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what limits boost

deangtp

deangtp

New member
Something in the tune is limiting the boost to only 4 lbs. What is it?

The story.
I have a 2000 GTP that went down for a build up. L26 w/ 9.6.5:1 compression, XP cam, 105's, Dbl rlr, P&P Gen V, P&P heads, P&P LIM, headers, exhaust, all the crap. you know. I previously had a DHP 1.0 PCM and thought I didnt want to try and mess with that and not have anything to fall back on so i went to my local junkyard and picked up a spare. This PCM is in my car right now. I have three different files on my comp that i switch things up with and try to figure this out. With the standard DHP 1.0 file with the proper codes removed it runs great. I see 11.3 lbs of boost and everything is good. The base file that we put in to get the car running will not get but 4 lbs of boost. I went through and looked at the 1.0 file and the base file and changed everything to look like the 1.0 file but no dice. Changed the boost ramp rate. I see 16 inches of vacuum. I know the BBV and actuator are good and in working order. no leaks, no cracks. checked a hundred times. Could the VIN number be the root of my problem. IDK. Just throwing it out there. Sorry for the novel
 


I can take the DHP 1.0 open it up, look at it and make the spare PCM look exactly like it in every way right down to the codes reporting and everything and it still limits the boost to 4 lbs. Is there something about the VIN number or the OSID that needs to be changed for it to read correctly or am I missing something here. Also, with the spare PCM loaded into the PCM I can see several parameters for the transmission and a couple more for the engine that when I have the DHP 1.0 loaded I cannot see. Whats up with that
 
I'm not sure if you're suppose to be able to see the DHP 1.0. They don't like people knowing their secrets. Perhaps what your seeing is their way of screwing anybody that does. Just a thought, i'm pretty sure the dhp's are locked.
 
The PCM is like 4 years old. before tuners were available, before everything went down with ZZP. I paid 300 bucks for it. I'm not using it to make money or send to people or to screw anyone. it is my PCM. but i got it figured out. thanks
 


deangtp said:
The PCM is like 4 years old. before tuners were available, before everything went down with ZZP. I paid 300 bucks for it. I'm not using it to make money or send to people or to screw anyone. it is my PCM. but i got it figured out. thanks
Click to expand...

You cant say you figured it out and not tell us what you discovered.:)
 
dont throw that away or anything.

to run full boost with an l36 pcm just pull out the electrical portion of the bbv and then disconnect the lower vacuum line. thats how i have mine running in order to get full boost. top swapped a while back, never changed to an l67 pcm.
 


Did you know that the little box that has the plug in is the Boost Bypass Valve? The black cylindrical thing with plunger like action and vacuum lines connecting it is called the actuator.
 
deangtp said:
Did you know that the little box that has the plug in is the Boost Bypass Valve? The black cylindrical thing with plunger like action and vacuum lines connecting it is called the actuator.
Click to expand...

I thought it was actuator and solenoid and the valve being the blade in the s/c. But the whole thing commonly refered to as the BBV. I need to look it up, since I've ordered these pieces individually within the past year.
 
When I first started having these problems, everyone said BBV. So I bought a used one off of a member over on the other forum for 45 bucks. After I put that on and it didnt fix the problem I did some investigating. The BBV and actuator are the same 97-05. If you go to a GM dealership the part numbers go to 98-03. but if you look up an 04 and 05 they are the exact same part number as the 98-03. Yeah i know. It stumped him too.

Actuator kit.. call # 524/ part #89018120
supercharger bypass valve..call # 546/ part # 01997244
 
if youre truely using an l36 pcm that is your problem. unless you know that already.

just run it straight up vacuum controlled. disconnect it electrically from the system and disconnect the lower vacuum hose. bam, full boost.
 
deangtp said:
When I first started having these problems, everyone said BBV. So I bought a used one off of a member over on the other forum for 45 bucks. After I put that on and it didnt fix the problem I did some investigating. The BBV and actuator are the same 97-05. If you go to a GM dealership the part numbers go to 98-03. but if you look up an 04 and 05 they are the exact same part number as the 98-03. Yeah i know. It stumped him too.

Actuator kit.. call # 524/ part #89018120
supercharger bypass valve..call # 546/ part # 01997244
Click to expand...

Good info to have posted here:th_thumbsup-wink:. I looked though all of my purchases from Ed Morad and could not find one referencing the "BBV" parts. There was one receipt but I didn't specify the parts in the Paypal comments section.:th_bangheadonwall:
 


VIN 1G2WP52K4YF278575

If I did unplug the vacuum line, that wouldnt be considered a leak? That would make it harder to get out with the tuning, wouldnt it? Also, Why is it that when I have one program loaded I can see numerous things in scanning with the PT and with the other program loaded I can only see a few.
 
it doesnt cause a vacuum leak if you disconnect the bottom nipple on the bbv. you just cant still have the rest of your vacuum line still hanging there, it would then end at your fuel pressure regulator.
 
deangtp said:
VIN 1G2WP52K4YF278575

If I did unplug the vacuum line, that wouldnt be considered a leak? That would make it harder to get out with the tuning, wouldnt it? Also, Why is it that when I have one program loaded I can see numerous things in scanning with the PT and with the other program loaded I can only see a few.
Click to expand...

how do the parameters you can edit look when compared to each other? Can you post the two bins provided no one cares?
 
Well I am not gonna go posting around my 1.0 BIN file silly. That's a big no no and would put a bunch in many a panty. Lets say, you start your car. Go to the scanning and connect and it gives you the drop down for options you would like to see a gauge for and scan for. In my Transmission options for one file(L36 OSID) It shows shift time, gears, temperature, all kinds of stuff. With the other file(L67 OSID) it will only show me the temperature. Why the limited parameters. Should I try and put in the actual L67 PCM? Would that give me the ability to see the missing parameters? Or are the missing viewable parameters part of the 1.0 thing?
 
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