Recent top end an fault codes thrown

[JasonF]

My car just had a top end rebuild ('95 C4, 6speed, 93k miles on the clock) and a Durametric scan revealed the following fault codes:

49 Unknown DTC

53 Injector Valve Cylinder 3

Ironically, the wrench who did the top end (35 years air-cooled experience) noted that the wiring harness needed to be replaced again, even though the original harness was replaced under the recall several years ago. He showed me the insulation that had started to bubble/melt again. As part of the top end, just about every "while you're in there" item was replaced (plug wires, gaskets, etc, etc...)

These faults were not thrown prior to the top end rebuild.

What does a "Code 53" fault mean???

Thanks in advance,

Jason

[Loren]

According to my old 993 manual...

Fault code 53 is injector valve cylinder 2

Power supply

Disconnect valve plug, connect voltmeter to the injector valve plug terminal (refer to diagram and ground (engine)).

Ingition on.

Display: Battery voltage

If there is no 12 volts there then you need to look at the wiring.

Checking coil resistance of injector valves

Disconnect valve plug. Check coil resistance at injector valve terminal contacts with an ohmmeter.

Test value: approx. 16 ohms

If that tests ok then the injector is still likely bad - just the plunger is either stuck or damaged.

[JasonF]

According to my old 993 manual...

Fault code 53 is injector valve cylinder 2

Power supply

Disconnect valve plug, connect voltmeter to the injector valve plug terminal (refer to diagram and ground (engine)).

Ingition on.

Display: Battery voltage

If there is no 12 volts there then you need to look at the wiring.

Checking coil resistance of injector valves

Disconnect valve plug. Check coil resistance at injector valve terminal contacts with an ohmmeter.

Test value: approx. 16 ohms

If that tests ok then the injector is still likely bad - just the plunger is either stuck or damaged.

Thanks Loren, assuming the tests are ok and the plunger is stuck/damaged does that mean that the cylinder is not working? Would you think that it's a serious enough problem to trigger the check engine light? My check engine light has stayed off. Here's a screenshot of the durametric screen.

Jason

[Loren]

Well, the injector could still be working somewhat. It could be just not letting the right amount of fuel in - or sticking open and always letting fuel in.

I guess unless you have a way to measure the fuel injector cycle (oscilloscope) then you don't know for sure if it cycling properly.

So, if the injector is getting the 12 volts (as stated above) then chances are the injector is bad.