Cant Get More BOOST..

89BlackTGP · August 23, 2009, 12:55:34 PM

Well since the TGP has been done i drive it around the country here often.. i have only ran 2 tanks of gas so far since its been done.. So since i have been driving it it hasnt bothered me until now.. i cannot boost past 8 psi.. The chip has been tuned by adam for the 5 spd swap and to take more boost i believe 14 psi.. Well today i said screw it i wired shut the wastegate arm and disconnected the actuator and according my autometer boost gauge i am at a steady 10 PSI at WOT.. I cant not get any more boost.. I am confused.. someone please help me out.. Thanks

GPChief · August 23, 2009, 03:33:15 PM

Sounds like you make have a "leak" somewhere bleeding off boost. Check all hose clamp's to the IC & TB. The lower one for the IC used to give me issues once and a while.

89BlackTGP · August 23, 2009, 05:21:22 PM

i actually have just recently changed the IC pipes over from the older pipes i had.. i know the clamps are tight.. i remember tightening them down.. but its wierd that i cannot get anymore than 10 PSI its not going up or down its just a constant 10...

flybynite · August 25, 2009, 04:57:39 PM

Restricted exhaust system, blown compressor seal and low fuel pressure are a few possibilites.

89BlackTGP · August 25, 2009, 05:11:10 PM

Quote from: flybynite on August 25, 2009, 04:57:39 PM
Restricted exhaust system, blown compressor seal and low fuel pressure are a few possibilites.

Exhaust system is free flowing no cat and no mufflers.. but is a full system..

Blown Compressor seal?? now what other issues would i have with that being blown besides not able to boost?

Low Fuel pressure... I have a new WALBRO installed.. i have not checked the rail it will not hurt to check it either so i will do that but i know it has a high pitch whine to it and can hear it pump...

Is there any other possibiltys? its strange that it wont boost past 10 PSI wastegat wired shut at WOT..

flybynite · August 25, 2009, 06:33:41 PM

If the compressor housing seal was blown you would feel air blowing out around the housing. I can hit 16psi pretty quick with the same tune you have. Check fuel pressure, ohm injectors and check the palstic line for the boost gauge for any crimping or breaks. Whats the condition of the turbo???

89BlackTGP · August 25, 2009, 06:51:07 PM

Quote from: flybynite on August 25, 2009, 06:33:41 PM
If the compressor housing seal was blown you would feel air blowing out around the housing. I can hit 16psi pretty quick with the same tune you have. Check fuel pressure, ohm injectors and check the palstic line for the boost gauge for any crimping or breaks. Whats the condition of the turbo???

I will check fuel pressure. I think I had a gauge on it when I first started the car when it was pit back together but I'll check it again.

Fuel injectors are yellow tops from a 94 5.0 stang. I will ohm them to be sure they are good.

How would I check for leaks around the compressor housing? I have not noticed any air leaks around the turbo. But I do still have oil coming out the front breather but my motor only has 300 miles on the rebuild.

The turbo I got from a member in san Antonio from 60degreeV6. He stAted to me it was rebuilt and ran it on his Tgp for about 3,000 miles and then upgraded.

Edit: the autometer gauge was just put in. I did wrap it with wire loom for protection. But will double check.

flybynite · August 26, 2009, 07:42:15 PM

Flakey knock sensor?? Do you have access to a scan tool?

GhrarhG · August 27, 2009, 02:30:45 PM

If the gauge is right, it has to be a leak in the charge piping or restriction in the exhaust. I suppose a restriction in the intercooler is a possibility. I'm not sure what injectors or knock sensor have to do with anything if the waste gate is wired shut and the pedal is held to the floor.

Bad injectors/knock/knock sensor issues would be plausible if he was using the computer controlled waste gate actuator, but this

QuoteWell today i said screw it i wired shut the wastegate arm and disconnected the actuator and according my autometer boost gauge i am at a steady 10 PSI at WOT

kinda eliminates that.

An important question is where is your boost gauge tied into? It could be that you are in fact hitting 14psi and the gauge is wrong or the plumbing to it is leaking. Being able to log the run would be a big indicator. If your MAP sensor is reading over 170 kPa, your gauge is inaccurate.

flybynite · August 27, 2009, 06:26:07 PM

Quote from: GhrarhG on August 27, 2009, 02:30:45 PM
I'm not sure what injectors or knock sensor have to do with anything if the wastegate is wired shut and the pedal is held to the floor.

The way the code is designed if knock is sensed the ecm will reduce boost and retard timing. By retarding the timing you slow the exhaust flow dramatically reducing boost levels. If the boost solenoid if not being utilized the ecm will just pull timing at a much faster rate... :thumb:

GhrarhG · August 28, 2009, 10:07:08 AM

Interesting, I didn't realize that it pull enough timing to do that. Good to know.

89BlackTGP · September 01, 2009, 04:01:33 AM

Quote from: flybynite on August 26, 2009, 07:42:15 PM
Flakey knock sensor?? Do you have access to a scan tool?

I dont have access to a scan tool.. but should i try to change the knock sensor anyway?

flybynite · September 01, 2009, 05:31:09 AM

Quote from: 89BlackTGP on September 01, 2009, 04:01:33 AM
I dont have access to a scan tool..

A simple scan tool like this will pay for itself in a years time...
http://cgi.ebay.com/ebaymotors/Auto-X-ray-EZ-link-Scanner-GM-OBD-1_W0QQcmdZViewItemQQ_trksidZp3286Q2ec0Q2em14QQhashZitem2302b4e9e2QQitemZ150369266146QQptZMotorsQ5fAutomotiveQ5fTools

89BlackTGP · September 01, 2009, 07:19:29 AM

I am going to watch it and see what the price will be toward the end. Do you know of any hardware and software for a laptop that does just about the same?

GPChief · September 01, 2009, 08:25:40 PM

Tuner pro??