WOT Hesitation-Different than other threads-This problem will leave you baffled...

[prophecymiller]

Ok, to start off, I will tell you that I am at work right now and have been looking through threads for the last four hours trying to find one with the same problem as me. No Luck! I work on my car with two mechanics that I know and they are also wondering what could be causing this...

About six months ago I was starting to have problems with my acceleration. First gear would be fine under WOT and seemed ok if I shifted through the gears from then on in WOT. The problem happens when I would put it in 2nd gear at 15-20mph just cruising and then give it WOT after it is in gear. The rpms would start to rise slowly as normal and hit boost at around 3k but the car would not accelerate harder until it would hit like 4k and then would feel like it all of a sudden kicks in and goes from there. There was also a sound kind of like some kind of rubbing that would happen when I would give it WOT when it was under the boost threshold and would be drowned out by the sound of the engine and turbo when boost would hit.

After a while one night on my way home i had a total loss of power and my mechanic buddy and I did some inspecting the next day and determined that the compressor blades had made contact with the housing in the turbo. So I sent it to FP and got the Big28 mod done to it and put it back in.

The car was absolutely 100% better after the new turbo and ran very strong and smoothly.........for the next day or two. Then we realized I needed a new clutch. I bought and installed a new ACT 2100 kit over the last month slowly and install was fine.

Now, last night I tightened all of my boost hoses up and took it out for a spin. The car is very dissapointing and is vibrating under boost now- mind you I havent gotten the front end alligned yet. Now for the mind boggling part- I noticed that the hesitation in 2nd is back somehow and making that same rubbing noise only when I give it WOT under the boost threshold- I can't believe that it could be back again even though after I replaced the turbo before the new clutch was put in there was absolutely no problems in 2nd and would accelerate and build boost smoothly all the way upWTF . When I put it in neutral and give it some revs it sounds fine, its only when i'm in gear and floor it will it make that weird noise like brake rotors barely scratching against pads .

Tonight my mechanic friend and I are going to do some more checking and hopefully come up with some answers- I just thought maybe you guys have heard of this or could offer some insight- I couldn't seem to find another thread with the same symptoms- oh yeah, the engine is running just fine without any misfiring or any weird activity so I don't think there is anything wrong with the engine. Sorry for making you tired after all of that reading but I would appreciate some input,

Thanks, Steven

 

[toybreaker]

When the old turbo was replaced, was the old oil supply line replaced/checked for restriction?

I've seen a couple of return turbo failures from lack of lubrication stemming from a clogged oil feed line or drain line to the pan.

Hopefully, someone else will have more to add.

Keep us posted!

 

[underpressure25]

Yea deffinately check the turbo lines. Also are you throwing any codes.? I would also check your map sensor this could give you troubles under load.
Good Luck

 

[prophecymiller]

Today my friend and I looked the whole engine over for any unconnected wires or vacuum lines. Next we are going to warm it up and unconnect the maf connector while it is running to see if it runs better or worse to see if it is running in limp home mode or closed loop. Tomorrow we are going to hook up his scan tool to monitor the system. Im sure it is something dumb that is causing the problem...

Thanks for the advice with the turbo oil line. I will undo it tonight to make sure everything is ok. I will update again tomorrow after the scan.

Steven

 

[prophecymiller]

Yesterday we unconnected the maf while it was running and it tried to die and barely ran in limp home mode. Very soon it turned on the CEL and so we think there is nothing wrong with the vortex pattern inside of the maf since it did not run better or teh same without it plugged in. We then plugged in his Genesis and looked for any problem codes and nothing came up except for three that all had to do with the maf being unplugged, so we cleared the codes and turned off the CEL. Next we got onto Alldata and got the normal parameters for running conditions and they all checked out. We even checked the fuel trim parameters and they checked out just fine.

After everything was done, there was nothing running out of the ordinary but it is still having power problems and I have even put a hundred miles on it last night to see if the fuel trim would be modified to fix the problem but no good results. The car is very dissapointing compared to when we changed the turbo and still had the old worn out clutch. Tonight I am going to swap intakes with a buddy of mine with a 97GST to make sure we can fully rule out all possibilities of the maf not functioning. If anyone is having some sort of the same problems or had teh same and know a solution, it would be greatly appreciated...

Steven