extreme bogging?

[JScoob]

I don't know what to call it. So I'll just describe it and hopefully someone has a better idea of whats happening...

I'm driving on the freeway, under some mild boost ~ 1 bar in my wrx (not stock, btw). My 2D is set to engage at 1/2 bar and I'm running a dual 0.8 and 0.9 nozzle on a 10% toluene mix on a 2.5L. My WI mix is 50/50 meth/water. I've been running on this for over a month without problems.

Then just last night, right after I exit, I stop at a light. Car is fine, idles ok. As the light turns and I try to accelerate, I can't. Its like the car is bogged or something. The engine has trouble turning over, I can feel 1 or more cylinders not even firing.

All the while a huge cloud of smoke is coming out of the tailpipe, I have just enough momentum to limp to a parking lot. Interestingly enough, no Check Engine yet. I turn off the engine and let it sit for a bit. I get brave/stupid and decide to try to start it. It doesn't like it...at first, but then the engine got a little better and I just sat there revving it until the engine sounded perfectly normal. I drove around the lot for a few minutes and decided I would risk continuing on...and I did so, everything was fine.

Now...my question is, wtf just happened to my car? My first guess is that I'm injecting too much water...ok. Fine. But why was the engine fine for over a month? Why all of a sudden now throw the hissy fit? Anyone else run into this problem?

[dc96819]

Sounds like the pump was on at the wrong time :?:

[JScoob]

You mean the injectors?

I could see that happening somehow, since the fia2 taps an injector signal from the ECU - maybe its grounding out somehow and causing an injector to fire when it shouldn't.

Any comments from the aquamist experts?

[Richard L]

dc96819 was very accurate, the 2d system must be injecting water where it shouldn't. check all the wiring.

The brown wire that goes into the HSV should not be grounded until injection start.

[JScoob]

Richard,

I will recheck the wiring later tonight.

While I don't discount the possibility, I do have a water pressure gauge and it didn't show any signs of injecting while boosting. I do have an accumulator, so I guess it could have injected for the duration of the accumlator charge - but I can usually hear the gauge needle fluttering even then, and I don't quite remember hearing it.

Still, its weird that it would only happen this time, but be fine for many, many hundreds of hours of driving...Keep in mind that everything is fine now. I didn't touch or fix anything. I can drive it on hard boost, WI engages as it did before, no loss of power or anything. Its like it never happened. This makes finding the problem all the more difficult.

What happens if the pressure switches fail? Have you heard of cases of random switch activation when not at target boost?

[DuMaurier 7]

Why do you use methanol ? , are you are at the limit with your fuel ?. reason I asked is that I ran the same 50/50 meth / H2O mix and every time it came on the car would bog and sometimes foul the plugs , on the wide band the ratio would go extremly rich . I have found (with my motor at least ) that an overly rich mixture isn't necessary or appreciated , in fact the leaner I went the better ir ran !!. I know some guys use that mix when their fuel suytems are maxed out , so its like they have a secondary fuel system providing the added enrichment . For cooling and detonation control , nothing is better than streight (pure ) water .

[hotrod]

A random failure like that usually indicates a faulty connection or something simular. What happened over the previous15 - 30 minutes. Did you hit a bump or dip hard, go over rough RR tracks etc. Sounds to me like an intermitent short is triggering the system when it should not.

I had a recent experience like that only in the other direction. My WI suddenly quit spraying ( I have a tell tail light that comes on every time the boost sensor switch closes, so I knew immediately I was not getting any spray when I was clearly in boost --- I trigger at 8 psi)

I drove home easily and when I checked things I found the weight of my wires had pulled the bayonet connectors (one of them at least) off the relay.

I must have hit a bump hard enough to knock the connection loose.I put the bayonet connector back on, and rigged a support for the wire loom and no more problems.


On a pound for pound basis water has more cooling power than methanol, but methanol mixes will cool to lower temperatures than water alone will. At typical humidities water alone will cool things about 20 -25 degrees F (at atmopheric pressure) where 50/50 methanol will cool the air stream something like 42 deg F. In the post turbo/pre intercooler part of the intake system where temperatures are well above the boiling point of water, --- water alone will cool quite a bit until air temps get down to 212 deg F. or so and the air stream gets to 100% humiditiy, then you get no further cooling from the water spray by evaporation.

Larry