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Letter 8

Isuzu Trek Owners Infoletter #8 


Annoying Dash board squeaks

Ken Harmon (kharmon (at) or kencathyh (at) reports

My ’94 Trek was plagued with very annoying squeaks coming from behind the dash.  I tried a number of things including getting behind and under the dash with a mechanic’s stethoscope while the unit was underway.  The final clue came when I realized the squeaks were changing with humidity – the coast verses the desert.

The problem turned out to be the area where the plywood deck ahead of the dash rests on top of the sheet metal firewall of the chassis.  What I call the firewall is the vertical sheet metal part of the chassis ahead of your feet when you are sitting in the driver’s and co-pilot’s seats.  The plywood deck extends foreword from the top of the firewall to the fiberglass cap of the motorhome just below the windshield. The firewall has a 90 degree flange at the top where the plywood deck rests.  On my motorhome there were three sheet-metal screws installed, two were loose and the third one missed the metal when installed.  There was no sealer of any kind installed.

To access this area, remove the large curved cover behind the dash.  Remove the decorative upholstery panel that surrounds the dash and attaches to the side cabinets.  My fix was to remove the three plywood-to-firewall screws, lift the plywood deck and install 1″ wide foam tape across the top of the firewall.  To lift the plywood I went outside the unit and worked through the “hood” access below the windshield.  By inserting screwdrivers between the top of firewall and the plywood deck and moving them in sequence from outside and inside the coach I was able to get the foam tape in position.  I left the paper backing on the foam tape because it was just too hard to work with sticky foam. With the tape in position and the screwdrivers removed I installed new fasteners.  After a three month road test in all types of conditions we have had no squeaks from behind the dash.

(Dale) Thanks, Ken, for taking the time to write this up so well. See you in Baja!   Hey, everybody, we need more of this sort of thing. Take a moment and write up something interesting about your TREK and send it to me!

 Cold Starting and Glow Plugs

I had mentioned in a previous letter that my diesel engine makes a lot of white smoke when starting for the first time in the morning if it is cold. The colder it is, the more smoke. A credible mechanic in Phoenix told me that when starting with no vacuum buildup, to expect to see white smoke because the timing is adjusted by vacuum.  Stan Denoo wrote me saying he had solved the problem by converting the glow plug control voltage from automatic to a user operated toggle switch, thus solving the problem.  I asked Gordy Morris, manager at FMI (the Isuzu Truck dealer in Portland, OR) what he thought of doing this, and below, for our education are his comments.
Gordy Morris, FMI in Portland, reports:

This is an interesting subject and we first need to dispel a myth.

Low vacuum has no effect on the glow plug system. The only adverse effect of low vacuum on the starting process is that the exhaust brake is operated with vacuum and will not close to aid in the engine heating process.

Stan is correct in that there are two relays in the glow plug system.  However, we need to clarify a few things. First, there is also a glow plug timer that we should be mindful of when running new wires, fuses and other electrical connections in the system. If the glow plug timer has been damaged the system will not work!

When the key is activated, 12 volts of battery voltage is sent to both relays and they activate at the same time. The first relay sends 12 volts to the glow plugs. When the glow plug indicator light on the dash goes out the first relay drops out and the second relay continues to send 7

volts to the glow plugs for a period of time equal to ½ the time the glow plug lite was on. That is called the after glow system. The system knows the ambient temp and adjusts the activation time accordingly.

Here is a little tip. When you turn the key on to cycle the glow plugs make a mental note of how long the glow plug light stays on because after the glow plug light goes out is when the after glow system is operational. If the glow plug light is on for let’s say 3 seconds the after glow system will be on for half that time or about 1.5 seconds. If you can wait half the time

the glow plug light was on to activate the starter, you will get a little extra heat in the cylinders.  The system is good but if you are in temperatures below freezing you will still see some white smoke. It is, after all, a diesel engine. White smoke is the result of incomplete combustion and is common in diesel engines. New technology has improved the white smoke condition over the years but the very nature of a diesel engine lends itself to the condition.

Next we should talk about the charging system. It is correct thinking that the charging system is not operational unless the alternator is excited. The way you can tell the charging system is not putting out is when you start your engine and the dash indicator lights or idiot lights remain on after the engine is running. A quick touch to the throttle will raise the engine RPM enough to excite the alternator and get the charging system going. Be advised that if the RPM is raised above about 1000 RPM the glow plug system will be shut off until the RPM goes back below 1000 RPM when it will kick back in.

