TBI Code 43

[grampadirt]

EGR opens anytime above idle or not WOT.

 

[c1500deathtrap]

Is the engine otherwise quiet? Noisy timing chains or valvetrain can trick it into tripping.

 

[randomguy]

Is the engine otherwise quiet? Noisy timing chains or valvetrain can trick it into tripping.

Very quiet. Since I replaced the knock sensor the only time it trips is high load, light throttle conditions. I can cruise on the interstate at 70 mph without a code tripping. It’s not until I start climbing some of our steeper grades I get a code 43 and can hear pinging.

One of the other causes of this code is a knock lasting more than 4 seconds. I only hear the knock for about a second but obviously the sensor picks up knocks we can’t hear. Once it trips and pulls timing no more pinging but if course power is down.

My theory is the EGR valve opens fine under full vacuum but when the engine is lugged with light throttle the solenoid does trip but the valve doesn’t open due to the leaky diaphragm. Higher combustion temps can cause pinging.

I can watch the solenoid open with a vacuum gauge tee’d in between the solenoid and the valve, just looped the line under the wiper and drove it with the gauge on the windshield. If the new valve doesn’t solve this I’ll end up getting a cable and doing some data logging.

 

[DerekTheGreat]

Very quiet. Since I replaced the knock sensor the only time it trips is high load, light throttle conditions. I can cruise on the interstate at 70 mph without a code tripping. It’s not until I start climbing some of our steeper grades I get a code 43 and can hear pinging.

One of the other causes of this code is a knock lasting more than 4 seconds. I only hear the knock for about a second but obviously the sensor picks up knocks we can’t hear. Once it trips and pulls timing no more pinging but if course power is down.

My theory is the EGR valve opens fine under full vacuum but when the engine is lugged with light throttle the solenoid does trip but the valve doesn’t open due to the leaky diaphragm. Higher combustion temps can cause pinging.

I can watch the solenoid open with a vacuum gauge tee’d in between the solenoid and the valve, just looped the line under the wiper and drove it with the gauge on the windshield. If the new valve doesn’t solve this I’ll end up getting a cable and doing some data logging.

Well, EGR wasn't the cause with my old engine. Like mentioned before every sensor got reused, including the intake manifold itself along with my throttle body. Old engine was set by me at 0 degrees... Anyway, I thought the EGR was the cause of my high/eratic idle problem with the new engine so took it off and cleaned it, wasn't really dirty nor were the passages clogged up and diaphragm was holding vacuum. Idle turned out to be a bad TPS.. Anyway, I think you might want to look into timing chain slack. Just to rule it out. It's the one thing I never checked but has me wondering in your case.

Sent from my SAMSUNG-SM-G891A using Tapatalk

 

[89RCLB]

Do yourself a favor and don't cheap out on the EGR valve, you'll also want to get the correct replacement (OEM part #17113446 and will be stamped with an "N"). The wrong valve will cause you further headaches.

Have you tried tapping on the passenger side exhaust manifold to manually set a code 43? If a code 43 cannot be set by doing this then it may be time to look at the ESC module.

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Hope this helps.

 

[randomguy]

I will try tapping on the manifold today.

The valve on the truck is 17087196. I ordered an AC Delco 214-5074 as its supposed to be a direct replacement. Is the part you listed a better one?

 

[randomguy]

Good call on tapping the block, timing is not changing while the truck is running and no code trips tapping on the manifold for 10 seconds so there is something not right with the circuit or sensor. I even tried tapping the block next to the sensor.

Could I have a bad sensor? Is there a way to test the wiring harness?

Wondering if I could pull the wire out of the loom far enough to solder the connection.

 

[89RCLB]

I will try tapping on the manifold today.

The valve on the truck is 17087196. I ordered an AC Delco 214-5074 as its supposed to be a direct replacement. Is the part you listed a better one?

The part number I listed was straight out of AllDataDYI, no idea if it's better or not. It's possible that you have a wiring issue between the ESC and KS...try using the flow chart in the earlier post to make that determination.

 

[randomguy]

I’m thinking the knock sensor wire has a break in it somewhere in the harness. Ground at the ESC is good. I got nothing while attempting to make a knock with the test light attached to the knock sensor plug and then tapping a 12v source. I even cut the new pigtail off and hooked the light to the wire. I put my multimeter on the knock sensor wire at both the ESC side and the sensor side and got unlimited resistance. Should there be any resistance in the knock sensor circuit between the ESC and the sensor?

I’m thinking I may need to run a new wire. I’d like to just pop the wire out of the plug on the ESC and put a new pin on it. Looks like a Delphi connector of some sort?

 

[89RCLB]

I’m thinking the knock sensor wire has a break in it somewhere in the harness. Ground at the ESC is good. I got nothing while attempting to make a knock with the test light attached to the knock sensor plug and then tapping a 12v source. I even cut the new pigtail off and hooked the light to the wire. I put my multimeter on the knock sensor wire at both the ESC side and the sensor side and got unlimited resistance. Should there be any resistance in the knock sensor circuit between the ESC and the sensor?

I’m thinking I may need to run a new wire. I’d like to just pop the wire out of the plug on the ESC and put a new pin on it. Looks like a Delphi connector of some sort?

Should there be any resistance in the knock sensor circuit between the ESC and the sensor?

With your meter set at 200 ohms (not 200K) you should see a very small amount of resistance (00.4 ish) No reading would mean a break in the wire. If your meter has an audible continuity test setting I would use that, it will tell you immediately if the wire is good or not.
Make sure you have 12V on pin B at the ESC (no power and this subsystem ain't gonna work, period!)
Continuity test or ohm out lead E, if good then continuity test or ohm out lead C.