Nkelso

Hey guys i have a 91 rs 5.0 tbi. Its throwing a code 43. While driving at cruising speed with low rpm if i press on the gas when it downshifts it makes a knock noise for a couple seconds then throws the 43 code what could cause this? No engine tick while idling or driving just on downshifts for acceleration have a new esc module knock sensor timing is good.

navy02ws6

Are you running premium gas? Octane may be too high if so.

Nkelso

Just regular unleaded

Tuned Performance

iTrader: (92)

Have you checked your base timing ? Tdc with the est connector unplugged.
The code 43 can be caused bye a bad ks or faulty ecm.

Nkelso

Timing is good and ks? Not sure about the ecm yet

Jacobaxeman

Knock sensor

Nkelso

I got it after i asked the question haha and im replacing it today but can you think of anything else that might cause it if it doesnt work

Tuned Performance

iTrader: (92)

Watch it’s torque. It’s about 14 ft lbs .

Nkelso

Sorry misread what your wrote haha and got it on the torque

Nkelso

I put a new knock sensor and a new esc module in and its still making the noise and throwimg the code so im not sure whats causing it. New plugs, wires, cap, rotor, esc module, knock sensor. At 40mph and 1100 rmp if you stop the gas it knocks for 2 seconds if that then throws the code 43. It doesnt knock any other time after that with the SES light on. Anyone know what it could be?

W.E.G.

If you have an inappropriate PROM installed in the ECM, you will have the same drivability issues if you swap ECM’s and use that same inappropriate PROM in the next ECM.

Nkelso

I havent touched the ecm yet and idk if the previous owner did either.

Tuned Performance

iTrader: (92)

I’m wondering if maybe the egr is stuck, just a thought. Idle would be alittle rough though.

Nkelso

It does have a little bit of a rough idle but how would that cause it

Tuned Performance

iTrader: (92)

Read the symptoms portion of this article.
https://itstillruns.com/symptoms-bad...e-6157262.html

Nkelso

Very informing thank you i will take a look at the egr in the morning and will let everyone know if it fixes the problem

Tuned Performance

iTrader: (92)

You can clean the egr with carb choke cleaner . Just avoide spraying the diaphragm.
You can push on the diaphragm to open the pintle to clean the passage.btw if it is bad it has a p or a n on the top body. This indicates if it’s a positive or negative back pressure valve.

John in RI

iTrader: (167)

My fingers are crossed dude !! I'm REALLY hoping that you're not dealing with the same problem that my last 91 TBI RS had.

Do you drive your car "hard" ?!!?

I didn't get a code - but I also quit driving it right away because I had a feeling what the problem was and started working to replace the engine within a day of my "knock on hard acceleration" problem staring. My knock was only present when the RPMs were high, and the idle did get worse once the knock began.





Reasonable to think that if you spun a bearing that a code 43 might get set in the ECM due to the excessive engine knock. I hope it's something minor like a bad wire to the ESC module, but you MIGHT have a much more serious problem on your hands.

Nkelso

I know what your talking about i have spun a rod bearing before this sound is completely different i cleaned the egr this morning and same noise and code came up. It happens at lower speeds and real low rpm no noise until i press the accelerator for it to drop a gear and go faster. It sounds like a spray can you just threw on the floor if that helps describe the sound and only for 1 second maybe 2 then the light comes on if i drive around with the light on no noise nothing.

RBob

iTrader: (1)

The knock detection & reporting system isn't functioning correctly. The knock you hear is caused by the ECM forcing knock to occur. It is part of the knock system diagnostics.

Code 43 is being set because the knock was never reported to the ECM. Need to run through the ESC system diagnostic tree is see where the issue is. Could be as simple as the connector has fallen off the sensor.

RBob.

Nkelso

Connector is on the knock sensor, knock sensor is new, new ESC module, power going to plugs on both as well

Nkelso

Could it be a bad ecm or prom?

Tuned Performance

iTrader: (92)