Log results - lots of knock! Eeeek!

[Gromit]

Looking for some thoughts on this log. Mods in my profile are correct. Pull was in 3rd gear from roughly 2500 rpm - redline. SAFC settings are:

LO Throttle - 30%
HI Throttle - 80%

Ne Points
1k
1.6k
2.2k
2.8k
3.4k
4k
4.6k
5.2k
5.8k
6.2k
6.6k
7k

Corrections are -15% across the board (chosen for slightly rich 1st tune with 550's).
Boost is 17-18psi.
Pump Gas - 94 octane

24° 0.84V 421.4Hz 2406 0
24° 0.84V 434.0Hz 2438 0
23° 0.84V 452.9Hz 2469 1
22° 0.84V 459.2Hz 2500 1
22° 0.84V 478.0Hz 2531 1
22° 0.84V 496.9Hz 2563 1
21° 0.84V 522.1Hz 2625 0
21° 0.84V 540.9Hz 2656 0
20° 0.86V 553.5Hz 2688 0
20° 0.86V 585.0Hz 2750 0
20° 0.86V 622.7Hz 2781 0
18° 0.86V 647.9Hz 2844 0
18° 0.88V 691.9Hz 2906 0
17° 0.88V 729.6Hz 2938 0
15° 0.88V 798.8Hz 2969 0
15° 0.88V 861.7Hz 3063 0
15° 0.90V 918.3Hz 3094 0
14° 0.90V 987.5Hz 3156 0
14° 0.90V 1044.1Hz 3219 0
15° 0.88V 1088.2Hz 3313 0
15° 0.88V 1144.8Hz 3375 0
15° 0.88V 1201.4Hz 3438 0
15° 0.88V 1207.7Hz 3563 1
15° 0.88V 1201.4Hz 3625 1
15° 0.88V 1220.3Hz 3656 0
16° 0.88V 1239.1Hz 3750 0
17° 0.88V 1245.4Hz 3781 0
17° 0.88V 1295.7Hz 3906 0
17° 0.88V 1314.6Hz 3969 0
18° 0.88V 1358.6Hz 4063 0
18° 0.88V 1364.9Hz 4094 0
18° 0.88V 1409.0Hz 4156 0
18° 0.88V 1440.4Hz 4219 0
18° 0.88V 1484.4Hz 4250 0
18° 0.88V 1522.2Hz 4375 0
18° 0.88V 1515.9Hz 4375 0
18° 0.88V 1528.5Hz 4469 0
18° 0.88V 1541.1Hz 4500 0
18° 0.88V 1522.2Hz 4594 0
18° 0.88V 1534.8Hz 4625 0
18° 0.88V 1528.5Hz 4688 0
19° 0.88V 1585.1Hz 4750 0
19° 0.88V 1553.6Hz 4813 0
19° 0.88V 1547.3Hz 4875 0
19° 0.88V 1591.4Hz 4938 0
19° 0.88V 1604.0Hz 5031 0
19° 0.88V 1604.0Hz 5000 0
19° 0.88V 1604.0Hz 5156 0
20° 0.88V 1604.0Hz 5156 2
19° 0.88V 1604.0Hz 5250 2
20° 0.88V 1604.0Hz 5281 2
20° 0.88V 1604.0Hz 5406 1
21° 0.88V 1604.0Hz 5438 1
21° 0.88V 1604.0Hz 5438 1
21° 0.86V 1604.0Hz 5500 1
21° 0.88V 1604.0Hz 5563 1
21° 0.88V 1604.0Hz 5656 0
23° 0.86V 1604.0Hz 5688 0
23° 0.88V 1604.0Hz 5781 0
24° 0.86V 1604.0Hz 5844 5
22° 0.84V 1604.0Hz 5844 5
22° 0.86V 1604.0Hz 5938 4
23° 0.86V 1604.0Hz 6000 4
23° 0.86V 1604.0Hz 6063 4
22° 0.86V 1604.0Hz 6094 4
22° 0.86V 1604.0Hz 6125 11
22° 0.84V 1604.0Hz 6250 10
22° 0.84V 1604.0Hz 6250 11
22° 0.84V 1604.0Hz 6344 11
19° 0.84V 1604.0Hz 6313 11
20° 0.82V 1604.0Hz 6438 11
19° 0.84V 1604.0Hz 6500 10
20° 0.82V 1572.5Hz 6563 10
22° 0.80V 1604.0Hz 6656 15
20° 0.78V 1427.8Hz 6625 15
22° 0.10V 1327.2Hz 6594 15
27° 0.00V 1409.0Hz 6719 14
19° 0.57V 1604.0Hz 6688 14
18° 0.78V 1528.5Hz 6781 14
26° 0.02V 1390.1Hz 6781 14
18° 0.72V 1604.0Hz 6750 14
16° 0.82V 1604.0Hz 6781 13
18° 0.80V 1509.6Hz 6938 13
16° 0.82V 1604.0Hz 7031 13
16° 0.82V 1604.0Hz 6969 13
16° 0.82V 1604.0Hz 7000 13
15° 0.82V 1591.4Hz 7000 12
17° 0.82V 1440.4Hz 7125 12
18° 0.62V 1604.0Hz 7094 12
17° 0.84V 1402.7Hz 7094 12
28° 0.88V 987.5Hz 7094 12
30° 0.92V 585.0Hz 7063 8
37° 0.88V 239.0Hz 7156 0
45° 0.84V 132.1Hz 7063 0
45° 0.82V 195.0Hz 7000 0

