Need some help on a 2g GST

[Redlinegvr4]

all,

my friend just got a 2g GST and dropped it off to me today to give a once over and figure out a problem its having. The problem is its pulling timing to 2-0 degrees when it starts to build boost. I have no clue where to start or how to fix it. Any ideas? only mods are a Evo 3 16g and a bov.

Thanks!

 

[92_talon_awd]

Is it seeing knock?

 

[Redlinegvr4]

No knock. Just driving it it pulls timing.

 

[GSTwithPSI]

What are you monitoring the timing with?

 

[Redlinegvr4]

Using my tatrix cable and evo scan.

 

[Wizardawd]

So EVO3 16g and a bov ONLY? As in still running stock fuel pump not rewired? Stock 450cc injectors? Stock side mount intercooler?

Wiz

 

[GVR4kauai]

What temps is it runing at? Is it on the stock maps or has someone changed things? You really need to get the supporting mods to run a evo3 16g on a 2g. That turbo can support 47lb/min airflow that like 3 times what a t25 can handle lol!

 

[Redlinegvr4]

Quoting Wizardawd:
So EVO3 16g and a bov ONLY? As in still running stock fuel pump not rewired? Stock 450cc injectors? Stock side mount intercooler?




Yes those are the only two mods on the car. its running whatever boost pressure the wastegate is set to. Yes its on stock injectors and intercooler. Im not looking to get flamed here about not having supporting mods on this car. my friend got it for 1500 and im just trying to get it to run so he can just drive it. It does not have a CEL nor does it knock at WOT but its running between 2 and -4 degrees of timing. Im going the hookup a new maf to it and start from there...

 

[Redlinegvr4]

More info... under boost the MAP sensor maxes out at 46.24 but its only making 10lbs and the Barometric Pressure sensor is reading 98.98 constantly. I assume the ECU is thinking the car is over boosting so thats why is pulling timing... Any ideas? Could the car need an ECU?

 

[Wizardawd]

His point is that even at 10psi, the new turbo is pushing 3 times what the stock setup was made for. And remember the stock setup wasn't even enough for the stock setup when turned up a tad. And stock everything, means easy knock and lean mixtures. So I wouldn't be surprised it is pulling timing hardcore.

Other that the fact he desperately needs to do some upgrades (at least rewire the damn stock pump), check for boost leaks, vaccumn leaks and make sure the all the maintenance items are done. Fuel filter, plugs, etc. Theny can only help and may be the difference between bit of detonation or a melted piston.

And as far as getting flamed...look at the situation. Car has massive turbo over stock and NOTHING done to support it. And it's knocking and detonating. Things that make you go hrm?

Wiz

 

[Redlinegvr4]

Touche...I told him to get injectors a fuel pump and a wideband. The car is gonna need tuned. It keep throwing a code for the Barometric Pressure sensor, I have tired 2 mafs and 2 maps on the car and its still showing 98.98 baro pressure , and the map sensor is maxing out as well. Thats the part I cant figure out. also its not Knocking, so the timing retard is not from knock. im pretty sure its becasue the Baro sensor and MAP sensor are not reading correctly.

 

[bradrs]

Remove unknown BOV, put it back on ebay. Replace with 1G. Or at the very least, make any adjustments on it to maximize its holding pressure.

Check for boost leaks.

You don't provide units for the 46.24, but I will assume it is PSI? If so, that could be some calculated value based on airflow, with a massive boost leak. An example of a massive boost leak could be an aftermarket BOV.

 

[Redlinegvr4]

Sorry yeah its PSI... I will do a boost leak test today and see what happens.

 

[gvr4144]

I had a gst with mhi evo3 with an ets kit, full exhaust, greddy bov on stock fuel ran great on 17 psi probably the restrictive/heat soaked stock setup like posts before. I do have a greddy hard upper intercooler pipe flanged for a 1g/greddy bov that goes to the stock side mount you can rid of the crappy plastic bend by the intake and run a decent bov.

 

[quato]

I don't believe this has been mentioned yet. Have you verified that the knock sensor is behaving correctly? It seems VERY suspicious to me that all of this would be going on and you're not seeing any knock. Try and switch it out with a known good KS and see what it does.

If you are logging with EvoScan that means that you should also be able to pull the configs from the ECU using ECU Flash. I would check to make sure the knock sensor settings have not been messed with. I can give you my values later on today after work.