False knock? WTHeck?

[UR50SLO]

Put the 65lb/hrs in..... Part of the 65lb/hr program in along with some of my old settings.

I was getting 17or more deg of knock between my 1st/2nd gear shift where there was NO load! I could see if I'm flooring it or half throttle or somthing but this is very light throttle and a noticeable hesitation when it's taking out timing.

I decreased the decay rate under 4500rpm along with pasting the 65lb starting bin timing table and it helped.

I was running more timing with the other injectors and no hesitation or timing pull.

Weird weird....

I need a driver so I can realy monitor the lap top.. Tooo many idiot drivers on the road tonight I was getting pissed. I think I'm going to plant a pipe bomb in a mini van! I swear they have a govener that doesn't go over 35mph.

Rant rant... Anywho.... Think I'm getting false knock or should I try and get a new GM knock Sensor and try again? I tried the aftermarket and it set a code 32 if I remeber right. Just when I got it started so I put the old one back in... problem solved.

Thanks for the help. Only a couple more things to go before she can race... and a goood tune. That'll take the most time.
~Scott

 

[UR50SLO]

Re: False knock? WTHeck?

Got further with it today... It can't be real knock I was getting. There was very little load and the timing is at under 20deg when the knock retard go's bonkers. It's right before the 2-3shift.

Light throttle... No more than 1/8th or so.

I was able to correct it by setting the ESC Recovery rate VS RPM as follows:

%/SEC RPM
15.63 6400
15.63 4800
498.05 3200
498.05 1600
498.05 0

I tried the other setting (very low) and the problem got worse. .so the higher the number (498.05) the faster it recovers from "knock" I'll leave the higher RPM levels alone so it can hear REAL knock instead of this false knock. I don't know if it's somthing in the transmission that's making noise and setting off the knock sensor just before it shifts or if it's somthing hitting. I can't hear or feel anything in the truck.. IE.. exhaust or mount ect hitting.
Think the solid engine mounts would have anything to do with it?
I've not had a knock sensored setup with total solid mounts.

The other thing is the harder you push on the gas.. (load) there's no knock retard.. So I'm prity confident that it's false knock from somthing.

If it were not for this program and being able to watch what's going on and change everything I'd be pulling my hair out for sure.
Thanks again for all tthe hard work you put into code 59 and Tuner Pro RT.
~Scott

 

[George Blake]

Re: False knock? WTHeck?

Are you locking up the TCC when you hit 2nd? This puts an increased load on the engine. If it's a really good TCC then it will pull down really hard. If you are try not locking it up until 4th and see if any of the issues go away or are affected at all.
I'm sorry if you've already started this conversation and done this stuff but you have an original Syty prom? The squishy part under the chip in the carrier has the knock sensory interpretation(I'm sure there's a better name for it). So if the carrier is from another type of vehicle, that could cause problems.
This is assuming you took out timing or added fuel and it did nothing. Something you could do that is easy is just turn up fuel pressure manually slightly and see if the knock is affected. If it is, you'll know it's a fueling issue and you can adjust from there.

I read your first post better. Duh...you changed injectors. Did you do an injector pulse check to make sure the injectors were all flowing the same? It's the one where you hook up a fuel pressure gauges and pulse each injector and monitor drop. It could just be that one injector isn't doing its job if that makes sense. Another way that this can be checked is by holding a really accurate infrared heat detector and looking for the hottest runner. Ours are short though so it may be too tough to tell using that route.

 

[UR50SLO]

Re: False knock? WTHeck?

Thanks for the Ideas George....

It's the oem Mem cal... I'm using the Burn1 from moats and code 59. I run a wide band real time and the AFR's are right on. (high 13's low 14's) I'm shooting for 14.7 at that low load and rpm.

I'm not doing anything with the lock up other than stock. So, It should be only locking up in OD.

I'm refering to the knock at the shift point because that's where it tends to act up. I think it's the 2-3 shift... Might be 1-2 shift or both. Either way the problem is under 3200rpm under light load. The truck only acts weird when it pulls timing. (boggs down) Now that the decay rate is changed it flashes knock and go's away.... truck does not bogg. Very smooth.
Like I said.. when she go's more than 1/2 throttle under heavy load there's no knock. Maby valve train noise is setting it off at that rpm???? It's a .551lift cam (hyd roller) with roller rockers. There is little inside truck noise.

They are new 65lb/hrs. Idle is darn near dead smooth. Even smoother than the stock inj. cleaned and flowed. I'm betting it's not a weak injector.

I'll order a new knock sensor from GM for it today. I tried a "advance auto" one and the ECM rejected it right away setting a ESC code. I put the stock one back in and no more code. That sensor has 109,000 on it now and was rusty looking. I think it's the only sensor I have not replaced.

I'll then try putting the decay rate back to stock and see what happens.
Not a big issue... I like to see NO knock retard on my GM stuff. Jeff said 5degrees is ok.
I'll try and keep it in the safty zone.
Thanks again,
Scott~

 

[JSM]

Re: False knock? WTHeck?

Let me rephrase my knock statement

0 degrees is good
5 is what I consider the upper limit before I tell someone to get off the throttle.

I don't tune for 5 degrees though, I try to tune for zero.

 

[UR50SLO]

Re: False knock? WTHeck?

That was a full day of learning when I was down there... You guys taught me so much in 8hrs that I was in overload. Lol...
I rememberd the 5deg of knock I I thought you said up to 5 was ok. Which we have the same basic setup in the GN's. I'm usto shooting for almost 0 knock.
So.. I must have been in overload mode and not remembered right.
Thanks for clearing that up!
~Scott
Have you ever changed the settings in the ESC recovery rate? (Higher number the faster the recovery rate.. lower the number the slower it returns timing to normal after knock)
That's how it acts anyway.