Aradin

I'll try to keep this short.

Installed an AEM V2 water/meth kit(has a check valve built in the nozzle to prevent siphoning) a couple weeks ago, only been through about 1/2 gallon so far. Using 500cc nozzle. Retuned it and only tuned the fueling/timing in boost. Vac/cruising/idle maps were never bothered obviously. Meth is set to come on at 5psi and max at 25. Car rarely gets beat on in town as it is my daily. The below issues were not after any hard pulls or anything, just normal cold starts and getting back and forth to work.

Past couple days the car has been cold starting hard(low rpm and off-the-gauge rich until I blip the throttle then the idle will go up to the cold start rpm and be fine).

If I try to drive it while it's cold, the AFRs are extremely erratic. Using an AEM wideband, it will go from --- on the rich side to 16/17/--- on the lean side when driving and alternate randomly given the amount of throttle it's getting. It will never completely hesitate but you know how you can feel the loss of power when you're overly rich or lean? I can feel that in and out as I watch the gauge dance around. It will steady out at times and run like it used to until it decides to randomly freak out again.

All these issues are not prominent when the car is warmed up. AFRs and driveability are exactly as they should be. idle, part throttle/cruising and WOT are all spot on as they were.

I'm using a GM 3 bar map kit I got from phearable. Is it possible the meth/water mix has damaged this or is causing issues? What else should I be looking at? Fuel pump? TPS?

wantboost

iTrader: (2)

There isn't any airflow through the sensor, it only reads pressure. so the methanol should never reach the pressure transducer.

your issue is elsewhere. also is your peak boost 25psi? you should really the methanol injection rate at it's maximum or you won't get the full benefit

Aradin

Yeah. I peak at 25psi. I was running 18 on pump and turned it up to 25 on meth/water.

Okay, well that rules out the map. I guess I'll have to do some diag on it but it's difficult because it's solely a cold start issue. I even double checked the cold start parameters in my tune and they're all the same as before.

If I sit a light when it's cold and it idles for more than 30 seconds it will start to load up bad until I blip the throttle again. I can watch the gauge go from 14 AFR down to --- on the rich side. Injectors are PTE 680cc. Bought them used a few months ago but had them cleaned and flow tested before I installed them.

stupidhard

do you need the meth at 5psi?

if you couldn't boost higher than 18psi on pump gas, I would maybe set meth to come on at 15psi.

I would look at the fuel pressure regulator, iacv, pretty much anything that would manipulate how the car runs when cold.

-chris

Aradin

The thing is that it's a progressive controller so it scales with boost from the "start" setting to the "end" setting. It's not pumping the full volume at 5psi, it starts with a little and continues up to the full volume at peak boost. The sooner you start spraying, the sooner you get the benefits. So, with the kit I was able to not just get more peak power, but increase power across pretty much the whole powerband in boost.


Anyhow I haven't really had this issue much since I posted this thread which is why I never bumped it. I may have inadvertently fixed it and don't know it or it was just a fluke.

Dark_Teg

Be very careful using water/meth to extend your fuel system. I blew up my Mustang when the AEM pump went out. They replaced the pump but that did little to console me.