Cam/Stall/Headers and STILL Slow! Logs inside.
Dec 17, 2009 | 03:55 PM
#43
I really don't think the cam is off a tooth. We spent 30 minutes making sure it was right, and it looks just like the picture on ls1howto.
Did some new logs. Seems the LTFTs were all over the place. On my truck, they never go higher than about 3, where as his go to 10.
And when cruising, bank 1 LTFTs stay around .8, where as bank 2 are at about 5.
Overall it seems to be running alot better, but needs alot higher shift points and seems that it's running too rich throughout the RPM range.
Opinions?
Did some new logs. Seems the LTFTs were all over the place. On my truck, they never go higher than about 3, where as his go to 10.
And when cruising, bank 1 LTFTs stay around .8, where as bank 2 are at about 5.
Overall it seems to be running alot better, but needs alot higher shift points and seems that it's running too rich throughout the RPM range.
Opinions?
Rich does not a slower truck make. 11.5:1, 12:1, 12.5:1, 13:1 will all make within 2-3hp
Additionally, in the first log file there, with the air filter on, total airflow peaks at 34lb/min at 5400rpm. With that cam, peak airflow should be MUCH higher than that and should be increasing steadily til the shift point, not flattening out like it is. A stock 5.3L pulls 32-33lb/min on average.
Last edited by dc_justin; Dec 17, 2009 at 04:11 PM.
Dec 17, 2009 | 05:03 PM
#44
i didnt get that computer out.... why would the air filter make that much difference in how much air im pulling? ajs fuel trims are alot tighter than mine and his runs alot better? you see anything off in the new logs?
Dec 17, 2009 | 05:06 PM
#45
We compared an SSS on the dyno with vs without on the dyno, 8hp difference, equivalent of less than 1lb of air.
Dec 17, 2009 | 11:22 PM
#47
Cam a tooth off, retarded specifically, causes idle airflow requirement to increase due to decreased DCR. Tune is looking for right at 10g/sec of air to idle at 675rpm. Should be PLENTY for that cam to idle nice and stable without any fluctuation like that. Recent one that was tuned in person was idling with 9g/sec with no issues with a similarly sized TC and two other tunes that I've pulled up with the 220 are right where yours is without these issues.
For reference, Spoolin's truck required nearly 50% more air idle than a similar truck with 1 point more CR.
You can send your other PCM back in and I can update it; make it idle just fine given it's increased airflow needs, bump your shift points up like they should have been in the first tune. However, I would not expect the extra 600rpm bumping you up to 6500 that you're asking for to make up for the lack in a significant power gain in your mid-range.
For reference, Spoolin's truck required nearly 50% more air idle than a similar truck with 1 point more CR.
You can send your other PCM back in and I can update it; make it idle just fine given it's increased airflow needs, bump your shift points up like they should have been in the first tune. However, I would not expect the extra 600rpm bumping you up to 6500 that you're asking for to make up for the lack in a significant power gain in your mid-range.
Dec 18, 2009 | 06:55 AM
#48
check your rockers again . . . and the low oil pressure could be from a loose cam plate
I had a guy bring me a truck one time with a loose cam plate, and a gear that was a tooth off. He had the same idlig problems. It would idle all over the place or non at all.
It was like having a truck with a stock ported TB and not being tuned for it.
I had a guy bring me a truck one time with a loose cam plate, and a gear that was a tooth off. He had the same idlig problems. It would idle all over the place or non at all.
It was like having a truck with a stock ported TB and not being tuned for it.
Dec 18, 2009 | 07:28 AM
#49
Hmmm.... Well mine only idles like that sometimes the rest of the time it idles good.... I really hate to pull the front of the motor back apart but I guess I can pull it apart and see if its off or not. And recheck the rockers... And what if it is lined up and everythings fine? Then its gotta be in the tune yea?
Dec 18, 2009 | 08:16 AM
#50
Hmmm.... Well mine only idles like that sometimes the rest of the time it idles good.... I really hate to pull the front of the motor back apart but I guess I can pull it apart and see if its off or not. And recheck the rockers... And what if it is lined up and everythings fine? Then its gotta be in the tune yea?
was the cam new or used ? . . . are you sure on the cam specs ?