The Saga Continues: More, More Ram Fun
 

As expected, the next thing has cropped up. I sure did pick a project vehicle - at least it runs and drives still.

So, after finishing my last major project on this truck, the computer has finished its self diagnostic. Two codes and a pending EVAP slow leak fault. The codes? P0172 and P0175, system too rich bank 1 and 2 respectively. As part of my overhaul I included new fuel injectors (old ones had lots of gunk buildup) , a new MAP sensor (also lots of gunk buildup), a 180° thermostat (previously had 160°), and a new Engine Coolant Temperature sensor (old one failed).

With all new seals on everything, I doubt there's a vacuum leak - plus vacuum leaks typically lead to a lean condition. I've double checked hoses in the engine bay as well, no cracks or breaks, no exhaust leaks. I am thinking it might be bad O2 sensors or failing catalytic converters. It was burning a lot of coolant before.

The truck is running great though. No misfires, no stumbling, starts right up hot or cold. I am getting the best fuel economy yet at estimated 18.9 mpg so far mixed driving.

What does the brain trust think? Do I need to have the ECU remapped? Custom tune? Luckily parts are inexpensive and I am getting more time for smaller fixes.

Run a bottle of Cataclean Fuel And Exhaust System Cleaner through it. That will clean your Cats and O2 sensors. I wouldn't get a car tuned without baselining it for proper stock performance first. You won't get the benefits.

I had the same codes on my BMW. It was a torn intake boot. Unmetered air is still a possibility.

This. Pretty regularly its a small vaccum leak - a line or intake gasket or...the o2 sensor sees it as slightly lean and cranks the fuel trim to the point where it trips the obd.


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Something I had a prob with on my Chev truck, O2 sensors were old, MPG down so figured I would change them, installed Bosch I have used for years on other cars, it would not run properly, backfire crap idle not drivable, so ordered NGK installed and ran fine and MPG back to norm. I think the new engines rely on the O2 sensors a lot more and are picky on what goes in. I can not remember the fault codes.

Beat me to it. I would not even consider putting a tune on something without having a good, stock baseline performance first. You are talking about fixing a herniated disc w a nose job.

Figure out what's wrong w your vehicle first and you may not even desire a tune once it's running and performing properly.

Also, new seals do not preclude a leak. Diagnose it properly from start to finish of the IC process, don't be lazy and don't assume.

"Assumption is the mother of all fk-ups."

Steven Segal

Thanks guys, I'll go over all the hoses again and double check for cracks/breaks. I will also double-check where the EGR pipe goes into the back of the intake manifold. I kind of remember it not sitting completely flush so I can start there. I still have the old MAP sensor so maybe can try using that as well? Wasn't throwing a rich/lean code with the old sensor.

Now I'm tempted to buy/rent one of those fogger machines to look for leaks.

exhaust manifold crack yet?

HAH, no. It's a Ram not a Ford! Exhaust is actually pretty freaking sturdy, thick-walled cast iron. I took a wire brush to it looking for cracks before reinstalling it.

So that 18.9 MPG... is that off the trip computer or is that based on actual distance travelled and how much fuel you put in? With my Dodge, those were 2 widely different things...

That was off the trip computer. I just did the math, 239 miles and burned through about 13 gallons yesterday so estimated 18.38 MPG. I'll have to do a more accurate on next full fill-up.

I just ordered a smoke machine/leak detector tool: https://www.amazon.com/gp/product/B07JVT1NG2/

That should help me hunt down if/where a leak is. I've wanted one for a long time anyways, so this was a good reason to pull the trigger. Some tools pay for themselves over time - the vacuum coolant bleeder I bought certainly did, I hope this one does too.

Why are you searching for vac leaks if it has rich codes? Rich codes means its pulling fuel out, and has reached its limit to do so and is still rich. If it had vac leaks it would be adding fuel and setting lean codes.

Does the PCV flow adequately? Has the oil been changed recently? Fuel pressure checked? For pressure and for bleed down through injectors? You mentioned evap leak, is it sucking fumes straight from tank, causing it too be rich?

Per the workshop manual with a rich running condition it says to check for vacuum leaks, so that's where I am starting.

Yesterday I pulled the EGR pipe that goes into the back of the intake manifold, sure enough the seal was cocked/crooked. Took it off and cleaned everything before putting it back in. Also put the old MAP sensor back in with a new O-ring, viola system is no longer reading too rich.

Apparently the 2 different styles of MAP sensors are functionally different. One is bolt-on, the other is twist-in. Mine has the twist-in style whereas I bought the former by mistake.

I still have an EVAP leak to trace down, so that will continue once the tool arrives.

Now for a new update... It has still been running rich. The smoke machine arrived, we got a ton of rain, and I was able to smoke the EVAP system. I found 2 leaks: first was a vent line from the top of the gas tank to the filler neck. Inspecting the line, I found the plastic fitting off the tank had snapped. The second was the inlet on the top of the gas tank from the fuel filler. Some gasoline-safe plastic epoxy later - no leaks!

I also was stumped, since I could not find any leaks in the engine bay; Intake, vacuum lines, EVAP lines - nada. Using my OBD2 scanner app I was seeing LTFT values of -32.8% to -33.1%, constantly. I've been consulting with a Chrysler tech nearby and he said something is still making it run rich, even after he was introducing vacuum leaks. This is after a brand new MAP sensor and brand new (MOPAR) pre/post catalyst oxygen sensors.

We went back through my parts ordered and checked the new injectors I used and... They're rated for 300cc/min @ 3 bar. The OEM injectors are rated 283cc/min @ 3 bar. So, new OEM injectors on the way. I seriously hope I'm at the end of this so I can get it passing smog.

Damn. That's worst than mine.
So how many miles?

207,693 as of today... Runs really strong, just rich. Maybe I should leave the bigger injectors and just throw a 5psi blower on it :D

Yeah no kidding.
Can't go wrong with a low psi power adder.

Can you get the computer flashed for bigger injectors? I've had tuner services flash a ecm for the last 5.3 build I did.

Good news! New OEM injectors installed today, went through checking the fuel trims. Long-Term fuel trims are 0%, passed all readiness tests - I think it's ready for smog this week! Woohoo!

Man, what a roller coaster. Here's the full list of what was done:

• 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)

I think next I need to investigate a leak on my transmission (output shaft maybe), new shocks, and steering rack. Then poly bushings all around with a bushing press/puller tool. The projects never end!