Lo, these years latter, its done. <img src="/forums/images/graemlins/notooth.gif" alt="" /> <img src="/forums/images/graemlins/rolleyes.gif" alt="" />
I finally had to start over from where we swapped the engine into the bay. While I got the FIC to work - and work pretty well - I never got the injector code and CEL to go away. Now that CO fails emissions if ANY code is present, that was kinda out for me. <img src="/forums/images/graemlins/frown.gif" alt="" /> So, everything back to bone stock.
I replaced every sensor, solenoid and electronic 'whatsis' under the hood and all the emissions stuff in the engine bay as well. I had an entirely new exhaust installed from the manifolds back. 3.5L FED passenger side down pipe and 3.0L FED driver side down pipe (they don't make the 3.5L anymore) - the 3.0L pipe slightly lengthened to mate to the 3.5L down pipe. New OEM CAT and the little elbow pipe after that that normally bolts to the muffler, then 2.25" pipe to the back with the new Flowmaster "SUV" muffler. New OEM O2 sensors as well.
Along the way doing all this fixed several persistent problems I've had for years and uncovered a few problems I didn't even know I had. <img src="/forums/images/graemlins/smile.gif" alt="" /> At this point its now running like a brand new vehicle. So, that's all goodness! <img src="/forums/images/graemlins/kewl.gif" alt="" /> <img src="/forums/images/graemlins/smile.gif" alt="" /> I also finally had to replace my rear D44 and rebuilt my front D44. ProRock 44 in the rear now and beefed up the front with new cromo shafts and outers. Been an expensive year. <img src="/forums/images/graemlins/frown.gif" alt="" />
So that's the good part.
I readjusted the electric fans to come on (50%) @ right about 186 with full on at 208. So, fan one is running at about 85% at 200. That's good about 90% of the time. It sucks because the running the fans constantly and at that speed drags on the 175A alternator and uses more gas, but that's the only way I could finally keep it the temps from bouncing all over the place and horking up the ECM.
Ironically, this setting works better OFF ROAD than on pavement. At low speeds - below about 35-40 - it still warms up. I can't hear it but its pretty obvious its detonation caused. <img src="/forums/images/graemlins/frown.gif" alt="" /> The lower the gear (timing increases) - the worse the problem. So, no different than before. I need to try dropping the fans about 5 degrees while keeping full on at 208. That should keep the temps down closer to 200-205 rather than 208-210 as it sometimes gets now. This is not ambient related - it'll do this when its 50 degrees just as bad as when its 98.
On the highway it'll still get to 208-210 but won't get any worse so that's ok. I should say, as far as i know. I haven't tried taking it over the passes in 90 degree temps.
Off road will run up to about 212 before the fans start pulling it down into the low 200s where it pretty much stays. That is a huge improvement. I think the majority of the issues here were caused by issues with the vehicle - sensors, egr, whatnot. Fixing the EVAP and EGR got rid of a LOT of issues, so .... Still, I think pulling the start temp down 5 degrees here will even things out a little more.
The biggest improvement to operation was just getting the engine temp stabilized. Climbing from 195 to 208/210 and back is fine AS LONG AS it doesn't do it 15 times a minute. Right now I have the cooling behaving very similarly to my '03 3.5L Sport and the '97 ECM has no problems.
I don't know how or if this conversion would actually run at sea level. There's still too much timing and that shows up now and then. All that I've done with the fans and radiator is nothing but a huge band-aid. I haven't actually fixed the problem of too much timing from the 3.0L ECM for the 3.5L engine. <img src="/forums/images/graemlins/frown.gif" alt="" /> It runs good - I have no complaints with the power. Gas mileage is crappy compared to what I'm used to with the 3.0L. Interestingly, its only a couple MPG worse than my stock AWD '03 3.5L. Just depends on where and what. Better in the mountains doing 45-50 MPH than my '03 but worse on the flat highway. Timing goes up - gas mileage goes down and vica versa. Sigh. <img src="/forums/images/graemlins/frown.gif" alt="" /> The FIC helped this considerably but ....
I guess the larger question is how long the engine will actually last with the 3.0L ECM. Detonation will beat the crap out of an engine eventually.
Anyway, conclusions ... I ALMOST wish I'd never done this swap. The extra torque is really nice and the overall performance is a good bit better than the 3.0L in a 6000lb vehicle. Driving at low speeds in the mountains is a dream compared to the 3.0L. The mileage is nowhere even close to what I used to get with the 3.0L. 300-315 miles a tank w/ 3.0L vs 230-250 (closer to 230 in the winter) with the 3.5L. So, while performance is good, cost to operate has gone through the roof. 2.5/3 tanks a week. <img src="/forums/images/graemlins/frown.gif" alt="" /> And, again, engine life is an unknown. I really doubt this one will make it past 200K.
On the other hand, I'm glad I have the 3.5L with the ProRock. The new axle is quite a bit heavier than my original D44 so the 3.5L keeps things comfortable in the mountains.
Anyway, so that's it. Maybe now I can get started on my other Sport.
Edward
