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[Mike2909]

98 ZJ 4.0 .A couple of weeks back I went through some deeper water at Glentarkie. Went through a few times just up to the top of the sills and was not having any problems. A few minutes later started to get a misfire. This cleared itself and then came back after another 10 minutes.I decided to call it a day and go home. Had the misfire better and worse all the way home , had  backfire in the cat next to no power and then 5 minutes from home it cleared and was back to normal.
Put it on the OBD and checked for faults and the P0132 and P0138 codes had returned that I had a month or so back before I changed the O2 sensors.
I cleared the faults and took her back out and no problems.
I have not been out in her for 2 weeks as I had to fix a broken CV joint but went  out today. 10 minutes out and the backfire/misfire came back again and I had to turn back.
Same fault codes are back again.
Plugs , armor tech leads dis cap and rotor all replaced less than 4k miles ago.I have used Universal O2 sensors but they have been working ok for a month. Can the deeper water have damaged the O2 sensors??

[bigjeepzj]

this my be a long shot but has the throttle position sensor been changed ever.
as the original TSP was not water proofed and i killed mine driving though a big puddle  or three
the replacement one are

 

[gordy]

Not sure if your scanner has live data but if so makes diagnosis a whole lot easier if fault codes are thrown or not as in my case it will display sensor voltages that's how I sorted my O2 sensor issue out, have read stories about non oem sensors failing almost straight away so I bought an NTK (oem) from Rock Auto.

This vid from Bullshit Korner shows how a dodgy O2 sensor behaves on the scanner.

[Mike2909]

this my be a long shot but has the throttle position sensor been changed ever.
as the original TSP was not water proofed and i killed mine driving though a big puddle  or three
the replacement one are

 

No TPS has never been changed.When the fault disappeared after changing O2 sensors I left it at that. I will change it just to discount it.Thanks

[Mike2909]

Not sure if your scanner has live data but if so makes diagnosis a whole lot easier if fault codes are thrown or not as in my case it will display sensor voltages that's how I sorted my O2 sensor issue out, have read stories about non oem sensors failing almost straight away so I bought an NTK (oem) from Rock Auto.

This vid from Bullshit Korner shows how a dodgy O2 sensor behaves on the scanner.

Yes the scanner does give live data, I am not sure how much data it gives as it is a bluetooth scanner that works through my android with pro-torque. I will try it and see what it gives , thanks for the advice                                                                       

[Mike2909]

Is there anyway of testing the TPS before replacing it. Its not a cheap part and if I need to replace the O2 sensors I do not want the to waste the money on the TPS.

[j33pky]

Just changed tps on my zj... Don't buy crown!  Lighthouse said they were hit or miss.  New one worse than fucked one.   Mopar one fixed it.  £128 worth 

[bigjeepzj]

Is there anyway of testing the TPS before replacing it. Its not a cheap part and if I need to replace the O2 sensors I do not want the to waste the money on the TPS.

the best way is to nick one from a working motor

[j33pky]

 

[bigjeepzj]

all 4.0l use TPS same xj yj zj tj

[gazjeep]

Rockauto
http://www.rockauto.co.uk/catalog/raframecatalog.php?ck[ID]=0&ck[idlist]=0&ck[viewcurrency]=GBP&ck[PHP_SESSION_ID]=r7ffesnj6dr36l03qcpoaa2du6

£18 - £26 usually delivered in about 3 days

[gordy]

Rockauto
http://www.rockauto.co.uk/catalog/raframecatalog.php?ck[ID]=0&ck[idlist]=0&ck[viewcurrency]=GBP&ck[PHP_SESSION_ID]=r7ffesnj6dr36l03qcpoaa2du6

£18 - £26 usually delivered in about 3 days

What he says, NTK is what the dealer sells for about 130, mine from Rock cost 42 inc VAT and delivery, you can check the O2 sensor, the Bullshit Korner vid I posted above shows you how to do it and there are plenty more on YouTube on what to look for, the voltage from the sensor should pulse from 0.1 volts to .99 volts at idle (mine was 0.5 all the time that's how I found out mine was duff) even though it did not throw a fault code.  Get an OBDII scanner that has live date like the D900 that I got for 15 quid it works with jeep on the Chrysler setting.  Run a snap test with the scanner on and the voltage should instantly jump to 0.99 volts or there abouts, mine was lazy and under the snap test hardly went up at all, the snap test is wide open throttle for a second then off. 

