Smoke machine to locate vacuum leaks?

[GNVYUS 1]

By taking the FP vacuum line off and plugging it you didn't really find any new leaks, your fuel pressure went higher and made it fatter lowering the BLM. Say line on it's 37psi and line off it's 42psi, you made the car fatter at the same rpm hence lowering the BLM. If you swapped lines and the car went down to 131 that would've meant you found a leak in the FP line.

128 should be achieved with the proper fuel pressure the chip was set up for and 0 leaks.

You're still paying mechanics $70-80 an hour labor to inject smoke huh??
Could've had that boost leak tester by now and done it all yourself Rick.

 

[GNRick]

By taking the FP vacuum line off and plugging it you didn't really find any new leaks, your fuel pressure went higher and made it fatter lowering the BLM. Say line on it's 37psi and line off it's 42psi, you made the car fatter at the same rpm hence lowering the BLM. If you swapped lines and the car went down to 131 that would've meant you found a leak in the FP line.

128 should be achieved with the proper fuel pressure the chip was set up for and 0 leaks.

You're still paying mechanics $70-80 an hour labor to inject smoke huh??
Could've had that boost leak tester by now and done it all yourself Rick.

LOL Yes it is expensive! Mechanic is $65/hour. OK I'll call Kirban and ixnay the fuel pressure regulator. I think we might be past the smoke test phase. The smoke test didn't find the leak at the PCV valve or the injector. The PCV leak was found when he sprayed Brake Clean on the PCV valve. BLM went to 128 so I thought that ended it. But replacing the PCV valve just lowered the BLM, but not to the desired 128. The injector O ring leak was found when he wiggled the injector. So I'm making progress, but I'm stumped again.

 

[GNRick]

I think I got it figured out :biggrin: I removed the vacuum block and put a piece of cardboard over the throttle body holes (thanks 87Nat and Pronto). BLM went to 120 :biggrin: Then I put the vacuum block back on and capped off all ports EXCEPT for the line going to the fuel pressure regulator (thanks Dr. Booster). I played with the vacuum hose a little and noticed it was a little loose. I was able to get BLM to 128:biggrin: So I will head to parts store and get some new hoses and that should fix it. Thanks Dr. Booster for saving me $105 plus shipping on a new fuel pressure regulator (although I really wanted it!).

 

[87NAT]

I think I got it figured out :biggrin: I removed the vacuum block and put a piece of cardboard over the throttle body holes (thanks 87Nat and Pronto). BLM went to 120 :biggrin: Then I put the vacuum block back on and capped off all ports EXCEPT for the line going to the fuel pressure regulator (thanks Dr. Booster). I played with the vacuum hose a little and noticed it was a little loose. I was able to get BLM to 128:biggrin: So I will head to parts store and get some new hoses and that should fix it. Thanks Dr. Booster for saving me $105 plus shipping on a new fuel pressure regulator (although I really wanted it!).

Didnt I tell you to do that about 2 months ago. Glad you found it. My consulting bill is in the mail and I accept monthly installments at a very low interest rate.:biggrin:

 

[Razor]

Note to self: If you replace all the vacuum hoses, check valves(GM), PCV, and gaskets.. not much else left.

Understand that 128 doesnt mean squat.. its just a reference. As long as the numbers are close.. thats all that matters.

See its like this. You tell the chip guy you have 50 lb injectors. He makes a chip ASSUMMING your injectors flow 50 lbs. Now if your injectors let say flowed 47 lbs.. then with the recommended fuel pressure lets say 43 PSI.. the car will be leaner since the injectors flow less than spec'd. So a simple adjustment to the fuel pressure regulator fixes this issue.

But correcting this imbalance while having leaks.. then your creating more problems.

You want fun.. find vacuum leaks with an aftermarket ECM like a FAST, BS3, etc.. as your fixing the vacuum leaks with keyboard tuning and masking the real problem.

