4.2 Envoy Turbo Build

[ConeKilrAutoX]

correct but I no longer have an intake resonator so where should it go do you think?

 

[gmcman]

It needs to go between the TB and the air filter. I would try to locate it closer to the TB. Can you post a pic of the current configuration?

 

[gmcman]

Something else came to mind and I hear of people using rising rate regulators for forced induction. This is an area I don't have much experience with and I'm curious how well the stock FPR works with forced induction. Someone else will need to chime in on that.

 

[ConeKilrAutoX]

sure thing. its dark but this is an older pic from a few days ago with my testing intake with MAF sensor and the hose leaving the intake tube goes to the fpr. thanks for the help!

 

[Sparky]

It needs to go between the TB and the air filter. I would try to locate it closer to the TB. Can you post a pic of the current configuration?

How well is that going to work with positive intake pressure though instead of vacuum?

 

[gmcman]

How well is that going to work with positive intake pressure though instead of vacuum?

That was my question in the next post, #243.

I don't know how our FPR's work under forced induction.

 

[gmcman]

sure thing. its dark but this is an older pic from a few days ago with my testing intake with MAF sensor and the hose leaving the intake tube goes to the fpr. thanks for the help!

Is the MAF clean? From what you describe there is an abundance of fuel so check the FPR for leakage out of the vacuum port when running as well as the MAF operation.

 

[STLtrailbSS]

im pulling for you man, All i want to see is this thing idle take it to like 5000rpms and let the waste gates blow. i think we are on the right path here. Throw a post on TBSSowners some great knowledge on there as well. they know engine operation and modification. Opinions never hurt

 

[gmcman]

The fact you aren't running boost yet takes away the positive pressure issue to the FPR.

What is the vacuum at idle or around a steady 1K?

 

[ConeKilrAutoX]

I will be posting around the internet looking for all the help I can haha. Where would everyone suggest connecting the fpr line? and I am going to test for a fpr gas leak tmrw. Then I will reclean the MAF and see how that goes!

I really do appreciate all the help from everyone thank you It sounds like some people want this build done almost as much as me haha! waaaa pssssh!

 

[limequat]

Hi. Thanks for the question and concern I appreciate any suggestions and help. I believe my tune is set atmospheric and the MAF sensor (when the turbo is installed) will pick up higher than atmospheric psi and will inject fuel accordingly based on the tables limquat has set up for me. After a scan I should hopefully have an idea of what is causing the problem.

This is correct. The P12 does fueling with a combination of MAF and MAP. The MAP is used mostly in low loads and after that it goes 100% MAF. Going to the 4" MAF allows the P12 to detect about 12 psi worth of airflow and fuel accordingly.

 

[limequat]

Why is it wet that far from the nozzles? Not sure what type of DMM you have but can you measure the pulse width of the injectors? Can you find out what the tune is calling for?

How limited are the stock injectors for 7-8 PSI of boost?

Just a hunch but it sounds like you need to cut the pulse width way down for these high flow injectors if they are functioning properly.

Is your FPR functioning properly?

At idle the pulse width is going to be as low as 0.3 ms. So we need to get the scanner on it. I'll be sending one out to ConeKiller on Monday. Stock injectors are nearly maxed even before boost. You might be able to do 3-4 psi with added fuel pressure though.

 

[limequat]

Just thought of another test to run:

Unplug injector harness to disable them. Run the engine on starting fluid. If it cleans up, you'll know that there's something wrong with the fuel as opposed to spark. If it runs rough on starting fluid too, the problem is probably spark related.

Also the squirting of water on the exhaust runs is a quick and easy test.

 

[ConeKilrAutoX]

Thanks man I appreciate all the help you have been. I will keep testing out the fpr, the MAP, the MAF, etc until the scanner comes in.

 

[bruhaba]

fpr - if you have a return style system, these typically run referenced to manifold pressure, so the vacuum line on the regulator should come straight from the manifold(behind the throttle body). Same whether you run boost or not. As I said earlier, the point is to have the injector seeing the same differential pressure between the rail and the intake all the time. This is how every boosted/non boosted vehicle with a return line has been for me and also how my supercharged 06 is setup now with an AFPR and return line. What kind of system do you have? Did you put in an aftermarket regulator?

crankcase venting - these motors are tricky, my stock 06 pulled from the crankcase directly into the intake by way of the valve cover. the valve cover breather was connected to filtered and metered air. So if you left that open to atmosphere, the engine would breathe a bunch of unmeasured air. If yours was like this stock, you will need to do some rerouting otherwise the first time you make boost you will be pumping your crankcase full of boost...not good.

Can you please describe where you have the following routed...
the vent on the intake manifold between intake ports 3 and 4? did you leave it stock? to run boost you will have to move this.

Your valve cover breather?

your throttle body EVAP line?

