Knock Retard (long)

[dgoodhue]

I need help with my Knock Retard. I am getting a bunch of it (usually 14-16 degree by the top of first) with my T1-16 programming. On some of my track runs, I got a tons KR in 1st but it takes so long to ramp out, I don't get any additional KR until the top of 3rd.

I am running 93 octane and I have done a bunch of stuff to try to remedy it. It isn't false, I tried reloacting the knock sensor with the same result (the knock comes in the beginning of 2nd gear instead of top of first) and race gas does help. I don't any have ignition flutter at all. My truck finally idles very good. I use diacom and have some files.

This is what my truck has (I am sure I will forget some things)

-Conrad Cap and Rotor, UR6 gapped at 0.030, MSD 8.5 mm Wires All replace 1200 miles ago.
-TEDC CLeaner around 2K miles ago
-New A/C Delco Coil
-MSD 6AL (tested with and without)
-3-4K miles aog O2 sensor.
-Redid all the intake, TB gaskets and cleanout out the intake.
-1.6RR's I know the adjustment is right, I re-did it with the engine running.
-Tried swapping ECM's, same result
-Have higher output alternator same result.
-IC pump works, Soft lines, IC temps usually start off at around 110 degrees.
-Radiator temps around 160-165
-Doesn't overboost, does have Random Tech Cat.
-New knock sensor.
-I have a 255L walbro, the fuel pressure is set at 52psi (My BLM's are at 128) The FP gauge say the fuel pressure is holding properly and tracking under boost.
-Checked balancer with piston stop.
-professionally clean the injectors and had them flowed.

The only problem I know I have is a dead Park/Neutral switch. Also Sometimes I get a dip in the O2 mV (down ot 200mV or so) right at a launch, but it comes right back up (I am wonder if this is a delay)

The truck was 100% stock and untouch when I bought it. It has 48K miles on it, never been driven in snow and the previous owner claims it was never driven in the rain, (though that has changed), so its not rust and is very clean.

 

[dgoodhue]

edited

 

[bezerk]

there are are alot of topics about this issue, have you read them?
read your sparkplugs, and see what they say, if you don't see anny deto on those, you should start looking for the false knock, (or it's an engine knock)

Good luck finding it, had the same problem....tried almost everything couldn't get rid of it,
At what boost level do you get the knock?

 

[bezerk]

i saw you have 1.6 ratio rockers, are u using vortec heads?

 

[dgoodhue]

there are are alot of topics about this issue, have you read them?
read your sparkplugs, and see what they say, if you don't see anny deto on those, you should start looking for the false knock, (or it's an engine knock)

Good luck finding it, had the same problem....tried almost everything couldn't get rid of it,
At what boost level do you get the knock?

I have done tons of reading/searching on the subject.

Stock Heads/Turbo/Cam and they are Crane Gold RR's

I am getting knock somewhere around 13-14psi, my truck doesn't hit full boost in 1st gear anyways.

My next step is probably retarding the distributor timing 1 or 2 degrees.
I have also tested/swaped the chip to make sure its fine. (I am using an Ultimate V7 programming)

 

[bezerk]

did you diacom the truck before you start moding it?

yeah, start by changing the timing alittle bit, maybe it helps.

 

[dgoodhue]

did you diacom the truck before you start moding it?.

I think it had some but it was pretty good in 1st and 2nd gear. The first year I raced it I basically put in the reliabilty mods and an ultimate. I did use Xylene and my Diacom files for that combo had some KR (5-6 degree and on 16-18psi programs)

This last round of mods was a do it while your in their and go through the truck to make it more relaible (new engine mounts, hoses, ect) I had bad valve seals, so that is why the RR were done. I am pretty the motor is NOT ticking or rapping.

 

[93 TY 2185]

Any idea on where I can upload a diacom file to?

Email your file Dave and I'll host it for ya.

You can read Diacom files with DataMaster for those who didn't know.


Daves Diacom File Here

 

[dgoodhue]

So, I retarded my timing 1 and 2 degrees to see if that would help, it didn't do much. (I actually change the timing table in my romulator from 2800-4800 under more than 9.5psi boost) My results still sucked. I hit 13 degree of retarded with 1 degree reatrded and 12 with 2 degree retarded, the only positive about this is the KR is happening at higher speeds, so my first gear KR is better. As you might imagine this is still unacceptable.

