knocking problem

[fred79]

my 95mtx is knocking when driving up hills and now has started to post a CE when its knocking its way up hill.
I am getting the codes as 181,189,528,542. I know the one is from stalling it , but what does it mean that I am posting all these lean running codes, is this a injector, fuel pump, sparkplug issue? what could cause these symtoms, my koer test also said my idle was out of speed it idles nearly at the 1000 rpm mark is this too high. thanks for any help, so far I have tried througging in some lucas injector/decarbon treatment but it only helped it for a few miles before the end of the tank it was back to normal.

 

[SHO green like$]

As my machinist always tells everyone.....Sensors, Sensors, Sensors......

You probably should check fuel filter, fuel pressure, O/2 sensors... How old are they? If original you might consider new.

When my O/2 sensor is failing I'll get CE also.

If it's so lean that it pings/knocks under load, you might be close to burning a hole in pistons. I had a Nissan p/u, burn through the space between two cylinders, trashing the block, another one burn hole the size a quarter in piston, from running lean.

Are all the vacuum lines on? A cracked line would cause lean too.


181 - Fuel system was lean at part throttle Single, Right or Rear HO2S - Fuel control
189 - Fuel system was lean at part throttle - Left or Front HO2S - Fuel control
528 - System shows voltage at pin 10 (is A/C on ?) or pin 30 (PNP, CPP switch) - PNP
542 (O,M) Fuel pump open, bad ground or always on - - Power / Fuel Pump Circuits

 

[Rockledge]

Lean Condition = Too much air or not enough fuel (or a combination of both).

The most common cause of lean codes is by far a vacuum leak allowing unmetered air into the engine. As such, all vacuum hoses and their connections should be checked, all the upper intake gaskets should be checked, etc. for any possible sources of air leaks.

A dirty MAF can also cause a lean condition. Have you tried cleaning it?

Low fuel pressure (clogged fuel filter, a failing pump or regulator, etc.) might also contribute to a lean condition by depriving the engine of the proper amount of fuel. A fuel pressure check should therefore be on your "to do" list.

Your engine is knocking because the lean condition is resulting in the A/F charge burning hotter (due to more oxygen) in the combustion chambers, causing detonation (a/k/a engine knock a/k/a "pinging").