This is the 1st of 4 pulls I did over several days, making slight changes each time (both richer & leaner), but not seeing any reduction in the level of knock. There is a pronounced stuttering approaching 6k rpm that lasts for a second or 2.

Can anyone point me in the direction I should go? Nathan (spyderturbo007) has been helping me with all of this but we're kind of stuck at this point.

 

[power=dsm]

have you checked for a boost leak yet?? i noticed your eunning i colder spark plug, try going back to the 6es

 

[weith1111]

Did you not let off the throttle? The only way your rpm's should drop is if you were misfiring or hit fuel cut. With the AFC -15, I'd say fuel cut isn't likely.

I like ^^^^. Check/swap your plugs.

 

[Gromit]

Yes, boost leak test was done. Had a few - all the usual places like TB shaft seal, BISS o-ring, BOV, etc. All been fixed. Only place there's any air escaping now (minimal) is in the crankcase itself - maybe worn valve stem seals? Can't do anything about that right now.

As for plugs, I thought the slightly colder plug was recommended for the set-up I have? I see most people running that plug with these mods.

And no, I did not let off the throttle at any point during the pull. I don't think it was fuel cut, either - stuttering, but no "slamming your head into the steering wheel".

How does the timing look overall? It gets pulled a lot when all the knock occurs, but otherwise does it seem OK or is it too high?

 

[Ultimatedsm]

Just gap your plugs properly. You shouldn't have problems with the 7es anyway regardless of anything. I have seen many people go to those plugs without any issues. Just make sure the gap is at 0.028-0.029 range.

Now it can be two types of knock, Rich knock or lean knock. Phantom knock usually occurs at lower RPM but I noticed your car does well up until 6000RPM, than after you start to knock.

Anything under 5 counts of knock is alright, so your good to 6000 RPM. To be safe, I would try to richen things up at 6000-7000 and see if the knock goes away. If it gets worse, than you know your running to rich and try to lean it out a little. One of these will most likely cure your problem. You should get a DSMLINK, that way you can mess around with timing as well. I hate how the SAFC advances timing if you start to go into the negatives with it (Taking away fuel).

If my advice doesn't help you, than your problem is somewhere else. Maybe they are not really 550's or something else is causing the knock.

 

[weith1111]

Either swap back to OEM plugs or just put in a new set and make sure they are gapped correctly. Easiest and cheapest thing to check.

You could check IDC too, but there is no way you should be outrunning those 550's at 18psi. If you have enough fuel, and air isn't a problem, that only leaves spark: plugs, wires, coil pack.

Your timing looks peachy. Maybe a bit high when boost comes on. Is base set at 5 btdc, for sure?

 

[weith1111]

Where's your AFPR?

 

[Ultimatedsm]

Uh oh, no AFPR with a 255? There is your problem right there. Get one and log your car again.

 

[Gromit]

Uh oh, no AFPR with a 255? There is your problem right there. Get one and log your car again.

Oops! Guess I lied about my profile being up-to-date! I do have an AFPR - Buschur, to be exact. Forgot to put that in the list.

I've got a new set of the 7's I can put in.

Timing has been checked - it was up to 9* but I reset to 5* BTDC.

