fault at knock sensors, 94 855 turbo

worbneklip · Post by **worbneklip** » 23 Jun 2008, 10:44

i am getting 4-3-3 and 1-4-3 after new knock sensor kit install (and oil trap). also i've done a tune up and new fuel filter. wondering if i need to start checking for continuity in connections, and how and where to do that. i have the wiring diagram but not sure what procedure or equipment to use. it looks like each KS has its own signal wire and then they both feed back using same return wire. anyone have an idea here?

thanks,
matt
nashville, tn

Post by **MadeInJapan** » 23 Jun 2008, 11:05

Hey, welcome to MSV...another Tennessee Member! Glad to have you!!

After the knock sensors were replaced, do you know if your fault codes were cleared? If not, just try resetting them to see if this makes a difference. If you checked the A-2 loop then you are getting front and rear knock sensor codes. If clearing the codes still bring them back, then the place that did this didn't plug them in right or they aren't set at the right angles...and you'll need to complain and they'll need to redo the install.

If you did the install, post back and I'll try to send you some information on the correct angles they have to be at before retightening.

worbneklip · Post by **worbneklip** » 23 Jun 2008, 11:58

I can clear them but they come up just like before, 4-3-3 and 1-4-3. when I swapped ECUs, I got the memory failure code, but that is expected, right? you don't think it is open circuit between sensors and ECU? does the angle make that much difference?

thanks for your help,

matt

Post by **MadeInJapan** » 23 Jun 2008, 12:39

The angle makes all the difference:

Looking at the engine from the front of the car, the one on the left (front sensor) must be exactly at 3:00 position. The one on the right (rear sensor) must be exactly at 5:30 (as if it's a clock). You might also have the connectors wrong between the two so try both connectors. Tighten both to 20Nm's or 14.75 lbs. ft. Hope this helps.

Didn't realize you changed ECU's....not sure what you mean by memory failure codes, but try what I said above first.

worbneklip · Post by **worbneklip** » 23 Jun 2008, 12:47

thanks, didn't mean to ignore the Tennessee comment, glad to know an expert is close.

I think it is 5-3-2 "ECU memory loss" is the code that is set when the battery is disconnected for awhile or a new ECU is put in. After the shop installed the knock sensors, the codes for them immediately came back. I will ask their mechanic if he paid any attention to the angle. Can this be double checked without removing the IM (the reason I let the shop do it but now regret it, to the tune of $370 in labor!). Can you see them from underneath if you remove the splash pan under the radiator? otherwise this may be tough to verify...

thanks,

matt

Post by **MadeInJapan** » 23 Jun 2008, 17:02

Sorry....no way to see them without the IM taken off. If you paid to have this done, tell them they fubarred it and are going to have to do it again, on their dime.