 

[gmcman]

fpr - if you have a return style system, these typically run referenced to manifold pressure, so the vacuum line on the regulator should come straight from the manifold(behind the throttle body). Same whether you run boost or not. As I said earlier, the point is to have the injector seeing the same differential pressure between the rail and the intake all the time. This is how every boosted/non boosted vehicle with a return line has been for me and also how my supercharged 06 is setup now with an AFPR and return line. What kind of system do you have? Did you put in an aftermarket regulator?

OK, so I'm confused. Factory vacuum for the FPR is ported. How should it be manifold? Just curious.

If the manifold ends up being ported, then the current routing should work being in the intake tube. ConeKiller mentioned it was in the intake, I assumed the intake manifold.

 

[ConeKilrAutoX]

Ok. stock fpr with vacuum line connected to a vacuum block distributer that is connected to the intake maniold via the manifold port that was under the stock intake resonator.

throttle body evap vent is hooked up stock

the crankcase vent hose I have running to an oil catch can

the breather for the crankcase is to the intake pipe post MAF and pre TB.

thanks for the help!

 

[gmcman]

Ok. stock fpr with vacuum line connected to a vacuum block distributer that is connected to the intake maniold via the manifold port that was under the stock intake resonator.

This is what I have trouble grasping, sorry if I sound so hard-headed.

fpr - if you have a return style system, these typically run referenced to manifold pressure, so the vacuum line on the regulator should come straight from the manifold(behind the throttle body). Same whether you run boost or not.

Under boost I cannot really see the difference in ported vs. manifold. However in a non-boosted state, as what your running now for test purposes, how much difference is there with the FPR on manifold vacuum vs. ported vacuum? Because clearly in stock form, the FPR is running off ported vacuum as shown in the pic. The intake resonator is mounted in front of the TB.

The nipple under the FPR line is the manifold port.

 

[bruhaba]

regarding the Fuel pressure regulator discussion...

I was assuming he had an aftermarket regulator. Typically to run boost you want a manifold referenced regulator. There is another option, and from what you've shown GM may have done this. I have an 06 which did not have a regulator. I added one to be able to run boost and not have a nightmare tuning it.

Bottom line, in order to be able to calculate how much fuel is flowing through an injector, you need to know pressure on both sides of the injector and the size of the injector. Here's a couple different methods.

fixed pressure differential- uses a pump that is always running full blast and a regulator that bleeds off the right amount back to the tank to keep the rail at a certain pressure above the nozzle side of the injector. So in most cases, the regulator would be set for 43 psi with no vacuum line connected. Then when you are at -12psi vacuum at idle, the rail pressure would actually show 31 psi relative to atmosphere. However the injector will still have 43 across it so the flow rate of the injector does not change. This allows the calculations for fuel flow to be a bit easier because an injector size of X will always be X.

Fixed rail pressure - this is something GM started doing (like on my 06). Several ways to do it, but on my 06 there was a regulator in the tank that keeps rail pressure at 58psi relative to atmosphere regardless of all else. Since the ecu knows the map pressure, it calculates the differential pressure across the injector and looks up the injector flow rate based off this differential. It needs a lookup table for injector flow because at idle the injectors would be running 58-12~46psi fuel pressure, but at wot they would be running the 58psi rail pressure. Injector fuel pressure = 58psi-manifold pressure

On the picture you show, it appears from the factory is was connected to as you say "ported vacuum". This likely means GM was running fixed rail pressure on the trailblazer from the factory. Only reason I can see connecting it to ported is to prevent a fire in the event that it leaks. Ported vacuum doesn't change much. I'm a little confused too. Not typical to see a regulator that is ported to anything but atmosphere. What does a manual say about fuel pressure on these model years? Anyone know?

 

[bruhaba]

Ok. stock fpr with vacuum line connected to a vacuum block distributer that is connected to the intake maniold via the manifold port that was under the stock intake resonator.

throttle body evap vent is hooked up stock

the crankcase vent hose I have running to an oil catch can

the breather for the crankcase is to the intake pipe post MAF and pre TB.

thanks for the help!

I'm confused, do you have a turbo installed? What year pcm are you running? if you do have a turbo, is your maf pre or post turbo.

Need to see your tune to go with this. If you have the fpr connected the way you have it(manifold vacuum), then the IFR (injector flow rate) table needs to be flatlined in your tune. Ask limequat if it is flatlined. If it is like mine, the table maxes out at 63.5 lb/hr, I don't know what he would have done to run 80's. Have to scale lots of other stuff to do that and it gets complicated.

Also, explain further your crankcase vent please. The side that comes out of the crankcase on the intake you have routed to a catch can, did you then plug the huge hole in the intake? What about the other side of the catch can?

Regarding the valve cover breather, we'll revisit this after you explain your crankcase venting.

 

[ConeKilrAutoX]

alright... the turbo is not installed yet because I wanted it to run before pumling the turbo with all the gas/soot that it has been putting out through the exhuast. once I get the engine to fire correctly I then planned on putting the turbo on.