 

[Pronto]

If you have other mods besides the translator you should get an adjustable regulator anyway. Soon as you add a chip and up the boost your going to need to mess with the pressure. Glad the leaks are showing up. Don't forget the ones over at the charcoal canister.

 

[GNVYUS 1]

Good to hear, those pesky lines are always messing with us. I now have a leak at the spacer due to a couple deep scrapes in the intake that the red gasket spray along with the gasket didn't help so I feel your pain. Back to the black Permatex and gaskets.

And I agree with Razor, I can clearly see a leak at the spacer but the BLM is not far from 128 and I could easily have just added 1psi and masked it. The injector scare is why I always flow them prior to installing them, worth the $50 to make sure I have exactly what I ordered and that they are all spraying well etc.

 

[GNRick]

Didnt I tell you to do that about 2 months ago. Glad you found it. My consulting bill is in the mail and I accept monthly installments at a very low interest rate.:biggrin:

Well, not so fast. I replaced the little hoses at the vacuum block. Started car and BLM's were 127. So I thought SUPER.......then they climbed to 139 which is where they are now. So as I fix one leak, it appears somewhere else. So I have a couple questions....could the hose coming off of the boost solenoid be a source of a leak at idle, and also the "y" hoses going to the wastegate? Second question is....the hoses connected to the throttle body that some people cap- you know, the ones that are supposed to heat up the throttle body for emissions I guess- do those hoses carry vacuum or coolant? Thanks guys.

 

[GNRick]

If you have other mods besides the translator you should get an adjustable regulator anyway. Soon as you add a chip and up the boost your going to need to mess with the pressure. Glad the leaks are showing up. Don't forget the ones over at the charcoal canister.

I capped the line to the charcoal canister and that didn't make a difference. Too bad because that is an easy hose to replace. I have an extender chip, not sure if I mentioned that.

 

[GNRick]

Hey, if I can't get this figured out by Bowling Green, would someone like to help me at Bowling Green? If you're successful (and maybe even if you just give it a good effort) I'll buy the beer (and maybe the pizza too if I drink enough beer :biggrin: )

 

[Pronto]

The throttle body heater is coolant. If your concerned about hoses coming off you can put small zip ties on them but since there is no boost at idle that shouldn't effect your blm issue. Are you using the stock vacuum block? Maybe it's warped.

What fuel pressure is the extender supposed to be set for a idle?

 

[GNRick]

The throttle body heater is coolant. If your concerned about hoses coming off you can put small zip ties on them but since there is no boost at idle that shouldn't effect your blm issue. Are you using the stock vacuum block? Maybe it's warped.

What fuel pressure is the extender supposed to be set for a idle?

Yes, stock vacuum block. Doesn't look warped and I bought a new gasket for it. Extender chip uses 45 psi line off fuel pressure. I'll go back to capping the lines coming off the vacuum block, one at a time until I hopefully find the problem .Thanks.

 

[GNRick]

I capped all lines again. When I capped the PCV line (last line to cap) blm's dropped to 127. I kept the fuel pressure regulator line hooked up. So this should mean either it is the grommet at the PCV, or the intake is leaking, right? (PCV valve is new AC Delco). Since blocking off the throttle body with vacuum block removed caused blm to go to 120, can I rule out the intake leaking, and should I concentrate on putting in a new PCV grommet? There is some flashing on the intake that interferes with a good seal at the grommet. My friend tried grinding it off with a dremel tool. Maybe he didn't do a good enough job. I also removed the PCV valve and put some Vasoline on it before I reinserted it, but that didn't help. One other thing I noticed....blm was 135 with PCV line and fuel pressure regulator line connected. As I connected the three remaining lines, blm went up by 1 for each line, so now it shows 138. Does this sound normal? Am I being too anal?

 

[noslo6]

You said you have a translator. Try adjusting your base fuel up a little bit that'll bring down your blm.