Yes you can check the TPS with a multimeter probed into the output of the sensor twist the throttle open and the voltage on the meter should move up STEADY to 5 volts as you open the throttle, if the voltage is not going up in relation to the opening of the throttle or there is a flat spot you have the evidence you have a duff TPS.

[gordy]

One more thing, Bullshit Korner has a YouTube vid on TPS! Equally informative and containing the odd expletive lol!

[Jonny Jeep]

Another way of seeing if the O2 is casuing the misfire is to unplug it. If the issue goes away with the sensor unplugged then it's practically certain the O2 sensor is faulty. The TPS test is best done with an analogue multimeter as it's easier to see any flat/dead spots.

And yes driving through deep water or mud can affect O2 sensors. They have to be able to compare air in the exhaust to air from outside. If the way the outside air gets in gets blocked the sensor can malfunction.

[JamesH]

all 4.0l use TPS same xj yj zj tj

Yes but different connectors, some have round pins and some have flat pins.

[Mike2909]

One more thing, Bullshit Korner has a YouTube vid on TPS! Equally informative and containing the odd expletive lol!

I was looking through his vids yesterday, don't know here he lives but it looked "fookin cold"

[Mike2909]

Another way of seeing if the O2 is casuing the misfire is to unplug it. If the issue goes away with the sensor unplugged then it's practically certain the O2 sensor is faulty. The TPS test is best done with an analogue multimeter as it's easier to see any flat/dead spots.

And yes driving through deep water or mud can affect O2 sensors. They have to be able to compare air in the exhaust to air from outside. If the way the outside air gets in gets blocked the sensor can malfunction.

What happens if you remove the O2 sensors altogether- obviously just asking as I would not want to add to global warming or pollution ? I noticed on a few US websites they sell lambda sensor plugs to fill in the holes after you remove them.

[Mike Pavelin]

Another way of seeing if the O2 is casuing the misfire is to unplug it. If the issue goes away with the sensor unplugged then it's practically certain the O2 sensor is faulty. The TPS test is best done with an analogue multimeter as it's easier to see any flat/dead spots.

And yes driving through deep water or mud can affect O2 sensors. They have to be able to compare air in the exhaust to air from outside. If the way the outside air gets in gets blocked the sensor can malfunction.

What happens if you remove the O2 sensors altogether- obviously just asking as I would not want to add to global warming or pollution ? I noticed on a few US websites they sell lambda sensor plugs to fill in the holes after you remove them.

You end up with high fuel consumption, your MIL light on and no MoT

[Jonny Jeep]

With the upstream O2 sensor unplugged the Jeep will run using preprogrammed fuel tables and other engine sensors. It is likely that it will run slightly rich to ensure there's no damaged caused by running lean. It does not necessarily mean it will use significantly more fuel. I have actually run with my upstream sensor unplugged the last time I noticed the symptoms of the O2 heater element failing. How much of change there is in MPG is likely to be affected by how well everything else is. I had no noticeable difference in fuel economy. You will also get the check engine light illuminated, which would fail an MOT.

[Mike2909]

There are 2 Jeeps at my local scrappys untouched by human hand. I am going to relieve them of there TPS and O2 sensors.There might just be a good one amongst them.

[Mike2909]

Went to scrappys today and got 4 TPS , 2 off  ZJ's and 2 off XJ's. There should be at least 1 good one between them The XJ's were high output engines, would there be any difference in the TPS?
I did not get any O2 sensors as the cats were removed and the sensors ripped out, the front ones had  also disappeared.
I am going to try swapping 1 of the sensors tomorrow and see if there is any difference.

[Hillbilly]

Hi Mike. Just out of interest what did the scrappy want for the sensors

[Mike2909]

Hi Mike. Just out of interest what did the scrappy want for the sensors

Believe it or not got all 4 for £15.

[Mike2909]

I do not think they are even interested in bits like that.There is a 98 Ford Explorer there with the 8.8    and they only want £150 for both axles .  I have been reading up a lot on different forums and it seems it is a good buy even if I am not sure what to do with them

[bigjeepzj]

Add
http://www.ironrockoffroad.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=IR-ZF88BK
and put it on the back of your ZJ