Boost issue

[chops]

Just bought a we4 all stock drives well but as soon I start to build boost it pulls back and chokes up put new fuel pump fuel filter mass air flow with translator I taped a fuel gauge to the window as it happens and when I build boost the needle starts going crazy!!! Amy help guys

 

[forcefed3.8's]

What is the base fuel pressure? What chip, octane, boost level, fuel pump?

 

[chops]

Stock chip deatchwerks 340 pump 38 psi fuel pressure 93oct fuel the issue was there before the pump it's just getting worse the car was garaged in Maryland for 15 years before I bought it am driving it everyday since I bought it getting all the flaws out

 

[DaRonne Edwards]

You may need to invest in an injector and chip combo.

 

[chops]

I have 120 injectors with chip on the way am switching to e85

 

[20psiofevil]

Any update to this? I'm having similar issue thats driving me crazy.

 

[TurboDave]

I have 120 injectors with chip on the way am switching to e85

You're going to switch to huge injectors, chip and e85 before you even have the car running right????????? Good luck with that.

 

[20psiofevil]

I have been racking my brain over this issue the past week. Running an external tial 38mm gate with 10psi spring, boost cntroller unhooked until I find this issue, vac sourced from the manifold to rule out pressure drop from intercooler, and rest of the mods in my sig. So far have tested the cold side for leaks and it held 25psi. Leak tested inatke manifold. Found no leaks. Bench tested wastegate and it's doing what it is suppost to. No exhaust leaks.

Part throttle it builds 10psi like a champ, go full wot and the pressure imediatlly drops to 7psi and car feels like it's loosing power.

Called precision and spoke with a tech and they seem to think the .63 ar is the problem and I'm running into back pressure issues. My exhaust pre and post turbo both flow very well. Cam is a little big for the turbo. 218/224 114* .580 lift. Springs are new style comp 26918 lsx behive springs. 6262 turbo has new cea turbine and is buick housing. Personally I dont think the issue to be bp although I havent logged that yet.

I can post a log but to view it you need to download sct livelink.

 

[bison]

I have been racking my brain over this issue the past week. Running an external tial 38mm gate with 10psi spring, boost cntroller unhooked until I find this issue, vac sourced from the manifold to rule out pressure drop from intercooler, and rest of the mods in my sig. So far have tested the cold side for leaks and it held 25psi. Leak tested inatke manifold. Found no leaks. Bench tested wastegate and it's doing what it is suppost to. No exhaust leaks.

Part throttle it builds 10psi like a champ, go full wot and the pressure imediatlly drops to 7psi and car feels like it's loosing power.

Called precision and spoke with a tech and they seem to think the .63 ar is the problem and I'm running into back pressure issues. My exhaust pre and post turbo both flow very well. Cam is a little big for the turbo. 218/224 114* .580 lift. Springs are new style comp 26918 lsx behive springs. 6262 turbo has new cea turbo and is buick housing. Personally I dont think the issue to be bp although I havent logged that yet.

I can post a log but to view it you need to download sct livelink.

backpressure isn't an engine performance problem at this point. The wastegate seems to be doing what it should. The ex pressure is higher with the throttle open and engine loaded. What are you looking for your wastegate to do with no pressure signal? I've never had a wastegate that was 100% flat across an entire rpm range with just the spring. what if you keep your foot in it till about 5800 rpm? Does it start creeping up?

 

[20psiofevil]

backpressure isn't an engine performance problem at this point. The wastegate seems to be doing what it should. The ex pressure is higher with the throttle open and engine loaded. What are you looking for your wastegate to do with no pressure signal? I've never had a wastegate that was 100% flat across an entire rpm range with just the spring. what if you keep your foot in it till about 5800 rpm? Does it start creeping up?

Tested the wg to insure it was not sticking by hooking a compressor tothe side port. Funny you ask about what it does at higher rpm because this is where it gets interesting. Maf ad counts are static/ flat line once the turbo spools at full throttle, engine load fall of in linear fashion. I will post a log this weekend of the issue but you will need to download livelink 6.5 or another version of livelink from sct web site.

Dont know if I mentioned but am running a hpx slot style maf in 3" tube in blow through config.

 

[87buickracer]

I have been racking my brain over this issue the past week. Running an external tial 38mm gate with 10psi spring, boost cntroller unhooked until I find this issue, vac sourced from the manifold to rule out pressure drop from intercooler, and rest of the mods in my sig. So far have tested the cold side for leaks and it held 25psi. Leak tested inatke manifold. Found no leaks. Bench tested wastegate and it's doing what it is suppost to. No exhaust leaks.

Part throttle it builds 10psi like a champ, go full wot and the pressure imediatlly drops to 7psi and car feels like it's loosing power.

Called precision and spoke with a tech and they seem to think the .63 ar is the problem and I'm running into back pressure issues. My exhaust pre and post turbo both flow very well. Cam is a little big for the turbo. 218/224 114* .580 lift. Springs are new style comp 26918 lsx behive springs. 6262 turbo has new cea turbine and is buick housing. Personally I dont think the issue to be bp although I havent logged that yet.

I can post a log but to view it you need to download sct livelink.

I had similar problem where my car would get up to 85 mph and start to fall on it's face(boost gauge would flutter under wot and go crazy) ..I recorded the run and found out I had a bad tps sensor..It would get to 3.66 volts and drop back to 2.5volts, and I quickly let off gas..I replace my tps and wastegate actuator and no she is a beast,just need some race fuel and drag radials..hth
note-- also check translator settings and make sure you have the right chip in it(translator) for you combo-I also had that problem before as well..

 

[GNRick]

Sounds like a bad fuel pump to me. That is exactly how my car acted when the pump went south. Oh yeah then I blew a head gasket...in my younger days.

 

[Joeld]

Fuel regulator?

 

[20psiofevil]

Found this issue. Modified a 75mm tb to work on my car and used stock tps. Max tp on my programing is 1023, the new tb is full open at 700. So the throttle was almost closing with 1023 throttle position. Gonna make myself a throttle stop and go through the tune to adjust quite a bit probably.