2012 E450 5.4 214k

Back on here again, and I got another bus giving me trouble. Like my last one, first, a bit of the backstory. May seem a long story, but there may be some combination of events someone else may have an 'ah-HA!' moment. Just for the record, I know for a fact this bus does't have any diesel in the tank.

4/19/18:
Drove 250 miles over three mountain passes to the west-side to pick up this new (to us) 14 passenger airport shuttle bus. Me and a co-worker took it for a test drive. Ran and drove real nice. Only 'issue' it had was a transmission 'noise', and it only happened when I put the pedal to the floor and got the RPM's up to like 4k or more. A vibration noise is the best way I can describe it. Checked the computer and there were no codes, present or stored. While idling in the parking lot, all numbers looked good (fuel trims, temps, steady idle) and the exhaust smelled good and clean. They had recently had the water pump replaced and whoever did the work filled it with green coolant (should be yellow G-05 AFAIK).

So, on the drive home. I brought my OBD reader with me, so I set up a single gauge to monitor the coolant temp (water pump and green coolant are red flags to me) on the return trip. We drove about an hour and stopped to fill up the tank before hitting the first mountain pass. Somewhere along that hours' trip, something changed. When I came to a four-way stop, the engine was chugging. Not a random miss per-se. More like a dead hole. I figured, like all the other buses we've gotten, desperate need of a tune-up. Filled the tank and on down the road.

Now I start to notice the temp climbing, but we're also starting to climb up the first 3,000 foot pass. As it hits 210, I kick on the heater full bore. Then the back heater, full bore. Kept it at 200 max. As soon as we got over the hill and onto the flats, the temp would drop to 170, so I'd kick the heater off and it stayed around 195. I just had to replace the radiator in our other 2012 E450 (also with a 5.4, and I drove that one back last year) and the replacement radiator is a 2-core, stock is a single core. Based on what the temp was doing, $150 for a radiator upgrade was happening too (this rig will be transporting 14 workers at a time in triple digit temps with the AC cranked).

As for the power. While on the flats, power was alright. The first pass? WOW. Like, maybe 40 MPH. I kept the RPM's under 3,500 the whole way up, and that was about a half-hour pull. DEFINATLEY getting a tune-up. But, the next pass is 4,000 feet, and longer. Well...I managed to pull that pass at 60-65 MPH except for the last mile, which is what I expected. Same thing, 40. Temps climbed, heaters came on, yadda yadda.

So I finally get to twist some wrenches on it today. Set up some better gauges on Torque. Here's what I got:
LTFT1: +12% to +16% and it fluctuates quick.
LTFT2: +10% to +14% and it fluctuates quick.
STFT1 and 2: -3% to +6% and they fluctuate quick.
O2B1S1: Nothing. No voltage whatsoever. Swapped with B1S1 from other 2012 5.4 and same thing.
O2B2S1: 1.24v and flat-lined there.
Timing advance: 3 to 6 degrees.

LTFT's do NOT drop when I take the RPM's up to 2,500. I think I may have an intake manifold gasket leak...when I introduce propane around the inside edges of the IMG, the STFT's drop to normal ranges...but they stay there after I remove the propane. If I shut off the rig and fire it back up, STFT's return to the -3% to +6% fluctuation.

When I remove the air filter, STFT's dive to +35% and the engine stumbles and almost dies. I can move the filter enough to get the tip of my propane tube in and I can adjust the amount of propane to get the STFT's to normal ranges, but it still ran real rough. I can even get them to head to -15%. Still rough. No changes in LTFT's.

Fuel pressure KOEO at 55psi. KOER at 56psi. After 5 minute bleed down, it was at 35psi.

So I pull the plugs. All had some white buildup on them except cyl 2. That one had black buildup but smelled of fuel, not oil. Gap on all plugs (except #2) was at .070"+. #2 was at .060". According to the records I got when we bought this, which I didn't get until a week later, they had the plugs changed about every 40k miles. These things look like they are 10 years old.

Tomorrow I will pull a compression test on all holes, test ALL the COP's (#2 and #6 tested the same and within spec), maybe even pull the injector rails off and ohm the injectors. Think I'll swap B1 and B2 O2's and see if the no voltage follows. Maybe I got some bad wires. #2's plug is telling me I got a stuck injector (open). But the pressure did't bleed down out of spec...?

Side note regarding the O2 sensors. If I unplug them while the engine is running, passenger side (B1?) seems to kill the LTFT gauges, and the driver's side (B2?) kills the STFT's feed. I'll double check this tomorrow as well and write it down.

None of the plug wells had coolant in them (I'm replacing the intake on the other 2012 because of that).

I think they did have the intake off at some point because they clamped (with hog-ring style clamps...no WAY they got THAT tool in there with the intake on!!!) chunks of vacuum line on all the 9 factory vacuum tips (?) and put screws in the ends of them...just checked. According to the records, nobody has pulled the intake. Unless it was done before 36k and they were driving it like that for 185k.

Well, that's all I got for now. Tomorrow's coming fast.

-McMechanic

 

You're doing the right things determining what's at issue and I'd strongly suggest posting your info in the Modular Motors V8 forums here. Many of those guys there are quite well experienced with interpreting your readings.

FWIW I'd suspect an intake leak as part of your fuel trim issues---not sure what to think that they remain normal once your propane is removed. Removing the air filter shouldn't spike your STFT's that much---could your MAF be acting up or dirty?

 

I did in fact swap the MAF from the other '12 bus, but it only made a marginal improvement, if any, and I had that one on it for all the testing I did.

As for the STFT staying after removing propane...I'm guessing maybe once the manifold was good and warmed up the gaskets seal a bit better? Maybe because the intake is plastic and has stock gaskets, when I shut off the engine and remove vacuum from inside, the intake cools and the gaskets go back to leaking next time I start it?

I know the gaskets are leaking. Propane does indeed affect the STFT'S, and I can see 'moisture' all along the inner edge of the gaskets. Its only $240 for a new Doorman intake. And, since I've already done one....

I'll look into moving the thread to the Mod v8 forum.

Thanks for chiming in so quick!!!

-McMechanic

 

Not sure if this question is specific to the E450's or what. I'm changing out all the idlers/tensioners while I'm in here replacing the intake. Problem I have is I can only find 90mm (3.54") idlers and the pulley for the tensioner (75mm/3"). On my two 2012 E450's, I have three idlers AND the tensioner.

Passenger side idler is 90mm. Driver's side is 100mm (4"), and the one under the alternator is 74mm (2.92"). The passenger and driver's idlers are your typical stamps steel. The center one (under alt) is a heavy, machined steel pulley.

Only reason I bring it up is because with the original pulleys, the ribbed side of the belt where it goes over the tensioner-around the lower AC-around passenger idler, the gap is only like 1/4". If I put a 90mm pulley in place of the 100mm on the drivers side, that will make the tensioner come up more to take up the slack, making that gap even smaller.

Do I just run the smaller pulleys and get a short belt?

-McMechanic