Orange4boy's Rescue and Revival of a 2003 Prius

[Daox]

Great restoration orange4boy!!! Let us know what you think of the vehicle now that you have it running.

[orange4boy]

We took it for a drive on the driveway last night which is long and steep and it did fine although too slow and bumpy for a good feel for the car. Today we got the tags so I got to drive it around a bit on the island.

Fun car to dive and very quiet. Handles very well. You can't tell if the ICE is running unless you are accelerating at a good clip. In the van, I can coast almost all the way into town except for three short bursts of the ICE. I'm hoping to do the same or better in the Prius but I will need a tach or a light to show when the engine is running. I noticed you can trick it into shutting off if you tap on the brakes enough to regen for a second then lightly back on the throttle.

Interesting but strange sometimes when it decides to run the engine. It runs when you have the fan/heat on probably to keep the heater core full of hot coolant. Or is it to run the A/C for fast defrost? Or both? At first I thought it was for the 12v but that would come from the DC-DC.

Weirdly, the ICE starts when I put it in park after stopping while on electric only. It may be charging the battery but I have waited long enough for the MFD delay to pass. Will have to check that out.

I got a first MFD mileage of 5.4 L/100Km - 43.5 mpg. Not bad for Bowen where the van gets about 10.5 L/100Km - 22mpg. It will be a bit lower for Honey's commute because it will be cold at each end.

It definitely will need a grille block and some more engine bay blocking to stay warm as it cools off in just a few minutes at 10˚C. Finally, a chance to use some of the Soundown acoustic / thermal insulation I got at a thrift shop. A block heater,and two sump heaters are also on the menu.

Now I have to clean up the chaos in my garage...

[Daox]

The usual technique to kill the engine is to simply let off the gas pedal and reapply a tiny amount of pressure to it (at least on the 2nd gen).

If you use the heat, your engine will stay on more to keep the heater core hot. Not sure about running A/C. I know on the 2nd gen, the compressor runs off the high voltage pack.

I'd also highly suggest a scangauge for the car. It can really help you dial in your driving. There are special codes to read out state of charge of the hybrid pack, how many amps you are pulling/regening (very useful to see how hard you can brake before physical brakes engage), and a few other prius specific read outs.

[bwilson4web]

Hi,

The A/C compressor is belt driven on the NHW11. Although it tries to cycle the engine off at a stop, almost any use of A/C tends to run the engine. To keep the engine on constantly, use "MAX AC." Defrost is a known mileage killer to the extent I've even experimented with chemical defoggers inside the car (not very successfully.) They tend to cause more problems with internal glass vision than they cure.

When the engine is cold, for the first 30-40 seconds, the car moves on traction battery power while letting the ICE spin at about 1,200-1,300 rpm with gentle accelerator use. You'll hear the engine rev up once this initial warm-up (lighting the catalytic converter) is done. My strategy is to gently accelerate to the highest speed during this 30-40 seconds and then gently sustain or let the speed bleed off. A brief but obscure mileage trick that works if I can pull from my work parking spot onto a 60-65 km/hr street.

During the rest of warm-up, the car goes into a rich mixture mode that is pretty fuel inefficient. For the first 3 km, I try to keep the speed as low as practical, at or under 40 km/hr, by cutting through the neighborhood and using "N" whenever possible. For example, at a stoplight, I'll shift into "N" and you'll notice the fuel burn is a little lower. This continues until the engine coolant reaches 70C.

Ken@Japan has documented the warm-up stages but the last and final, Stage-4, happens when the car has come to a stop and the engine auto-shuts down. Thereafter, the car hybrid control laws work including shutting off the engine when it can. The car really has to be stopped and I've even pulled into a parking lot to stop just to trigger the Stage-4 transition.

Any speed above 67 km/hr (42 mph), the engine has to run. But I prefer to keep a 'guard band', below 62 km/hr or above 72 km/hr, to avoid transiting this critical speed and triggering inadvertent engine operation.

