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Old 03-21-2010, 08:41 PM   #1
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Default okay, this one's really got me.

okay, as if my car dumping boost after 3psi wasn't bad enough.

yesterday my buddy and i decided to replace the vacuum lines routing to the boost controller, gauge, and all around the turbo bascially. and it turns out that whoever installed the boost controller did it wrong and it would do nothing in terms of "boost control" so we changed it, and installed it the way it was supposed to be.

we crank the car, it cannot idle. it tries to around 400-500rpm but it floods itself to death. it can be driven, but it's dumping gas through like a ****. anyone have a clue what changed it THAT much? i can datalog if you guys think it's worth it.
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Old 03-21-2010, 08:47 PM   #2
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So changing vac lines results in pig rich idle. My guess it that you are getting a signal to your MAP sensor thats more or less ambient due to a leak, as opposed to vacuum. MS sees that ambient pressure, fuels accordingly and bam you are rich. That or maybe a line to a fuel pressure regulator is not right. The you would get more fuel pressure than you should, as vacuum will reduce fuel pressure. If your base FP is 43.5 psig for instance, and you run at 12InHg of vacuum at idle, then your FP at idle should be 31.5 InHg. If you have 43.5 in that situation, then even if MS is getting decently accurate MAP signal you will get too much fuel.

Where does your boost controller get signal from? How about your BOV?
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Old 03-21-2010, 08:56 PM   #3
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Originally Posted by Sparetire View Post
So changing vac lines results in pig rich idle. My guess it that you are getting a signal to your MAP sensor thats more or less ambient due to a leak, as opposed to vacuum. MS sees that ambient pressure, fuels accordingly and bam you are rich. That or maybe a line to a fuel pressure regulator is not right. The you would get more fuel pressure than you should, as vacuum will reduce fuel pressure. If your base FP is 43.5 psig for instance, and you run at 12InHg of vacuum at idle, then your FP at idle should be 31.5 InHg. If you have 43.5 in that situation, then even if MS is getting decently accurate MAP signal you will get too much fuel.

Where does your boost controller get signal from? How about your BOV?
the boost controller is a shitty manual one, i have it installed just like diagram B on this link:
eBay Guides - NXS Manual Boost Controller Installation Install Guide

except i have a T fitting going to the boost gauge.

the BOV i have no clue, i didn't install it.

also, i looked at the boost controller and for some reason it has no breather hole as stated on those diagrams. would that cause problems down the road?
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Old 03-21-2010, 09:05 PM   #4
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OK. So the line from the turbo goes to both your boost guage and to the MBC. Does anything else connect to that line now or in the past?

With my last project I had my boost guage on the same line that went to my adjustable fuel pressure regulator. I checked that line any time I happened to be in the engine bay because if it has a leak, then I would get too much fuel pressure at idle and too little under boost, both bad things.

If you had a setup like that, then left that line open, you have your problem right there.


The real answer is to go over everything you did, paying special attention to any vac leaks on the intake manifold and most especially to any lines that are connected to the fuel pressure regulator.

All the BOVs I have seen will take a signal from both sides of the throttlebody. So it will have a vac line from the intake manifold. I would check that too.

What would be a good idea (required IMHO) is to do a true boost leak test. That will make it very easy to find any leaks or open ended lines.
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Old 03-22-2010, 12:13 AM   #5
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Quote:
Originally Posted by Sparetire View Post
OK. So the line from the turbo goes to both your boost guage and to the MBC. Does anything else connect to that line now or in the past?

With my last project I had my boost guage on the same line that went to my adjustable fuel pressure regulator. I checked that line any time I happened to be in the engine bay because if it has a leak, then I would get too much fuel pressure at idle and too little under boost, both bad things.

If you had a setup like that, then left that line open, you have your problem right there.


The real answer is to go over everything you did, paying special attention to any vac leaks on the intake manifold and most especially to any lines that are connected to the fuel pressure regulator.

All the BOVs I have seen will take a signal from both sides of the throttlebody. So it will have a vac line from the intake manifold. I would check that too.

