Category Archives: School Bus

Replacing the IPR *or* No more Hot Start Fail!

So, I finally got to replace the IPR (Injector Pressure Regulator), in hopes of tackling the very frustrating Hot Start Fail problem that I’ve been dealing with on the bus’ T444E engine.  The IPR is attached to the base of the high pressure oil pump, between the valve covers and kind of under the fuel filter/water separator, and lots and lots of wires and air ducting.

The IPR is right where I’m pointing – between my finger and the white of the chuck pad.

In doing my research on changing this part, I found that I’d have to be prepared for some oil leakage from the high pressure pump’s reservoir, and that I’d need a deep socket to get the regulator itself out.  I had a chuck pad I could use (they’re really absorbent) and was able to slide it in under the old IPR to catch the escaping oil – though no quantity had been specified, just that I should “have a bunch of paper towels ready”.  I hoped I was ready.

The new, shiny IPR, disassembled.

The IPR is a solenoid valve, and the electromagnet comes off the stem that houses the moving bit to control oil flow.  So, to take the piece off, you first have to remove the holding nut, a spacer, and the electromagnet from the stem, which can then be unscrewed.
All in this very small place.

The IPR plug.

But it can be done, and relatively quickly, it turns out.  The electromagnet has an electrical connection for controlling it, and that just has two clips on either side, then slides out and can be woven back around some pipes and wires to keep it out of the way.  The upper portion of the plug is wider than the lower, so you can’t plug it in the wrong way – an important detail for putting everything back together and doing it by feel.

The 3/4″ wrench getting the holding nut loose.

The next thing is to take off the 3/4″ nut that holds the electromagnet and spacer onto the stem.  This is a very thin metal nut, so it doesn’t take much to get it off, but if your 3/4″ wrench is long (like mine), be prepared to make a bunch of very tiny pulls to get it finger-loose.

Electromagnet, spacer, and holding nut.

Once the nut is off, the electromagnet and spacer should come right off.  I ended up having to unscrew the spacer for a bit along the threads for the holding nut before it broke loose enough to slide.  And a little wiggling was necessary to get the electromagnet to slide, but it came more easily than the spacer once I got it wiggling.

The 1 1/8″ deep socket.

It was then time to get the deep socket.  In doing my research, I had taken the new IPR I had apart and fitted the stem to a large (shallow) socket that I had to find that it was a 1 1/8″ size.  Our local Autozone had a deep socket in stock for $8, so that wasn’t bad at all to get the right tool.  However, the stem is so long that you need every bit of space in the deep socket (I wasn’t sure that the ratchet end would sit in the socket securely), and it turned out that the deep socket’s center hole wasn’t a full 1/2″ in diameter, so it wouldn’t fit the stem up into it.  And of course, that would mean that the socket wouldn’t engage the points.  Luckily, I was able to use a 1/2″ drill and get the hole open so that it would work.

Deep socket and ratchet in place to remove the IPR.

Then there was just the matter of getting the socket onto the stem, which involved some wiggling, moving of wire harnesses this way and that, and then, once on, doing some more of it it get the ratchet down to engage it.  For this, I ended up using the 3/8″ ratchet with a 1/2″ adapter on it to be able to get a better pull, as well as to get a spacer between the socket and ratchet that was long enough, but not too long, to work around hard engine elements.

The old (and somewhat blurry) IPR is all out!

The stem broke loose fairly easily, and with some wiggling and shifting, it came out!  I could see that the chuck pad had collected some oil, but couldn’t see how much at that point.  But the important step of removal was now complete.

The new IPR in place!

I transferred the protective red plastic cap from the new stem to the old one, and set about reversing the process to install the new IPR.  The only real difference was that as I was tightening the new stem in place, I slid the chuck pad back away from the high pressure oil pump, so it wouldn’t have a chance of getting caught and messing up the seal.  Once the stem was nice and snug, and the electromagnet, spacer and holding nut were on and secure, I plugged the control wire back in.

Easy clean-up for the planned oil spill.

In cleaning up, I checked out the chuck pad.  It looks like there might have been about 4-6 oz of oil that drained out when the stem came out of the pump.  I don’t know if that’s typical, but it’s my best estimate.

Once all the bits were stowed away, I started up the bus.  It cranked without starting at first, but knowing that it would have to pull enough oil to the high pressure pump before it would start, I kept it cranking, and then it caught.  It ran rather ragged for the first half-minute, then smoothed out pretty well.

Note the missing bit of green gasket at the bottom of the stem!

The new IPR is more responsive than the old one, but some of that could be  in the fact that part of the seal on the bottom of the old IPR was missing!  I’m wondering if that, coupled with either less viscous hot oil, or perhaps some dynamic of the metal being heated was what was causing the hot start fail.

At any rate, a quick test-drive, then attempted restart of the engine proves that the engine now starts up fine when hot.  It also seems a bit more responsive to the accelerator pedal, so I have to get used to starting off in second all over again.

Replacing a Linear Actuator

So, you may remember that I removed a section of the bar that opens the manual door and replaced it with a linear actuator, which was then attached to a remote unit that meant that the door could be opened and closed by the use of a remote fob.  And the system worked really nicely for a couple of years.

The broken back plate from the Firgelli 8-12-12 actuator.
The broken back plate from the Firgelli 8-12-12 actuator.

Unfortunately, it was subjected to stresses that I hadn’t foreseen.  While I had looked at the 300 lb holding ability, and the 8 lb press (not 150, I came to find out – a labeling error) power as sufficient, I hadn’t prepared for a teenager who was trying to pull closed the accordion door while the hand-control was locked closed.  The back plate of the actuator snapped under the stress.