As far as rich knock vs. lean knock, my 1st thought was that it was a little lean above 6000 rpm, too, so for my 2nd pull I added just a little more fuel, but leaned it out a bit where there was no knock. Here's that data:

Ne POINTS
1k -15%
1.6k -15%
2.2k -15%
2.8k -17%
3.4k -17%
4k -17%
4.6k -17%
5.2k -17%
5.8k -17%
6.2k -14%
6.6k -13%
7k -12%

28° 0.76V 396.3Hz 2625 0
28° 0.31V 408.9Hz 2688 0
28° 0.60V 408.9Hz 2719 0
28° 0.72V 415.1Hz 2750 0
28° 0.62V 459.2Hz 2750 0
25° 0.20V 522.1Hz 2813 0
24° 0.84V 553.5Hz 2875 0
23° 0.84V 578.7Hz 2875 0
22° 0.84V 616.4Hz 2938 0
21° 0.84V 660.5Hz 3000 0
20° 0.86V 710.8Hz 3031 0
19° 0.86V 742.2Hz 3063 0
17° 0.88V 811.4Hz 3156 0
16° 0.90V 868.0Hz 3219 0
15° 0.88V 937.2Hz 3250 0
15° 0.88V 1006.4Hz 3344 0
15° 0.88V 1088.2Hz 3406 0
15° 0.88V 1144.8Hz 3469 2
14° 0.88V 1182.5Hz 3531 1
15° 0.88V 1182.5Hz 3594 1
15° 0.88V 1214.0Hz 3688 1
16° 0.88V 1188.8Hz 3750 1
16° 0.88V 1226.6Hz 3844 0
17° 0.86V 1289.5Hz 3875 0
18° 0.88V 1302.0Hz 4000 0
18° 0.88V 1333.5Hz 4031 0
18° 0.88V 1383.8Hz 4125 0
18° 0.88V 1415.3Hz 4219 0
18° 0.88V 1421.5Hz 4250 0
18° 0.88V 1421.5Hz 4344 0
18° 0.88V 1446.7Hz 4438 0
18° 0.88V 1440.4Hz 4500 0
18° 0.88V 1490.7Hz 4531 0
18° 0.88V 1471.9Hz 4563 0
18° 0.88V 1528.5Hz 4656 0
18° 0.88V 1446.7Hz 4688 0
18° 0.86V 1484.4Hz 4813 0
19° 0.86V 1402.7Hz 4875 0
19° 0.84V 1484.4Hz 4906 0
19° 0.86V 1528.5Hz 4969 0
19° 0.86V 1547.3Hz 5031 1
18° 0.86V 1585.1Hz 5094 1
20° 0.86V 1585.1Hz 5188 1
20° 0.86V 1604.0Hz 5188 0
20° 0.86V 1604.0Hz 5250 0
21° 0.86V 1604.0Hz 5344 0
21° 0.86V 1534.8Hz 5375 0
21° 0.86V 1604.0Hz 5406 0
22° 0.84V 1497.0Hz 5469 0
22° 0.84V 1497.0Hz 5563 0
25° 0.80V 1553.6Hz 5625 7
20° 0.82V 1566.2Hz 5688 7
23° 0.76V 1591.4Hz 5781 7
23° 0.82V 1446.7Hz 5813 8
24° 0.64V 1559.9Hz 5875 19
20° 0.80V 1490.7Hz 5875 19
21° 0.68V 1522.2Hz 6000 19
22° 0.62V 1604.0Hz 6031 19
20° 0.78V 1585.1Hz 6063 19
19° 0.82V 1604.0Hz 6125 18
18° 0.82V 1604.0Hz 6156 24
17° 0.82V 1597.7Hz 6281 24
16° 0.80V 1585.1Hz 6281 24
20° 0.10V 1270.6Hz 6125 24
18° 0.66V 1604.0Hz 6188 23
19° 0.66V 1226.6Hz 6250 23
21° 0.04V 1339.8Hz 6313 23
20° 0.04V 1314.6Hz 6469 28 WTF
20° 0.00V 1528.5Hz 6688 28 WTF
12° 0.70V 1604.0Hz 6531 27
16° 0.64V 1566.2Hz 6594 27
21° 0.04V 1503.3Hz 6688 27
16° 0.04V 1459.3Hz 6625 27
17° 0.06V 1226.6Hz 6531 27
21° 0.00V 1604.0Hz 6906 26
14° 0.78V 1578.8Hz 6844 26
14° 0.78V 1578.8Hz 6750 26
15° 0.74V 1390.1Hz 6750 26
19° 0.00V 1604.0Hz 6906 26
12° 0.66V 1572.5Hz 6844 25
15° 0.60V 1402.7Hz 6813 25
18° 0.00V 1453.0Hz 6844 25
11° 0.66V 1604.0Hz 6969 25
12° 0.78V 1604.0Hz 6938 25
12° 0.72V 1604.0Hz 6969 24
14° 0.57V 1377.5Hz 7000 24
22° 0.00V 1364.9Hz 7094 24
16° 0.43V 1604.0Hz 6969 24
11° 0.80V 1604.0Hz 7063 24
12° 0.80V 1446.7Hz 6875 23
31° 0.84V 195.0Hz 7156 14
40° 0.80V 138.4Hz 6844 4
44° 0.82V 119.5Hz 7031 0
45° 0.84V 69.2Hz 6938 0

