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Discussion Starter #1
Several months ago I needed to rebuild the motor in my 2000 Saab 9-3. the place that rebuilt the motor, for the most part does nothing but rebuilt motors, one of the motors they were working on was the size of my 9-3. Anyway the block of my 2.0 motor was pretty much toast. so they went to the yard to get another one but the 2 that came in were also junk. the third one was rebuildable so they did there thing. Well it turned out not to be a 2.0 block but a 2.3 block. I do not know what all the differences are between the 2 motors but it all went back together using all the electronics and head from the original car.

There is a serious increase in power now, (hard to pull out fast without lighting up the tires) all in all it runs good, there is an occasional stumble and I am throwing a P300 code. also if I am running highway and get off at an exit. if I push in the clutch and let it coast for 100 yards or so the engine will stumble and sometimes stall with the oil pressure flickering on.

neither the motor guy or my main mechanic have been able to pin down the problem. it is easy to prevent it from stalling by just slowing down with the clutch engaged and putting it in closer to stop and it is fine with its near normal idle. I do not think the stumble is related to the plugs or wires as the P300 code tells me it random. so I am guessing it is further down the line. My question is would the ECU for a 2.3 motor be different from a 2.0. can anyone think of what may be causing the problem or should be changed..
 

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IIRC 2.3 blocks are the same as 2.0 blocks - only stroke changes.
Is that all that was used from the 2.3 - the block? If so - I dunno man.
If they used the crank/rods from the 2.3 donor motor you'll need a tune (ecuproject.com) for the .3l difference.

The ecu is physically the same between the two but the software differs to allow for the 'extra' .3l.

Good Luck
 

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Several months ago I needed to rebuild the motor in my 2000 Saab 9-3. the place that rebuilt the motor, for the most part does nothing but rebuilt motors, one of the motors they were working on was the size of my 9-3. Anyway the block of my 2.0 motor was pretty much toast. so they went to the yard to get another one but the 2 that came in were also junk. the third one was rebuildable so they did there thing. Well it turned out not to be a 2.0 block but a 2.3 block. I do not know what all the differences are between the 2 motors but it all went back together using all the electronics and head from the original car.

There is a serious increase in power now, (hard to pull out fast without lighting up the tires) all in all it runs good, there is an occasional stumble and I am throwing a P300 code. also if I am running highway and get off at an exit. if I push in the clutch and let it coast for 100 yards or so the engine will stumble and sometimes stall with the oil pressure flickering on.

neither the motor guy or my main mechanic have been able to pin down the problem. it is easy to prevent it from stalling by just slowing down with the clutch engaged and putting it in closer to stop and it is fine with its near normal idle. I do not think the stumble is related to the plugs or wires as the P300 code tells me it random. so I am guessing it is further down the line. My question is would the ECU for a 2.3 motor be different from a 2.0. can anyone think of what may be causing the problem or should be changed..
Address the flickering oil light immediately or you'll be very sorry. It could be a bad rebuild where the oil passages weren't cleared properly or the oil pressure reducing valve is scored and stuck in an almost closed position. Other possibilities may be clogged oil pickup screen with debris circulating after the rebuild or even a bad oil pump.
 

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I am going to go out on a limb here and say absolutely the tuning is different from a viggen to a 2.0... sure the block is the same but the stroke changes.. doesn't that seem like it could be an issue? that means that the ECU is going to inject fuel and fire the spark at the wrong time in the sequence when the piston is either too low on the compression stroke or on the power stroke. either way this is bad news. you need to have that ECU re tuned to run for a 2.3l engine. Im actually surprised it runs, but the difference must not be bad enough. Regardless, re-tune that ECU pronto, or at least get the Viggen ECU out the the donor car and have it married to your vehicle.
 

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It scares me that the mechanic would actually do this without knowing the difference...
 

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Yeah even to someone without a ton of knowledge of the specifics about this **** it seems pretty obvious that the computer would need to work differently.
 

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I don't think timing/sequencing (due to stroke differences) will be an issue, as the ECU will be able to sense crankshaft position etc. I would guess fuelling/ignition would be the main problem if the ECU thinks its a 2.0. Good problem to have though (i'd rather have a bigger engine than a smaller one!!!)
 

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Discussion Starter #10
Ecu

So you think there is a big enough difference between the ECU for the 2.0 and a 2.3. I was told that the setup is the same but if that is the case, the ECU used on the 2.0 and the ECU used on the cars with a 2.3 would be the same..
 

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So you think there is a big enough difference between the ECU for the 2.0 and a 2.3. I was told that the setup is the same but if that is the case, the ECU used on the 2.0 and the ECU used on the cars with a 2.3 would be the same..
Yes its a huge difference. Every single map in the ECU is going to be different pertaining to idle control, boost control, ignition advance/retard control, fueling, warm regulation, etc.

The physical ECU is the exact same between a T7 2.0 and a T7 2.3. It's only the parameters loaded in the software on the maps that differs. Get a standard 2.3 tune on it for a b235 and you'll be much better.

Also get that oil issue figured out before you toast another motor.

Find a new mechanic btw too.
 
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