7.3 LOW BOOST - Diesel Forum

WALKERPLAY · 08-22-2010, 07:27 PM

I have 2000 f350. the motor was in there lost compression on 2 cylinders. so just got another motor. other thing i did was put my
turbo on there its is banks, its has a turbo tri power chip in it.
before i always have around 30psi now cant get but 10 to 12psi.
thought it was the chip so i took it out,still same thing 10to 12 psi.

**woodnthings8** · 08-22-2010, 07:41 PM

The first thing you should check is the intercooler boots. One of them may be leaking causing boost loss. Other than that a thorough inspection of the up-pipes and the turbo wastegate would also be in order.

WALKERPLAY · 08-22-2010, 07:44 PM

i checked the boots. where is the wastegate and how u know its bad?

thanks

**woodnthings8** · 08-23-2010, 08:57 AM

The wastegate actuator is attached to the compressor housing, it goes across the top of the turbo to a lever that opens the wastegate in the turbine housing. The actuator should be set where there is a little tension to hold the wastegate closed. When you are on the throttle hard the WG solenoid should allow some of the manifold pressure to be ported to the WG actuator to open the WG. This keeps the turbo from prematurely failing when you are asking for lots of boost, then let off the go pedal.
WASTEGATE

Wastegate Actuator

WALKERPLAY · 08-23-2010, 03:32 PM

Thanks woodnthings8. i have the same one in the picture. i took the turbo off and check everything the gate was opening good without the big head on .put everything back together still no boost. what else

**woodnthings8** · 08-23-2010, 03:40 PM

Have you looked into the MAP sensor? There should be a hose that runs from the intake spider to the MAP sensor on the firewall (passenger side). I suppose if you had a faulty sensor it could cause low boost. Where is your boost gauge plumbed into? It should be off of that hose or the intake spider.

WALKERPLAY · 08-23-2010, 03:43 PM

its plumbed right off the spider. when i had it off it was clean. how can u test the map sensor?

Jay Brunson · 08-23-2010, 03:45 PM

HAve you cleaned or replaced your air filter? Mine will fall on its face with a dirty air filter. I know it may seem obvious...but you never know.
Good Luck, please post when you find the cause.
Jay

**woodnthings8** · 08-23-2010, 03:47 PM

I would read it with my scan software. I have not looked up anything on testing it individually. Are you running a basic gauge, or through something like an Edge tuner?

If everything is good intake wise, I would look into the exhaust. Have you made sure no up-pipe leaks or the EBPV isn't closed or something? If the exhaust isn't spooling up the turbine wheel, you will have low boost.

WALKERPLAY · 08-23-2010, 03:48 PM

i know it wasnt good but i took it out for a test run.

WALKERPLAY · 08-23-2010, 03:54 PM

its a banks gauge. what is EBPV and where is it? i check the exhaust nothing there either.

RIStroker2000 · 08-23-2010, 06:05 PM

i cant seem to get over the fact after reading that you got the same boost with the chip in as when its out (no ideas at the moment though)... and as far as EBV when mines closed i get 0 boost, if i get 'on it' when its closed (really bad for the motor FYI) i can only get 5-7...

what year motor did you have put in?

**woodnthings8** · 08-23-2010, 06:21 PM

Quote:

Originally Posted by WALKERPLAY

its a banks gauge. what is EBPV and where is it? i check the exhaust nothing there either.

The EBPV is located in the outlet of the turbo just before the exhaust down pipe. It is a big butterfly valve that closes to warm up the truck.

WALKERPLAY · 08-23-2010, 07:15 PM

Can the turbo go bad? what is the normal boost on 7.3? i clean the tube from the exhaust to the sensor,its clean.

**woodnthings8** · 08-23-2010, 07:32 PM

"normal" boost is around 24 psi. With a tuner you can get up to about 30 psi. Yes a turbo can go bad. Pull the intake off of the turbo and spin the compressor by hand. Make sure you can spin it freely and it has no side to side play that can be felt by hand. It it feels OK and the compressor blades look normal, I would pull the exhaust pipe off of the turbine side and do the same inspection. It may be harder to see the wheel, but with a light you should be able to look at it.