This was a lot worse. So then I went the other way - leaned it out a wee bit more where there was no knock & leaned it out above 6000 rpm where the knock got worse. Here's that data:

Ne POINTS
1k -15%
1.6k -15%
2.2k -15%
2.8k -18%
3.4k -18%
4k -18%
4.6k -18%
5.2k -18%
5.8k- 17%
6.2k -17%
6.6k -17%
7k -17%

33° 0.74V 295.6Hz 2781 0
33° 0.76V 295.6Hz 2781 0
33° 0.62V 295.6Hz 2813 0
33° 0.37V 308.2Hz 2813 0
30° 0.68V 471.8Hz 2813 0
27° 0.80V 503.2Hz 2875 0
26° 0.84V 522.1Hz 2875 0
25° 0.84V 553.5Hz 2906 0
24° 0.84V 572.4Hz 2938 0
24° 0.84V 597.6Hz 3000 0
23° 0.84V 622.7Hz 3000 0
22° 0.84V 660.5Hz 3031 0
22° 0.86V 717.1Hz 3094 0
19° 0.86V 742.2Hz 3125 0
18° 0.88V 798.8Hz 3156 0
17° 0.88V 861.7Hz 3219 0
16° 0.88V 912.1Hz 3281 0
15° 0.88V 962.4Hz 3313 0
15° 0.88V 1037.9Hz 3344 0
15° 0.88V 1081.9Hz 3438 0
15° 0.88V 1132.2Hz 3531 1
15° 0.88V 1157.4Hz 3563 0
15° 0.88V 1176.2Hz 3625 0
16° 0.88V 1176.2Hz 3656 0
16° 0.88V 1169.9Hz 3750 0
17° 0.88V 1176.2Hz 3813 0
17° 0.88V 1201.4Hz 3875 0
17° 0.88V 1270.6Hz 3906 0
18° 0.88V 1314.6Hz 4031 0
18° 0.88V 1320.9Hz 4000 0
18° 0.88V 1352.4Hz 4094 0
18° 0.88V 1358.6Hz 4156 1
17° 0.88V 1396.4Hz 4219 1
17° 0.88V 1415.3Hz 4250 1
17° 0.88V 1421.5Hz 4281 1
17° 0.88V 1415.3Hz 4375 0
18° 0.88V 1440.4Hz 4438 0
18° 0.88V 1459.3Hz 4469 0
18° 0.88V 1490.7Hz 4500 0
18° 0.88V 1490.7Hz 4531 0
18° 0.88V 1459.3Hz 4594 0
18° 0.88V 1459.3Hz 4656 0
18° 0.88V 1421.5Hz 4719 0
18° 0.88V 1478.2Hz 4781 0
19° 0.86V 1446.7Hz 4750 0
19° 0.86V 1503.3Hz 4844 0
19° 0.86V 1490.7Hz 4844 0
19° 0.86V 1503.3Hz 4938 0
19° 0.88V 1547.3Hz 5031 0
19° 0.86V 1559.9Hz 5094 0
19° 0.86V 1585.1Hz 5125 0
20° 0.86V 1604.0Hz 5125 0
20° 0.88V 1604.0Hz 5156 0
20° 0.88V 1553.6Hz 5188 0
20° 0.86V 1585.1Hz 5281 0
21° 0.86V 1604.0Hz 5281 0
21° 0.86V 1604.0Hz 5344 0
21° 0.86V 1597.7Hz 5375 0
22° 0.86V 1547.3Hz 5438 0
22° 0.86V 1604.0Hz 5500 0
22° 0.86V 1597.7Hz 5594 0
22° 0.86V 1604.0Hz 5594 1
22° 0.84V 1604.0Hz 5625 0
24° 0.84V 1604.0Hz 5656 0
24° 0.86V 1585.1Hz 5750 0
24° 0.86V 1591.4Hz 5781 0
25° 0.86V 1553.6Hz 5844 7
21° 0.86V 1604.0Hz 5875 7
22° 0.86V 1604.0Hz 5969 6
23° 0.86V 1604.0Hz 5969 6
25° 0.86V 1604.0Hz 6031 6
24° 0.86V 1604.0Hz 6063 12
23° 0.84V 1604.0Hz 6063 12
22° 0.84V 1534.8Hz 6094 11
22° 0.82V 1604.0Hz 6188 18
20° 0.82V 1604.0Hz 6219 23
20° 0.80V 1547.3Hz 6313 23
18° 0.80V 1604.0Hz 6313 23
15° 0.84V 1604.0Hz 6313 22
17° 0.82V 1604.0Hz 6375 22
18° 0.84V 1604.0Hz 6469 22
18° 0.82V 1604.0Hz 6438 22
18° 0.84V 1604.0Hz 6531 22
17° 0.84V 1604.0Hz 6563 21
16° 0.84V 1547.3Hz 6594 21
17° 0.82V 1604.0Hz 6563 21
15° 0.84V 1604.0Hz 6594 21
15° 0.82V 1515.9Hz 6688 21
18° 0.78V 1604.0Hz 6750 20
15° 0.82V 1604.0Hz 6719 20
18° 0.80V 1604.0Hz 6781 20
18° 0.82V 1604.0Hz 6844 20
16° 0.82V 1604.0Hz 6813 20
14° 0.84V 1522.2Hz 6906 19
16° 0.82V 1604.0Hz 6875 19
15° 0.82V 1604.0Hz 6938 19
14° 0.84V 1509.6Hz 6906 19
18° 0.78V 1591.4Hz 7031 20
15° 0.80V 1604.0Hz 7031 19
16° 0.80V 1490.7Hz 7063 19
15° 0.82V 1604.0Hz 7156 19
14° 0.84V 1604.0Hz 7031 19
16° 0.90V 717.1Hz 6906 18
39° 0.86V 220.2Hz 7094 4
44° 0.82V 195.0Hz 7031 0
45° 0.82V 201.3Hz 7000 0
45° 0.84V 132.1Hz 6969 0

