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crash_out

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Discussion starter · #1 ·
I finally got my 90 GS-T running, and it's already got a problem.

When you rev the engine, it seems as if it's lagging bad. You can hear the turbo begin to spool, but as soon as the stock boost guage reaches 0 vac/boost, it sounds like the turbo dumps and the guage bottoms out. oddly enough, it sounds like the turbo stops spinning as well.

The car has sat up for several years, not sure how many, with a bad ECU. After three weeks of chasing wires and what not, I finally got it running, but it just seems as if either the turbo is having problems, or maybe I have a boost leak. All of the hoses and tubes are still present, but being as most of them were dry rotted anyway, there may be a leak somewhere. I just wasn't sure what kind of signs it would have if it was a boost leak.

Thanks for all the help!

Nick
 
Discussion starter · #4 ·
I went ahead and took the intercooler out to check it-it was full of oil, among other things.

A hickory nut fell out of it:eek:

Dont' know how it got in there, but it can't have been good.

I'm off to the parts store in the morning to get some new vacuum lines and a vacuum tester, so maybe I'll get this one figured out soon.

Nick
 
#5 · (Edited)
crash_out said:
The actuator arm is still attached, but need to check and make sure it moves under vacuum. I'll have to wait till Wednesday to get a hand vacuum pump to test every thing.

Nick
Click to expand...

The actuator works under positive pressure, not vaccum. Check out the link at the bottom on how to build a boost leak tester.

http://www.vfaq.com/mods/ICtester.html

Here's a link to help you with that oil in the intercooler problem. It's not really a problem, more of an occurance. Bascically the valve cover vent tube is a jerk and dumps oil residue into the intake pipe which then makes it's way through the turbo and into the intercooler where it generally collects. Clean it out with gas and you'll be fine. Yes it says it's for a 2g but you get the idea....

http://www.tgilmore.com/talon/catchcan.html

While you're under the hood might as well.....

http://dsmloggers.com/DSM/taboo/emissions.htm

Just call me Santa Clause. :rudolph:
 
Discussion starter · #6 ·
Cool, I appreciate the links.

I did eliminate the vent line-I replaced the intake tube with a Dejon unit, and put a Mr Gasket fuel filter on the line coming out of the valve cover. Am I correct in leaving the "output" side of the filter unplugged to allow the air to vent out?

Thanks again for the links. I had been looking over Vfaw but somehow missed the book leak tester...

Nick
 
#8 ·
You are all mixed up. The wastegate actuator pushes the rod which opens the wastegate, which bleeds off excess exhaust pressure. This actuator works off positive pressure coming from the intake mainfold. The blow off valve opens as the throttle plate closes and creates vacuum, this releases the excess air pressure in the system.

That boost leak tester connects to the inlet of the turbo and allows you to pressurize your entire intake tract and check for leaks. Boost leaks will cause an overly rich condition and will cause you to hit fuel cut prematurely. Basically the MAS meters the air coming in and adds fuel accordly so leaking metered air means you now have fuel being added that is not needed as the air leaked out. Makes sense?

As for the valve cover vent line, yes it must be left open to the atmosphere.
 
Discussion starter · #9 ·
Okay, I've got you now. I was under the impression that the wastegate actuator created a vaccum signal that caused the blow off valve to vent...

I'm fairly familiar with mass air systems, I've tweaked them on my Mustangs in the past. Most of my experience with forced induction stems from work with superchargers, so the wastegate was a misunderstood device.

And yes, this sounds exactly what the car is doing-running very rich(even if there isn't smoke coming out of the tailpipe, the fumes will burn your eyes). I just wasn't clear on the operation of the wastegate and BOV.

Thanks for all the help. This is my first turbocharged vehicle, so it's a learning process....

Nick
 
#10 ·
It's not a problem everyone has to start somewhere and thats what theres forums are here for. Use the search function as much as you can. You'll be surprised what you can dig up! There's tons of excellent information on this site so use it to your advantage.
 
Discussion starter · #11 ·
Yeah, I've picked up A LOT of good info. For some reason though, I can never find what I'm searching for...maybe I use the wrong words...

Well, by afternoon tomorrow, I should have found any boost leaks....hopefully.

Nick
 
#12 ·
Be sure to pressurize to at least 20psi. Set the regulator to around 25psi is my suggestion and have someone watch your boost gauge. Spray down all the connections with soapy water. Lots of small leaks > one big leak. If you need a run down on possible places for leaks let me know.
 
Discussion starter · #13 ·
I did build the tester, but didn't have time to check it.

I did check the wastegate actuator and blow off valve as per the Haynes manual-both seemed to operate correctly. I still need to check the wastegate solenoid to make sure it opens and closes properly.

The intercooler is cleaned out, and I pressure tested it-it checks out okay, other than looking like crap.

Will let you know as soon as I get it tested on whther it's loosing boost and where I can find it.

Nick
 
Discussion starter · #14 ·
Okay, checked the solenoid, working properly.

I attached the boost tester, set the regulator to 25, and let her rip...

Okay, I hear a leak...From the valve cover??? I checked again, and it's coming from the vent line that used to go to the intake....okay. I assumed it was coming through the PCV valve, so I unhooked it and plugged it.

Check again-I can't isolate the leak, only that is coming from the front of the intake, between it and the valve cover. I do smell fuel when it starts hissing, if that helps.

I can't pressurize it and locate the leak right now-I don't have anyone to help me. Hopefully my brother will wake up soon and apply pressure while I probe the area for developments.

Thanks for all the help so far!

Nick
 
Discussion starter · #15 ·
Well, after changing the vacuum lines, several hoses, and finding out that even though I had the Evap Cannister line connected to the intake, it wasn't connected to the cannister itself, I took it down the road.

I've got boost, about 7 on the stock guage, which I understand means that there is more than 1 pound of boost, but probably less than 10.....

The problem now is that the car will barely idle, and below 3000 revs it will spit, sputter, buck, snort, and try it's best to die. If you keep pumping the gas and get it to about 3, it will lunge forward and scream like a banshee. The same thing trying to take off in gear-if you try to take off without revving it to nearly 3K, it will try it's best to sputter and die. When it does this there is a lot of smoke out of the tail pipe, and you can smell lots of fuel..

I'm going to do some searching for answers, in the meantime any help is appreciated.

Thanks again for all the help, without you guys I wouldn't have gotten it even to this point.

Nick
 
Discussion starter · #16 ·
After some more screwing around, I've figured this much out.

If the car is cold, it will start up after several tries, and will idle really well. After a varying length of time, the car will begin to try to quit-it sounds as if it's either missing off a couple of cylinders, or that there is some heavy load placed on the engine. It begins to vibrate really bad, and if you're driving it will stall out. It may or may not start right up, one time it took 30 minutes for it to cool down, then cranked right back up.

Once the engine starts to bog down, there is quit a lot of smoke that begins to come from the tail pipe. You can pump the throttle, and eventually it will build itself up to about 2500 rpms, at which time the car "comes alive." From that point on if you keep it above 2500 or so, it will pull like a demon, and rev pretty freely with little or no vibration.

I'm about spent on this thing. I'm one step away from scrapping the ngine in favor of another, if I can find one...

Nick
 
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crash_out
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