Uh, addendum to my last post ...
Fun times in UT. I got lost between Meeker, Steamboat and Rifle. Ended up coming down some canyon north of Rifle. Well, I hadn't bothered to drop into Lo anything, so I was still in 1st gear 2WD at the head of the trail doing about 5 MPH when I ran head first into a boggy, dugout collection of flooded holes big enough to swallow a 3500 king cab. After clawing my way out while experimenting with randomly rearranging all my gear by bouncing it all over the interior of my vehicle and checking everything for damage, I continued on my way. Slower.
Didn't think too much of it 'till I got about half way between Grand Junction, CO and Green River, UT. Truck exhaust started sounding a little loud. Not much so I figured my existing little leak had gotten slightly worse with the bouncing and crashing so I continued on my way.
About 10-12 miles from Green River I suddenly lost power and everything got REAL loud. I was on the down-hill stretch practically coasting in by then so limped it to the hotel and parked figuring I'd deal with it in the morning. By this time it was running like hell, spitting and sputtering and idling horribly.
Got up the next morning, had breakfast and headed to the truck stop across the road figuring I just needed to have a pipe re-welded. Advice? Never break down in UT. Ever. After four shops - none of which either had a welder or someone who could run it if they did, I decided to do what I SHOULD have done first which was crawl underneath and see what the problem was instead of making assumptions.
Lo and behold, I'd managed to blow a hole through the flex joint where the down pipes transition to the exhaust pipe, CAT, etc. Not just a hole, but a hole the size of a 50 cent piece - right in front of the forward O2 sensor. Well, that explained the way it was running.
Also, made further running around pointless 'cause I don't carry a spare for that and I wasn't about to wait around to have Napa air drop one in via carrier pigeon in three or four days. And, I couldn't drive it like that to Price, so ....
It occurred to me that one of my handy 3" wide stainless exhaust band clamps would be very handy right about now. All of which were at home, of course. Well, off to Napa. Figured all they could do was tell me they didn't carry them. Surprise, they did. They even had a 3" diameter one which is the exact diameter of that flex joint. It took about five minutes to install and the minute I started the vehicle everything was back to normal. Cheap $8 patch which I will take any day. The bad part was that patch pretty much killed any chance of wheeling for the rest of the trip. <img src="/forums/images/graemlins/frown.gif" alt="" />
So, with everything back to 'normal' I decided to bail and head home a day early while my luck was holding. I decided to take the long way back to Denver by driving up to Price and cutting across on US 40. About half way back to Denver I noticed that the Sport wasn't running quite like it had been on the way out before I decided to be an idiot and not watch where I was driving. It actually seemed to steadily be running better. Which is saying something because it ran really good going out. Anyway, that persisted all the way back to Denver and its actually running smoother and with more power than it has before with the 3.5L.
I checked the entire exhaust before leaving Denver for UT and I couldn't see or hear a leak in the flex joint but now I'm starting to think that there was one and there has been one for quite some time. Which, now, makes me question several previous assumptions. <img src="/forums/images/graemlins/frown.gif" alt="" /> It takes VERY little outside air hitting the exhaust stream right in front of the primary O2 sensor(s) to really hork up the ECM/PCM, so ....
On my list anyway here shortly to accommodate the anti-wrap bar is an entire new exhaust from the manifolds back. The existing exhaust has about 150-200K and has been chopped and hacked so many times in the last three years that it's a wreak, so its definitely due for replacement. I was hoping, given the way its running now, that I was right on the edge of being done with this project but I want to get rid of ALL the leaks and possible leaks before any finish fine-tuning tweaking on the F/IC maps.
Like I said, its running like a top. Even with about 800 lbs of gear, gas and water in a vehicle that weighs about 5700 lbs now I had no problems tooling up and down the mountain passes and doing 70-75 MPH in 90 degree weather in UT. No over heating, no audible knock nor any discernible through the shifter. Power is excellent. I figured the extra weight would make a huge difference, but it doesn't really seem to care. Mileage is like my dad's '76 F250. 17.5-18.5. Loaded, unloaded, it just doesn't care.
I am STILL not happy with the mileage. Its not as good as the 3.0L was under the same circumstances with the same load. But, there's no way to tell if its just the way the 3.5L works, this engine just isn't as tight as my 3.0L, I beat the crap out of this particular engine trying to get to this point, or what without installing a brand new engine once I'm done so I can compare results. And, I ain't going there.
Right now its running like a top so I'm pretty happy. The torque is great. The new 1 ton steering drag link and RS7000 stabilizer make it drive like a brand new vehicle - smooth and straight even in the wind. Switching to 17"s running 35"s should take what little tracking on the ruts is left out.
I'll get the exhaust done, retest and see how it goes from there.
Edward
