several times and then it's fine. Thanks again for your time.

[tazinhawaii]

Why does your boost VE table drop by 100 at 285 kpa?? This could be the problem I think. I've done this by forgetting to select the last row of a table while editing before and pulled my hair out trying to figure out what's wrong.... I imagine the PCM is trying to compute airflow at 14+ psi with the 0 psi VE numbers in the 285kpa column of this table....

Also, what setup are you running? Just curious because it sounds/looks like you are very similar to me (2001 Z06, 427 C5R, PTS twin turbo, 60# injectors, etc.)

Derrick