I'm trying to locate the RPM sensor for the tachometer of my Trooper's C223 (N/A aspirated) engine. Most of the wiring is either not original or cut up making tracing difficult. The diagram Eric sent me has been a big help but locating this sensor physically has been a mystery.(This is my first diesel restoration project)

Can anyone help?

Boyd

Trooper C223

It is on the side of the injection pump, if originally equipped so. right around the throttle valve on the injection pump.

Found it! Thanks a lot for the help from Rbt and Jeff(who sent e-mail). My pump is a Bosch but the two black wires were there.

Probaly was cut when the engine was overhauled.
I will have to check if the sensor works or not. How do you test this? Is it a hall device?

I'm not sure either about it being non-polar or not. The diagram shows one side to ground and the other end connected to the Tach. Don't want to damage it.

Thanks

Boyd

I had some fun diagnosing the dead tach in my Trooper. It turned out to be a misaligned needle spindle, but I went through the wiring before figuring that out.

I cut the wires going to the tach sensor in order to fit a socket in there to remove the sensor. There is a connector behind the fuel pump, but I couldn't fit the socket over it.

Side rant: why did Isuzu use those crappy slide-on connectors for the temp and oil pressure sensors? It's disconcerting seeing my oil pressure drop off as a cross-wind moves the connector around.

Cruiserman,

I've been wondering the same thing about them connectors; the ones that keep sliding off the oil and water temp sending units.

I did ask a GM tech since I found the same type on my Opel and Isuzu Gemini.

He says that tab type terminal connectors are more prone to breaking since they are long. So they made the terminals round and as flat as possible to keep the connector cable close to the sensor.

I solved my slipping terminal problem by using small zip ties, the ones used by electronics techs. It's more reliable than rubber of vinyl tape and lasts longer too. Try Radio Shack.

Boyd

Boyd, Did you just zip tie the two together? I was thinking of cutting out the connector and splicing in alligator clips to grab the pressure sensor :-).

Eric

<small>[ April 29, 2003, 06:17 PM: Message edited by: cruiserman ]</small>

I just zip tied the wire to any logical place (i.e. other wires, places on the engine that don't get hot, etc.) to keep the wire harness from moving and vibrating and eventually cause the connector to slip off.

My brother went a step further by using ATV sealant over the connector covering the whole top of the sensor. Just make sure the terminals are clean and corrosion-free. It will be difficult to get the hardened goo off should there be bad contact.

Boyd

1986 Isuzu Trooper C223
1982 Isuzu Gemini 1800 Coupe

BTW, you can use 'gator clips however these clips rust (which will eventually break)and have too much metal on it that it can affect the temp reading on the sensor.

Try Utilux brand (german) of crimp type connectors. They grasp better than those crappy stock connectors.

Boyd