Saturday, May 21, 2005

Well, I have news to report, and it's not as good as I'd like...

The guys finished getting the engine back together this morning, including the FuelPro 380 fuel separator thingy, got it all primed and ready to go, and started it up. It took some fiddling with connectors and plugginng the ProLink into the DDEC port to get it to stay running, but after half an hour or so it started reliably, there were no codes on the DDEC, and it looked like we were ready to roll.

It was pushing noon at this point, and Virgil pointed out that, if we were to leave LA today, we'd need to be on the road by 1:00 to avoid the traffic madness. But first we needed to road test.

So we took Odyssey out onto a couple of the local freeways and put it through some moderate testing. Just pulling away from the shop, it felt sluggish, and half an hour on the freeway demonstrated a marked lack of horsepower. At one point on I-605, we dropped down to 40mph climbing a moderate hill, I'd estimate no more than 5%. Turbo boost pressure wouldn't climb past 11 or 12 psi during the testing, either.

We returned to the shop around 1:00 and reported the issue to Virgil and Armando. The first suspect was fuel delivery, given that we made changes to the fuel system by installing the FuelPro. Putting a pressure gauge on the secondary filter manifold showed good fuel delivery pressure, though, and fuel delivery rate was nominal according to the computer during the road test. While not ruling out a fuel problem completely, we started to look elsewhere.

It turns out that the pressure valves on the airbox drains were stuck open. That would account for some loss of turbo boost pressure, which should build to around 20psi or so under load. While I doubted enough air could be lost through the two little 1/4" orifices to account for the problem, the valves were changed as a matter of course.

At this point I persuaded Virgil to come with us on a second road test, since I was beginning to doubt my own subjective observations about the power availability. But it was clear to both of us in the first few blocks that something was, indeed, still wrong. Suspecting it might be the ECM, Virgil made a quick call to Valley Detroit Diesel, and we were off to their shop to put Odyssey on the rolling dyno. (PEDCO's dyno is the type which requires the engine to be out of frame.)

We had to crest a pretty good hill to get to Valley, and it became clear during the drive that turbo boost was inadequate. No power on the hill, along with black smoke, pretty much implicated the aspiration system. Boost grudgingly climbed to a high of only around 16psi. Nevertheless, we decided to go ahead with the dyno anyway.

We did one run on the dyno, with me in the driver's seat, Virgil watching the smoke, and the Valley technician running the dyno. Louise took some photos, which she will probably post here at some point. The huge amounts of black smoke and the lack of power precluded doing a full dyno run. But the one quick run showed only about 275 horsepower on the ground, and our 475 horse rated motor should put around 360 on the ground at full tilt.

Based on the smoke and the power loss, Virgil thinks that perhaps the turbo went south on us. We've all got our fingers crossed that this is, indeed, the problem, since the turbo is pretty easy to remove through the access panel in the bedroom, which I have yet to dog down. They were getting another turbo ready for us even before we left Valley Detroit, and tomorrow morning they'll get to work on swapping them out.

We've also agreed to swing back through here after our visit to San Jose. This will give PEDCO an opportunity to look over the engine and make sure everything looks good after the first thousand or so miles.

If all goes well and the new turbo fixes things, we should be on the road tomorrow.

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