A little better, but still not great. And the stuttering was still present at the same spot for all these pulls. Any other ideas? Thanks for all the replies so far.

 

[weith1111]

Dude. That's hella knock. Turn the boost down all the way, and set your AFC at -10 across. Don't keep hammering it with all that knock.

That was a great find on the base timing but are you sure you did it correctly (grounded the plug, etc) because it didn't seem to effect much and if you just put a timing light on it will show around 9-10 degrees, or if you got this figure from a logger it's incorrect.

Is your base fuel pressure correct (did you change it when you installed the AFPR)???

Something MAJOR is wrong. You aren't going to make 20 counts of knock disappear with a little fuel in or out.

 

[Gromit]

Dude. That's hella knock. Turn the boost down all the way, and set your AFC at -10 across. Don't keep hammering it with all that knock.

That was a great find on the base timing but are you sure you did it correctly (grounded the plug, etc) because it didn't seem to effect much and if you just put a timing light on it will show around 9-10 degrees, or if you got this figure from a logger it's incorrect.

Is your base fuel pressure correct (did you change it when you installed the AFPR)???

Something MAJOR is wrong. You aren't going to make 20 counts of knock disappear with a little fuel in or out.

Yeah, I know it's nasty knock. I only did 1 more pull after those 3 - I don't normally drive around at 6k rpm so I'm not worried from that aspect, but I do want to get it sorted out.

I followed the VFAQ for setting the base timing - grounded the plug, etc. Unless I read the marks wrong or from a bad angle it should be right.

When I installed the AFPR I set & checked the fuel pressure per the factory specs in the service manual, so that's good there.

For the record, I also checked the knock sensor for leakage - it's goo-free. This car is in good shape - my wife is the original owner. So I'm stumped. Notice the slightly erratic MAS values & the RPM's bouncing around a bit? Thoughts on that?

 

[weith1111]

At this point it's not really tuning advice

I honestly don't know where to go from here, just go with your gut. Pull your plugs, do they all look the same? Maybe one injector isn't working correctly. Look for a plug significantly different than the others.

You don't have an EGT do you? Is your coolant temp ok?

In one of your earlier logs you were getting o2's of 0.00v and such, mid WOT run. This is a bad o2 sensor or something else not functioning correctly. Everything wired up correctly and soldered? Loose AFC wiring? Just make a list of all parts involved and start checking them off the list one by one.

I'd check your o2 sensor, plugs and wires if they aren't relatively new/in good shape.

Good luck!

