Step One Remove Engine

[kevm14]

I'd give the waste gate linkage/stuff a closer look.

Can you force it closed for testing purposes? You could free rev and listen for the turbo. Or drive with it and not exceed some RPM where it would be clear if it was working or not, but not so high that you'd be over boosting. Maybe 2500 rpm (or whatever the soonest RPM is that you think the waste gate would normally begin to open).

[Fast_Ed]

So given my "expect the worst" approach to this car, I've been looking at TD04's for sale. And they aren't bad...

http://www.cxracing.com/mm5/merchant.mv ... _Code=TD05

$244 for a complete, correct, new turbo including wastegate actuator. I was looking at $207 or so from Rockauto for a replacement CHRA (turbo speak for the center section with bearings/turbines but no housings)

I was hoping my wastegate door had just fallen off, but getting boost back last night pretty much rules that out.

There might just be some 'stuff' in there, either in one of the turbines, or in the oiling system for the bearing itself I guess.

Kevin suggested I do a turbo upgrade instead.. And I can get a GT28 for about the same price, but:
Downpipe connection doesn't match, same with intake snorkel.. can be solved, with money.
Need upgraded fuel pump and injectors
intercooler likely inadequate
Traction inadequate even with stock TD04 (Limited slip $1000+ with parts/transmission expert labor)
Would require a real dyno tune $$$
And the kicker: The Viggen engine is only good for 300hp, a number than has been reached on the stock TD04 many times. To really use the GT28, I'd need to build a new engine (b234 bottom end with the current Viggen head would do). $1000 to buy the bottom end and parts to freshen it.
So I estimate about $3000.. plus many weekends of my labor... And I end up with a 400hp FWD saab of even more questionable reliability than stock (?!)

A 400hp car was kind of impressive...... 15 years ago.

If it comes down to it, I'll take a TD04.

[Fast_Ed]

I'd give the waste gate linkage/stuff a closer look.

Can you force it closed for testing purposes? You could free rev and listen for the turbo. Or drive with it and not exceed some RPM where it would be clear if it was working or not, but not so high that you'd be over boosting. Maybe 2500 rpm (or whatever the soonest RPM is that you think the waste gate would normally begin to open).

I plan to give it a look. Part of the reasoning of taking the down pipe off to look at the turbo is that I can check the wastegate as well.

I can easily keep the WG closed by disconnecting the vacuum hose to the actuator.

There is a fuel cutoff that happens if you overboost the car. My BPC (Boost pressure controller) valve failed at one point, and I got to experience this phenomena. It's quite unpleasant, but beats the alternative.

[kevm14]

And the kicker: The Viggen engine is only good for 300hp, a number than has been reached on the stock TD04 many times. To really use the GT28, I'd need to build a new engine (b234 bottom end with the current Viggen head would do). $1000 to buy the bottom end and parts to freshen it.

You need to build a new engine if you want over 300 hp??? That can't be right.

What tuning options are available to a DIY person? Even if you turned up the wick on the TD-04, you'd probably want a wideband and the ability to adjust the calibration.

[kevm14]

I can easily keep the WG closed by disconnecting the vacuum hose to the actuator.

I guess depending on the WG system issue (if any), ensuring it is really closed may be difficult.

There is a fuel cutoff that happens if you overboost the car.

You have to love the factory approach. Too much boost could lead to a lean condition. The solution? Pull (all the) fuel. The aftermarket would elect for an ignition cut instead. But then your $9,000 (approx.) cat converter would fail after 3 crank revolutions with no ignition.

(some quantities adjusted for hilarious intent)

[kevm14]

I still don't understand why this car is such a pain in the ass.

On the other hand, having to replace a turbo isn't totally unheard of. It has been 160k or whatever. Maybe you should just do that (if that is the problem).

[Fast_Ed]

I still don't understand why this car is such a pain in the ass.

Me neither....

I bought it with the intent of keeping it forever. Unfortunately, I'm not sure it's makers intended it for that purpose...

[Adam]

I still don't understand why this car is such a pain in the ass.

On the other hand, having to replace a turbo isn't totally unheard of. It has been 160k or whatever. Maybe you should just do that (if that is the problem).

The turbo was already replaced once.

That wastegate actuator did look terrible when I reassembled it. Also the clip that holds it to the wastegate on the turbo was.....expertly crafted...

[Adam]

Knowing what is inside one of those now and how to take it apart, you could easily pull it off and disassemble it for inspection.

[kevm14]

The issue he's having now, I think I am putting my money on a wastegate issue. I don't think the turbo is seizing and then unseizing.