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Discussion Starter · #1 ·
So I replaced my ECU today on my '06 9-3 2.0T (Thank you Brew City Boost! Stage 1) and all of the problems that I'd had have disappeared. My A/C works now, and the car has dramatically reduced the number of personalities that it has. It has reduced to only 2 now... hot and cold.

When the car is cold, it runs amazing! It pulls strong and hard and sounds amazing. But then after about 20mins, it seems to lose some of the performance just a bit. It goes from Wow to "meh"... knowing that there is nothing wrong with the newly upgraded ECU, what direction should I be looking to figure out this mystery?
 

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Discussion Starter · #3 ·
Diggs.... I appreciate the suggestion, but do you mean remove and replace, or is there some type of troubleshooting that can be done? I'm new to this whole intercooler/turbo thing. The car did the same thing again this morning... ran like a beast when it was cold (I was testing to see if it did the same thing as yesterday) but then after engine temp got up to normal, performance dropped off. When it's cold, it seems like it relies more on the turbo, but when it's warm, it relies more on gear changes for acceleration... and not nearly as impressive.
 

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I believe He is suggesting upgrading your intercooler. The engine could be getting heat soaked and the intake temperature is too high so the ecu regards timing and reduces power

Sent from my LG-H872 using Tapatalk
 

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I believe He is suggesting upgrading your intercooler. The engine could be getting heat soaked and the intake temperature is too high so the ecu regards timing and reduces power

Sent from my LG-H872 using Tapatalk
Yup. Evo 8/9 intercoolers fit well and are pretty cheap used.
 

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Discussion Starter · #6 ·
So is there no need to take a look at the current unit? The car is mostly stock with only the Stage 1 updrade to the ECU. I know that since it runs well when cold then not so well when hot, this should remove doubt about the unit working at all. The suggestion that the engine temperature is "tricking" the ECU makes sense, so upgrading the intercooler should work. I'm just trying to understand why it would need an upgrade with only the Stage 1 mod? Seems strange to me.

Another issue as well, when the engine is cold and the turbo seems to be working it's best, I notice that there are some hesitations all through the RPM range. It pulls very hard, but with very short, instantaneous "blips"... like stutters. Any clue what this might be?

I appreciate everyone's patience... all of this turbo stuff is new to me, so I sincerely thank you for your help.
 

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Even stock without tune you can have these issues ... Ambient air temp outside has a big impact on it as well. As for the sputter I would try running a fuel system cleaner through it. I had a similar issue on my 07 2.0T. One of my injectors was clogged. Mine was probably more serious though ... Couldn't accelerate 90% of the time without a hard shutter and ended up burning a hole in my cylinder wall because the injector failed

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The suggestion that the engine temperature is "tricking" the ECU makes sense, so upgrading the intercooler should work. I'm just trying to understand why it would need an upgrade with only the Stage 1 mod? Seems strange to me.
It is not the engine temperature per se and by itself that is having the effect you describe. It is the temperature of the charge air that affects performance more. And the temperature is not tricking anything - the temp sensor's function is to report to the ECU what the actual charge air temp is so that the ECU can control combustion to avoid bad things like knock.

If you are starting with ambient air temperatures in the 90s or so, imagine what the air temperature must be by the time that air has been compressed to 20ish psi and pumped through a lengthy tract of plumbing in close proximity to and abutting a hot engine?

When air is heated, it expands, meaning that the concentration of O2 molecules per volume is lessened. O2 is REQUIRED to support combustion. The way forced induction engines try to combat this negative effect of compressing the air, which unfortunately heats that air, is to provide additional cooling to the charge air. This is done by forcing that charge air through an additional heat exchanger called the intercooler.

So, even without powerful engine management in play (and Trionic 8 is very powerful engine management) and all other things being equal, an engine receiving a cooler air charge will deliver better performance, since there will be a greater density of O2 molecules in a given volume to support combustion.

Now, when you factor in engine management, the difference can be substantially greater.