 

[Gromit]

At this point it's not really tuning advice

I honestly don't know where to go from here, just go with your gut. Pull your plugs, do they all look the same? Maybe one injector isn't working correctly. Look for a plug significantly different than the others.

You don't have an EGT do you? Is your coolant temp ok?

In one of your earlier logs you were getting o2's of 0.00v and such, mid WOT run. This is a bad o2 sensor or something else not functioning correctly. Everything wired up correctly and soldered? Loose AFC wiring? Just make a list of all parts involved and start checking them off the list one by one.

I'd check your o2 sensor, plugs and wires if they aren't relatively new/in good shape.

Good luck!

Thanks for your help/suggestions. Unfortunately, this is the same point Nathan got to as well. It's perplexing.

The plugs all look the same - I've pulled them several times to see if I could see anything from them. If anything, they tend toward looking slightly lean. Both plugs & wires have less than 500 miles on them. O2 sensor is also a brand new Bosch unit. No EGT. Coolant temp seems fine - 209 on the logger when fully warmed up.

I'll keep plugging away at it. The car runs great & pulls like a son-of-a-b#%!&h, aside from all the knock at the top end.

 

[Ultimatedsm]

I was looking at your timing and its too high to be running 18 psi on pump gas. Re-do your timing again and lower it by a few degree's. The o2 voltage looks a little low which can indicate a lean mixture and sometimes your o2 isn't working at all which isn't good either. How old is your knock sensor. They should be replaced every 100,000 miles. For now like some people sugguested, start to tune at boost pressure maybe at 14 psi and start you way up, thats how you do it.

 

[Gromit]

I was looking at your timing and its too high to be running 18 psi on pump gas. Re-do your timing again and lower it by a few degree's. The o2 voltage looks a little low which can indicate a lean mixture and sometimes your o2 isn't working at all which isn't good either. How old is your knock sensor. They should be replaced every 100,000 miles. For now like some people sugguested, start to tune at boost pressure maybe at 14 psi and start you way up, thats how you do it.

Thanks for the suggestions. By lowering the timing a few degrees, do you mean if it's set at 5* BTDC to take it a couple degrees below that? I've read some other posts talking about how the 1G's have a more aggressive timing map & sometimes a particular car needs to have the timing retarded slightly. How does this effect overall responsiveness?

I don't know what's up with the o2 voltage - the sensor has only a couple hundred miles on it. The knock sensor is the factory original - but the car only has 89k. I checked to see if it was leaking & its not. If it wasn't working right wouldn't I be seeing more erratic knock readings at varying points of the pull? The high knock counts have been very consistent through all the pulls.

I'll try lowering the boost & work up, but there's no reason I shouldn't be able to run 18 psi on pump gas on this set-up if everything is in correct working order. The car is in great shape & has been babied all its life, not beat on like is often the case. I'd rather find the cause of the problem than just settle for a lesser tune that works OK.

Did you have any thoughts on the slight variations in MAS & RPM readings at the higher RPM bands?

Thanks for all the replies so far - I appreciate the insights & it gives me different ideas on where to look! I'll put in the new set of plugs, reset the timing, lower the boost a bit, & try a pull this weekend.

 

[spyderturbo007]

Just to chime in one this, Neal and I have been working with this, on and off, for about 2 months. We have done everything......

1) New plugs
2) wires
3) multiple leak tests
4) checked knock sensor
5) pulled and examined ECU
6) new TB seals
7) checked SAFC wiring
8) fuel filter
9) checked TPS
10) blah, blah.

^^^Jump in here, Neal, if there is something I have forgotten.

I have been through this over and over, and this is as far as I can get him. The only thing I noticed was the bouncing MAF values??? He said that there is noone that he can borrow a MAF from and I don't know if there is a way to test it. It seems to be the only thing "out of wack". Even before the onset of knock, you can see the values changing. But I can't justify telling him to pay a couple hundered dollars on a hunch.

Also, there is no reason with his setup that he can't be running 18 or 20psi all day long.

Oh, the only thing we haven't been able to do yet, was throw in a tank of race gas. But by the changes in knock correlating to the change in SAFC settings, I can't see phantom knock being the problem


Where's that Andy guy when you need him. Probably off baking cookies again.

 

[Gromit]

Just to chime in one this, Neal and I have been working with this, on and off, for about 2 months. We have done everything......

1) New plugs
2) wires
3) multiple leak tests
4) checked knock sensor
5) pulled and examined ECU
6) new TB seals
7) checked SAFC wiring
8) fuel filter
9) checked TPS
10) blah, blah.

