Hey everyone, working on a 2000 4x4 F350 with the 7.3 and a ZF6. The truck is lifted on 38 inch tires. It has an S&B intake and the wastegate actuator was upgraded to the 33psi actuator from swag performance. Outside of that its stock. No chip no tunes nothing.

Complaint is that EGTs are climbing faster than before and it won't hit 15PSI unless youre really in it. Took it for a test drive and read live data from it along with watching the guages that are installed. Boost will climb rapidly but falls off at like 11 PSI. Meanwhile the EGTs are around 1200. Fuel pressure stays at 55-60 PSI regardless of how hard you run it. As far as I can tell everything is within parameters. ICP maxed out at just over 3500, I think it was 3558PSI and IPR was 65% i think. Back pressure sensor was reading, looked to follow boost pressure as it should. Map sensor was reading boost like it should. Pressure tested the intake/ charge pipe and didnt find any leaks. Pulling the red line off the wastegate made zero difference.

For ****s and giggles I pulled the muffler off and that seemed to help just a little. Boost climbed a little quicker but still falls off at like 12 PSI. I don't see any leaks in the exhaust system as there is no soot on the firewall or sides of the block.

Any ideas? If needed i can give more information just not sure what else to add.

 

On a stock setup, 15psi boost is where it should be. Have you checked for boost leaks by putting pressure on the system at the turbo intake tube...

 

Im aware that 15 psi is where its gonna sit stock but it shouldn't be so difficult to get there. I was working on a bone stock '96 7.3 and almost effortlessly it would spike 15PSI. Didn't have to be over 2500RPM at wide open unlike the current truck. Which having the lift and tires it does should put enough of a load on the engine to hit 15PSI without a second thought.

And yes. As stated in the original post I pressure tested the whole intake side. Pressurized the system to 20-25 PSI and sprayed down all possible components. No bubbles anywhere.

 

How long did it hold 20-25 PSI? I just pressure tested my 2000 excursion with a 7.3 because after changing the up pipes I didn't return to as much performance as I would have expected. I couldn't find any exhaust leaks so I pressure tested with a homemade tester. I found a few leaks, turbo to spider clamp, hose to MAP sensor was split at the sensor. Took care of those and a good bit better now. But there's a small leak at the intake heater element on the spider and/or the boot right there, and the driver side intake plenum boot is leaking a bit I think. Wastegate vacuum hose may leak a little. When I pressurize the system to 30psi it drops to zero fairly quick, maybe 15 seconds. I haven't tried blocking the CCV tube to see how long it holds. I'm wondering if I block CCV tube and it holds air, does that mean my piston rings are worn/cracked? I have a new boot kit coming.

I have Forscan to read MAP boost. At idle I have 14.5 psi, which I think is atmospheric for where I am. If I romp on it going uphill it maybe reaches 23psi (so only 8psi boost). Hard for me to watch my phone and drive to see the peak and I haven't figured out how to data log and retrieve it later yet. (just got Forscan a week ago and haven't played with it much). I'm getting EBPV codes and have a new tube and sensor on the way, hoping that will help. Or a may decide to delete the EBPV, I have a deleted pedestal and outlet. After I get the EBPV codes taken care of, I'll pressure test again. I didn't spray check all around the plenum cover or around the intercooler ends, maybe there's a leak I'm not hearing.

Good luck and let us know if you find an issue that's escaped you so far.

 

Your PCM is defueling the engine. Anytime the PCM sees more than 21-22 psi, it defuels to limit boost. You won't notice it driving down the road it's that seamless. If you're going to be running higher boost, you need a chip an a Riffraff OCR (depending on who you get the chip from) because you can feed the engine too much air and throw off the AFR. (Ask me how I know)

 

I have a Power Hungry Performance chip and run it on a 24hp tow tune 99.9% of the time. I’m guessing I don’t really need more boost? I’m wondering if I should be reaching peak boost at lower rpm’s though?