Vaccuum line off - idles good?

[Bama87GN]

My GN idles and runs ok with the vaccuum line (one that goes to cruise) disconnected. When I connect it back it idles rough and runs rich. When it is disconnected it drives ok but doesnt pull hard and boosts up real slow. Any ideas?

Thanks

 

[TurboRegal84]

When you pull the vacuum line off you are creating a leak which is causing the rpm to increase. Doing this is also allowing un metered air into you engine (Air not passing through the MAF)......I would not suggest driving your car with unplugged vacuum lines.

With the vacuum line connected what are your IAC Numbers in park?

 

[Audie1]

When you pull the vacuum line off you are creating a leak which is causing the rpm to increase. Doing this is also allowing un metered air into you engine (Air not passing through the MAF)......I would not suggest driving your car with unplugged vacuum lines.

With the vacuum line connected what are your IAC Numbers in park?

What TurboRegal84 is asking. Sounds like your IAC is out of adjustment or you might have other vacuum leaks.

 

[darkred87T]

Would an increase in RPM due to pulling a vac line be a sign of other leaks. I would have thought the opposite.

I have the same issue. For some reason my car runs PIG....PIG rich and pulling a vac line momentarily wakes up the idle because of the added air introduced. If you wait long enough with the line unplugged, you will see IAC counts decrease to compensate for the unmetered air.

 

[Audie1]

Would an increase in RPM due to pulling a vac line be a sign of other leaks. I would have thought the opposite.

I have the same issue. For some reason my car runs PIG....PIG rich and pulling a vac line momentarily wakes up the idle because of the added air introduced. If you wait long enough with the line unplugged, you will see IAC counts decrease to compensate for the unmetered air.

You are right. I said that so that he would more carefully check the simple things, since bad/disconnected vac lines affect idle problems in a big way. It's funny what folks will find and correct when double checking simple things.

 

[ESP Products]

If you still are having a problem, try unplugging the MAF and note your idle quality. You may have a bad sensor. Check your plugs, you may have a bad injector. Let the engine warm up and try resetting the Min. Air Rate. I'd check the Min Air Rate first.

Hope this helps you.

 

[Bama87GN]

Thanks for the replies. I finally got around to working on it this weekend. The IAC numbers were off and I had a code that read EGR Solenoid was bad. I had an extra one on the shelf and switched it and it fixed that problem.
NEW PROBLEM
Now, the car overboosts. I have adjusted the wastegate (modified stock wastegate) and it doesnt change anything. And by overboosts, I mean, it goes from 15psi to 30 in a blink of an eye. Could the wastegate be bad? Or could it be another line somewhere else off. I thought I heard a hissing sound when I drove it, but couldnt really tell.

Thanks

 

[Bama87GN]

I think I just found the problem. I guess one of my lines going from the y restrictor fell off. All three plugs should be going somewhere right? I dont have one going to the wastegate solenoid.

 

[Chuck Leeper]

I'd suggest you replace all the lines and ty wrap the connections. A couple of those 30psi blasts and you'll be a member of the DOTCC...

 

[darkred87T]

Could the wastegate be bad? Or could it be another line somewhere else off. I thought I heard a hissing sound when I drove it, but couldnt really tell.

Thanks

Or the actuater could be bad.

 

[ESP Products]

To test these items, forget about all the hoses and just run one hose from the turbo to the wastegate actuator. Check the actuator arm to be sure it is just pulled out a little to slide over the swing arm. Also make sure the swing arm moves freely. If all this is good, take it for a smooth test drive and bring the car up to boost. With only the one hose and the WG adjusted down, you SHOULD be getting low boost readings, I'd guess around 8-10 psi. If you still have an overboost issue, it's most likley to be a bad w/g.

Hope this helps you.

 

[Bama87GN]

Ok I will try that this afternoon. Can I leave it like that or do I need to attach all the hoses on the y fitting. What does the wastegate solenoid do?

Thanks

 

[ESP Products]

You could leave it like that but you loose ECM control of the boost. you also loose boost retard, should you detonate. Once you do the test and all is OK, start returning things back to stock, one at a time, until the problem returns. Good luck.

Hope this helps you.