Crazy Freeway Knock Retard

[SuperSy]

Re: Crazy Freeway Knock Retard

Truck is not running any better at WOT. Tried retarding the base timing by up to 4 degrees, took two full turns out of the wastegate rod, no difference. Around 12 degrees KR in 3rd gear. Pulls right around 6 degrees on the 2-3 shift then 12 degrees when TCC locks up, 1st and 2nd gear are fine.

 

[dgoodhue]

Re: Crazy Freeway Knock Retard

Man that sucks. I would put in the stock chip and see if that helps.

 

[SuperSy]

Re: Crazy Freeway Knock Retard

I really wish I had the stock chip, it had a jet chip in it when I bought it. I had that one reburned by hoodtuned.

 

[dgoodhue]

Re: Crazy Freeway Knock Retard

Oh well. I was trying to rule out the chip as being the problem. I would raise your fuel pressure 5psi to see if that helps.

 

[SuperSy]

Re: Crazy Freeway Knock Retard

This knock is definitely real. I mixed up 2 gal of xylene with about 2 gal of 100 octane I had and dumped that into my gas tank. Also loosened the wastegate another turn; I was hitting a little over 15 psi today. Letting the wastegate rod out doesn't seem to change the overboosting problem. I've let it out like 5-6 turns now.
Truck ran great on a couple of runs once the xylene got mixed in. KR in 3rd gear went away; now it wants to KR 4-6 degrees in 1st gear, then flattens out. Once heat soak set in, things got a little random. Boost control s still crappy and peaks at 15.2 ish.
Lterm counts seem to stay at 128, sterms look wicked lean until I get into the throttle. It looks like I might be lean for a second until the ECM compensates at WOT?

http://www.filehosting.org/file/details/463213/added 2 gal xylene.uni

My next move is to start throwing fuel pressure at it.

 

[Don W.]

Re: Crazy Freeway Knock Retard

I just went back and looked at your original post. You say you have a Hood tuned 2 bar chip. A 2 bar chip cannot read boost past 14psi. Anything beyond that and your chip will think you are still making only 14psi boost. Is that a misprint or did I miss something?

 

[SuperSy]

Re: Crazy Freeway Knock Retard

I just went back and looked at your original post. You say you have a Hood tuned 2 bar chip. A 2 bar chip cannot read boost past 14psi. Anything beyond that and your chip will think you are still making only 14psi boost. Is that a misprint or did I miss something?

Yes. 2bar chip, 2 bar map. DM is showing 15 # at times with the stock boost controller hooked up. I've got the wategate rod let out quite a bit.

 

[dgoodhue]

Re: Crazy Freeway Knock Retard

The 2 bar map sensor will only read to 15.2 or 15.3 psi. I would reduce the boost to below 15psi and then add fuel pressure to see if that helps.

 

[Don W.]

Re: Crazy Freeway Knock Retard

Thanks, I was just picking round numbers.

 

[SuperSy]

Re: Crazy Freeway Knock Retard

The 2 bar map sensor will only read to 15.2 or 15.3 psi. I would reduce the boost to below 15psi and then add fuel pressure to see if that helps.

It's been a secondary effort to try to get the boost under control. The waste gate rod hole is just about flush with the pivot pin. It's looser than the 7/8 stock spec. Sticky waste gate maybe?

 

[sytyguy]

Re: Crazy Freeway Knock Retard

I'll gladly reburn the chip if you suspect it to be the problem or if you just want to go more conservative on the tune for the heck of it. Though I never go aggressive on timing unless specifically asked to.

My advice, bypass the WG solenoid (run a vac line from comp housing to WG) to force base boost and see if the KR persists. If it does, then you have a fueling or excessive timing issue or it's false knock.

 

[SuperSy]

Re: Crazy Freeway Knock Retard

I'll gladly reburn the chip if you suspect it to be the problem or if you just want to go more conservative on the tune for the heck of it. Though I never go aggressive on timing unless specifically asked to.

My advice, bypass the WG solenoid (run a vac line from comp housing to WG) to force base boost and see if the KR persists. If it does, then you have a fueling or excessive timing issue or it's false knock.

I don't think its the chip at this point, in fact its never idled or driven smoother until I put your chip in. I believe its a combo of sitting in storage for three years and crappy hippie california gas that have really not done this truck any good. I also dont trust the timing mark on the harmonic balancer at all now. Ill try bypassing the solenoid in the am and see what happens.

 

[johnboy89]

Re: Crazy Freeway Knock Retard

Has this truck ever ran without any KR? You mention that it ran good when you first bought it, but don't mention if you data logged it back then?

