JET Stage-2 Question

Does the Jet Stage 2 chip absolutely positively need an 180 degree thermostat to work. I wanna try mine out but no thermostat available at the moment, will I break something important if I try it without the thermostat?

Joe B

It'll work fine even with the stock t'stat. The only reason for the 180* t'stat is to keep the engine running cooler to prevent pinging because the JET chip has more aggressive fuel and timing curves. That's also the reason why JET specify premium fuel.

OK so here is what happened to me today....

My car was low on gas and I had the Jet stage 2 chip I want to test out so I filled up on premium and installed the chip. However, the "Check Engine" light continues to be displayed despite the premium gas. Note that I have not put the 180* t-stat in yet but I fully intend on doing so within the next week, I merely wanted to test this stage-2 chip. Has anyone run into a similar problem as I have and is there any way to successfully correct it (besides installin the t-stat unless that is my problem). Any information will be helpful. Thanks.

Joey B

I ran a stage 2 chip for a while. I never ran it without the thermostat, but with it the check engine light never came on. I did however have a code in the system for the engine temp taking too long to reach operating temp. I took the chip out because even with my exhaust and intake mods I never saw an increase in power(from the chip), and got tired of paying for premium gas.

joey99jb said:

OK so here is what happened to me today....

My car was low on gas and I had the Jet stage 2 chip I want to test out so I filled up on premium and installed the chip. However, the "Check Engine" light continues to be displayed despite the premium gas. Note that I have not put the 180* t-stat in yet but I fully intend on doing so within the next week, I merely wanted to test this stage-2 chip. Has anyone run into a similar problem as I have and is there any way to successfully correct it (besides installin the t-stat unless that is my problem). Any information will be helpful. Thanks.

Joey B

Click to expand...

Did you disconnect the battery before installing the JET chip? If you didn't, that might explain why the check engine light is on. In any event, you should be able to retrieve a fault code and find out what's going on.

Dr. Dyno said:

Did you disconnect the battery before installing the JET chip? If you didn't, that might explain why the check engine light is on. In any event, you should be able to retrieve a fault code and find out what's going on.

Click to expand...

Yes I did disconnect the battery and I filled up with premium gas...there might be a little unleaded gas in there left but less than 10%. Maybe that is causing all the commotion. I tried letting my engine cool down and when I tried to start it with the stage-2 it stalled on me. I don;t know it probably has to deal with the thermostat I am guessing but I don't know. I'll fill up again on premium gas this week to ensure that the engine is only getting premium gas and then I will try again mid-week. Hoepfully it works....

Joey b

Neither the chip nor the ECU can tell the octane of the gas. Try reseting the computer by unhooking the battery again.

Should I unhook the battery for a long time? say like half and hour for it to fully reset? Maybe that is the problem?

Joey B

joey99jb said:

Should I unhook the battery for a long time? say like half and hour for it to fully reset? Maybe that is the problem?

Joey B

Click to expand...

You need to discharge the power from the ECU. To do that, take off the negative cable and then hold the key as if you were trying to start the car for 30 seconds and your done.

I just tried your method GoJeep, disconnecting the ECU and holding the key in for 30 seconds. The result is that the car starts up for two seconds and then dies, which could be worst. I actually noticed today on the chip some grease material on the pins. Has anyone else has some time of grease material on the pins to their chips when they got it? Maybe this might be the problem? Regardless I am going to autozone to get this "code scanned" so hopefully that will help me alot. Any further suggestions would be awesome. THANKS!

So I went to Autozone and I got my XJ code scanned. The result was the floowoing error: P0463, Fuel Level Sensor, A Circuit High Input Malfunction.

Now, I have to tell you that my fuel gauge has been acting up, actually its been acting up since I had the car. Would this be the reason the chip doesn't work, becuase the fuel gauge is malfunctioning. Basically the guage goes from the correct level to empty and back to the level. It just goes back and forth. Maybe this is causing the chip to malfunction. I don't know. Anyone please help!

Joey B

I wish i could help, but i know nothing...I'll buy the thing off you if you decide to go that route. I am also in Ma, and work in Malden so I am in Boston every day durring my commute.

joey99jb said:

Yes I did disconnect the battery and I filled up with premium gas...there might be a little unleaded gas in there left but less than 10%.

Click to expand...

