Carwash almost killed my car
 

Not really, but tbh I'd like some insight if anyone has any ideas.

Car runs fine normally, never had this issue. Went through a car wash after getting gas, car sounded like a cammed out V8 (like if the map line were to be disconnected, but it wasn't). I start checking the car immediately in the parking lot, and the engine just dies.

I turn the key off and on, the PFC Commander freezes at the Apexi flash screen. I hear an electrical noise under the UIM and near the relays on the strut tower (almost like an electrical creaking sound). Car will crank and not start. I let the car sit with the hood up, eventually the PFC gets past the splash screen when I turn the key off/on, but it shows no values for anything I go to look at under monitor, they're all blank. My tach starts jumping around, my exhaust temp light flashes on and off randomly, the whole car is just losing its mind at this point, then gradually stops. At this point my battery is dead. I wait an hour-two hours for a tow truck, I notice that the noises/behavior have stopped, The PFC starts displaying sensor values again. A friend arrives and jumps me, and the car starts up perfectly fine.

Ive had the car through numerous car washes, and this has never been an issue, but it sounds to me like something definitely got wet. Car has its wheel well liners.

Anyone have any idea of what may have happened?

Refresh my memory, didn’t you have the relocated battery ground going down to the rear subframe? It sounds like the battery shorted. The stuff you’re describing happens when the voltage drops below 9v.


~ GW

Something got wet that wasn't supposed to, you'll have to go through and check things. Also worth figuring out why it did that when it got wet, if a car wash can do that a hard rain storm on the highway can do the same thing.

Dale

Is yours a sunroof car? I had water get in my passenger footwell area a while back and I had to clean out the drain holes. I really don’t remember much else though tbh.

I'd never... put ... my... car... through.... a... car... wash...

Nope, my grounds are all factory as far as I know.

That's what I figured, I was curious as to where I would start. That's never happened in a year+ of car washes, but it's definitely a concern now.

Mine is thankfully a non sunroof car.

Is ANYTHING in your FD's electrical system modified? And by modified, that also includes just relocating or re-orienting components from their stock positions (e.g., some V-mount kits make you have to relocate & re-orient the relays up front). Doing so may cause water to be trapped & accumulate in places it normally wouldn't, which can cause electrical headaches and accelerate corrosion of said components.

My best educated guess is that water got someplace it shouldn't have and created a parasitic current path to ground - enough current draw to cause a system wide voltage drop down to where the ECU would go wacky, but not enough current to blow any fuses. Troubleshooting to recreate the issue will be difficult, but perhaps you can isolate it by strategically using a hose or pressure washer to direct water to various parts of the car in sequence while it's running at idle in your driveway to see if the problem reoccurs? That might help isolate to the susceptible wiring or components.

What kind of car wash was it? Does it spray water from the top, sides and underside of the car?

Car wash spray water up from under and it can get to a lot of places a normal rain can't, your starter will get wet and the motor itself where the big ground go. You still have the belly pan and transmission pan on?

It was a touch free that to my knowledge only does the sides and top. I don't believe it sprays the undercarriage.

I'm going to get it up on a lift hopefully Monday when I get it to Pettit Racing and get a look.

There's a touch-free place by me that does the sides/top only if you choose the cheapest option - opt for the next $ step up, and it does the undersides too as you drive into the wash bay. I'll take my daily there when the weather is too cold for a hand washing, never tried it with the FD though.

Sounds like you got water in one of the relays, probably the egi main one or circuit relay. They act super goofy when that happens.


~ GW

JDM has a sensor that senses when you take the car through the car wash and throws the car into limp mode.

Read your manual. It says, if the car is dirty, take it to the dealer for detailing.

:nod:

https://cimg2.ibsrv.net/gimg/www.rx7...c0be21705b.jpg

If in limp mode how can you take it out? Im trying to track down this random electrical issue and idle issue and am at my wits end so ill try anything

Just for S&G, I threw that into google translate and it did not disappoint...

I was just joking with the owner, as we had been in close contact in those days. Did he mention he did not have his undercover on?

Akagi is just joking as well.

Or maybe Google translate is playing AI games.

The text roughly says "if you are driving and there is a smell, or an odd sounding noise, get to the dealer to have thee car diagnosed. In such circumstances, if driving the car is unavoidable, drive with the windows open."

This one is more fun. Mazda drops the usually polite manual speak and gets to the point.

Heading says : WATCH OUT FOR THESE THINGS!

Basically text says: "don't add aftermarket stuff that changes the way the car functions or operates. You have no way of sufficiently understanding how we have designed this car."


https://cimg8.ibsrv.net/gimg/www.rx7...37f820c06f.jpg
"don't f*ck with it!

Limp mode
 

Limp mode for life!

JDM does not have a check engine light. The ecu monitors for about 50 malfunctions, and in many instances will switch to 'limp mode".

Limp mode makes the car run very poorly and is meant to signal to the owner to get the car to the dealer.

The dealer has/had a diagnostic tool for reading the "codes" the ecu shows to identify the problem.

As it is hard to find a dealer outside Japan (or maybe in Japan) that still has the diagnostic tool, you have to learn to do a DIY code read.

This is done with a simple led light (with resistor) and a jump wire, both of which have their wires inserted into specific terminals in the diagnostic plug (front left of engine bay in front of the shock tower).

Hook those wires up right and the ecu will cause the LED to flash. Count the long and short flashes then look up the issue in the FSM.

Codes in the USDM FSM largely are the same as for JDM FSM.

Anyone new to JDM should look into reading codes at an early stage.

Before you start swapping stuff out in search of a fix.

Codes will only work with the stock ecu.

After market ecu may have other ways to show faults.

If you have a stock ecu, but have done a lot of deletes (like emissions solenoids) the ecu will throw the car into limp mode.

You sometimes can fool the ecu by putting resistors in where the solenoids used to be (assuming your harness is still intact).

Disconnecting the battery for a period, or just turning the car off, might get the cu to reset.

But it will go back into limp mode, the next time it does a diagnostic cycle.

If it seems you are seemingly stuck in "limp mode for life", seriously consider replacing the ecu with an aftermarket alternative.

Thankyou! I need to look up how to do the diags wothout a key specifically and correctly. I suck at wiring though. I have a power fc but it was set up by my mechanic while I was deployed so everything is a crap shoot since he won't come out and help with the issue. I'll try and look further now

There are all kinds of threads on here that deal with tuning the Power FC.

If you have a Power FC, I suspect you will not be experiencing limp mode, as that is a stock ecu thing (afaik)

Guy in New Zealand sells a tool called a datalogit that you can hook up to your laptop and analyse the hell out of the Power FC.

It may even have correcting software.

It expensive, but so is spending hours guessiing what is wrong.

Reminds me of a car wash experience I had.

In the '60's I had a red Triumph TR4 which I (stupidly) took to a car wash. They had a plastic rod that rubbed along the left side of the car as it passed through attached to a sensor to tell the equipment a car was still there. Unfortunately, there was a sharp edge on it and it made a deep scratch in the LF fender. I almost got arrested arguing that the car wash caused it. They wouldn't do anything about it except deny it was their fault. Since then I only take cars that are not special to car washes (unless it's a DIY one) and then only when we are travelling and the car REALLY needs it..

This is all good warning. I have been running through the touchless wash ($25) from time to time specifically for the underspray, in order to get the winter road salt off.

Might need a new plan........