Supra Forums banner
1 - 9 of 9 Posts

·
Registered
Joined
·
475 Posts
Discussion Starter · #1 ·
Ok all, Here is a good one for you. When I start my car up in the Mornings, It starts up and Idles fine. Once it warms up, It has a small backfire sounds or a pop from the Muffler. Ive checked the timing and When I jump the Diagnostic port and use a timing light, The Timing mark is jumping around from 10 to 15 degrees. If I put the engine under a Load, It starts to Pop and sputter its Ass off.

We have changed the Wires and Plugs, Checked for Frayed wires and Done a Diagnostic test. Came up with Code 11 and 52.

52- Knock Sensor
11- Mementary Interruption in Power Supply to ECU

Would a bad Knock Sensor Cause bad timing and Backfire under a Load?

Any Help would be Greatly Appreciated. Been working on this for about 2 weeks now without and Resolution

Robert
 

·
Stormcock approves
Joined
·
1,859 Posts
Yes the knock sensor could caues this problem, because the system would retard the timing excessively, possibly causing a misfire.
 

·
Registered
Joined
·
475 Posts
Discussion Starter · #3 ·
Thanks for the Info, How can you check to see if you have a Bad Knock sensor or not. Im sure they are Pretty Expensive and I dont want to buy one if its not needed. Let me know if you will....


What about the Timing. Will a Knock sensor make the timing mark bounce?


Robert
 

·
Stormcock approves
Joined
·
1,859 Posts
I'm sure there's a way to check them, but the general consensus is to replace them when they start to go bad because of their location and importance. However, some people have found that rewiring the knock sensors cures this problem. My guess is that their wires corroded to the point where they wouldn't work or would work on/off, throwing the code and ruining driveability. I would suggest checking your knock sensor wiring (they are located at about #2 and #5 cylinders on the intake side), but you may need to remove the upper intake manifold to see anything. Maybe you can access it from underneath? I'm not sure.
 

·
Registered
Joined
·
175 Posts
Kinda having the same problem here, except mine dies off @ exactly 5 pounds. I replaced them both, still code 52, it's probally the wires for one/both of them.

FYI: You don't have to remove anything to get to the front KS and the rear I had to remove the Vac line rail and the top bolt of the mani brace so you can move it a little.
 

·
Destroyer of Turbos
Joined
·
4,461 Posts
see KS rewire....
 

·
JZA70 448 rwhp everyday
Joined
·
2,994 Posts
Check out the knock sensor re wire, just search threads with my name in it, and you will find a tutorial. It only took me 45 mins, and my car felt like i got a turbo upgrade once i did it. Code 52 is common.

~scott
 

·
Registered
Joined
·
475 Posts
Discussion Starter · #9 ·
Well, Here is a Little update to my Situation. I got the Timing Issue corrected. My Timing Mark isnt Jumping around anymore. Didnt have that Small grounding wire that goes Between the coil base and the Head.

Now she fires up real well and Idles ok until The motor warms up, Then there goes the pop from the Exhaust again. Noticed the other day that when it pops, a Small cloud of black smoke will come out right afterwards. Is this a Sign of being a Fuel Issue or will a Knock Sensor do that. Its still a Little Sputtery when you hit the gas at Idle and the Pop is still there.

Any more Suggestions?
Robert
 
1 - 9 of 9 Posts
Top