Maintain filters, sensors

I know this is a long post but...well...it's a long post. If it's a problem, sorry.

1990 4.0 220K

My Jeep runs like a top. I've had some issues over the years but the fact that it has 220K on the clock and has so far avoided many/most of the pitfalls I read in here. I live in Northern CA and have little or NO body eating, bolt wrecking rust. I've yet to encounter a bolt/nut that I couldn't turn with a small amount of PB. I wheel it moderately, mostly in snow, no rock crawling. Try not abuse it too much as I can't afford another vehicle.

My question(s) have to do with maintaining filters & sensors so that I don't find myself stranded wishing i would have taken care of it at home.

1. Evap. Canister Filter - Chilton's says change every 30K - I didn't even know there was a filter that could be changed. Just noticed this in the book yesterday.

2. O2 sensor - Some say don't change it til you fail a smog test. Some say every 30K. It can't hurt to have it in tip top shape, so I change mine (just the 1) every 2 years just before smogging. Haven't failed yet (I also change out the gas cap)

3. Coolant Temp Sensor - (not the sender) I'm having a hard time with this one. The NAPA guy keeps trying to sell me the sender (for the gauge). So, are both of the these the sensor? And if so which is the one I want?
#1 http://www.napaonline.com/masterpages/NOLMaster.aspx?PageId=470&LineCode=DEM&PartNumber=TS10192&Description=Coolant+Temperature+Sensor

#2 http://www.napaonline.com/masterpages/NOLMaster.aspx?PageId=470&LineCode=DEM&PartNumber=TS10139&Description=Coolant+Temperature+Sensor

4. CPS - Should it be changed at regular intervals or just carry a spare and fix it on the side of the freeway in the rain at night.

5. Oil Filter - I run Castrol 10/30 full synthetic with a Purolator filter (that's the filter the lube guy gave me). I change oil every 5-6K and the filter somewhere halfway between. I've heard horror stories about Fram. Why?

6. Fuel Filter - I just changed mine, I've put a good 85K on this Jeep and it's never been changed, never any issues. When I removed the old filter it took a long time to drain, so is that normal or ?

Thanks.

P.S. I'm not a mechanic, but I can turn a nut and fix most of the stuff on the Jeep.

I'll answer the ones I can....

The CTS - I've got no idea if you've got the right ones or not. I've recently run into the exact same problem....nobody seems to have one. The dealer is the only place I can find one.....$32 and 2 weeks wait to get it into town.

O2 sensor - Mine needs changed, I've yet to do it. I've been told that you can test it with an analog volt meter.....It's on the list of things to do this weekend.

Fuel filter - I usually change this about once per year...at my current commute, it will be about 50k miles

Oil/filter - I use Quaker State (flame on!) 10w-30, year round. Used to use Fram filters, but have switched to STP. Fram filters have some history of falling apart, and causing low oil pressure symptoms in our motors. I believe it's because the backing plate in the filter is cardboard, instead of metal. Search for "fram oil filter" here, or "low oil pressure". Some of the threads are pretty interesting.

CPS - I've not changed mine, 235k miles and still running strong. (I have no idea if it's been changed before)

Evap Canister filter - This one is a new one on me, too.....I'll be watching to see what you find out.

The EVAP Cannister filter is just a section of fibrefill in the bottom of the cannister - you should just be able to pinch it and pull it out with your fingers. It's there mainly to keep road crud and dust from getting sucked up into the cannister - I honestly think "every 30K" is huge overkill for that thing. I've got 300K on my 88, and it hasn't been changed (airflow is slight, and there's no PD to worry about, really.)

I'm inclined to think the first link is going to be for your CTS (the one reporting to the ECU,) since the second one looks like it has an "air tip" instead of a "water tip" (the second one looks like the IAT, but that should be changed out at infrequent intervals as well.) It's definitely going to be a two-wire job, you can tell the counterman that.

Why change it? For the same reason you change anything else with "moving parts" - it can wear and develop "flat spots" in the response curve - just went through this last year with the TPS. I know there aren't any real "moving parts" in a thermistor, but the principle is the same.

Spec life of a HEGO is ~80Kmiles, but RENIX can go longer (I think mine had ~140-150K before I felt the need to change it.) Same reason, plus carbon particle blockage in the sensing element (it's porous ceramic.)

MAP sensor? Yeah - change it as well - but the RENIX MAP is a standard GM part (get the regular 1-bar sensor, found pretty much anywhere.)

Take comfort - most of the RENIX sensors are standard GM parts, save the HEGO and possibly the TPS. Everything else should be readily available pretty much anywhere - the HEGO is available from Bosch (aftermarket,) and the TPS from Borg-Warner (aftermarket) - so both can be had cheaper than from the dealer. Everything else is easy, save possibly the thermal fan switch in the radiator tank.

Link #1 is the IAT (intake air temperature) sensor. (Goes on the manifold by the TB)

Link #2 is the Coolant Temp Sensor for the ECU (Goes in the block, almost directly below the motor mount near the knock sensor) NAPA Also lists this one besides the link you provided:
http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=ECH&PartNumber=TS5018&Description=Coolant+Temperature+Sensor

The Coolant Temp Sensor for the fan is in the Radiator near where the lines for transmission fluid go into it.

The Coolant Temp Sensor for the sender is at the back of the head almost below the MAP sensor

Thanks guys,

Those are all great answers/advice. I'll admit my ignorance to what HEGO stands for but the other stuff I can absorb. It'll be interesting to read further posts to this. I should be done with my short list before summer.

ParadiseXJ said:

Thanks guys,

Those are all great answers/advice. I'll admit my ignorance to what HEGO stands for but the other stuff I can absorb. It'll be interesting to read further posts to this. I should be done with my short list before summer.

Click to expand...

Sorry - HEGO = Heated Exhaust Gas Oxygen (sensor.) How's that?:wave:

I may have gotten the links reversed in my mind. The sensor with the plastic "cage" around the sensing tip is the one I referred to as the IAT. Still, you get the idea.