LastBlack02SS

iTrader: (21)

So i just got a call from rick at synergy and he had my car on the dyno for a while yesterday and he can't get the car to create positive boost! He checked the piping and there aren't any leaks. Mods are in sig. What do i need to start troubleshooting with. O, and they just swapped a built 4L65E tranny so no slipping issues either. He even couldn't get boost just driving around off the dyno. Help.

Boostaholic

iTrader: (4)

Well one of the first things you can do is disconnect the lines from your wastegate, also verify that you have a spring in there, you should probably have a 6psi spring in but be warned, that the boost will keep going with no line to the gate.

Zombie

iTrader: (2)

no boost = something is wrong, probably a boost leak.

What is your exhaust setup out of curiosity, headers, manifolds?.

c5_ls1_6spd

iTrader: (-1)

it's more than just a "leak"
something isn't hooked up right....

Zombie

iTrader: (2)

Depends, i've had all sorts of leaks in all the years i've owned turbo cars, usually due to forgetting to tighten a clamp, install an intercooler pipe , etc. Some were pretty funny.

trtturbo

iTrader: (25)

I'm sure Rick knows, but with the fmic, you need to have your boost reference run to the engine, not the compressor housing.

67Firebird455

iTrader: (27)

I ran my reference for the wastegate just before the MAF/TB assembly. I get my boost for my guage off the brake booster.

SAM98WS6

my reference for the wastegate is off the brake booster per instructions...no problems...

67Firebird455

iTrader: (27)

The reference for my BOV is off the brake booster, since it needs manifold reference... the wastegate asked for reference on the charge pipe... BEFORE the throttle plate... as it would be the reference when under boost and letting off when the throttle blade closes and spikes.

LastBlack02SS

iTrader: (21)

Boost reference is taken from the compressor housing. That may be a problem. I called Rick however and he said that he should be seeing more than .8 lbs on the dyno even with that problem. He said it was only a 1-2lb difference with the intercooler added. He took the car to 5k rpm. He said he can't get boost on the street either. Said it was something else he didn't know. Any other ideas guys? He checked the pipes, tightened all the clamps, no leaks.

trtturbo

iTrader: (25)

Even with the reference from the compressor housing, it should see some boost. I would go ahead and move the reference and go from there.
Check the turbo and see if there is excessive play. I have had one turbo that lasted all of a mile and wouldnt spool after that. Everything installed right; just luck of the draw.
I'm sure Rick will find it.

67Firebird455

iTrader: (27)

Yeah, good luck to you and Rick. Rick is a very smart guy, he'll figure it out. If you brake boost it at high rpm, you should achieve max boost, try that, see what happens. That is strange, I had something similar go wrong with mine, found out it was the boost controller was backwards + and -, turned it all the way the other way and immediately made 12#, without even trying.

DarkblueTA

Check the vacuum line on the back of the manifold. When that pops off you get no boost. Make sure its on there good and tight. Happened to Dave at the track.

Schantin

iTrader: (6)

I think many of the suggested fixes and troubleshooting are good. I'll add my $0.02. When I installed my TRT FMIC, I still had the reference on the compressor housing. I was pretty suprised to see that I was only making 1lb of boost. After rereferencing the boost to the vacuum line off the throttle body I was back to 5psi. Actually 4.5. The slightly low pressure I register is a function of the lines I'm using to run my boost gauge. I didn't have a long enough strand of nylon line and have a rubber vacuum line coupledd into it. This threw off the reading by .5PSI for whatever reason on the gauge (line swell?....not totally sure).

In short I'd rereference to wastegate to the throttle body vacuum line and also make sure the boost gauge line is good (and not pinched.)

Hope this helps.

LastBlack02SS

iTrader: (21)

I'll have to try the boost reference switch. Looks like i'm gonna have to pick the car up to do it and then bring it back for tuning. Sux, nearly 1k miles back and forth but thats what they said i gotta do.

Assassin

iTrader: (3)

about 10bucks in parts you can find if there's a boost leak on the charge side, get a 2" and 4" pvc plug, take the silicone off the compressor and plug that w/the 2" (the silicone will stretch smaller to seal), then you'll also need a tire gut or something of the sort and a vaccume port put onto the 4" peice, take the silicone off the TB and plug that(and plug any other ports in your charge pipe), run your boost gauge to the vaccume port(on the 4"pvc plug) and fill w/ air, the gauge should stay up, if its going down fast you will probably be able to hear air coming out of the pipe somewhere, I have heard of guys having broken intercoolers, but if you said he just put a tranny in and it was boosting before the tranny install then thats when the problem happened, maybe a loose connection, a massive boost leak dosent usually happen when nothing has been changed from one day to the next...

LastBlack02SS

iTrader: (21)

well, the car made close to wastegate psi before the IC install i did a few weeks ago. Then it didn't make practically any boost but i figured it was b/c the tranny was getting worse and slipping a bit. Now i just hope its the boost reference. I also have an EBC (E boost 2) hopefully install soon to replace the manual boost controller. I guess we'll see. It would have been nice to have it tuned and running first. As always, a project long in the running.

RHall8612

A turbo has to work mighty hard to pressurize the earth. Check for boost leaks. Make a pressure tester.

chuntington101

i know its a long shot but check the turbo. i have heard a few people that have had turbos with broken shafts! i know it sounds stupid but worth a quick look

Chris.

WIPLSH

sounds like a boost leak. pressure test your entire system. check waste gate make sure it is not stuck open, check the bov if the system would not build pressure. check to make sure turbo is actually boosting.