And the other shoe dropped...

[Brando_SLT]

So following my head replacement, the truck has been running great. Even for a 200k+mile engine I'm getting about 18.9mpg on the freeway, runs good, idles good, feels like the engine has new life.

But, now throwing codes. P0172 and P0175 - System too rich bank 1 and 2 respectively. Plus a small EVAP leak (at my gas tank). I am speculating that it may be old O2 sensors and worn CATs. Here's why: As part of my last project...

I replaced all 8 injectors.
I replaced the MAP sensor.
I installed a 180° thermostat (it had a 160° previously)
I replaced a faulty Engine Coolant Temperature sensor.
I replaced all seals on the top end (required as part of the last job).

Rich condition is typically when there is not enough air to the mixture, so it should not be related to an intake leak.

What do y'all think? Would be nice to get your guys' thoughts here. I saved my old MAP sensor and fuel injectors, but they're all gummed up with oil and carbon.

 

[Brando_SLT]

I just ordered a smoke machine/leak tester tool to see if I can find any intake and/or EVAP leaks. Now that the truck is cooled down a bit, I'll start climbing around and looking for leaks with the normal culprits:

• EGR Tube to intake manifold
• MAP Sensor
• Any other areas with new seals

 

[El Huapo]

Any possible chance the air intake is restricted? Dirty air filter? Not likely you missed that with all the work you did.
I love those smoke detectors, found a tiny leak in my old Pacifica where the cross-over vent tube fitting on top of the gas tank was cracked. Throwing a code for "very small evap system leak". Plastic saddle tanks still a touchy job to drop and fix but at least I had a definite direction to go. Good luck!

 

[Brando_SLT]

This afternoon I pulled the EGR tube from the back of the intake and sure enough the seal was cocked/crooked. Took it off, cleaned the area, put it back on and reinstalled the tube. I also put the old MAP sensor back in. I cleared the CELs and will drive it some more. I think when I ordered the new MAP sensor I got the wrong version. There were 2: Twist-in and bolt-on. I went with the bolt-on version when my truck had the twist-in version.

I did get two new pending faults almost immediately: Cylinder 8 misfire and Cylinder 8 fuel injector. I recall the plastic retaining tabs inside the connector from the harness were broken, I had to ZIP tie the connector down. By hand I could wiggle the connector and feel the cylinder cut out. So I'll see if I can find an OEM replacement or splice in a new aftermarket one.

Once the smoke machine shows up, I'll get to try and trace down any other leaks.

 

[Brando_SLT]

So time for an update! I got the cylinder 8 misfire/injector circuit failure resolved with a new electrical connector. It sure sounds/feels a lot better with all 8 firing.

When I get more time tomorrow I'll try to trace down the EVAP leak since the smoke machine showed up. It's pretty nifty!

 

[WhiteExpress]

Those smoke machines are SO handy for finding little evap leaks.
I found that as soon as I touched almost any of the lines, I just replaced them anywho as they'd fall apart in my hand. I spend about $40 in vacuum hose and a solid afternoon on my '99 and all my codes went away.

 

[10 Break]

If you have a scanner, look for negative % long term fuel trim in both banks like the 02 sensor codes. Maybe the evap system is continuously pulling vapor making the exhaust too rich? I'm kinda green with this issue...I chase down lean conditions in all my Mopars.

 

[Brando_SLT]

Some great insights here from you guys - I definitely appreciate it. So, I believe I have resolved the issue. During my rebuild process I installed "new" fuel injectors that were not OEM. They were rated at about 300cc/min while the OEM injectors are spec'd to 283.5cc/min. I ordered a set of Chrysler injectors, swapped them in today, and now my Long-Term Fuel Trims are 0% (previously were -33%) and it passed all readiness checks! I should be ready to do a smog check this coming week. Here's the full list of everything I did:

• Replaced Head Gaskets
• Installed remanufactured heads (OEM spec)
• New spark plugs
• New OEM fuel injectors
• New top-end gaskets (Intake gaskets, injector o-rings, throttle body, etc.)
• New MAP sensor
• New air intake temp sensor
• New coolant temp sensor
• 180º Thermostat
• Drained and refilled coolant
• New EVAP Canister
• New EVAP vacuum pump
• New EVAP purge valve
• Repaired broken EVAP line on gas tank
• Repaired leaking filler inlet on gas tank
• New exhaust gaskets, bolts, & studs
• New oxygen sensors (pre & post cat)

Man, what a project. All of this stemming from a head gasket leak back in November.