^^^Jump in here, Neal, if there is something I have forgotten.

I have been through this over and over, and this is as far as I can get him. The only thing I noticed was the bouncing MAF values??? He said that there is noone that he can borrow a MAF from and I don't know if there is a way to test it. It seems to be the only thing "out of wack". Even before the onset of knock, you can see the values changing. But I can't justify telling him to pay a couple hundered dollars on a hunch.

Also, there is no reason with his setup that he can't be running 18 or 20psi all day long.

Oh, the only thing we haven't been able to do yet, was throw in a tank of race gas. But by the changes in knock correlating to the change in SAFC settings, I can't see phantom knock being the problem


Where's that Andy guy when you need him. Probably off baking cookies again.

Yeah, that Nathan guy has been a real drill sergeant with all of this - "Check the ECU! Boost leak test! Check the knock sensor! Check the timing!" Sheesh! Just kidding - Nathan's been a great help & I've probably caused him undue stress with all these goofy problems! Thanks for posting up the background briefing -I think you pretty much covered all of it.

I've yet to check the factory service manual to see if there's a way to test the MAS - I've added that to the list of things for the weekend.

Mmmmm...cookies...

 

[Ultimatedsm]

The 1G's have more aggressive timing to make up for the lower compression ratio the motor has. The 1g has 7.8:1 VS 8.5:1 on the 2g thats why the 2G guys timing sucks from the factory . Yes you have to drop your base time a notch or two, if you had a dsmlink, you could of just started anywhere in the RPM range. The SAFC likes to advance timing further when you start to compensate for larger injectors. The SAFC tricks the ECU by telling it there is less air than there really is, the ECU thinks "Hey, theres not a lot of air, so we are not making enough power, lets advance the timing" Well if it had a brain, thats what it would say . However, sometimes this timing advance isn't a good thing specially if your boosting 18 psi and up.

Having that said, drop your base timing a little more, that would hopefully either get rid of the knock or lower it further.

I know your setup can take 18 psi no problem, but its always good to start at a lower boost level at first and work your way up to 18 psi. That way you will know what boost pressure the knock kicks in at which will help us to determine the problem even more.

A bad MAF sensor can mess up everything. I had a bad MAF and the stupid car would knock a lot and when I tried to hit boost, it didn't go anywhere. It felt like a huge boost leak.

I wish I knew more variables in the log such as:

Intake Temp
Throttle postion
Injector Duty Cycle
LTFT low, mid, high
STFT

If I knew those variables, I probably get figure your problem out pretty fast . Let me know if its possible to log those variables.

 

[Gromit]

The 1G's have more aggressive timing to make up for the lower compression ratio the motor has. The 1g has 7.8:1 VS 8.5:1 on the 2g thats why the 2G guys timing sucks from the factory . Yes you have to drop your base time a notch or two, if you had a dsmlink, you could of just started anywhere in the RPM range. The SAFC likes to advance timing further when you start to compensate for larger injectors. The SAFC tricks the ECU by telling it there is less air than there really is, the ECU thinks "Hey, theres not a lot of air, so we are not making enough power, lets advance the timing" Well if it had a brain, thats what it would say . However, sometimes this timing advance isn't a good thing specially if your boosting 18 psi and up.

Having that said, drop your base timing a little more, that would hopefully either get rid of the knock or lower it further.

I know your setup can take 18 psi no problem, but its always good to start at a lower boost level at first and work your way up to 18 psi. That way you will know what boost pressure the knock kicks in at which will help us to determine the problem even more.

A bad MAF sensor can mess up everything. I had a bad MAF and the stupid car would knock a lot and when I tried to hit boost, it didn't go anywhere. It felt like a huge boost leak.

I wish I knew more variables in the log such as:

Intake Temp
Throttle postion
Injector Duty Cycle
LTFT low, mid, high
STFT

If I knew those variables, I probably get figure your problem out pretty fast . Let me know if its possible to log those variables.

Thanks for that explanation - it makes sense. I'll reset the timing to 2-3* BTDC, put in the new set of plugs & try another pull this weekend if the weather is OK. What do you want the SAFC settings to be? Right now, they're roughly the base setting for 550's - i.e., -18%. I can leave them there or richen it up a bit to be on the safe side.

I can also log the other variables you wanted. I am running MMCD so I'm not sure what values are available for Injector Duty - I think there's an injector duty cycle & an injector pulse width. Also, the 1G's do not have LTFT & STFT - there is only Low, Medium, & High Fuel Trim. I can log Throttle Position, too, but I have already verified it is above 90% (99.6%, I think it was). I think Intake Temp can be logged, too, but I'll have to check on that to be sure.