 

[87NAT]

Rick once you determined blocking off the TB that the BLMs go to 120 THEN put the vac block back on... with no lines connected to it. Block off all 5 ports on the block. Check your BLMS. (Reset ECM between tests also) THen hook one vac line up at a time and check BLMs. Go in sections..example: Hook PCV vac line up and plug the end of it with no PCV attached to it. THis will confirm the integrity of that line. THen hook up pcv and recheck. Next go to second port and just hook up line until you get to whatever it is its hooked up to. MAP sensor, vac tee, etc...

What I am saying is to check each part of the system in pieces..not as a whole. If you just put vac block back on all lines connected it could be 1 of 20 places that could be the culprit. I did this method to locate a cracked line on the back of my climate controls. It just took time and testing each part of the system. I used a handheld vaccum pump from Carquest and pulled vaccum on each section until I found the one area that didnt hold vacuum.

 

[Pronto]

I had a similar vacuum leak in my old T/As climate controls too. I forgot to hook a line up after working under the dash. A small split can be anywhere. I replaced my grommet in the intake with one from "HELP". It works fine. Do what 87NAT says, check one line off that block at a time a mity vac to see if it holds. If you replace any of those little hoses at the block make sure you get the right sizes, they are not all the same which is a pita.

 

[GNRick]

I guess maybe I wasn't clear, since this is a pretty long thread now. I did plug every line from the vacuum block, including the fuel pressure regulator line. Dr. Booster informed me that I need to leave that line connected, or fuel pressure will go up and reduce blm's, a scenario that doesn't help me. So I left the line connected to the fuel pressure regulator, and plugged the other 4 lines one by one. The last line I plugged was to the PCV valve, and voila! BLM went to 128. I also shoved a big screw in the hose to the pcv valve, just to make sure the hose was good. The hose is good. This is after I replaced the PCV valve/grommet/hose, gasket under vacuum block, fuel injector O rings, and two little hoses at the vacuum block (parts store had correct size hoses). And lets not forget a couple hours labor at the mechanic! So now what I did was smear some high temp silicone under and around the pcv valve grommet. The package says it works on metal, rubber, etc. and is good up to 600 degrees. I'll let it sit 24 hours to cure and see if that fixes it.

 

[unix_punk]

The pcv is a controlled leak that may need to be compensated for in your chip or translater (as mentioned before) or at the throttle plate. I assume you have valve cover breathers on there so air is free to flow into the pcv valve regardless of the state of the grommet. The only restriction there is the weak spring inside of it. Since you found that the issue is fixed by removing the pcv, the next thing I would do is compensate for the extra pcv air by loosening the so called idle screw on the throttle body to close the plate a tiny bit. Any idea what your IAC counts are when the pcv is hooked up as it was before? My guess would be that they are pretty low if not 0 (not sure if that was mentioned before or not).

 

[87NAT]

Rick, get a mity vac hand pump and check all your lines. Dont just keep resetting the ECM and starting the car.

 

[GNRick]

The pcv is a controlled leak that may need to be compensated for in your chip or translater (as mentioned before) or at the throttle plate. I assume you have valve cover breathers on there so air is free to flow into the pcv valve regardless of the state of the grommet. The only restriction there is the weak spring inside of it. Since you found that the issue is fixed by removing the pcv, the next thing I would do is compensate for the extra pcv air by loosening the so called idle screw on the throttle body to close the plate a tiny bit. Any idea what your IAC counts are when the pcv is hooked up as it was before? My guess would be that they are pretty low if not 0 (not sure if that was mentioned before or not).

I would like to try to fix the problem without masking it with more fuel or air, if possible. IAC is around 40ish.

Rick, get a mity vac hand pump and check all your lines. Dont just keep resetting the ECM and starting the car.

I wasn't resetting the ecm. BLM's move up and down as vacuum changes, whether I capped/uncapped vacuum lines or in my mechanic's case, as he sprayed brake clean on the pcv valve. I'm not sure if the mityvac would work too well on the pcv line if the vacuum is leaking out from around the grommet and not the valve itself. But I could be wrong.