Oil warning light

[Bundy1]

My son has just bought a 2002 KJ petrol, which is in very good condition for its age. It does have one small issue though, and I'm hoping someone on here will be able to point me in the right direction.

When travelling along the highway, normally around 80-90 km/hr, the oil light will come on for a second or two, and sound the bing as it does so.

It's just been serviced, and no codes have been recorded.

I'm suspecting a faulty oil pressure sender, but wonder why no fault code would be triggering

Any advice greatly appreciated.

[Hayesio]

Generally, in my experiance, this type of intermitant oil pressure light is usually a faulty sensor/wiring as you've suggested. However, I wouldn't just make that assumption as if it is a lost in pressure it will have a catastrophic effect. I would suggest you check the wiring and change the sender asap. It would also be a good idea to buy a oil pressure gauge for 30 buck off ebay and install it. Then you can monitor oil pressure (in an analog fashion) as it fluctuates with engine speed and be 100% confident it's ok.

[Bundy1]

Originally Posted by Hayesio

Generally, in my experiance, this type of intermitant oil pressure light is usually a faulty sensor/wiring as you've suggested. However, I wouldn't just make that assumption as if it is a lost in pressure it will have a catastrophic effect. I would suggest you check the wiring and change the sender asap. It would also be a good idea to buy a oil pressure gauge for 30 buck off ebay and install it. Then you can monitor oil pressure (in an analog fashion) as it fluctuates with engine speed and be 100% confident it's ok.

Is there a spot for a second sensor for the aftermarket gauge?

I run the Torque App with a BT OBD2 sender on my JK. Would this work on the KJ?

[Hayesio]

Yeah, you should find a plug or two along the main gallery of the engine or around the oil filter / bypass area. Another way is to put a 'T' into the OEM sensor hole with both on it. Alternator feed line might be yet another option.

Not many cars have an analog transduce for oil pressure unfortunately (wish they did!), as it is not a PID loop control device. They're usually just a simple digital (on/off) device set to a specific pressure (pressure switch) - as is the case with the JK. So no, wouldn't think torque would be much help.

You probably arn't getting a code because the pressure switch is not in the off condition for long enough and the ECU is programmed to delay an output for a couple of seconds or so. They would do this to prevent it "nuisencce tripping" TDC on start-up etc.

[Bundy1]

Originally Posted by Hayesio

Yeah, you should find a plug or two along the main gallery of the engine or around the oil filter / bypass area. Another way is to put a 'T' into the OEM sensor hole with both on it. Alternator feed line might be yet another option.

Not many cars have an analog transduce for oil pressure unfortunately (wish they did!), as it is not a PID loop control device. They're usually just a simple digital (on/off) device set to a specific pressure (pressure switch) - as is the case with the JK. So no, wouldn't think torque would be much help.

You probably arn't getting a code because the pressure switch is not in the off condition for long enough and the ECU is programmed to delay an output for a couple of seconds or so. They would do this to prevent it "nuisencce tripping" TDC on start-up etc.

This advice has been a great help. Thanks for taking the time to help us out.

[Bundy1]

I thought I'd better do an update to this post to maybe help other KJ owners out, who may have had, pr are having, the same oil pressure warning light issues as we've had.

After doing this original post I decided to buy a new oil pressure sender as the easiest and cheapest option to try first. I ordered an aftermarket (Crown) sender from the States with exactly the same part number as the original sender, and had it fitted to the KJ. First impressions were good after fitting the sender, with no sign of the oil pressure warning light or chime. That lasted for a day and a half, after which time the oil pressure warning light displaying got worse, and would come up every time the Jeep was started, and stay illuminated continuously. Very worrying when you aren't 100% certain it is a sender problem.

I did a bit more research on the net, and read where a few people had said that aftermarket senders were not completely compatible (read, didn't fix their oil pressure warning problems) with their Jeeps, and that genuine (Mopar) senders were the way to go to solve similar issues to mine.

I didn't want to keep throwing good money at this problem, but there were enough people saying the same thing, that I thought it would be worth a go.

I ordered a genuine oil pressure sender from Jeep Australia (about $125) and fitted it to the KJ.

It's now over a week since fitting the genuine sender, and the oil pressure warning light and chime haven't been heard or seen since (except as part of the start up check of course), touch wood.

[DarrenR]

Sorry I missed this post earlier..

The 3.7lt V6 petrol
*Common failure is the oil pressure sensor.
*Only use genuine as any other brands wont work.
*its the same as the 4.7lt V8 sensor BUT, I think from memory the KJ is a 2 pin, where as the 4.7lt is a 3 pin.

Regards
Daz