Thanks again for your help & input!

 

[Ultimatedsm]

Yeah, the 2g's have the LTFT and STFT, I always confuse myself when talking about the 1g's . Well IDC or pulse width, pretty much tells you the same thing. Well the 550's flow 18% more fuel than the 450's so -18 is a good point to start, but I noticed when you at -15 across, you had a lot less knock so lets start at -15 again. What is your AFPR set to? Is it base or is it something else, that can make a big difference when setting up your fuel injectors with the SAFC. And remember to log all those variables if you can.

 

[Gromit]

Yeah, the 2g's have the LTFT and STFT, I always confuse myself when talking about the 1g's . Well IDC or pulse width, pretty much tells you the same thing. Well the 550's flow 18% more fuel than the 450's so -18 is a good point to start, but I noticed when you at -15 across, you had a lot less knock so lets start at -15 again. What is your AFPR set to? Is it base or is it something else, that can make a big difference when setting up your fuel injectors with the SAFC. And remember to log all those variables if you can.

OK, I'll start with -15% correction across the board.

The AFPR is set to base - I forget what that is at the moment, but I set it per the factory service manual.

Planning to do the pull early Saturday AM if the weather is OK. Should be no problem to log all the extra variables.

 

[andymoraitis]

Now that I'm done baking cookies, let me start by saying you've had some exceptional suggestions here and Nathan helping you personally is always a bonus (even if he is dorky).

I don't have too much to add since so many things have been covered correctly, but I will say that your knock doesn't resemble PK in the least. Nevertheless, I'd like for you to check the torque on your knock sensor or inspect it for any black discharge coming out of the back just in case.

Also, the FIRST thing I do in the presence of knock to ensure that it's real is add higher octane fuel. If it dissipates or is greatly reduced as result, it was real and it needs to be tuned out. The problem with AFC's is what Ultimatedsm alluded to: the airflow subtraction will throw the timing out of whack, but there's no reason that smaller correction values from running 550's would make that much of a mess.

Check the knock sensor, try some octane and please post back. If the octane doesn't fix it, I'd re-check voltage to the fuel pump to make sure it's not starving and also consider bumping fuel pressure a bit to see if it helps. I had similar knock issues on the old 2.0 that carried over to the stroker and even at reasonable boost levels, it turned out to be a fuel volume issue. Replacing the pump made all of my problems dissapear (well at least my tuning related ones).

Oh and Nathan, NO COOKIES FOR YOU!

Good luck guys and please keep me posted.

Andy

P.S. I want to take a moment to compliment the participants in this thread. You guys make me proud!

 

[spyderturbo007]

Now that I'm done baking cookies,

let me start by saying you've had some exceptional suggestions here and Nathan helping you personally is always a bonus (even if he is dorky).

Um, thanks, I think .......I remember that last PM you stated that "Fat jokes are acceptable". Might just have to send you a PM later for the dork comment.

Nevertheless, I'd like for you to check the torque on your knock sensor or inspect it for any black discharge coming out of the back just in case.

I had Neal check for leakage, but I never thought to have him check the torque specs. Good thought.

Also, the FIRST thing I do in the presence of knock to ensure that it's real is add higher octane fuel. If it dissipates or is greatly reduced as result, it was real and it needs to be tuned out.

That's one thing that Neal hasn't had a chance to do yet.

The problem with AFC's is what Ultimatedsm alluded to: the airflow subtraction will throw the timing out of whack, but there's no reason that smaller correction values from running 550's would make that much of a mess.

I agree, 100%. Maybe when you're running 720's but definately not 550's.


Andy, what do you think about the bouncing MAS numbers? Is there anyway to test the MAS short of replacing it?

 

[andymoraitis]

Andy, what do you think about the bouncing MAS numbers? Is there anyway to test the MAS short of replacing it?

Look, I'm fat and I sweat on relatively cool days. Get over it or there WILL be cookie warfare.

As far as the MAS signal bouncing around, I'm not sure what to make of it but I'll see if I can find some info about testing it.

Also, don't forget to look into the fuel pump as a possible culprit. Part of this smells badly like a fuel volume/fuel delivery issue.

I'll be back as soon as I find something out about the MAS.

 

[andymoraitis]

Here you go guys,

According to this post, you can test the MAS with a meter:

http://www.dsmtuners.com/forums/showthread.php?t=9232&highlight=MAS+test

Might want to grab a manual and see how it's done.

Keep me posted.