Throttle body slamming shut under boost

[TheRodFather]

Hi, I have a 06 hummer h2 with twin turbos and when I go over like 10psi the throttle body slams shut. It throws a P0068 code when it does it and I lose all throttle. Dylan Nickerson - 2006 Hummer - 6.0 - Turbo - MRP 750cc - pump gas - TSP stg2 - DDTECH - TEST 1.hpt hummer log 95%.hpl

[Russ K]

Your not going into PE, but is going into boost enrichment. That's why closed loop is still active causing -34% fuel trims. To fix the PE, set the min PE torque to 0% instead of 80%. Then you will need to lower the VE table, which should lower the cylinder air mass enough to stop the P0068/P1514.

Russ Kemp

[abc]

Assuming your running a Map referenced fuel psi regulator, your injector data is set up wrong also.

[edcmat-l1]

Need to check the fuel pressure in that thing. The VE is way too high everywhere. And the shape isn't right.

[Alvin]

Your not going into PE, but is going into boost enrichment. That's why closed loop is still active causing -34% fuel trims. To fix the PE, set the min PE torque to 0% instead of 80%. Then you will need to lower the VE table, which should lower the cylinder air mass enough to stop the P0068/P1514.

Russ Kemp

That's interesting.. Sounds like a bug in the custom OS. If not commanding stoich (BE) the fuel trims should be off. I've ran in to this about 2 years ago and just had to give up on it. It was a truck that came from a few other shops and I assumed something in the ECM was corrupted. I was working on it remotely.

I would have though i had it in PE first. I usually set TPS qualifiers fairly low and torque pretty low but keep it off with a fairly high MAP min on boosted things like this.

[TheRodFather]

So what do I need to do?

[gtstorey]

Post 4, 3 & 2 in that order and see what happens.

[TheRodFather]

Fuel pressure is good. And it?s got a boost referenced regulator.

[gtstorey]

Fuel pressure is good. And it?s got a boost referenced regulator.

So have you changed your injector data to work with boost referenced regulator, assuming that abc is correct that it isn't set up for referenced pressure?

[TheRodFather]

I haven?t touched the tune, I had Nate aka Dr tuneemall mane the original tube then he backed out, then I had pcm of nc tune it but they couldn?t tune it correctly so now DDTech is tuning it but he can?t figure out why the throttle body is slamming shut. Where do I find minimum PE torque in the tune? And how do I lower the ve table?

[abc]

Hold on, something sounds fishy. You need to find out what injectors you have in it and get the correct injector data first. After that put a fuel psi gauge on it that you can either data log or see from the drivers seat and read while it is under load and ultimately view it at WOT at some point, but now before you get most of the VE table sorted.

[bk2life]

I haven?t touched the tune, I had Nate aka Dr tuneemall mane the original tube then he backed out, then I had pcm of nc tune it but they couldn?t tune it correctly so now DDTech is tuning it but he can?t figure out why the throttle body is slamming shut. Where do I find minimum PE torque in the tune? And how do I lower the ve table?

sounds like you need to contact a reputable tuner and start over.
Where are you located?

[TheRodFather]

Minnesota, I thought DDTech was a reputable tuner

[gtstorey]

There are hints on here that DDTech might not be too great if you search, but it's hard to tell how good or bad they are. PMCofNC is Alvin so I'm curious about what he has to say since he has already weighed in on this thread.

[Alvin]

This might be the hummer that I couldn't stop the fuel trims from moving in PE. Despite being in PE STFT would suck all the fuel out of it. It had been touched by a few tuners before me and figured something was changed that I couldn't see so gave him his money back. Either that or bad PCM's can do odd stuff like that.

[gtstorey]

This might be the hummer that I couldn't stop the fuel trims from moving in PE. Despite being in PE STFT would suck all the fuel out of it. It had been touched by a few tuners before me and figured something was changed that I couldn't see so gave him his money back. Either that or bad PCM's can do odd stuff like that.

So probably needs a rewrite with TDS/SPS or another ECM rewritten to stock?

[RDF1]

So probably needs a rewrite with TDS/SPS or another ECM rewritten to stock?

I vote trying another PCM and starting all over.

[Russ K]

This should get into power enrichment before boost enrichment. And your injector tables are not set up for a boost referenced fuel pressure regulator, fix that.

Now retune the VE table. It will need to be lowered above 90 KPA.

Russ Kemp

[TheRodFather]

This might be the hummer that I couldn't stop the fuel trims from moving in PE. Despite being in PE STFT would suck all the fuel out of it. It had been touched by a few tuners before me and figured something was changed that I couldn't see so gave him his money back. Either that or bad PCM's can do odd stuff like that.

yes it?s the same hummer, we had Nate kuhle build our base tune then he backed out, I think Derek said he was able to fix the fuel trims but I?m not 100% sure. I think the tune no to be rescaled because it?s running out of graph I think.