I am using a p12 pcm and to do that I had to also use the 06 engine wiring harness and do some re wiring only on the first c1 connector.

as for the crankcase vent, I have one hose going to the oil catch can and then another hose going from the can back to the corresponding port on the intake like the normal hose is set up to do.

 

[limequat]

ConeKiller you may want to post this on vortec4200.com. Lot's of expertise there...

 

[ConeKilrAutoX]

ok I will post over there too thanks lime

submitted my registration application and it doesnt like my email over there haha

 

[gmcman]

ConeKilr, is this the vent you have going to the catch can? Just trying to map this out in my head.

 

[ConeKilrAutoX]

damn sorry I was getting confused I have the catch can installed to the PVC side

View attachment 28236


not the crankcase vent ... sorry about that. the crank case vent I have hooked up to the intake pipe post MAF but pre throttle body.

 

[gmcman]

damn sorry I was getting confused I have the catch can installed to the PVC side

View attachment 14664


not the crankcase vent ... sorry about that. the crank case vent I have hooked up to the intake pipe post MAF but pre throttle body.

I'm curious as to why the crankcase vent hose wasn't kept in it's stock location? Did you use a different intake without the provision for the tube?

I don't know for sure but did all the years have the crankcase vent tube on the left side of the intake?

 

[ConeKilrAutoX]

I'm curious as to why the crankcase vent hose wasn't kept in it's stock location? Did you use a different intake without the provision for the tube? I don't know for sure but did all the years have the crankcase vent tube on the left side of the intake?

I had a cold air intake that move the location to a port on the intake tube
View attachment 28237

 

[gmcman]

Ok I went back and found this pic. Is this the current routing for the catch can? Not that it doesn't look freakin cool... I'm just curious why the catch can is being used. Are you just reducing the amount of contaminants in the intake?

 

[ConeKilrAutoX]

haha thanks and yes I was just trying to keep some oil residue out of the intake which seems to be working haha but now with the new issue I just have slimy gasoline so..we shall see haha

 

[gmcman]

OK, all coming together now... What's the other hose in the pic on the intake? Does this hose require manifold vacuum?

I assume the FPR hose is the FPR?

Reason I'm asking all this is the motor ran in this setup based on the earlier video you posted when you removed the A/C from the belt routing.

 

[ConeKilrAutoX]

OK, all coming together now... What's the other hose in the pic on the intake? Does this hose require manifold vacuum?

I assume the FPR hose is the FPR?

Reason I'm asking all this is the motor ran in this setup based on the earlier video you posted when you removed the A/C from the belt routing.

correct ! and it ran great only had a cracked manifold but ran excellent other wise, however that was also before the p12 swap, the 80lb injector swap, and the new 06 wiring harness. That other hose went nowhere it was just capped off but I needed there because I was not provided enough plugs for the number ports on the intake pipe adapter the the FPR was connected to

 

[gmcman]

Basically trying to rule out a monster vacuum leak. Can you put a vacuum gauge on the nipple at the front of the intake and get a reading at idle? Pretty much looking like an parameter in the injector pulse so hopefully Limequat has some input on this.

All I wanted to do this spring was get rid of some crabgrass and grow a lawn this fall. Now you're really giving me the itch to burn a hole in the bank and get some HPTuners and spend a lot of money.....lol.

 

[ConeKilrAutoX]

hahahaha well actually my boost gauge is hooked up to that port and upon starting the vacuum bounces so fast between high and low vacuum that the needle cant stabalize so theres an issue there but is that a vacuum leak or just an engine not acting stable

 

[gmcman]

My gut tells me it's the TB opening and closing rapidly but worst case it would be a valve hanging open. If you can rev it up and the needle is steady then the valve is fine. I assume the valves are fine.

 

[gmcman]

When you removed the old injectors, what happened to this seal? Did you recover it?

 

[ConeKilrAutoX]

yes reving keeps it fairly stable

and ( as I sent you in pm) no leak in fpr but I took map sensor out blew in it (dont have cleaner with me yet) and it actually started and ran normal for 25 seconds so im cleaning it later and trying again letting engine air out and pcm recalibrate with battery off

 

[gmcman]

That's great, hopefully all is good.

Something else to consider is when the plugs get fuel fouled so bad they sometimes are toast. Doesn't mean they won't work but it's risky. Hopefully when you get it running you can keep it running to get everything nice and toasty. Plugs may not come back 100% but we won't know until you try.

 

[ConeKilrAutoX]

Ok well I cleaned the throttle body again, sprayed the MAP and the MAF and it ran aweful, but then I unplugged the MAP and it is running like 75% healthy. just still smell gas really strongly and the engine is still shaking (not as severe) so its either getting too much fuel still somehow or (more likely) not burning up some causing excess fuel. I just dont understand how so much greasy gas is getting up onto the back side of the throttlebody plate. Hopefully Jeremy can figure that out when I get the scanner and email him the scan file.

 

[limequat]

That's a 1 bar MAP, right?

 

[ConeKilrAutoX]

That's a 1 bar MAP, right?

Stock MAP sooo i dont know off hand?