Since T8 tightly regulates ignition timing, fueling and boost in its attempt to deliver the greatest performance without deleterious consequences to the engine, any factor or parameter that contributes to the onset of knock will cause the ECU to react in an attempt to ameliorate knock. It begins by retarding ignition timing (advanced timing, up to a certain maximum point, contributes to volumetric efficiency and greater power output per air/fuel charge present). Performance suffers as a result, even more so than in an unregulated engine like we had back in the day before we had ECUs.

Among the factors that contribute to the onset of knock are combustion chamber temperature and air/fuel charge temperature. Cooling the air charge after it has been compressed by the turbocharger directly lowers the air charge temperature and indirectly lowers the combustion chamber temperature. The ECU can thus keep the ignition timing advanced a few degrees more than it could without an efficient and effective intercooler and performance is thus improved.

Another thing of tremendous importance to keep in mind is that higher octane fuel is massively important in delaying the onset of knock in just about any engine.

If you upgrade your IC and run the highest reasonably available and affordable octane fuel, you may discover that your tune delivers more additional performance than you ever imagined.
 

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Discussion Starter · #10 ·
Gentlemen,

Thank you SO much for all of the information (and education). Sounds like an upgrade in the intercooler is indeed a good idea, along with running higher octane fuel. I will check into the injector/coil issue as well. THANKS!
 

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I HATE taking apart VWs. Everything always snaps or breaks, no matter what you're doing. Or at least the Touareg.
 

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I HATE taking apart VWs. Everything always snaps or breaks, no matter what you're doing. Or at least the Touareg.
So, it's not just me!!!!!

Thing's I've broken on the GTI:

-Coilpack connector
-Hood release connector
-Those little air blockers for the ac condenser (black things sitting beside the car)
-Tabs that hold in the IC
-SAI hose connector
-Tab on left side of bumper

Plastic things broken on the Saab? Nothing that I can recall.

:roll::roll::roll:
 

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So I replaced my ECU today on my '06 9-3 2.0T (Thank you Brew City Boost! Stage 1) and all of the problems that I'd had have disappeared. My A/C works now, and the car has dramatically reduced the number of personalities that it has. It has reduced to only 2 now... hot and cold.

When the car is cold, it runs amazing! It pulls strong and hard and sounds amazing. But then after about 20mins, it seems to lose some of the performance just a bit. It goes from Wow to "meh"... knowing that there is nothing wrong with the newly upgraded ECU, what direction should I be looking to figure out this mystery?
What are you using for gas? Shell 93 here and I notice a difference in the pulls if I don't use it.
 

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Discussion Starter · #19 ·
So, as many of you suggested, the warm weather certainly has an effect on the performance. In addition, the octane, as well. I have yet to upgrade the intercooler, but started using higher octane. This, in combination with the cooler weather for a few days, made a huge difference.

HOWEVER... I mentioned a "stuttering" during hard acceleration. This is not consistent, and when the stuttering is absent, it's a blast to drive. But I noticed the stuttering becoming more and more prominent, even during mild (or sometimes very little) acceleration. So, I went with intuition and replaced the coils.

Happily, the stuttering is gone... but so is the grin-inducing acceleration. Now it accelerates, but not like before. In fact, I drove it home for lunch today and it was running quite well... impressive, in fact. But knowing that the stuttering is an inconsistent problem, I went home and changed the coils during my lunch break.

On first leaving my house, it felt alright, but when I left the stop sign, there was hardly any response. Knowing from past experience, I disconnected the battery and took it for another drive. Same basic performance.

Taking it back to my garage, I connected the code reader, and found a code for "throttle sensor" and a code for "cam position". I erased the codes and drove it to work. The throttle position is no longer an issue, but the acceleration is very unimpressive. The turbo seems to be active, but I suspect it's the timing being retarded or something because it just doesn't pull like it did before the new coils.

So... stuttering gone, but so is acceleration. Is this because of the coils, or where do I look now? You guys have been a ton of help and I truly appreciate it!
 
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