Faced with this situation, I obviously had to fix this, so that the door could be closed and secured, but still usable.  As a temporary solution, I had a piece of 2×10 that just fit in the bottom stair that would block the door from opening, and I could still climb in and out of the rear door which has the deadbolt lock.  I then set about trying to find a replacement plate.

The new end case for the ill-fated actuator.
The new end case for the ill-fated actuator.

Firgelli Automations no longer made the model that I had purchased, so had no parts for it available.  I then attempted to fab up a ‘sheath’ to enclose the back and secure the engine/shaft casing.  As I was finishing this up, the engine finally failed, which was very frustrating.  As I did some research, I found that many of this model had had the engine fail, and it was a usual end-of-life situation for it.

While this was disheartening, I contacted Firgelli’s support about getting specs on the engine to see if I could find a replacement somewhere, but no luck.  They make all their components themselves, so it was a special run.  They were able to point me toward a different model that was more rugged and had a more powerful (and durable) engine than the model I had.

Firgelli Mini Linear Actuator 15lbs Force – 12 Inch Stroke


List Price: $139.99 USD
New From: $139.99 USD In Stock
Used from: Out of Stock

The new actuator in place.
The new actuator in place.

This model is much more rugged than the original unit, and about twice as powerful.  And the connectors are an eighth of an inch bigger in diameter than the original, which meant that not only did I have to undo all my sheathing welding, but I had to fabricate new sockets too.  As we were right near the limit of when the inspection for the bus would run out, they’re, unfortunately, rough and unpainted.

New arm socket (note removal of stop-nut from threaded end).
New arm socket (note removal of stop-nut from threaded end).
The new handle-end socket. (Well, okay, to be fair it still has some old paint on it).
The new handle-end socket. (Well, okay, to be fair it still has some old paint on it).

It’s also an inch longer when fully retracted, and I was able to compensate for about 1/2 an inch with the adjustment threads at the door, but it means that the door doesn’t open quite as wide as the old unit allowed – but that’s just me being picky.  (It’s also cheaper to buy directly from the company’s site than through Amazon …)

While I’ve not got to painting the new unit, I do have to admit that the works are much smoother than the old unit. Check it out in action:

A Week in the Bus (Allegany State Park trip – Part III)

(Continued from Part II)

The Red House area of the Allegany State Park is really nicely suited to biking. All the camping and major cabin areas seem to be connected with paved trails, and all the roads within the tent/RV area were paved, with the sites having gravel parking area and some grassy area as well. Our site was actually very close to level, but many of the other sites were not, and I helped one of our neighbors with the ‘lego block’ style levelers, which worked for him nicely.

Staying for the whole week was great, and we only saw one other rainy day than the night of our arrival. However, we didn’t take advantage of any of the hiking trails, though we did bike the ‘on road’ biking trails and canoe on Red House Lake. This was due to my wife having a project that she needed to finish (and with the back of the bus pointed south, she got great natural light from all the windows), and our son spending most of the days at the Dresser-Rand Challenger Science Camp that one of our other homeschooling moms heroically set up and co-ordinated for other homeschoolers. A bunch of the homeschooling families were also staying in the Red House area (several right in our loop!), and so the kids were able to work at camp, then come back and play, grabbing their bikes (and often the wrong shoes) to go exploring the local playground in the camp area, or the park toward the lake, or the treed area between some campsites, or the creek that ran alongside the campgrounds down to the lake. As a result, we didn’t see our son much that week.

But having all three of our bikes meant finding a place to store them securely. I have a long Kryptonite lock and cable, and it worked out that I could lock all three bikes to the bus by fitting the lock around the bottom edge of the safety cage of the fuel tank.

Kryptonite Keeper 12 LS Bicycle U-Lock with Bracket Bicycle U-Lock (4-Inch x 11.5-Inch) (Sports)


List Price: $26.06 USD
New From: $24.90 USD In Stock
Used from: Out of Stock

KryptoFlex 4′ Cable (Sports)


List Price: $12.99 USD
New From: $8.95 USD In Stock
Used from: $10.00 USD In Stock

Our site Captain was from Bradford, PA, and lives right by a rail line, and noticed the Super Tyfon right away. After chatting with him a bit, I promised him that I’d sound the horns when we left, as I was concerned about disturbing other campers. Upon leaving, when I sounded the horn, I got a thumbs-up from the Captain, and a not-surprising number of looks from others nearby. I got a report from one of our friends who left after we did that lots of people in the campsite cheered and called for the horn to sound again, but unfortunately, I was already off on the road by then.

Our trip home was via the Quaker area, as we were due to meet friends there in October. This meant going over one mountain/ridge, and then back along the same route, and then out of the park over the mountain with the ski area and fire tower. This was probably the longest, steepest climb I’ve taken the bus on, and I ended up in third gear, doing about 25 mph and watching the coolant temperature climb. I gave the bus some time to cool at the top, then took it down the other side of the mountain (seeing some neat views from the overlook), really getting comfortable with letting the bus engine retard the speed, and using (gentle) stab braking.

A break in the trees while driving down the mountain shows the Allegheny River Valley at Salamanca!
A break in the trees while driving down the mountain shows the Allegheny River Valley at Salamanca!

(In case you don’t know what stab braking is, it’s when you push down hard on the brakes to dramatically lower your speed, then let off again, letting the engine and transmission slow you down, until you get over a speed where they lose efficiency, then you ‘stab’ the brakes again.  It keeps the brakes from overheating, and your vehicle well under your control.)