Well finally got the new motor up and running under a tight schedule, and it seems to idle fine, and drive normal, but has very low boost. I am only seeing up to 17psi max, usually around 5. This is the same problem that I had with the old motor, although even then I could hit 20. Before I had passed it off as something wearing out on the turbo or some other issue. My motor has the following parts:

New Shortblock
New GT38R
Stage 2 single shots
Gen 3 big oil
Custom DFA fuel system
4" MBRP exhaust
6637 filter.
Stock intercooler.

The only parts that were not replaced were the boost tubes, intercooler and up-pipes. The EBPV is connected, I replaced the Up-pipe gaskets a while back, and they do not appear to be leaking. All boots are new. What am I missing?? I don't know how it could happen, but could the intercooler be plugged?

Power level right now would be equivalent to an edge 60hp tune.

 

Maybe a small hole in the intercooler? Try hooking up a boost leak detector to knock out the chance of a leak somewhere.

 

HAve you adjusted the wastegate on the ballbearing? I've noticed that the factory preload on the BB turbos varies wildly from one to the next.

Mine for example, only made around 16 psi right after I installed it.....30+ after I pulled the wastegate down. The was no pre-load applied to it at all.

 

I guess it pays to check everything, even on new units.
Barring that, and since you had low boost before all this, I am thinking you have a hole in something somewhere that is bleeding off boost pressure.

 

Take a strong plastic zip tie, and tie the wastegate closed so that it can't open and do a quick test. If you have a strong spring handy, hook one end to the wastegate and the other to the actuator housing to make sure the gate can't open.

 

"Power level right now would be equivalent to an edge 60hp tune."

-exactly what sort of tunes are you running?
Stage 2 single squirts with 17 psi would smoke, smoke, smoke...

 

I am running a custom 6 position by Swamps, where I bought most of the stuff from.

I tried Zip tying the Wastegate and it helped a little, got another couple PSI out of it. but still only about 21-22. I wonder though, it does not smoke excessively evenin the highest setting. Can't help but think maybe something else is going on?? Off the line really lags as well, even with 4.56 gears. It really does drive very similar to before I replaced the motor. I checked and double checked for potential leaks and didn't find any.

Is it possible for the map sensor to be causing the motor to defuel, but not trip a Check engine? I installed an air compressor pressure regulator in the MAP line about 2 years ago. Also, I am getting no codes on the scanner.

 

What do your EGT's look like? That will tell you what you should be looking for.

Low boost + high EGT's = lack of air

Low boost + low EGT's = fuel problem

 

Very good point. My Egt's have not reached more than 1100. So it is looking like a fuel problem. Or at least a fuel control problem.

 

Alright, hooked up the AE, and here is what I am seeing. First off, HPO is certainly not a problem. Under WOT I get about 2800psi @ 30%DC. Injector PW of only 3ms though. is there anything else I should or could look at? Oh yeah, my Wastegate Control is permanantly stuck at 99.1% . Will this cause the computer to defuel all the time?

 

Check out the new AE section on 7point3

http://www.7point3.com/AETips/Docs/Wastegate.pdf

 

If I were you I would talk to Swamps and see what they have to say. I'm not sure what their pump and injectors should look like at WOT, but they might have some more info for you.

BTW, what kind of fuel system are you running? I see you have a custom DFA, but I'm not familiar with it. Also are you still using the stock fuel pump?

Your wastegate solenoid should set the check engine light and a code if it's stuck like that. I'm wondering why you don't have the MIL coming on.

 

Is the WG control valve unplugged? Or a break in the wire between the ECU and the control valve?

 

Did you check the pipe fitting in the pass side exh manifold front? Its the plumbing for the backpressure sensor. (I left it off one time) Not good.

 

I have been talking with them as well. Talked with Jonathan this evening and he thinks he just tuned it too conservative since I asked for a tow motor, not a race motor. He is making me a new chip and sending it to me asap. Too Bad I will be camping Next week for spring break. One thing is for certain, I am not getting the fuel. In the extreme mode I get very little smoke, and the egt's never get above 1100, no matter how hard I push it.

The DFA fuel system is one of my Own design that works with my WVO system(dormant until motor is broke in and running right). Basically a Fass 95 GPH HPFP set to 80 psi mounted on the Frame with a Donaldson 2 micron filter mounted after that, then deadheaded to the motor. My Diesel feeds the front 2 ports (OEM fittings removed) and the WVO feeds the back two. Both ends T'd together for balanced pressure, and the WVO system serves as the purge line for removing air. I monitor the fuel pressure from the WVO side opposite of the Diesel side and have not seen my pressure drop under 75.

Amiller- Thanks for that link. I printed it out and will follow up on it when I have an extra 2 seconds. Looks like some good info. Swamps thinks it is a conservative tune, I think it is another issue since this the same problem I have been having. What is itneresting is that AE document says that the WG control should drop when driving above 5mph. The only time mine ever dropped was in an overboost condition, 20psi, when the SES light came on.

Kwik- I will be checking wiring while camping. Bring my Helm with me and pinout the whole truck if need be. I have replaced the engine loom with no change though.

Kennedy- Good call, will check that tomarrow.