This might be my general lack of experience with XJs coming into play here, but... Aren't they *all* supposed to run on unleaded? Catalytic converters + leaded fuel = not good.

I suspect that by 'premium' gas he meant 'premium unleaded' - to those of us who live in parts of the country where we haven't been able to get leaded in years, the two terms are synonymous. Just something for anyone where leaded is still sold to be aware of.

I honestly don't remember...I better check up on that, man I hope I wasn't an idiot and put lead in but I don't believe they have premium lead up here in the northeast. I honestly can't remember. That may be it though so I appreciate the suggestion casm.

joey b

I haven't seen leaded fuels up here either... ANYWHERE... so i don't think that's your problem... but i'd still check on that if I were you...

joey99jb said:

So I went to Autozone and I got my XJ code scanned. The result was the floowoing error: P0463, Fuel Level Sensor, A Circuit High Input Malfunction.

Now, I have to tell you that my fuel gauge has been acting up, actually its been acting up since I had the car. Would this be the reason the chip doesn't work, becuase the fuel gauge is malfunctioning. Basically the guage goes from the correct level to empty and back to the level. It just goes back and forth. Maybe this is causing the chip to malfunction. I don't know. Anyone please help!

Joey B

Click to expand...

PO463 indicates that the PCM saw the fuel sensor exceed the 5volt nominal range and did'nt like it, throwing a CEL. One possible reason is that the sensor is shorting to ground on it's 12volt source. The JET chip would not be the cause of this code, rather it may have exacerbated an already existing problem or simply revealed the already existing problem. If you were having fuel level related issues since you acquired the Jeep than you need to have that issue addressed before going further with any modifications. What you could try initially is to go on the advice of GoJeep and disconnect the neg battery cable to clear the code, remove the chip as well, and then reattach after 5 minutes. :wstupid:

I have the JET stage 1 chip with a 98. My fuel guage is wacky, too. I also get the 463 error code you mentioned, but it does not cause my Check Engine light to come on.

When they checked your codes, did you have them cleared with the scanning tool? If you take the JET chip off, does the light go away after resetting the computer?

Speaking of codes, I found this recently and think I may order one.
http://obddiagnostics.com/
It's less expensive than a tool and great if you already have a laptop.
Does anyone have one of these?

Here are the steps I have taken several times.

(1) Disconnect negative lead on battery
(2) Discharge ECU by placing key in ignition and holding there for 30 sec - 1 minute.
(3) Disconnect the black cable on the ECU unit and place jet stage 2 chip firmly in place. Reconnect ECU and check to make sure all plugs are securely in place.

(4) Connect the negative lead back onto the battery
(5) When I turn the ignition to the "on" position so that electricity is enabled, there IS NO check engine light on whatsoever. A-ok up until this point...unless i screwed up above somehow
(6) Start the engine, the jeep starts and for about 2-3 seconds everything looks ok (idling @ 1000rpm), starts up fine...then the check engine light comes on and one of two things happen
- the RPM starts to slowly drop and the engine eventually stalls
-the engine stalls quickly

If I turn off the car and then turn it back on to the electrical position in the ignition, the check engine light is now on! So, I don't think I am actually installing this wrong, so I guess it does have to deal with that faulty fuel gauge...dammit, I wonder how much this is gonna set me back. Thanks everyone who posted, if any more ideas, suggestions arise feel free to post!

Joey B.

OK first things first. Unless you punched out the neck of your gas tank, you can't get the nozzle for leaded gas into a no lead tank. You can't even buy leaded fuel around here except for specialty hot rod shops.

You keep saying the chip isn't working, but the vehicle is running. You have a check engine light and a failure code. The failure code is related to a sensor failure from what it appears. You already have said your fuel sensor/guage isn't working correctly. That is one fluid level sensor in the rig and you admit it isn't working correctly.

Unless there is another fluid level sensor, such as the low oil on my Exploder, this is probably the source of your error code. Just because it happend at the same time as the chip was changed, does not necessarily mean the chip caused the failure.

Simple troubleshooting tip #1: Remove the Jet chip and put the old chip back in. Does the problem go away? If not, then the problem is not the chip, so use the diagnostic code and fix the problem causing the check engine light before replacing the Jet chip.

If the problem goes away, then clean the jet chip leads and put it back and see if the problem returns. If if does, call the manufacturer, Jet and tell them you are having this problem and ask their advise. If it doesn't the problem was dirty leads.