Your plan to install block and pan heaters has a lot of merit. I find it saves about a minute of the initial 5 minutes of warm-up. Any block heater, warm-up interval of 30-60 minutes works great but then comes the problem of what to do when there is no power outlet. You may want to look at this temperature hack inspired by the work of Clive Burk of the UK.

If you can keep your maximum speed at or under 105 km/hr, you'll get excellent highway MPG. This chart shows what I've found to be the mph vs MPG curve (sorry, I don't have a metric version):


During warm-up when stopped at an intersection, sometimes the engine can be trigger to auto-stop by shifting into "R" and with the brakes held, briefly stab the accelerator. It doesn't always work, mostly in the first 1-2 minutes, but if you are stuck at long light and the engine coolant isn't warm enough, engine off is better than even idle in "N."

For the most part, I run my tires at maximum sidewall pressure. The ride is slightly rougher but it improves the ability to take turns at higher speeds. When you get the alignment done, this might help with doing a four-wheel alignment.

The steering has neutral stability. I found that switching to a slightly larger diameter tire seemed to marginally help. But the car can take turns at high speed like nobody's business.

When approaching home or work, I try to find a route that for the last 3-5 km I can keep the speed at or under 50 km/hr. This relatively slow speed maximizes hybrid operation and use of the traction battery. The NiMH batteries have a self-discharge characteristic so I prefer to use the charge and save the gas.

After 70,000 miles (112,000 km,) my lifetime mileage continue to run just over 52 MPG (4.52 L/100km). The car now has over 123,000 miles, nearly 200,000 km. You and your wife are in for a treat.

Bob Wilson

[MetroMPG]

Again, I have Prius envy.

Congrats go to yet another EM member for restoring/repairing a fuel efficient hybrid back into service. You're going to have lots of fun with it.

[orange4boy]

Defrost is a known mileage killer to the extent I've even experimented with chemical defoggers inside the car (not very successfully.) They tend to cause more problems with internal glass vision than they cure.

I used to have a VW beetle with chronic fogging. The only thing that worked was dishsoap or a mild detergent on the glass. If you applied it right, it was pretty good but if it dried out, it left a film. I also used a squeegee but on a beetle you don't have to reach far to use it. I'm already thinking about some better cures:

1) Very clean glass. Like in cloud formation, window fogging can be hastened by particles and films.
2) Dehumidifying. One TSB suggests turning on recirc. during parking and storage to reduce interior moisture build up. I also put my dehumidifier in my vehicles overnight every few weeks in the winter. A space heater also works.

During the rest of warm-up, the car goes into a rich mixture mode that is pretty fuel inefficient. For the first 3 km, I try to keep the speed as low as practical, at or under 40 km/hr, by cutting through the neighborhood and using "N" whenever possible. For example, at a stoplight, I'll shift into "N" and you'll notice the fuel burn is a little lower.

Aha! very good. I was wondering about using neutral. I can coast a really long way like this on the first leg of my drive.

The car really has to be stopped and I've even pulled into a parking lot to stop just to trigger the Stage-4 transition.

Excellent.

But the car can take turns at high speed like nobody's business.

I have no idea why the reviewers I have read complain about the handling but I suppose they are comparing to the last Ferrari they test drove. My comparison is the mid engine Previa, probably the best handling minivan ever made but still a minivan.
And the Prius turning radius is so wonderful!

Honey has nicknamed it Chewbacca. First for the "face" it has and second for the regen growl which does sound quite a lot like Chewy. I suppose the colour isn't right unless there is a Wookiee arctic morph. (goes to check Wookieepedia. Yes, that's right... Wookieepedia.) Turns out there are albino Wookiees. Now... where can we get seat covers that resemble an albino Wookiee?

Hmmm. No seat covers yet but a Wookiee wash mitt.

Oh! the Geekery!

[orange4boy]

Getting closer...



