Knock and more knock

[TurboTrader]

Basically, I'm seeing huge knock counts in the lower RPM range and lower TPS position. If I go WOT, the knock never, if rarely shows up, but it does occasionally. If I baby it (50% tps or less), it shows it's face the most, but not always, and it's really messing with any driveability the Galant once had. It seems to be staying steadily the same, but perhaps just getting slightly worse if any.

The only mods are FMIC, 2.5" in/out, Small 16g @ 12 psi, stock MAF, stock FPR, Walbro 190, 2.5" DP back exhaust, stock 450's. Rebuilt top and bottom end, possible 2g piston swap (unsure about that one, not sure if it matters for the issue). I previously had a 14b and stock fuel pump, and I was still feeling the timing pull before putting the Small 16g and 190 pump on. I originally thought it was the 14b living out it's death.

The knock only starts at the onset of boost. Stay out of boost all the time, there is zero knock.

I have replaced the O2 sensor and Knock sensor with brand new units. The knock sensor is BWD, the O2 is Bosch. With that, I almost have ruled out Phantom knock, but I suppose it could very well be. I have also replaced the top and tranny mount with Prothane inserts, but I don't recall seeing knock after swapping those, and I just recently put the front Prothane in as well, although I doubt any of those are the issue, shouldn't be anyway.

Pretty much at a loss here, as I've done everything possible including new NGK's gapped properly. It does not seem to misfire one bit either.

All I have to go on is the most recent log. Hopefully it can be of some help, or any of the above, any help is much appreciated.

I'm almost at the point of believing it's a bottom end issue and should be torn down, however at the time of purchase, I was told the motor top and bottom has been rebuilt, the head looked fresh, that was about 12,000 miles ago. There is also an unusual tinny rattle sound as the RPM's increase and consistent with the RPM's, no where near a rod-knock sound, not a lifter tick. It actually sounds like a failed hydraulic t-belt tensioner as I've experienced in the past, but that feels solid and there seems to be no more than normal slack in the timing belt. It also has a BSEK with the stub shaft. I suppose it's possible something may have failed there possibly?

The timing, both mechanical and electronic is dead on as well. I thought about pulling the timing back to around 2-3 degrees advance instead of 5 degrees where it is currently set, but with the mods and relatively stock boost level, there is really no reason it should be knocking at stock timing.

Anyway, I'm hoping one of you can chime in with easy things to eliminate as a possible cause before I dig deep into the motor.

Any help much appreciated.

Thanks!

 

What's with the 140 fueltrims? That's VERY lean. Are you leaning it out with an AFC or something?
Does the knock stop as soon as you let off the gas, even the slightest?

 

[ktmrider]

If it truly does have a 2g piston swap then your compression ratio will be higher and definitely contribute to the issue. IIRC you will go from 7.8:1 to 8.5:1.
Yank a plug and try to view the piston crown. 1g piston have 63T ( the T being longer than the numbers ) and 2g have 63TF1 with F1 being small like the numbers.
Like Jeff mentions the trims show a massive lean condition.

 

[TurboTrader]

Quoting keydiver:
What's with the 140 fueltrims? That's VERY lean. Are you leaning it out with an AFC or something?
Does the knock stop as soon as you let off the gas, even the slightest?



I have zero tuning ability. Only pocket logger. The knock seems to stop the second I take my foot out, it mainly knocks right at the onset of boost, which is what is really making me confused as to why it would knock at only 1-3 psi, but I can at most times WOT at 10-12 psi see only 1 or 2 counts.

Quoting ktmrider:
If it truly does have a 2g piston swap then your compression ratio will be higher and definitely contribute to the issue. IIRC you will go from 7.8:1 to 8.5:1.
Yank a plug and try to view the piston crown. 1g piston have 63T ( the T being longer than the numbers ) and 2g have 63TF1 with F1 being small like the numbers.
Like Jeff mentions the trims show a massive lean condition.



A bit tricky to see since I don't own a scope, I haven't tried to take a good look either, and although it could contribute to the issue, I feel there are other underlying causes to be attended to first.

That's also what I was thinking. Although the trims are a long-term reading, I can definitely see the lean condition there now that it has been mentioned. The spark plugs also showed a slight whiteness to them when I had them out the other day (right after replacing them and a good drive) and the number 4 plug was slightly fouled with white speckles before I replaced them.

The condition did not seem to improve or get worse after I replaced the stock pump with the Walbro 190, other than starting. The first few days after the pump swap, it took 8 or 9 cranks before it would start, for whatever reason I started it today and it fired right up. I have been suspecting crappy gas, and after pumping 5 gallons out to stick in the new GSX, the next day was when it started right up. It has also done so the last few attempts, although it seems to be a crank more than it used to, but that's cold start. So far, the GSX seems to have no problem with the gas that was in the Galant. I'm not sure that crap gas could create a lean condition, but correct me if I'm wrong.

With that said, at least to rule the question of gas out completely, I'll take it for a nice drive tomorrow and see how things go. Hopefully well. /ubbthreads/images/graemlins/smile.gif

 

[TurboTrader]

One more thing I forgot to mention, do the IDC's look low?!? Or is that consistent with the 1g Maf/ECU and what the ECU would be calling for?

I'm looking at the airflow of 1,021 Hz and an IDC of 50.11. It seems like the injectors should be more than halfway maxed considering the ECU reads a max of 1,600 Hz, but I could be way off in my presumption.

