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I have a 99 Saab 93 B204L and I just got a stage 2 Tune done off a tuner I met online. Finally get the ecu today and I’m making the same boost I was stock. He says that my bypass valve or apc valve may be bad or I just have really bad vacuum leaks. Whatever the case maybe I’m concerned. I have the same power and I’m 225 into a ecu that’s no difference. Dont exactly know if that kind of stuff could even cause it. He said t5 cars care a lot about vacuum if anyone could provide some insight or something that would be great.
 

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My observations are limited because I have a factory set-up but based on my reading .. I'll throw out some suggestions. I'm sure others will give specific tune advice.
1. do you get any specific codes that you can look up?
2. Have a look at your vacuum lines - and check for damage, connections & sensors off.
3. Is the sequence of the lines into/out of your waste-gate correct?
4. Is stage 2 associated with a changed air intake ie Cone filter etc - do you have that?
5. Check your DIC & MAF.
6. Fuel pressure and filter all ok? - Fuel good?
7. Spark Plugs at the right gap spec?
8. I'm not 100% sure about B204L - but boost is normally limited in 1st and 2nd.
9. Do you have a stock exhaust & Cat Back ?.. If you have a modified exhaust that could be throwing the tune, because it might be expecting normal vs a say a 3" Cat. (I thought normally 1 = software, 2 = intake + 1, 3 = Cat + 2.)

I'm going to ask a stupid question here - Did the tuner get your VIN and spec correct?.. Do you have a version you can roll back to?
 

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First, are you saying the tune was supposed to be 225 HP? Just want to clarify that. Also, if you're in the USA with a T5 B204, it's actually referred to as a HPT or FPT with 185HP stock. LPT was other markets at 150HP.

What Mort said is on target. You want a solid "stage 0" before upgrading. With any Saab yo buy, you should replace all the 4mm - 5/32" vac lines. Mort's #2 - Buy 10' of vac hose, silicone or rubber. Do one line at a time, one end at a time. Slice off fittings, don't pull. Also, Mort's #7: be sure you have fresh NGK plugs, BCPR7ES for that engine and tune, gap .9mm. In the USA you can usually get those at Advance or Autozone. Fresh air filter too ( although the tuners that say "need intake mod for stage 1 or 2" are wrong, per the dyno).

The next thing I'd try is pulling the W hose off the wastegate. You can plug it, but it doesn't matter, it's a pressure line, not a vac line. Find a long, lonely, highway hill that's empty of cars so that you can go WOT in 3rd gear. Of course, don't exceed the speed limit at any time. You can start at a lower speed and just go WOT. See if you hit fuel cut. You will know it... it feels like you hit a brick wall when the ECU cuts fuel from overboost. The engine will come right back when you let off throttle.

Let us know if you hit fuel cut. Also, Mort's # 9: Switch back to the stock ECU if you have it... then we can better diagnose a tune issue vs. a general engine issue.
 

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The T5 engines spec spark plug gaps at 1.0-1.1mm. The Trionic system is more than capable of producing a fat spark at those numbers...there is no reason to run a smaller gap.

After you replace all the hoses and PCV valve, if you still have the issue...

WIS has a pretty good method to check base boost (third gear pulls while riding the brake pedal...the brake lights keep the ECU from requesting anything but base boost). Once you establish correct base boost, then work on full boost. Boost issues can be a bear to find...one must proceed methodically to limit frustration.
 

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The T5 engines spec spark plug gaps at 1.0-1.1mm. The Trionic system is more than capable of producing a fat spark at those numbers...there is no reason to run a smaller gap.

After you replace all the hoses and PCV valve, if you still have the issue...

WIS has a pretty good method to check base boost (third gear pulls while riding the brake pedal...the brake lights keep the ECU from requesting anything but base boost). Once you establish correct base boost, then work on full boost. Boost issues can be a bear to find...one must proceed methodically to limit frustration.
Boxer: I'm going to respectfully disagree on the spark gap. While it may indicated a marginal DIC, I've seen misfires with the larger gap and seen them go away with a .9mm gap. My T5 was misfiring on a DIC with mid-life miles... it "fixed" the problem for the rest of it's reasonable life. Also, the tuners e.g. Nick T, etc, all recommend .9mm for tuned motors.
 

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Fair enough. I run my '99 HOT at the larger side of the factory recommendation (~1.1mm) and have no misfire problems. More boost might lead to ignition problems with the larger gap, but I'm skeptical that stages 0-3 are that radical.

I don't like decreasing spark plugs gaps unless necessary.
 
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