99 Dodge Dakota 5.2, PROBLEMS THAT DONT ADD UP

[Bassblaster]

Greetings vehicle people of AK. looking for some suggestions, i was on here a little while ago and got a 4 cylinder misfire figured out, but now i have more issues that dont make any sense.

1: Anyone there with Dakotas with the 5.2, what gas mileage do you get? i top off the tank every week and my MPG varies from 7 (less than my RAM 1500 with the 5.9L gets) to about 15. ALWAYS changes.

2: How come the computer keeps spitting out a front left ABS sensor when there IS NO front ABS sensors?

3: i also keep getting O2 sensor codes, yet the O2 sensor its giving a code for, is literally not even there.

Any ideas?

 

[Eric H]

Does it have rear wheel ABS? Which O2 sensor is it calling out? On a 1992 V-8 there should be one on each bank., if it's missing a sensor maybe that's why it's flagging it?

Edit, got the year wrong, on a 99 there should be one on each bank plus one after the Cat if it's single exhaust. If it's dual exhaust with two Cat's there should be one in front and one after each Cat.

If everything is as it should be perhaps someone put the wrong PCM in it or programmed it for a different model.

 

[Bassblaster]

Yes it has rear ABS. its calling bank 2 O2 sensor. there's also no cat on it at all. i believe its a single exhaust even tho it has dual sticking out the back, most likely just a Y pipe. ive never heard of a vehicle having the wrong PCM. but i have read about them failing on 2nd gen dakotas and RAM's

 

[Eric H]

If there no Cat at all then someone has removed it, this will definitely set a code for the rear sensor.

 

[gadget73]

what codes exactly? Sometimes the codes are application-specific, not just a generic "one size fits all" type thing. I know OBD2 is supposed to be standardized but I don't quite trust that.

 

[Tim64]

If everything is as it should be perhaps someone put the wrong PCM in it or programmed it for a different model.

I am thinking the wrong pcm maybe a used one from the bone yard, especially with the front abs error code.

 

[Tim64]

If there no Cat at all then someone has removed it, this will definitely set a code for the rear sensor.

If you get under there I bet there is a connector hanging underneath there. And it should have a cat conv for sure.

 

[Bassblaster]

what codes exactly? Sometimes the codes are application-specific, not just a generic "one size fits all" type thing. I know OBD2 is supposed to be standardized but I don't quite trust that.

i dont know the exact codes, i just take it in and have it read. my local shops do free code readings. and since i also dont have my own code reader

I am thinking the wrong pcm maybe a used one from the bone yard, especially with the front abs error code.

Seems very possible , How would i even check something like that?

If you get under there I bet there is a connector hanging underneath there. And it should have a cat conv for sure.

Ive been under there several; times and for the life of me cannot find any plugs or wires anywhere. for both the ABS sensors and O2.
looking around there only 1 ABS module next to the master cylinder with a single line going to the rear.

 

[gadget73]

RABS then. Not real familiar with this model or its options but a lot of trucks had that. Should be a single sensor in the diff or maybe it uses a sensor in the tailshaft of the trans. Thats where the rear sensor for my S10 lives.

I'd expect (again, not specifically familiar with this model) 3 or 4 O2 sensors. Typically its one per-bank, one in front of the cat, and one behind the cat. Sometimes its just one per-bank and one behind the cat. The ones in each bank will be close to the outlet of the manifold, either in the pipe right below it or in the manifold itself. The rear sensor is to check catalyst efficiency. It will compare readings either to the pre-cat sensor or to the two on the engine. Its an OBD2 thing, they have to be able to determine if the converter is working through the diag port.


I'd figure the ECM has a program code or part number on it, or some other way of telling them apart. I'd wager somewhere there is a Dodge truck forum with a guru that can tell you what those codes mean, and what vehicle and option combos they go with. Its not impossible that someone thought they had a bum PCM and just got a junkyard one. You'd need to see what you have and then figure out if it matches what you should have. Also just possible it has gone braindead and you need a working one that matches what you have.

 

[Bassblaster]

Forgot all about this thread, thought i would post an update. found the issue. someone removed the single cat the the rear O2 sensor. doing so they got the plug and shoved it up the fire wall. doing that, one of the wiring harness was laying on the exhaust all melted and was shorting everything out. but that explains the "bank 2 O2 shorted" code i got a month ago or so.
After re building the harness and replacing that O2 sensor, it now runs way better and my gas mileage almost doubled

 

[damacman]

Well there you go... some idiot hooked you up.

 

[beat_truck]

Stupid people really shouldn't have access to tools. They usually cause more issues than what the one they are trying to fix. They probably hacked off the converter because they thought it would add 50 HP.

 

[arts]

Stupid people really shouldn't have access to tools. They usually cause more issues than what the one they are trying to fix. They probably hacked off the converter because they thought it would add 50 HP.

Or they found out how much they're worth as scrap metal

 

[beat_truck]

Or they found out how much they're worth as scrap metal

At one time, some were worth quite a bit. Lately, not so much. Scrap has been WAY down in value for a good while and still is as far as I know. Last fall, I junked a few vehicles and took a few smaller cats and aluminum wheels in and it was hardly even worth the effort. One cat was a cheapo aftermarket, and I was shocked when he said it was worth $5.

 

[gadget73]

yeah, there was a rash of stories of people coming out of stores or whatever to find someone had nabbed their converters. Cordless sawzall will make quick work of them.

Speaking of people that should not own tools, I found some evidence in the trans on my Lincoln that a butcher was at it. The filter holds on with 3 T27 Torx screws. Two of them look like someone hammered an allen key into them to extract, and one has chisel marks on it. I did manage to get them out and back in, but I was not sure it was going to happen. They also forgot the O ring on top of the filter. Same person that probably hammered the allen key into the Torx rear caliper slide pins to pull them out. Gotta love surprises.

 

[usedto]

At one time, some were worth quite a bit. Lately, not so much. Scrap has been WAY down in value for a good while and still is as far as I know.

Not any more. Gingerly trying to avoid a political discussion, the recent talk of tariffs on steel and aluminum has almost doubled the price of scrap here on the west coast, from what I've heard. I'll be finding out soon, as I have a bunch of junk to scrap.

 

[KentTeffeteller]

Greetings vehicle people of AK. looking for some suggestions, i was on here a little while ago and got a 4 cylinder misfire figured out, but now i have more issues that dont make any sense.

1: Anyone there with Dakotas with the 5.2, what gas mileage do you get? i top off the tank every week and my MPG varies from 7 (less than my RAM 1500 with the 5.9L gets) to about 15. ALWAYS changes.

2: How come the computer keeps spitting out a front left ABS sensor when there IS NO front ABS sensors?

3: i also keep getting O2 sensor codes, yet the O2 sensor its giving a code for, is literally not even there.

Any ideas?

4WD Dakota with a 5.2 realistically gets 10 MPG on a good day in perfect tune. Old Magnum engine got less MPG than modern Hemi does.

 

[gadget73]

Shouldn't be *quite* that bad, but I wouldn't expect more than about 14 typically. The 318 is many things, but a fuel sipper is not one of them. Its a very durable motor though.