The reason I ask is because my old truck behaved very similar to yours and I went through a lot of what you did only to find out my problem was the compression being way higher than stock. I ended up using alky to eliminate it for the most part.

http://www.syty.net/forums/showthread.php?t=87503

 

[SuperSy]

Re: Crazy Freeway Knock Retard

Has this truck ever ran without any KR? You mention that it ran good when you first bought it, but don't mention if you data logged it back then?

The reason I ask is because my old truck behaved very similar to yours and I went through a lot of what you did only to find out my problem was the compression being way higher than stock. I ended up using alky to eliminate it for the most part.

http://www.syty.net/forums/showthread.php?t=87503

I did do some datalogging shortly after I got it. It was bone stock at the time (2009), minus fresh AC Delco plugs, cheap duralast plug wires, and a delco cap. It would get 0-4* if I put a little race gas in it. All this with a 195 t-Stat and a non hot-wired IC pump. I never even bothered to check the timing.

I haven't done a compression check on it yet. I'll add that to my to do list. I haven't had much time to work on the truck with life and work. Seems like I can try about one thing a week these days, then I'm trying to fix new problems. I'm currently chasing down new problems:
1. IAC code, rough idle, stalling, stock IAC was stuck, took it out, caked with carbon, cleaned passages, replaced IAC valve. No more stumbling, now has high idle. 1100 in park, 800-900 in drive. Occassional IAC code 35. Tried the aldl jumper reset. no change.

2. Super lean Sterm counts, sometimes as high as 200, at cruise and idle. Base fuel pressure all the way to 50 psi. Have tried everything form 43-50#. Smells pig rich at idle. Fuel pressure rises with boost pound for pound. I even made a video of it.

3. Datamaster all of a sudden does not want to do a pcm sync. I got it to datalog for about 5 min tonight after messing with it for 2 days, connection died before I could get into boost. It never came back.

I swear this truck is getting sold once I fix these problems!! I've even got the ad drafted up.:rant:

 

[berzerker]

Re: Crazy Freeway Knock Retard

barrow a known good ecm or buy one from an autozone $125.00 a good friends typhoon always showed knock no matter what we did and all it was a bad ecm .

 

[dgoodhue]

Re: Crazy Freeway Knock Retard

It shouldn't have needed race gas to get the knock retard to 0 to 4 degrees. I would bypass the solenoid as sytyguy suggested. Potentially John maybe on to something with the wrong compression.

Don't worry about the s term counts. It just instantaneous adjust the ECM is making.

Your high idle is probably because some one adjust the throttle body stop screw because the iac passages were clogged up.

 

[SuperSy]

Re: Crazy Freeway Knock Retard

It shouldn't have needed race gas to get the knock retard to 0 to 4 degrees. I would bypass the solenoid as sytyguy suggested. Potentially John maybe on to something with the wrong compression.

Don't worry about the s term counts. It just instantaneous adjust the ECM is making.

Your high idle is probably because some one adjust the throttle body stop screw because the iac passages were clogged up.

What would cause excessive compression on a bone stock truck? When I took the intake off, that engine had never been apart.

I bypassed the boost solenoid last week. Knocked like 4 degrees at 9 psi boost. Then Datamaster stopped working. Just went into no pcm sync, recycling in the middle of a run. Got it to come back last night for about 5 minutes, hasn't worked since. Tried fiddling with it tonight for about half an hour, nothing. Replaced the ECM box with an extra one I had. Still no DM.

Throttle body stop screw plug is still intact. I started the truck this morning and the idle was stuck at 2000 rpm and wouldn't come down until I pulled the ECM fuse.

Idle is a little better, but still is around 900-1000 rpm in park.

 

[dgoodhue]

Re: Crazy Freeway Knock Retard

Idle should be around 600-700 rpm.

Ideally 0 degrees should what a stock SyTy runs on 92-93 octane. I would say a few degrees on shifts is 'normal' & should be attainable. 4 degrees at 9psi is too much knock. I would expect 0 across the board at that low of boost level.

 

[Don W.]

Re: Crazy Freeway Knock Retard

Dave brings up a good point. There is no harm is reducing base timing to, say, -2* and see what happens. The "ideal" 0* thing is not cast in stone.

 

[SuperSy]

Re: Crazy Freeway Knock Retard

Dave brings up a good point. There is no harm is reducing base timing to, say, -2* and see what happens. The "ideal" 0* thing is not cast in stone.

Tried reducing the base timing in increments a few weeks ago, all the way to -5 degrees, knock never improved. 13 degrees KR at -5. Set it back to 0. I feel I may be close with the wastegate, I'm just flying blind without datamaster working.