Two Big Problems!

[tweetdriver63]

Here's the first problem:

I just installed new AB shift cables. I had to have a machine shop modify the bracket that came with them because the cross-gate cable went through it pointed in the wrong direction. That part of the bracket had to be angled so the cable pointed a bit more toward the front of the car, otherwise I couldn't move the shifter side-to-side at all because the cable was binding. I think maybe a previous owner made a custom short-shift modification or something. The bracket that was in the car with the OEM cables had been modified, too. (see pic) Anyway, after that the cable goes through straight, but the shifter doesn't self-center like it should, and it takes more force in the side-to-side movement than it should. It makes third gear difficult to find. Any thoughts on what could be causing this? Would it cause this if the cables were twisted in the tunnel? I'd rather not have to take everything apart again, but I have to fix it.

Another possibility could be that I damaged something. The cable end (gearbox end) of the cross-gate cable was a very tight fit over the shaft it goes on. I tried gently tapping on it in an attempt to get it on (which didn't work) until I finally managed to get a spanner on there and squeeze it down. I know I didn't squeeze on anything that could be a problem, but could I have hurt it tapping on it?

The second problem I'm having (and this wasn't happening before the cable change) is with the turbo. My test drives to see how the shift cables were working revealed the turbo problem. At the point where the turbo should kick in, all I get is some noise (which seems to indicate it's turning), which I can't think of the right words to describe, and the boost gauge shows nothing. I think the needle did flicker a little once. I also feel no boost. I know nothing at all about turbos and could really use some help.

[Monty]

Another possibility could be that I damaged something. The cable end (gearbox end) of the cross-gate cable was a very tight fit over the shaft it goes on. I tried gently tapping on it in an attempt to get it on (which didn't work) until I finally managed to get a spanner on there and squeeze it down. I know I didn't squeeze on anything that could be a problem, but could I have hurt it tapping on it?

When i fitted the AB cables i noticed that the cross gate conection end was a tight fit on the pin , so when i came to fit Dave`s shortshifter i drilled the hole slightly bigger which cured self centering and the stiffness (hope Gary doesn`t read that last bit ).

[tweetdriver63]

Another possibility could be that I damaged something. The cable end (gearbox end) of the cross-gate cable was a very tight fit over the shaft it goes on. I tried gently tapping on it in an attempt to get it on (which didn't work) until I finally managed to get a spanner on there and squeeze it down. I know I didn't squeeze on anything that could be a problem, but could I have hurt it tapping on it?

When i fitted the AB cables i noticed that the cross gate conection end was a tight fit on the pin , so when i came to fit Dave's shortshifter i drilled the hole slightly bigger which cured self centering and the stiffness (hope Gary doesn't read that last bit ).

If I read you right, the tight fit on the pin may be the cause of the stiffness and self-centering problems. I'll try drilling out the hole slightly and see what happens.

Now, is there anything in the area of the shift cables that I could have messed up to cause the turbo problem?

[Doug]

sounds like you need to check the integrity of all the turbo ductwork from the turbo to the intercooler and then up to the throttle body -- any split/crack could lose the pressure.

a crack in either plastic endtank of the intercooler could cause a problem too. to check that you'd likely have to remove the IC and visually check it. I gave mine a good blow with my hand over the other side to pressurize it to check for leaks--the hardest part was wrapping my lips around the big pipe (sorry couldn't resist--hope I didn't arouse anyone/Gary) you can clean the inside of it too with your favorite solution and a lot of shaking too while at it!

if you were to take of the intake duct to the turbo so you can see the compressor wheel, if you rev the engine and hold the throttle plate open long enough you would see the turbo spin up and could verify that it is turning like it should

[needless to say keep your hands from it while running and keep FOD away too! -- putting this as a disclaimer only]

[tweetdriver63]

OK. Since I was just driving to check the shift cables, I put the intake pipe back on (the one going into the intake plennum), but I didn't tighten the clamps at either end so it would be easier to remove again for adjusting the cables. I take it that's going to allow the pressure to escape and cause my problem, right?

I won't be able to do any more work on it until Sunday, but it sounds like boring out the hole in the cable end and tightening the clamps on the intake hose should fix all my woes.

I'll come back with the results some time on Sunday.

Til then, thanks for the help guys.



(I'm not actually an idiot, in fact I have application papers for MENSA around here somewhere. I just don't know squat about turbos...but I'm learning, thanks to LEC)

[Doug]

Chris,

let me bring it up to your knowledge level

think of a turbo engine as a variant of a turbojet

(diagram here makes the most sense to show similarities but none at hand)

turbojet: intake compressor fan -> burner where the fuel is introduced -> exhaust with turbine to extract energy to power compressor

turbo engine: intake compressor blades -> reciprocating engine parts to further compress air charge and introduce fuel and ignite it -> exhaust compressor wheel to extract energy to turn intake compressor


seriously, get your brain thinking this way and it will make more sense to you

[GeoffSmith]

The higher the pressure/speed on the input/exhaust side, the higher the pressure/speed on the output/air inlet side. Together with an engine, it's an unstable system and would run away to infinity and beyond if it weren't for the wastegate valve being opened by the ECU and releasing exhaust pressure across the input side.

I found this really useful picture as well:

[tweetdriver63]

I hate having to wait to fix a problem, so I went out and tightened the clamps on the intake pipe. Voila! Turbo is fine.

Thanks.

[tweetdriver63]

I drilled out the hole in the cable end with a 5/16th bit. The cable end then slipped onto the pin with ease (but not loose). It freed up the shifter noticably. I can now move the shifter side-to-side better than before, but the self-centering still isn't working, so it's still a lot more work finding the right gear than it should be.

Should I bore the hole out a little more, or is there something else causing this?

[mikeydude]

I had the same problem with stiff cross movement, I found it was partly due to the routing as the cables went into the tunnel, make sure they are not tight and not trying to cross over each other. Mine was still stiff after that, but now seems to have eased off.