Hope this helps,

Gordy Morris, FMI


 A Reminder about expensive oil changes

FMI is a good source for filters for the Isuzu engine. If you call them on the number above, ask for parts and mention you are a Trek owner. They will give you a 10% discount on parts.  I buy my oil at Sam’s Club and Grease Monkey or one of the other fast oil change outfits will change the oil, filter and do the lube for $15-$30.  When they lube, I ask them to count the number of zerk fittings they pump grease into. If the answer isn’t “13”, I get out the Isuzu owners manual and show them the diagram of where the grease fittings are.

 Southeast TREK Fun Club Rally

There was a technical discussion session on Saturday afternoon. After listening to the trials and tribulations of the GM chassis owners I put my hands together and thanked GOD that I owned an Isuzu Trek!  Here are a few things I learned there:

124,000 miles

Sam and Meri Churchill (merisam (at)  have over 124.000 miles on their ’94 Isuzu Trek now. Sam says he’s looking forward to a million miles so he can sell his coach as a low mileage Trek (the odometer turns over at 999,999.9 miles). We can learn a lot from his experiences.  He replaced the brakes at about 80,000 miles and the tailpipe (after the muffler) at 105,000 miles. Does anybody have more miles on their Isuzu Trek than Sam?

 Fuel Line problem

One very interesting problem  Sam described was an engine power failure that stumped the mechanics for awhile until one very sharp mechanic hooked up a gallon tank of fuel to the fuel line and they were able to drive around town with normal power.  Turns out they had a cracked fuel line inside the fuel tank near the top that was allowing air to get into the line!  So, don’t let a shop work on your fuel injector pump (unlike the GM engine, the Isuzu injector pump is virtually bulletproof but a likely and expensive suspect) until this kind of test is done. 

 Towing the Trek – Warning!

If you ever have occasion to have your Trek towed, insist that it NOT be towed until the towing company disconnects the driveline.  Sam’s coach was towed once and it cost the inconvenience of having to have the transmission completely overhauled.  If you have emergency road service, when you call them be sure to tell them the driveline MUST be disconnected before towing so don’t send a service unless they will do this.

 Water Heaters

Some owners were complaining that their water heater pop-off valves were leaking, and discussing how to repair them. Us more experienced Trek owners can tell them that if they allow their heater valves to continue leaking, the aluminum outside skin below the water heater will be eaten away by corrosion. The corrosion speeds up when the sacrificial zinc rod inside the heater is totally eaten away because the aluminum skin will become the sacrificial metal. Some Isuzu Trek owners have reported bubbles in paint below the water heater door. Investigation under the bubbled paint shows the aluminum skin has been eaten away.  Some owners (myself included have caulked to make any leaked water run outside (where the skin is protected by paint) instead of down the inside. My valve doesn’t leak but it could decide to at any time. One owner has installed a hose from the pop-off valve through the frame of the heater so it drips under the coach…a good idea. This should be a periodic owner inspection item.

Sliding Table Kit

One owner showed us their kitchen table which slid forward or aft on a track system to make more or less room for the person sitting on the side of the table nearest the bathroom. The kit is available from Forrest Heller in Florida (904-322-0701) for about $30, according to the owner.

 Beautiful Floor

Another owner proudly showed off his bathroom floor. He had removed the carpet and installed a flooring called PRAGO. It is a highly compressed tongue-and-groove composite that is virtually waterproof and looks like Italian tile, available from Home Depot.

 Isuzu Truck Service Facility Directory

If you would like a directory of where all the Isuzu Truck Service facilities are, you can get one by calling 800-785-5445 or visit

 Heavenly Electromagic Bed

Trish and I finally bit the bullet (about $600) and bought an expensive inflatable mattress. We found a company that would make a bed (nice, high quality, padded and quilted mattress with a heavy duty vinyl airbag inside) to fit the dimensions of our EMB.  It is totally comfortable to sleep on, can be inflated to any degree of hardness and, in the morning, deflated so the bed can go all the way up. Pump is inside the mattress with only the 110v. cord and control coming out. Power cord is long enough to easily reach an outlet. Side benefits, besides a great night’s sleep on an 8” thick mattress, are (1) my back pain slowly went away and (2) Trish is easier to get out of bed now, after the mattress is deflated.  When you decide you want to spend the money, email me for some important hints.

 Happy Trekkin’ everyone! Keep those emails coming with your Isuzu Trek experiences. If you have a Isuzu Trek related service or item for sale or want to buy, let me know.