1998 E300 will not pass CA smog because of bad glow plug. What to do? - PeachParts Mercedes-Benz Forum

Frank Reiner · #1 01-25-2017, 04:36 PM

Roller:

Pay the DMV the $20. Non-Op fee. Then fix it at your leisure.

Do you have a circuit diagram for the glow circuit, and in particular the diagnostic function? If so, the question is: Does the diagnostic circuit look for total resistance in the glow circuit, OR does it look for total current? If the diagnostics look for total resistance the work-around is easy; by pass the actual glow circuit, and substitute the appropriate (quite small) resistance to spoof the test circuit. If the diagnostics are looking for current however, you may have to connect a good dummy glow plug (or two), with the hot ends shielded.

ROLLGUY · #2 01-25-2017, 06:01 PM

Quote:

Originally Posted by Frank Reiner

Roller:

Pay the DMV the $20. Non-Op fee. Then fix it at your leisure.

Do you have a circuit diagram for the glow circuit, and in particular the diagnostic function? If so, the question is: Does the diagnostic circuit look for total resistance in the glow circuit, OR does it look for total current? If the diagnostics look for total resistance the work-around is easy; by pass the actual glow circuit, and substitute the appropriate (quite small) resistance to spoof the test circuit. If the diagnostics are looking for current however, you may have to connect a good dummy glow plug (or two), with the hot ends shielded.

The car is my friend Jim's only transportation, so he can't have it down for the time it takes to pull the head. He will sell the car to me before having to pay to have the work done.