Cascade Crew

[J-Dog-III]

Me and my dad have been tinkering with his car, doing a tune-up and everything and have it running great so far. But when you first start the car it runs fine, go down the road 30-45 mph fine, but as soon as you wood it the engine knock sensor goes off. So my dad Took out the ecm and it's pin # 1227165AMU, and it has a ACDelco AUM323 prom in it. So when we tried to run the self-diagnostic, grounding A and B of the ALDL it wont do anything. So my question is, Is the prom that's in it wrong? and is it sending the wrong code to the sensor making it go off?

[Twilightoptics]

Further explain your problem.

Do you guys have a scan tool reading the knock sensor?

[J-Dog-III]

No, Under Load you can hear the knock sensor going off and then the check engine light comes on. But after that the car runs fine with no problems but the check engine light stays on after the sensor has been tripped and no further sensor going off

[Sellmanb]

So you guys can actually hear it knocking on accell then? Or You can just feel the timing retard?

[Twilightoptics]

[J-Dog-III]

We already fixed the timing and that isnt it, and ran a new tank of gas through it. But it's weird becuase after the knock sensor goes off it runs fine, timing is normal and it dosent go off until the car is restarted

[Sellmanb]

Pardon me, I think I'm a bit confused. You say the knock sensor is going off, but you dont have a scanner or anything, so how can you tell? Does the SES light just pop up or something, and it's stored a knock sensor code?

Or can you hear knocking? Or what? Sorry if these are stupid questions, just want to get the facts straight.

[J-Dog-III]

You can hear the Knock sensor go off for like 2-3 seconds and then it goes off and the ses light comes on

[chevymad]

K.. I think whats confusing is that you can NOT hear a knock sensor go off. You can't tell if one's going off at all unless you have a scan tool hooked up or maybe if it turns the check engine light on. Now if you are just hearing some knocks.. then thats a different. It's possible maybe that the engine starts knocking heavily before the knock sensor picks it up. It's possible the ESC module isn't working correctly.. lots of other things. But to really see whats going on you'd need a scanner.

[Xophertony]

describe this "knock sensor going off" noise. what does it sound like? what do you think is creating this noise? (IE a speaker emitting a beep, or is it coming from the engine itself, like a mechanical noise?)

[Twilightoptics]

[Sellmanb]

OK, what octane gas are you putting in the car? I would put some octane booster (found at most gas stations and schucks, baxters, napa, etc) in the gas tank. If that helps, then you are just running too low a grade of gas.

[Twilightoptics]

[chevymad]

When I had the 305 in my car it wouldnt run on anything less then premium.. Traveling you could possibly get away with plus.. if you kept a light foot. That 305 knocked all the time.. and this is without an OD transmission. Now the 327 with lots more power runs fine on 87. Same ignition, same chip, no egr even.

EGR is another thing that helps prevent knock. If the valve isnt opening you can get knock too. From what I can tell from your description though I'm leaning towards an ESC module. I've had tbi trucks that would advance the timing, then you hear alot of audible knocking for a few seconds, finally the ecm would catch that and back the timing off and put the car in failsafe mode.

[J-Dog-III]

We already corrected the timing the first couple of days we had it, changed out spark plugs and it's still doing it. My dad was thinking it was the lower octane gas too. Probably gonna try that and see how it runs. Thx for the help