Heat Soak/open closed loop.

I have an 03 MSP, SMIC, GT28RS Running ~8 psi MAF before the turbo. It has a cold air drop in the front corner.

What I have noticed, is that when the car is just getting up to opperating temp. (So I begin using boost) The car is Blazing fast. Spinnin tires in first gear etc.

After a bit the car is a dog, will not even break the tires in first gear. It is noticably slower, as my friend even commented.

I was wondering if this was a heat soak issue? (because the car will not notice how effective the intercooler is ? (because the IAT is before the turbo))

Or I thought maybe it was a closed/Open loop issue, But if so, then when I tromp on the pedal and it goes to open loop, I should be running whicked fast again? and it is not.

Sometimes I will accelerate in 2nd gear and get my boost, but no zoom at all. ? In this circumstance it feels like the more psi i push (the more pedal I use) the more the car resisits and retards the timing...

I am wary of the reflash... and don't know if the driver before me used it or not etc.

I am going to look into some thermo probes for the intercooler, and possibly reading my IAT while I am driving.... Any suggestions?

Is there a way to tell if the car is in open/closed loop? can I probe some signal and get a yes/no for that?

Thanks

-Kyle

im pretty sure that if your car was flashed there would be a sticker on the drivers door sill, next to the one that has all the weight information and what not.
atlest there is one on mine, stating that it is an "authorized" modification.


do you have a wide band?

No, I do not have a wide band, guy before me used the short band on his gauge probably because he thought it "looked cool"
I do not know where to start looking for a good one, Innovative looks like a good buy... Any suggestions

I got some thermocouples from work today, I should be able to check for heat soak?

My big question is still being able to see the closed vs open loop, and possibly finding something to tap into that will give me an output (say 0v or +5v) to tell me if I am in closed or open loop....

I'm sure you are experiencing a combination of heat soak and the bad tune. A wideband should be the first thing on your list and yes I have heard nothing but good things about the Innovate wideband. Either that or the AEM.

I have the exact same problem with my stock set-up. I was convinced it was a heat soak issue. I picked up another stock msp intercooler and switched it out after running my car for ~15 mins. Ran a lot better until the second intercooler got heat soaked. Just my $0.02...

Same exact problem here, and I have a FMIC and stock turbo running 9 psi. Every time it does this my wideband is pegged at 10.0:1 AFR. When it doesn't bog It stays in the 11's. The ECU has to be pulling timing as the car just falls on its face.

Well if we think this is a heat soak issue, has anyone installed a Cry02 system? C02 spray to cool the intercooler.

As if this solves the problem, then it is definitaly heat soak as root cause... (seems very plausible from callITaDay)

My other question then is.... if it is heat soak, how does the engine notice? (sorry I was always a NA person before ) because the IAT is pre-turbo... or is it noticing the presence of knock (with the higher temps) and pulling timing? in that case i should buy a knock sensor? (Like the turbo xs one) or would that not notice it...

get a wide band, get a controller of some sort, get a tune/ tune your self.

these cars heatsoak very quickly, and they have a horible tune.

im sure you could completly eliminate the soak problem. and your car will still run like crap.
just be glad you dont live south of the mason dixon, you got it easy. lol

I still feel that this is a open/closed loop issue
Bat out of hell fast (seems to be b4 the engine/o2 sensor is warmed up)

I have checked this with temperature probes before and after the SMIC, (don't know if it is aftermarket or no?) at idle the system cools itself, when boosting the system cools very well compared to the hot pipe.

driving will have the bottom side nice and cool, The top will be blazing when boosting (upwards 115 degrees F) but lower cold pipe is nice and cool. No joke, go boost around and stop and reach under and touch the cold pipe.... mine was air temp ~ 85 (only did this because I had the probe on it ) I moved the probe next to the intake, and can report on it tomorrow...

worst case that I saw, boosting for a while getting onto the freeway... 20 degrees cooler on cold pipe than the hot pipe...

Anyways I will be looking into buying a O2 meter soon to check that.... but definitely not a heat soak issue....

My intake temp sensor is by the MAF sensor (injen cold air), since it is higher in the engine bay, will this be reading hot (engine bay) temp? if so can I do a resistance offset or just jumper a resistor in there? idk, just thinking how to remedy that...

f1yen said:

I still feel that this is a open/closed loop issue
Bat out of hell fast (seems to be b4 the engine/o2 sensor is warmed up)

I have checked this with temperature probes before and after the SMIC, (don't know if it is aftermarket or no?) at idle the system cools itself, when boosting the system cools very well compared to the hot pipe.

driving will have the bottom side nice and cool, The top will be blazing when boosting (upwards 115 degrees F) but lower cold pipe is nice and cool. No joke, go boost around and stop and reach under and touch the cold pipe.... mine was air temp ~ 85 (only did this because I had the probe on it ) I moved the probe next to the intake, and can report on it tomorrow...

worst case that I saw, boosting for a while getting onto the freeway... 20 degrees cooler on cold pipe than the hot pipe...

Anyways I will be looking into buying a O2 meter soon to check that.... but definitely not a heat soak issue....

My intake temp sensor is by the MAF sensor (injen cold air), since it is higher in the engine bay, will this be reading hot (engine bay) temp? if so can I do a resistance offset or just jumper a resistor in there? idk, just thinking how to remedy that...

Click to expand...

My MSP has been doing the same for a long while, and I still can't figure out what the problem is after changing out almost every sensor. It makes sense that the MSP ECU would be programmed to account for the difference of the intake temperatures pre and post intercooler, at least for the efficiency of the stock IC. Are you using an unflashed ECU by chance?

I checked the door sill, not listed, but read today that it might also be in the engine bay? But I can assume no to the flash because it stumbles...

I'm starting to think that this is a fail safe feature built into the non-flashed ecu map as I don't remember having this with a flashed ecu a few years back.