Car runs stupid lean after using water/meth injection

[turboAWDfanatic]

I just installed a Devil's Own meth injection kit. Before tuning for meth I wanted to test it out with just water to see that the trigger system and fail-safe that I set up is working. I flip a switch to activate the pump, it is triggered to flow by a hobbs boost pressure switch, and it works, but immediately after doing the water injection the car suddenly runs EXTREMELY lean at cruise and idle. The car barely runs and AFRs read between 18.0:1 and 21.0:1. This is after only momentarily using the water injection system. Over the course of an hour, the AFRs slowly return to normal.

Looking back, the exact same symptom showed up once after accidentally driving through a deep water puddle at a good clip during a rain storm.

I am using a speed density setup with a Zeitronix 3.5bar MAP sensor and a GM IAT. I am tuning it with TunerPro on an Ostrich chip emulator. The MAP sensor is threaded directly into the back of the intake manifold next to where the brake booster hose nipple is and the water injection nozzles are in the intercooler piping between the BOV and the throttle body. With speed density the only two major variables in what AFR you are at are the volumetric efficiency of the engine and the reading of the MAP sensor (with IAT adding a small change). With that in mind, I can only think that the surface of the MAP sensor getting wet is causing an inaccurate reading that would throw off the tune, but I contacted Crock at Zeitronix and he said that moisture getting on the sensor inside the intake manifold shouldn't cause a problem at all.

Is there anything I'm overlooking? Could something else be getting moisture on it that would have an affect on the tune? I am certain that introducing water with the meth injection setup is what's triggering the lean condition because it is very repeatable and only happens after triggering the pump to inject water.

 

[jlr2196]

I'm running same tuning setup with the AEM meth kit instead & the only thing I can think of is where is your IAT sensor located. Perhaps it's getting wet and causing your IAT enrichment to go lean? My IAT is located pre-meth inject nozzle.

 

[BrokenTsi]

It sounds like your causing puddles of water to pool up in the intercooler pipes. If the water isn't fully atomizing before hitting the injectors, it may be interrupting the fuel injectors somehow. Perhaps your nozzle of choice is too big? Maybe the nozzle is dripping after its being introduced into the engine? Did you weld a bung on the charge pipe? or did you tap/thread the pipe for the nozzle? Is it a progressive kit? or is it spraying full bore as soon as its on?

Try using a few bottles of HEET instead of water. you should see the AFR's get very rich when you arm the meth kit. I'm just spitballing ideas, I use meth injection myself and have not had this issue.

 

[turboAWDfanatic]

I'm running same tuning setup with the AEM meth kit instead & the only thing I can think of is where is your IAT sensor located. Perhaps it's getting wet and causing your IAT enrichment to go lean? My IAT is located pre-meth inject nozzle.

Forgot to mention, the IAT is before the nozzles, so it doesn't get wet at all.

It sounds like your causing puddles of water to pool up in the intercooler pipes. If the water isn't fully atomizing before hitting the injectors, it may be interrupting the fuel injectors somehow. Perhaps your nozzle of choice is too big? Maybe the nozzle is dripping after its being introduced into the engine? Did you weld a bung on the charge pipe? or did you tap/thread the pipe for the nozzle? Is it a progressive kit? or is it spraying full bore as soon as its on?

Try using a few bottles of HEET instead of water. you should see the AFR's get very rich when you arm the meth kit. I'm just spitballing ideas, I use meth injection myself and have not had this issue.

I had bungs welded for two 007 nozzles, and it's not progressive. This thing is, the lean condition results *after* activating the water injection, even if it's only briefly for one pull, and it then continues to run super lean for over an hour.

 

[BrokenTsi]

Interesting. Take off your intercooler pipe, inject your water while looking inside the pipe, and see if its being deflected against the inside of the bung and check to see if its dripping afterwards.

Some meth kits want you to thread your nozzle directly into the thin walls of the intercooler pipe so that the nozzle is right in the path of the air. Something to think about....

 

[turboAWDfanatic]

Assuming there is an issue with how the nozzles are mounted, what would cause the car to run so lean for an hour?

 

[turboAWDfanatic]

FOLLOWUP:

I moved the MAP sensor, which was previously threaded directly into the intake manifold, about 6 inches away by using barb fittings and some hose. I made the hose take a 90 degree turn. There is no longer a lean condition after triggering the water injection. I guess it was the MAP sensor getting wet that was causing the problem.

Thanks for the input. I'm still going to pull the section of the IC piping with the nozzles just to check the flow to see how it's doing.

 

[BrokenTsi]

Thats awesome you fixed it. I wouldn't have thought of that since I also have my map sensor threaded directly into the intake manifold and I don't have this issue.