What would be a good idea (required IMHO) is to do a true boost leak test. That will make it very easy to find any leaks or open ended lines.
yes, there is a vac line running from the FPR and the intake manifold. and one running from the intake side of the turbo, as well as a bung on the pipe on the intake side.

the way i have the boost controller hooked up now, off the top of my head is:
actuator to boost controller, directly.
fpr and intake manifold are both hooked to a T with a line running to the exhaust side of the motor, i have a T connecting that line to another line coming from the intake side of the turbo, back to the boost controller, i believe.

i may be wrong on the exact way i have it all routed, but it's all hooked up, is it right? i doubt it since the car wont idle and runs pig rich, lol.

my buddy had it running just straight actuator to controller, intake side to controller. and he leaves the other vac lines open, it did the same thing, probably because of what you said.

now, here's another question, could i run straight actuator to controller, intake side to controller, then run the vac line coming all the way from the other side (fpr and intake manifold) and connect that to the bung on the pipe coming from the exhaust side? i was going to try this but i was out of vac line and didn't have a long enough piece to do it.
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Old 03-22-2010, 12:21 AM   #6
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here's a pic of how it was before we replaced the bad hoses.

http://i2.photobucket.com/albums/y23...k/IMGP0013.jpg

it goes, intake manifold and fpr to boost controller, then from there to the bung on the intake pipe side of the turbo. then the actuator runs to the intake side of the turbo. but this caused it to only go by the spring in the actuator if i'm not mistaken, so i may as well not even had a controller to start with.
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Old 03-22-2010, 01:58 PM   #7
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Buy new vac line. I always have like an 8ft length around so I can do it right. Any parts store will have it by the foot for dirt cheap. I tend to get brass t fittings from aquarium shops if I cant find them at the parts store. The plastic ones can get brittle over time.

I am not sure what you would hook on a vac line from the exhaust side of the engine, except the EGR or the wastegate. And that EGR should have abso-*******-lutely nothing to do with the FPR or anything else.

What I would do:

On the MBC, run a signal line from either the intake manifold or the off the turbo/plumbing itself to the MBC, then from the MBC to the actuator. If you want a bleeder, put it between the MBC and the actuator. Nothing else on the line.

Run a line from the intake mani to the FPR, and with a good, quality T also connect that line to the boost guage. Nothing else on the line. This way, if you start seeing funny stuff from your boost guage, then you know that you may have a vac/boost leak affecting your FPR. Take this seriously.

Run a line from the intake mani to the BOV. Nothing else on the line.

Then make sure you have no lines at all just open from anything. Then do a good 20 psig pressure test to make sure.

Its sounds like the whole thing is pretty well FUBARed to me. When replacing hoses, its best to do them one at a time and go slowly. And do not listen to your buddy. And frankly I would start capitalizing etc on here, people will rip you to shreds otherwise. Which is a good thing, its keeps this place from ending up like the 5 million ricer forums out there.
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Old 03-22-2010, 07:50 PM   #8
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thanks. did all of this. still no luck. i'm going to buy some more adapters tomorrow and try something else.

Last edited by jarrett2k; 03-22-2010 at 08:04 PM.
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Old 03-22-2010, 08:09 PM   #9
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What kind of vacuum readings do you get from the boost gauge and MS?
--Alex
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Old 03-22-2010, 08:22 PM   #10
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Quote:
Originally Posted by AlexO35 View Post
What kind of vacuum readings do you get from the boost gauge and MS?
--Alex
i couldn't get the car to run well enough to give a reading on the boost gauge today. i'll hook up to the MS tomorrow and check that, it got really cold out all of a sudden for some reason.
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Old 03-24-2010, 08:33 PM   #11
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i got the vac problem fixed. thanks a ton Sparetire.

turns out the intake side had two bungs and i was trying to route them both in. so today i capped off the one on the actual turbo and used the bigger one on the intake side pipe.

i still have a boost leak or wastegate problem that i have to address.
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