I have a 97 SE 5spd with a JWT ECU. I always fill up with super 93 octane only. I only go to reputible gas sations too. Well I let my brother borrow my car to go to AC in NJ and he fills up supposely with SUPER at a generic *** gas station. He calls me telling me the car jerks, and doesn't rev pass 3k RPM. The car didn't stop accelerating when it hit 3k rpm in any gear, even in neutral. The exhaust had a stank cheap gas smell too. So I connected the stock ECU and all was fine, the car went back to normal. Well this thread maybe useless but I didn't know that the JWT ECU will limit your rev to 3k with cheap *** gas.

 

yeah, IIRC, there was a sticker on my JWT that said to use premium only

 

FAIL.

 

Please people, the ECU cannot tell what kind of fuel your using.

If the stock ECU put the car back to normal, then your JWT ECU is the problem, not the gas.

 

werd...... or he put diesel in it...

 

Well I thought the ECU monitors signals coming from the knock sensor. I thought that the ECU will slow your ignition timing when lower Octane is detected to prevent pre ignition. Only one way to find out is filling up on super this after noon and re connecting the JWT ECU,.

 

Try it. But I dont think the ECU can tell if the gas has 93 or 87.

 

go ahead and let us know.i dont beleive that it knows the different gases though.

 

I don't know this ECU but I'd guess the following:

The JWT ECU has a map that does not have fuel/timing parameters for gas that is something less than 93. When the KS starts to send a signal to the ECU that it is detecting pinging and the ECU has to respond by changing the timing or the fuel mixture, it has nothing in its map that fits the parameters it is getting from the sensors. So it can't appropriately compensate for the lower octane fuel, and bucks and jumps as it traverses its map looking for something that's not there.

The Stock ECU has paremeters that cover the low octane situation. When it detects knocking, it has enough variability in its fuel/timing map to cover what the sensors are telling it, it retards the timing (most likely) and you, the driver, hardly notices, other than a slight reduction in power. FWIW, I have 190k on my Max and have driven nearly all of that on 87 pump gas.

Contact JWT and see what they say.

I'd bet that if you go back to the better gas you speak of and plug the JWT ECU back in, the problem will go away because it will no longer have to compensate for New Jersey Swampwater.

 

I contacted JWT they said the ECU doesn't detect the type of gas being used, but doesn't mean that the knock sensor isn't giving signals. However I reconnected the JWT ECU and started the car after burning almost ALL THE GAS out, I had some super in it before the trashy gas was put in. So now it was on Empty when I put the JWT back on. I started the car, and reved it to 7,200. The whole time the CEL was off the CEL never came back on until I went to the gas station filled up with 93 octane. I turned the car on, CEL came back on as it normally should have, and since then the car has been fine. Thanks to all for the education suggestive help.

 

I was hoping you were selling gas for 60c a gallon

 

 

lol

 

Dont ya love the customer service at JWT. Its NEVER their product at fault.

 

lmfao diesel... i dont think the car would move with diesel.

 

The diesel nozzle won't fit into a gasoline filler...

 

this same thing was happen to me but they said it was my oxygen sensor