knocking on 94 Camry 4 cyl wgn

[Donald]

Oddly I get some knocking when doing light acceleration but none when doing medium acceleration. I am waiting for a manual to be delivered to read more on this. The only maybe related item is when its 90F out and the vehicle is not running 50 MPH or more, the check engine light comes on and if I remember it was a EGR code (71 I think). But the knocking does not seem to be directly related to when the check engine light is on.

Tried 89 octane and it did not help. (Now I cannot afford 89 octane gas!!)

Does one still time this vehicle with a timing light or am I showing my age?

 

[Gurkha]

Get your engine carbon cleaned, probably too much carbon build up, also replace your fuel filter and do an injector cleaning with something like Regane from Gumont. Actually two bottles of Regane in a full tank will also get rid of the carbon to a great extent, just make sure to change your fuel filter after that.

 

[kcryan]

Techron/FP mabye even some seafoam through the brake booster.

 

[Drew99GT]

If you have an EGR trouble code, even if it goes out occasionally, then you've found your problem. Probably carboned up and reducing flow. Unless the distributor was touched EVER then the timing is good.

 

[Donald]

With the check engine light coming on when its hot out (and the code being EGR), how do I know what to replace? I see a note that when replacing the EGR valva its important to clean the carbon out of the EGR valve passage. Maybe the EGR valve is OK and all I need to do is clean the carbon out of this passage. Any ideas on how to do this? The EGR is not cheap, like $150, so I would prefer not to replace it unless it really needs replacement.

I assume that running Techron in the gas tank will NOT clean the carbon from the EGR valve passage?

 

[punisher]

quote:

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Originally posted by Donald:


I assume that running Techron in the gas tank will NOT clean the carbon from the EGR valve passage?

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You are correct.

Assuming a vacuum operated valve, apply vac to it. It should start to move smoothly without sticking with around 5" of vac. Watch the pintle if you can and see if it moves as the vac is applied. Let the engine idle, apply vac to EGR, engine should stumble and/or die. If the engine idles fine with vac on the EGR, time to pull the EGR, verify it works properly and more than likely clean those EGR ports out. If engine stumbles and dies during above test, look for vac leaks to the EGR and EVR (EGR Vac Regulator).

 

[andyd]

Try dosing the egr and its passages with Sea foam carbon cleeaner and using some sucked into a vacuum line to clean the combustion chamber. IIRC, this engine is prone to carboning up.

 

[oilboy123]

Fix the the EGR 1st then......

I had knocking with light and medium acceleration, but none on heavy acceleration.
I went to Alaska and told my daughter to drive my car after dosing w/auto-rx and the pinging was gone when I came back.
It was still on the clean cycle. Don't know if it will help with yours but at the least it will clean the engine.....

 

[BlazerLT]

Yip, this is an EGR valve cleaning solution.

Throttle body cleaner and an old toothbrush and scrub it clean and reinstall with a new EGR gasket.