Longwool Sheepskin Car Seat Covers

[bwilson4web]

Originally Posted by orange4boy

. . . second for the regen growl . . .

Uh Oh. Please do not 'set your hair on fire' but regen should be fairly quiet. I typically hear inverter 'whine' a mosquito like noise and not a rumble:

• Does it remain if you shift into "N" while rolling? The reason is one of the symptoms of a failing transaxle is a short in the MG2 stator. This causes what has been called a rumbling sound that is proportional to the speed. The stator winding short also leads to excessive MG2 temperature, which the mini scanner can detect. I'll record the hill roll-down test starting at 0 km/hr and let it roll as fast as it can ... turned out to be ~38 km/hr.

I'll record regen down a hill on the way home this evening and post a URL where you can hear it. I'll call out the speed in km/hr since the fixed gear ratio will set the frequency. It only reached 38 km/hr on the hill roll down.

Tires and alignment can also cause a rumble as well as a bad wheel bearing. Let's keep the ambiguity group open. It is not uncommon to find one problem masked by another. Fixing the transaxle just means we can look at the next.

If on a highway run of moderately high speeds and 30 minutes duration the MG2 temps are lower than MG1, then I would give the transaxle a clean bill of health. Let me know what sort of convient highway speeds you have available and I'll replicate the test in Huntsville. We've had a cold front come through with night time temperatures around 0 C.

Hummm, you might want to double-check the transaxle oil level ... you never know. Oil helps dampen gear noise.

PLEASE don't take this as anything but curiosity. It may be your ear and mine hear different things. The iPod recording should help answer the question. The reason is the rotor speed is geared down compared to the wheel bearings. The frequency vs. speed should be a good tell.

About the old transaxle, folks are always interested in what the guts look like. I suspect we'll find the Power Split Device (PSD) is fubar; the 'silent chain' still there; and everything else ... most enlightening. Your friend interested in making an NHW11 into an EV might also want a bench 'test article.'

The position encoder of the NHW11 is a little tricky but obviously it works. Once he gets a chance to 'look at the guts' on the bench and run a few tests, he may come up with a better plan. <grins>

Bob Wilson

[bwilson4web]

Hi,

Here is the URL to the "D" roll-down. The hill is not steep enough to achieve high speeds but it is enough to give an idea of what my NHW11, 2003 sounds like in 'regen:'

Sound of NHW11

The same roll-down in neutral sound like this but achieves a higher speed.

Bob Wilson

[orange4boy]

No, no, Not to worry. The regen noise is very faint and high pitched and there is nothing whatsoever coasting in neutral. I wouldn't describe it as a growl and it's only audible when you brake pretty hard. It sounds like the Chewbacca call minus the throaty bits in that it starts higher and lowers in pitch as you slow down. And as tough as the walking carpet is, his voice is pretty high.

I will keep an eye on the temps at highway speed when we go to the in-laws on Tuesday.

Im very curious to see the insides too. I still have to do a big clean up and catch up on some work for a client though, so I'm going to have to be patient.

On another note, I bought some interesting 120V 140watt elements at Princess auto the other day for $4 ea. I had seen them before but had not thought of a good application for them. Now I have a candidate: Oil pan heaters for the Prius.

The elements are CSA approved, U shaped, made of aluminum with a resistive core and have seal on the end which I hope to finesse into two holes in the side of the pan so the element is suspended in the oil. I don't know about rubber seals and oil, though.

I will have to test them first to see that they don't overheat the oil or leak through the seals. I think I can install them in both the transaxle oil pan and the engine. Tested one today in a giant tin and it heated the water to 120˚F in about an hour. Next. I will test it in an oil bath in an old baking sheet to see if the seals work an test it's reaction to oil. If the seals don't work (and I suspect they might not) then they could be fairly easily surface mounted on the underside of the pan.

Fun fun fun.

Added. Thanks for the audio clip. Sounds the same as mine. And in neutral... dead silence.