 

[mooserage]

I am just going to throw a couple of things out there that I have experienced:
-I saw a couple cases of weird knock when coming out of throttle when I had exhaust leak issues. They stopped when it was fixed. I have also seen similar problems with boost leaks.
-About the compression ratios, I have been able to see the cast markings on the pistons with just the right light/flashlight. Just pull 1 plug and keep moving around until you can see it. It is a little difficult, but you can see them. And if they are the higher comp 2g pistons, the higher compression will definitely increase the likeliness of knock/detonation with stock timing maps.
-The spark plug whitening sounds like detonation/knock (although correct me if I'm wrong). I remember having reddened and white/white specks on my plugs from knock issues

One more thing, you don't have a hacked mas running on the stock ecu do you? Some people don't realize their maf is hacked until they check it.

Anyway, hopefully that helps with some things to look for. Good luck.
-shamus

 

[TurboTrader]

Thank you for the insight. I have zero exhaust leaks, at least not that I know of. The only part that is stock of the exhaust including O2 housing is the DP, which I have a new one to put in as well, provided all else is well, but even if the flex section on the DP is leaking, I don't see how that could contribute. If it were a pre-turbo leak, then I could see that making a difference.

Boost leaks I would not rule out, only since I have not tested for them, but there should be little if any at all, at least IMHO. The FMIC is almost brand new as is all piping, couplers and t-clamps as well as the J-pipe and gasket. The Intake manifold and throttle body gaskets have been replaced very recently as well, as were the injector seals. With the exception of the shaft seals at the throttle body, which I'm sure leak at least a little, but not enough to create 43 knock counts and run lean, I can all but completely rule out a boost leak being the issue. It is also my understanding that a boost leak usually causes rich conditions, not lean, so I'll put that to the side for now.

The MAF is 100% in tact. The honey combs are there and it appears there was nothing done to it.

I did pull a couple plugs a few minutes ago and am still having a hard time seeing any writing on them through the plug holes alone, and don't really see how it's possible. Being the same person that rebuilt the GS motor was an advocate of 2g pistons in a 6-bolt, I also recall him saying he had never done it before, but heard of good results in doing so, or something to that nature, so I will go with them being stock 7.8:1 pistons until I pull them, and eliminate that.

The plans for tomorrow are to go for a nice drive with the logger handy and see if it still shows up since the hard start issue has seemingly gone away. If it still shows, I'll set the timing back by a couple degrees and go for another run, and at that point if it subsides, I will know, there is either 2g pistons, or the Small 16g is pushing too much air too fast to keep with the stock aggressive 1g timing.

Sounds like a plan to me?

 

Quoting MadBeachDSM:
It seems like the injectors should be more than halfway maxed considering the ECU reads a max of 1,600 Hz, but I could be way off in my presumption.



The ECU can read a WHOLE LOT more than 1606 Hz, you just can't log anything higher than that.
As lean as you are, I'm going to have to go with the suggestion to do a boost leak test ASAP.

 

[TurboTrader]

As a last resort, I'll go ahead and do a boost leak tomorrow just to be sure.

At idle, especially in comparison with the new Eclipse GSX, I'm hearing alot of chatter around the bottom end, the harmonic balancer seems to wobble just slightly as well, not really in a circular motion as would be expected, but in a very slight up/down. The balancer was replaced new about 2-months ago since the old one was separating slightly. I've also heard a slight clicking when making left turns, which could be the CV, the passenger side is brand new, the drivers side older, but the boot is in tact and it doesn't appear to be leaking lube. Both axles are in the tranny solid as well.

With that said, I'm to some extent at this point leaning towards crank bearings, or something in the bottom end. Although I was told the motor was rebuilt, I can confirm the head was, as it looks very clean inside still, but considering the old dented and partially bare metal/rusted oil pan is still there (and leaking a tad), I don't take too much confidence that OEM parts were used, if even the bottom end was touched at all. Last compression test 10k miles ago yielded 190 across, although I haven't done one recently.

Oh well, I shall update soon.

 

[TurboTrader]

After all the headache the motor from the other project, an Eclipse GS turbo swapped has caused me as of recent, the same knuckle heads that did the work on that motor, also swear the motor in the VR-4 was rebuilt top to bottom as well, yet the same rusty dented oil pan is still there, and leaks only a little amazingly enough. At this point, I have strong reason to be suspicious of the work that was done and the parts used. I've already found numerous cheap/quickly failing gaskets, mainly the intake manifold and throttle body which I have already replaced with OEM.

I have decided #145 deserves much better, and I see no better way than to go through everything with a fine-tooth comb, so to speak. Take my time and get her absolutely right. With the recent Eclipse GSX purchase, and that it is a nice solid daily driver for now, I feel I can finally give her the time and attention she truly deserves.

This all originally stems from the knock issue I noted earlier in the thread. And also a contributing factor is the half-assed job (using used parts) when the other clutch failed, Basically I put a used clutch disc and pressure plate on the Fidanza flywheel that was already in there after a spring popped out of the 6-puck XTD and kept the car from going into gear.

I'm not entirely sure what is causing the knock sensor to go crazy, but there is noise coming from lower down in the bottom end. Whether it is real rod knock, or a failing oil pump, I feel the best way to know for sure is to dig deep down, as the noise is most certainly noticeable, and should not be there.

The last thing I will be doing is hooking up the sending unit that's already on the OFH to the oil PSI gauge and seeing what that's like. There is yet to be lifter tick, and the noise isn't coming from anywhere near the valvetrain, however I have also all but destroyed two 14b's in the past year, and that can certainly be cause to believe there is low oil pressure, neither turbo ever smoked either, so that could be a sign of oiling issues as well. Not sure until I pull it out.

With that said, the motor and tranny should be pulled complete as a whole in the coming weeks. I would love to get in there and shoot a fresh coat of paint in the bay if funds allow as well.

Oh well, do it right, and do it once. Should be lots of fun to come.

I would like to get her to the point where she can be 110% in service for years to come.

 

Have you tried using higher octane gas to see if your issue goes away?