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Mtb Jak
October 13th, 2017, 16:49
2000 Jeep 4.0 200k miles. Neon injectors, stock headers/precats.

Getting the jeep ready to pass emissions.. I am faced with a lot of check engine codes.

P0432 -Catalyst 2 1 Efficiency
P1282 Fuel Pump Relay Circuit
P0301 Cylinder 1 Misfire detected
P0420 Catalyst 1 1 Efficiency
P0700 Electronic Automatic Transaxle Controller
P0700 2x?

P0301 "Confirmed"
P0420 "Confirmed"

Ya I was even surprised by the number of codes. Here are the symptoms.

The jeep can take two times to crank over.
Sometimes I can hear a back fire into the air box area on start up.
Reverse lights work.
Gas mileage sucks worse than usual.
Exhaust smells rich at start up.


For My state I can pay 300 bucks towards a shop to trouble shoot it/towards solving it and I get a waiver. I just want to go in with a game plan on where to start and get the light off for once.

Jeep Driver
October 13th, 2017, 18:52
Loose exhaust manifold bolts......02 and Cat related.

Just a guess.

Tim_MN
October 14th, 2017, 08:56
Often, higher number trouble codes are triggered by the problem or faulty data created by whatever is causing the lower numbered trouble codes. Almost always start your diagnostics with the lowest numbered codes.

Are all of the tune-up parts fresh ? What brand and type of spark plugs are installed ? Have you tested the coil-on-plug spark rail and inspected the its wire plug ?

Test and inspect for excess fuel, both at start-up (drippy injectors ?) and while running. Test the O2 sensor function. How many miles on the cat converters and the O2 sensors ?

Mtb Jak
October 17th, 2017, 08:45
Dropped it off this morning, THANK you for your help guys. Gave the tech something's to think about. Fingers crossed they are honest. They came highly recommended for jeep 4.0 tech as a shop.

Heavyopp
October 17th, 2017, 09:01
Well at least the reverse lights still work...

Mtb Jak
October 17th, 2017, 17:12
LMAO 2250 for new cat and O2 sensor.

the_weirdo
October 17th, 2017, 22:06
Which shop? That's outrageous. If you are still in Seattle, know an honest shop on the Mill Creek/Everett border.

Jeep Driver
October 17th, 2017, 22:16
LMAO 2250 for new cat and O2 sensor.

NTK sensors ONLY!

One cat and 4 sensors will run you about $700........but you have pre cats too, right?

Buy your own parts and find an exhaust shop........maybe 300 labor.

Will cost you $1000 regardless.

clydefrog
October 17th, 2017, 22:41
2000 Jeep 4.0 200k miles. Neon injectors, stock headers/precats.

Getting the jeep ready to pass emissions.. I am faced with a lot of check engine codes.

P0432 -Catalyst 2 1 Efficiency
P1282 Fuel Pump Relay Circuit
P0301 Cylinder 1 Misfire detected
P0420 Catalyst 1 1 Efficiency
P0700 Electronic Automatic Transaxle Controller
P0700 2x?

P0301 "Confirmed"
P0420 "Confirmed"

Ya I was even surprised by the number of codes. Here are the symptoms.

The jeep can take two times to crank over.
Sometimes I can hear a back fire into the air box area on start up.
Reverse lights work.
Gas mileage sucks worse than usual.
Exhaust smells rich at start up.


For My state I can pay 300 bucks towards a shop to trouble shoot it/towards solving it and I get a waiver. I just want to go in with a game plan on where to start and get the light off for once.
Jesus, how long has your check engine light been on? These problems don't all happen over night, seems like you have been neglecting your Jeep.

The miss fire codes will and can cause cat efficiency codes. If you have a dead miss or slight miss due to inadequate spark then raw fuel will get into the catalyst system which will not be able to keep up and throw codes. If your miss has been going on for quite sometime then you may have toasted your cats. These are the P0301, P0432 and P0420 codes. This could also cause a rich condition and fuel smell. I would start by eliminating these codes.

For you trans codes, def not related to the miss. This would be a separate issue along with the fuel pump relay codes.

Mtb Jak
October 18th, 2017, 09:57
Jesus, how long has your check engine light been on? These problems don't all happen over night, seems like you have been neglecting your Jeep.

The miss fire codes will and can cause cat efficiency codes. If you have a dead miss or slight miss due to inadequate spark then raw fuel will get into the catalyst system which will not be able to keep up and throw codes. If your miss has been going on for quite sometime then you may have toasted your cats. These are the P0301, P0432 and P0420 codes. This could also cause a rich condition and fuel smell. I would start by eliminating these codes.

For you trans codes, def not related to the miss. This would be a separate issue along with the fuel pump relay codes.


You are correct, I have neglected the jeep, it hasn't been my DD and i did a few camping trips and just ran it. I am tempted to swap a 99 computer and get a stroker and ditch all the ignition rail/header cat bullshit. It's got tags now so we will see if I even get out much this winter and if I want to dump the 1k in parts and tinker on the current set up.

How would I check the misfires? Would that be on the spark plug rail or injector side? I have all my old injectors still from when I put in the "better" injectors. I am heading in person to the shop now, I almost laughed on the phone when they said 2500 but new customer discount brings it too 2250! I would be halfway to a full stroker build for that!

Mtb Jak
October 18th, 2017, 10:05
Which shop? That's outrageous. If you are still in Seattle, know an honest shop on the Mill Creek/Everett border.




Bernies Automotive on Leary. I see XJs from time to time in their lot so I thought they might have some kind of 4.0 savant but..no. The "forward cat piece" quoted at 950 for a part they had to "search online for 3 hours to find" I found 5 options and most expensive was 489.00 cheapest and best option was 208.37 in 3 minutes on my phone.

Any recommended exhaust shops? I'm in eastlake on lake union. I like the idea of gathering all the parts and just bringing it somewhere. It seems like I might have an injector fuel issue that Fouled the damn CATs so I have to look into that first. What shop up there is good? I just don't have the time right now to tinker on this the way I want. I have had some insane bad luck with shops and this jeep. Only place that was honest by me and great to deal with is Those Guys customs in Bremerton.

the_weirdo
October 18th, 2017, 13:14
General auto shops good for Jeeps:

In Auburn: Auburn Car Repair and Offroad - owner John Mathews is a die-hard Jeep guy and runs an honest shop. Almost every Jeep guy I know in the area goes here.

In Everett: NW All Auto Repair. I go here because it's much closer to my house. These guys do everything from race cars to minivans to Jeeps. Another honest shop, I even go wheeling with them once a month because they are just cool guys.

clydefrog
October 18th, 2017, 21:59
The mis is most likely on the ignition side. I would def fix it before thinking about doing a cat. I have personally seen bad misfires cook a new cat in a matter of weeks. To be 100% honest, I have no idea how to check for a miss on a non coil on plug motor. I would start by freshening things up if its been awhile (plugs, cap and rotor) then check timing. The run it and see what codes return.