I also fixed my park/neutral switch, so I can rule that out.

I am going to retry doing my top end cleaner, but do it with a smaller vacuum leak as Wade suggested. (last time my engine was singong along at 3K rpm or so)

 

[Turbo6]

Screw a knock sensor. I havent run one in over a year :wink:

 

[dgoodhue]

So I did another top end cleaner, this time with a slow idle speed. It sure did smoke much more than compare to the brake booster (3000rpm) top end scleaning I did before. I did the plugs, oil and O2 sensor and took my truck for a spin.

My truck is better but it still isn't great. I got 3 spikes of 6-8 degrees of knock retard, still better than 14-16 that I started with but not perfect. I was able to drown out the latter mostly with a 4 gallons of race gas (97 opctane), so I am going to try 100 octane and race it again at the track meet tomorrow.

I really am stumped on what to do about the Knock Retard, I don't know where or what to test next.

 

[gmcturbo]

i would try a 160 thermostat. also if your egr is disconnected, it can contribute to some knock. the egr actually helps with KR. i would hook it back up if its disconnected. also make sure knock sensor is in at right torque and look for loose gas lines or anything around the sensor that could be banging around.

 

[Falco]

Screw a knock sensor. I havent run one in over a year :wink:

I couldn't get rid of the knock whatever I tried, so I did the same for a year, run high 11's with my stock engine. Then it exploded. I'm pretty sure that the knock sensor could have saved it, or at least I could go off the gas if I've seen the red led blinking. Anyway it wasn't nice.

So, with my new build I decided the leave the knock sensor alone. If you can get rid of the false knock it's a big tuning aid. No I've no knock problems, but since I've changed almost everything in the engine, it's hard to tell what caused the false readings with the old build. My bet is on the pushrods rubbing against my head. I was using aftermarket rockers as well, but haven't used a louise(?) tool to make them fit better into the head. I've not made the same mistake again with my new Vortecs and knock went away.

I could be else of course...

HTH,

 

[dgoodhue]

i would try a 160 thermostat. also if your egr is disconnected, it can contribute to some knock. the egr actually helps with KR. i would hook it back up if its disconnected. also make sure knock sensor is in at right torque and look for loose gas lines or anything around the sensor that could be banging around.

I have a 160 thermostat

I have an EGR hooked up, but my Chip disables it. I only get KR at wot, it fine at 3/4 throtle and boost. EGR only enable at part throttle. (its is also open by vacuum, so it would work even under boost, plus their is a check to keel it operational at only vacum conditions)

Knock sensor is torque properly at 14ft-lbs ( I have two one is remote mounted on the intake with the same result)

I checked the fuels lines and the appear to be fine. The KR readings are real because they go away with race gas.

 

[lSyclonel]

iv had to deal with knock for 4 years too. now this year i dont use it. works great. but i run 110 all the time now. if you run 110 gas and only 15 psi. i can tell you it will not knock, unless internal motor noise or tranny nosie ect. it has nothing to do with your tune.

 

[Syclone#1992]

I have had knock retard problems too on my Syclone, where do you draw the line? I know there is such a thing as false....but it is very hard to determine. I have had high knock too, but the motor seems to perform fine. I know knock is dangerous to our motors. When people like, Dave and I have high knock, and have replaced ignition....ect ect... and know that the truck is performing ok, heck he has a consistant 13 sec truck, what do we do? I just don't understand this stupid sensor.... they seem very touchy.


My Typhoon is the exact opposite, and it has no knock retard at all.

 

[dgoodhue]

When people like, Dave and I have high knock, and have replaced ignition....ect ect... and know that the truck is performing ok, heck he has a consistant 13 sec truck, what do we do?

I really don't know what to do next. My truck doesn't run that bad of ET's, I can run 12.9 on T116 if it hooks with low 1.8 60' (and has some octane booster). I was running 12.9 with 2-3psi launch (and spinning) with T117.

Since my truck is coming off the road, I can dig into deep projects.

I finally have a WB02. Should I do a compression test? Rebuild, clean the pistons, and swap my L35 head on? Check my cam timng while if have the heads off? The only thing ignition wise I have replace is the ignition module, should I swap that? Should I try swapping Memcals, so incase the ESC circuit is on the wrong end of the variance? I really don't want to do anymore engine mods until I resolve this issue.