Warning! UTCIS DWUR users

[Dr J]

I have a UTCIS DWUR system with the stepper motor. The control box has a short hose inside with fuel that comes from the block of aluminum with the stepper motor. This is used to measure the control pressure. It appears that the hose inside the box is not compatible with the ethanol in the gas. In my system it slowly ate away inside the hose and eventually created a blockage. The hose was swollen and the blockage caused it to burst, spilling gas inside the control box which eventually made its way outside the box through the electrical wires. Fortunately, I was starting the car in a parking lot when it let go, and the mixture went so rich that the car would shut off.

Here is a picture of the hose:


Replaced it with a fuel hose 1/4" id. That id is slightly large, but the clamps caused the seal to be leak-tight seal.

New hose:


Old hose a day later when swelling was gone:


Open your box up, and if you have this hose, replace it.

[Tippy]

Nice find! Hmmm, fuel and electrical in the same compartment? Yikes

[Dr J]

You said it. That was one of my criticisms since the thin external hose is easy to kink. I would have put the sensor on the aluminum block with the stepper motor and send the electrical signal to the box. I considered doing that, even now, as an option.

[fanaudical]

Hmmm. My current business is design of fluid systems for various industries involving hazardous chemistries and flammable solvents. That original hose type is not generally not compatible with gasoline (never mind the ethanol). I would consider potting the electronics in that box or moving the pressure sensor outside the enclosure.

[boyt911sc]

Originally Posted by fanaudical

Hmmm. My current business is design of fluid systems for various industries involving hazardous chemistries and flammable solvents. That original hose type is not generally not compatible with gasoline (never mind the ethanol). I would consider potting the electronics in that box or moving the pressure sensor outside the enclosure.

+1. That braided plastic hose is not compatible with gasoline or strong solvent. The hose is commonly used in aqueous liquids. Whoever installed that hose has over-looked the chemical resistance against gasoline and the like.

Tony