Knock Sensor

Tiny
ROYF
  • MEMBER
  • 7 POSTS
If there is a corroded connection in the PCM, will it show an error code for that, or will it only show an error code for the pins that are corroded? Should I go ahead and take the PCM off and check for corrosion? Also is there a way for me to check for vacuum leaks that is easier, I am deaf in one ear and are unable to detect leaks by sound. Thanks again!

Roy F
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Wednesday, December 9th, 2020 AT 8:55 AM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
A few of those codes we don'thave in our manualsbut we do have a few so the others may be false codes. In your Haynes manual you neeed to do test e for egr, g for map sensor which could be a bad hose and collapsing and I for tps. Tehegr cold be partially clogged and staying open leaving a gad/rough idle or clogged passages or the solenoid for it. And yes corroded pins can caue a lot of problems. But be very careful and try not to bend any. When you put it back together put some dielctric compound in there to help alleviate that. Matbe for the vacuum test is hook up a tach and spray choke cleaner if the tach goes up you found it.
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Wednesday, December 9th, 2020 AT 8:55 AM (Merged)
Tiny
ROYF
  • MEMBER
  • 7 POSTS
I checked the egr valve and it was plugged solid. Picked up new one and put it on, I will reset timing to see how it performs. Thanks for your help!
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Wednesday, December 9th, 2020 AT 8:55 AM (Merged)
Tiny
ROYF
  • MEMBER
  • 7 POSTS
Well, I replaced the EGR Valve and put it on the OBD and it came up with these codes 22, 23, 31, 42, 63, 72 and 73.
22-MAP Sensor voltage out of spec
23-Throttle Position Sensor voltage out of spec
31-EGR Valve Position Sensor voltage out of spec
42-O2 Sensor always rich does not switch
63-Throttle Position Sensor voltage too low
72 and 73 have to do with not enough change with vacuum and throttle during Dynamic Response portion of test. I have tested the fuel pump and pressure is fine. In addition, although timing is perfect when you accelerate you get backfiring through the intake, like it is out of time.
Any suggestions?
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Wednesday, December 9th, 2020 AT 8:55 AM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check for a broken/bent pushrod and or a broken valve spring along with a worn camshaft. If the camis worn the rocker won't go up and down as much as other ones. If it backfires through intake like you can actually see it then it's an exhaust valve not opening.
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Wednesday, December 9th, 2020 AT 8:55 AM (Merged)
Tiny
ROYF
  • MEMBER
  • 7 POSTS
I understand, but how would that account for the air/fuel mixture being so rich. I really mean rich, the gasoline smell and black smoke out of the exhaust seems to be from more than one cylinder or valve. Acceleration is jerky as well sometimes, like the fuel is being restricted.
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Wednesday, December 9th, 2020 AT 8:55 AM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Because if you aren't opening the valves it creates a miss so it gets to much fuel. Also I have suggested testing fue pressure with a gauge and have not received an answer if your regulator is screwed up it will do that as well. I have no further comments or suggestions.
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Wednesday, December 9th, 2020 AT 8:55 AM (Merged)
Tiny
ROYF
  • MEMBER
  • 7 POSTS
I am sorry, I did check the fuel pressure with motor off and on demand and it performed according to specifications. I have noticed that the motor runs somewhat better when cold, it is when it heats up that I get the surging and hesitation.
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Wednesday, December 9th, 2020 AT 8:55 AM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check compression and vor vacuum leaks I have not further suggestions
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Wednesday, December 9th, 2020 AT 8:55 AM (Merged)

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