No CEL with or without knock sensor.

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SiRG EJ1

Junior Member
There is no CEL when the knock sensor on my b18c is either plugged or unplugged. Could the ecu be fried maybe, or any other ideas as to what would cause this? Thanks in advance.
 
Originally posted by SiRG EJ1@Oct 26 2004, 03:48 PM
There is no CEL when the knock sensor on my b18c is either plugged or unplugged. Could the ecu be fried maybe, or any other ideas as to what would cause this? Thanks in advance.
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Is the ECU obd1? Maybe its been chiped/programed not to even recognize the knock sensor. Or maybe the bulb for your CEL isint working or the CEL connections them self may be bad. Have you seen the CEL come on befor at all? Does it come on when you first start the car?
 
Originally posted by Slammed90Lude@Oct 26 2004, 04:22 PM
well what ECU are you using? lol
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Good point :D :p
 
It is a JDM P72 OBD1 ecu.

The CEL works, I have fixed some other ones such as the IAT and IAB. I am 100% sure it works. The ecu is not chipped, I bought it with the swap from hmotorsonline and it is completely stock. <_<
 
if the ECU was fried you would have more problems than not showing a check engine light without the knock sensor attached

i don't mean to be an asshole, but are you sure you're connecting and disconnecting the knock sensor?
 
Yes, I'm sure its the right sensor. It's not the oil pressure sensor. ;)

I read somewhere, I think honda-tech, that parts of the ecu can fry without affecting other parts. I have no clue. I'm going to take it apart tomorrow. Maybe the knock sensor just isn't making contact with the ecu. My friend kinda fucked up the connection where the pinout goes in. I can try replacing the whole D plug. But when the knock sensor isn't hooked up, won't it retard the ignition timing and affect the redline? My car's only redlining at 7000 RPM rigth now also. It should be 8200.
 
I would consider giving the boys over at hmotors a call and tell them that they sent you a bunk ecu, see if they'll do anything for you?

they didn't send me a mount with my swap and had no problem two daying one over to me at no cost-
 
Sounds good, I might do that. I'm going to take the cover off and scope it out first to look for any fried areas.
 
in my past experience, the ks won't throw a cel, the code will be present if you jump the service connector and check for codes, but it won't cause the cel to come on.
 
this is the first time i've ever heard anyone complain about not getting a cel :p does the car run fine?
 
No, it doesn't run fine. Vtec engages around 4000 and redlines 6800-7000. I'm thinking it might be the knock sensor, seeing that it puts the car in safe mode from what i hear-- retarding ignition timing, altering vtec, and changing redline.
 
Originally posted by SiRG EJ1@Oct 29 2004, 02:05 PM
No, it doesn't run fine. Vtec engages around 4000 and redlines 6800-7000. I'm thinking it might be the knock sensor, seeing that it puts the car in safe mode from what i hear-- retarding ignition timing, altering vtec, and changing redline.
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it's not the knock sensor, i've ran without a knock sensor on obd2 and obd1 and it ran normal.
 
wonder what else it could be. ive heard plenty of stories about how the knock sensor will affect that though. ill jump the ecu to find out if its the ks.
if not, i guess ill get a usdm p72 obd1 ecu and run that in the car to see if the car runs fine.
 
Originally posted by SiRG EJ1@Oct 29 2004, 03:02 PM
Not unless Hmotorsonline sold me a chipped ecu with my swap.
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very doubtful, just checking ;)
 
I jumped the ecu and it didnt give me a code... the light just came on and stayed whenever the paper clip was in.

Next step would be swapping ecus with someone and see what that does. I've also been told it might be the distributor... iono though...
 
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