HELP!! Bogging at 4K RPMS, No Boost.

[Metallic36]

I think I may have had the Unichip EBC hooked up wrong, thus no boost. But it still bogged down when I tried. Last night, I was able to boost a little, but after the one time I didn't try as my rpms couldn't go above 2k without jerking and bogging. I just got a wideband, but yes, it is running extremely rich. I was previously driving with the stock turbo, and I am planning to let it sit until I can figure out what's going on with it and then get an ems for it. The most I've driven it with the GT28rs was from the shop to my house last night to get it home.

so, your saying you cant boost? do you mean literally the gauge wont go past 0 and the turbo wont boost, or do you mean everytime you boost, the car bogs out.

it could be just a boost/vacuum leak, or a dirty maf. but what i honestly think is that the car is not getting enough full or it is running pig rich. i would check the fuel pressure and get a wideband on there to see the ratios.

btw- no engine mangament with a gt28rs is not the smartest thing you can do.

 

[Metallic36]

Yeah, I agree with you on that.. that's definitely what would cause the jerking. I think now I'll just get a whole assembly and go that direction instead of just the filter.

I dunno, im sure it would be alot cheaper to replace the fuel filter and see... but im pretty sure mine wasn't clogged because the psi in the fuel lines would hit normal amount then drop completely to 0psi, then jump back up to normal, then back to 0 which caused the jerking. Might be worth doin the filter first though if you can do it yourself.

 

[Fudgie]

Put a guage on it first to verify the diagnosis so you don't waste $$

 

[Metallic36]

I'll do that as well. Anyone know about the idle being high, is there a way to turn the idle down some or ?

Put a guage on it first to verify the diagnosis so you don't waste $$

 

[bazooka joe]

some have, but i hear the ecu learns around it and adjusts accordingly...you really wanna find out why the car is doing what it's doing and not adj something else like the idle, prob cause more issues for you

 

[Metallic36]

I'm just wondering why the heck it's idling so high and running so rich. Didn't idle that high before I took it to the shop, so I was thinking maybe they made it idle higher than it's supposed to be set at.

some have, but i hear the ecu learns around it and adjusts accordingly...you really wanna find out why the car is doing what it's doing and not adj something else like the idle, prob cause more issues for you

 

[shane02pro5]

Idle wont stay put if you adjust it...ecu will correct it. There aren't many things that can make the idle that bad and not throw a cel except for a major vac leak which can make everything screwy also with boost. Go crazy with some carb cleaner around the im and all vac lines and pipe couplers. Still might have a fuel pump problem on top but I cant see that causing a high idle.

Check the vac line to the fuel pressure regulator on the fuel rail!

 

[bazooka joe]

ya, i agree, a vac leak acts like all sorts of problems....fuel, dirty egr/maf etc...

 

[Metallic36]

I'll take a picture. It looks like there are two vacuum lines hooked up to the solenoid that bolts to the cold pipe now.. the loopy vacuum line on the intake mani I had cut and put a T in so that I could use that for a boost controller, but now the shop stuck that source to the solenoid.

Idle wont stay put if you adjust it...ecu will correct it. There aren't many things that can make the idle that bad and not throw a cel except for a major vac leak which can make everything screwy also with boost. Go crazy with some carb cleaner around the im and all vac lines and pipe couplers. Still might have a fuel pump problem on top but I cant see that causing a high idle.

Check the vac line to the fuel pressure regulator on the fuel rail!

 

[Metallic36]

Here are the pictures. In the one with my finger touching the hose, this hose was originally connected, and I cut it to add a line for my Greddy EBC. I have since took off the ebc a while ago and used that line for either the wga or bpv, can't remember. BUT, the shop added it as a source to the solenoid that's attached to the cold pipe. I'm forgetting what that solenoid is. There is another vacuum line running from the top of the solenoid to a vacuum source on the back of the throttle body.

If you see anything that isn't right, please let me know! I'm not really sure what to do with the small vacuum line going to the bottom of the solenoid, because I'm going to want it again for another Greddy EBC.

 

[Metallic36]

More pictures.. showing the intake mani. Yes, that is a leaf in the 2nd pic.. haven't had a chance to clean it since getting it back from the shop. So much for detailing my car prior to taking it there.

 

[shane02pro5]

That should be fine how you have the "T". That is the purge solonoid valve and pressure switch for it. I regulates how much air can bypass the throttle plate at idle while the electrical system is under load and bogs the motor. On top of the tb is a recessed flat/phillips head screw that is the adjustment for this which if the shop messed with this screw too much it can cause a vacuum leak if it's backed out too much and raise the idle but probably not much above 1000.

Does that one vac line to the valve on the cold pipe have a check valve on it? I don't think that should be there but to keep the valve from seeing boost. Maybe they put it back facing the wrong way so now it doesn't see vac??

 

[Metallic36]

If it is on backwards and I flipped it, do you know how I could tell which way is the right way that it should be on? Will it idle differently, etc?

Does that one vac line to the valve on the cold pipe have a check valve on it? I don't think that should be there but to keep the valve from seeing boost. Maybe they put it back facing the wrong way so now it doesn't see vac??

 

[Metallic36]

The thing that I don't understand is that my T didn't go to that solenoid before. Is there another source that I could use instead of the T? Here are more photos.. and is this the screw that they could have messed with?

 

[shane02pro5]

I have a vacuum block on the 3/8" brake booster line for all my vac sources. To check the valve you should be able to blow through it towards the mani and not towards the sensor. If it's not seeing vac it's not working. The screw is recessed in a hole on top of the throttle body closest to the firewall. If it's leaking it should be audible. Don't mess with it if it's not leaking.

If you haven't already I would unhook the ebc to take that out as maybe being part of the problem.

 

[Metallic36]

I haven't had the ebc in there for over a month, sold a long time ago.

If you haven't already I would unhook the ebc to take that out as maybe being part of the problem.

 

[Metallic36]

Here are some videos of what is going on. In one video, it shows the rpms rising from 2K to 2.5K rpms without me even hitting the gas. Also attaching a photo showing the aftermath of my running rich.. black carbon in the grass from the wind blowing it off the driveway.

In this video, I pushed the gas once, and the throttle stayed after I took my foot off the gas.

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[Metallic36]

Just hooked up my OBD2 scanner, has code P0300. Even though my car didn't show the CEL, this was on there.

 

[XoX1de]

P0300 means random misfire detected, to test yo wastegate actuator, discoonnect the hose and use an air compressor to test the psi range,

check list:
compression test
crank sensor, clean it,
maf sensor
tps
plug
camshaft sensor.

 

[MSP2k3]

P0300 random misfire is the SAME code i got when my fuel pump assembly was going out fyi... it popped on after the car almost died on me from jerking so bad. I would almost garauntee its from your fuel pump system like mine... I replaced it and it all worked perfectly