98' GST not running right!

[Mitsubishi_GST]

to start off, i bought a 1998 eclipse gst about two weeks ago, when i first got it was running great and then it started running really bad. 1. when i would get to about 2500 rpm in every gear the turbo seemed to be out because the boost gauges were bumping up and down and was making a loud blowing sound under the hood, like it was a bad boost leak, and had no power. 2. i took the car to a local mechanic and he said that the wastegate and maf sensor were bad, so i replaced them, and still the problem was not fixed at all. the car will barely idle and when you try to drive it just sputters and has no power, and the turbo is still making no boost. i know nothing about these cars. if someone has any clue to what it could be, please let me know, the advice will be appreciated thanks.

 

[bryanwheat]

Do a boost leak test.

 

[dsmcarnag3]

sounds like a boost leak. start with an inspection of the intercooler piping starting at the turbo and follow it all the way to the throttle body making sure that all connections are tight. also make sure all the vaccum lines are hooked up as well, chances are you'll see something outta place. try and find someone in your area that can help you do a boost leak check if everything looks in order, or check this out http://www.dsmtuners.com/forums/art...-boost-leak-test-how-boostpro-net-tester.html

 

[blkgst97]

Like already stated do a boost leak test. Is the maf plugged in?

 

[Mitsubishi_GST]

ok thanks guys, im getting ready to go do a boost leak test on it, and see if i can find a leak. and yea my maf is plugged in.

 

[92AWDHX40]

Let us know how the Blt went.

 

[rb26alpha]

You can do it yourself for $25 shipped to you

 

[Mitsubishi_GST]

Ok i did a boost leak test today, and i couldn't identify any leaks. But i did find one problem, the little hose the goes onto the wastegate was being pinched closed by my intake boot, so i took a little adapter and pointed in a different direction. This didn't fix everything though. I was told to replace the wastegate so i ordered a new one on ebay, and i have already installed it, but it obviously it was a dud. Because it doing the same thing the old one was doing, which is holding the turbo wide open at all times. The rod from the wastegate that connects to the turbo flange thing is pulling the turbo wide open at all times, for some reason the wastegate rod is not flexing in and out. So should i buy a different wastegate with a different psi setting? Also the turbo is working good so i dont think thats the problem.

 

[dsmcarnag3]

but you are building boost now?

 

[bryanwheat]

Did your leak test consist of a visual inspection or did you pressurize the system, and if so how many psi did it hold for how long.

 

[Mitsubishi_GST]

i did a visual test, how do you do a pressure test? And yea its building boost because when you rev it up the boost gauges max out because that wastegate rod is holding it wide open. Could the aftermarket blow off valve have anything to do with the problem? Note: the hose that comes from the wastegate runs into a three way adapter thing, which has one hose going to the wastegate, one going to the blow off valve, and one going toward the top back of the motor which i think its connected to the throttle body or something, like i said earlier in my post i don't much about these cars, and i have never had anything with a turbo.

 

[bryanwheat]

You must do a pressure test. A visual test won't tell you anything. Let me google that for you

 

[dsmcarnag3]

if your boost guage is maxing out, then your wastegate and or blow off valve isn't working properly. I would suggest picking up a shop manual, they can be very useful with diagnostic testing. to the best of my knowledge there needs to be a vaccum line hooked to the wastegate from a source after the turbo but BEFORE the throttle body. generally there is a vaccum port right on the turbo. but you'll need a boost controller if your not using the factory boost pressure sensor (located on the the passenger side frame rail directly under the MAS) IF you can't find it pm me and I'll take a pic of it so you know what to look for. my BOV is run to the top of my intake right after the throttle body, the left side port that faces the front of the car. hope that helps, good luck!

 

[Mitsubishi_GST]

I finally picked my GST up from the shop monday which made exactly a month that its been there, they told me that they couldn't figure out the problem with it, so they did nothing So yesterday i took a mac tools scan tool and it threw some codes such as PO335, PO340, PO505, P1400. So i took the crankshaft position sensor, camshaft position sensor, idle air control motor, manifold differential pressure sensor, and throttle position sensor off and cleaned them and put them back on. Then i figured i would reseal all my intercooler piping, jpipe, downpipe, bov, intake, and vacum lines. I removed my bumper to get to the intercooler and discovered my problem, my driver side intercooler pipe was completely disconnected. So i finished resealing everything and reset my computer. Then i got in the car and started it up and drove down the road. And it ran better than ever. Problem completely fixed. Thanks everyone for your help and knowledge!!!

 

[ktgurl87]

i did a visual test, how do you do a pressure test? And yea its building boost because when you rev it up the boost gauges max out because that wastegate rod is holding it wide open. Could the aftermarket blow off valve have anything to do with the problem? Note: the hose that comes from the wastegate runs into a three way adapter thing, which has one hose going to the wastegate, one going to the blow off valve, and one going toward the top back of the motor which i think its connected to the throttle body or something, like i said earlier in my post i don't much about these cars, and i have never had anything with a turbo.

um...excuse me? This is wrong. The bov should have its own dedicated line to the intake manifold. The line from the wastegate should go to your boost control solenoid and your "j-pipe". If you've still got a stock turbo, there should be a nipple on the turbo itself for this line. Then you should also have a vacuum hose from your intake pipe to the boost control solenoid. Fix this ASAP.