MMCD - lots of knock... suggestions?

[decathect]

Please take a look at the attached snippet of my mmcd log.

I'm getting lots of knock... on a pull up to 43 counts, and timing seems to be getting scaled back 10* or more. At that point O2-R seems a little low, what should it be at? I've been trying to diagnose an idle issue..

Any suggestions or help on this?

Thanks!

 

[decathect]

Update:

I'm just gonna post the whole log that I got today. I did a pull in 2nd at WOT from the beginning of the gear to about 6500 rpm. Also did a bit of full throttle in 3rd gear. I'm actually getting a lot less knock than part throttle.

Does anything still look wrong? It does look better... but the car is hesitating a lot and not accelerating anywhere near how it should be. I recently just set my base timing to 5* (ended up retarding a bit at the CAS to get it there) and ever since its just not getting up and going.

Here is the link to the file: LOG Click the "Download file" link at the bottom left to download it.

Help me out! I have an autocross on sunday, and I'd like my car to be able to actually accelerate. If I can't figure this out, i'll probably just crank my timing back advanced a bit at the CAS... at least it didn't hesitate a lot.

 

[bboyalan]

For the most part, everything looks normal in your log. It appears that you are running slightly lean between roughly 2500 and 4500. This is particularly evident with the pulled timing and increased knock counts. Then again, it might be phantom knock as well. You should log your IDC's too while you're at it.

Your mid/high fuel trims are good, but your low trim concerns me. At 134.9% the ECU is stating that it is adding a noticeable amount of fuel to compensate for a lean mixture. I usually lean out my low to attain better MPG while cruising hehe.

 

[habitatguy187]

Is your profile up to date? Is your car completely stock?

 

[bboyalan]

Is your profile up to date? Is your car completely stock?

He already stated everything:

car is completely stock other than an axleback exhaust, stock boost, fuel system, etc.

shoot, sorry. It is late. the car is a 93 eagle talon TSi

I concur with "->PrOjEcTGS<-" that you should test for any vacuum leaks. You're obviously getting in some unmetered air that the ECU can only adjust for in closed-loop. This is seen in your low fuel trim.

 

[steve]

It's also possible that his low trims are maxed out from a lazy O2 sensor.

 

[bboyalan]

It's also possible that his low trims are maxed out from a lazy O2 sensor.

Is that possible? I figured his car would throw a DTC for a malfunctioning o2 sensor if that were the case. Also, I think his o2 is cycling at idle; it's difficult to tell but "idle" would be where TPS is at 11% and his RPM's are higher than normal. Correct me if I'm wrong though!

 

[rush2252]

According to this article at WOT the ECU is in open loop mode and the o2 sensors arent even affecting fuel trim or knock. Heres the Link I hope this will give you some insight as to what is your problem.

Tuning & ECU Basics - Automotive Message Forums

 

[bboyalan]

Yes, that is common knowledge for those who tune their cars. That is why I pointed out his idle AND low fuel trim; they occur together. His idle RPM's are in the low 1000's + suspiciously high low fuel trim = vacuum leaks during idle. This is assuming that he's idling in the linked datalog of his.

I'm unsure, but he could also be cruising in first gear too.

 

[rush2252]

Wasnt trying to sound hostile I also read in the info that upping boost increase mani temps if the temp sensor reads 210 and the IAT sensor reads above 84 degrees simultaneously then this will cause knock counts + 1degree timing retard. BUT he said he is on a bone stock setup.

 

[steve]

At the time of that post he hadnst stated what car he was working on just to clarify.

Nice try. The fact that his log shows knock is a good clue he's logging a 1G. If you really didn't know then you should ask before telling somebody to start changing things.

Is that possible? I figured his car would throw a DTC for a malfunctioning o2 sensor if that were the case. Also, I think his o2 is cycling at idle; it's difficult to tell but "idle" would be where TPS is at 11% and his RPM's are higher than normal. Correct me if I'm wrong though!

It's pretty rare for a 1G to throw a CEL for the O2 sensor. I've yet to have one in 18 years but I've had to replace the sensor several times to pass emissions. If the sensor is slow or the heater is bad the sensor will read lean and the ECU will throw fuel at it until it goes out of range. Unless he resets the ECU before hand just sitting and idling for any length of time can cause the low trim to drop. As you point out there are other things that can do this. A unrecirculated BOV or some other vacuum leak are common.

Looking at the last log didn't tell me much other than he has serious knock reported from just off idle and his IPS is working. I wouldn't be surprised if the car still had the original knock sensor, if so it needs to be replaced.

Also Logging the FT02, MAFS, and INJP would help. Give a sample of just sitting idling.

 

[decathect]

Thanks for the suggestions guys. Tonight I put in a new knock sensor... pain in the butt. Didn't fire it up though, need to button things up tomorrow. I'll let everyone know how it does.

I may just throw a new oxygen sensor at it as well, for peace of mind.

I've boost leak tested the car, and the only significant leak left is ON the turbo (the compressor seal, haven't gotten around to replacing it) but its really not that bad, and its also intermittant. I've done boost leak tests where it doesnt leak, and everything is sealed up fine. I've replaced the TB shaft seals, replaced the ISC, blocked off the Cold idle thing on the bottom of the TB, new TB gasket, put some sealant on the turbo outlet pipe... etc etc etc. Like I said, I have been keeping tabs on that and making sure I dont have a huge boost leak.

BOV is recirculated.

I'll do another log, i was trying to eliminate things I didn't think were necessary for better accuracy.

Question - are there any other sensors that maybe I should test/replace that affect timing and fuel? IAT? Coolant temp sensor? Should I try a different MAS? I have another one sitting around.

Just to reiterate, my car doesnt idle very well either. But when I crank up the timing, it idles great.

I think this thread will be a great resource for other people diagnosing pulled timing/idle issues!

 

[rush2252]

In that Link I posted it describes how CTS and IAT sensors can retard timing under certain conditions. Its quite a read up but alot of good info on the 1gs

 

[decathect]

Alright, I replaced the knock sensor and O2 sensor, and I ran about 2/3 of a can of seafoam through my intake (don't know how much faith i put in that). I also advanced the timing a bit at the CAS, since it runs SO much better that way. I did a couple logs, I'll post them up here soon. So far it looks like less knock, although I think that advancing the CAS actually did that... oddly enough. I logged before I did that and I still peaked at 43 counts.

can I just say? ARRRGHHHH. I'm so frustrated.

I have a fuel filter that I'm probably gonna change out tomorrow. I'm about at the point where i'm gonna pull out my injectors and have them flow tested and checked as well.

Any other suggestions? Seriously, I'm downright determined to not give up on this right now. I'm learning a lot in the process.

 

[decathect]

oh yes, and woot for not being able to get aligned because my lower ball joints are bad ! >.<

 

[decathect]

My new log: LOG

It looks a lot better, a lot less knock.

This is weird. I advanced the timing. I haven't checked it with the light yet, but its probably 10*-12* BTDC. This is pretty high, right? I feel like I want to advance it more. I'm sure thats what did it. I lost my other datalog before I advanced it, but it was still hitting 43 counts.

Has my timing belt jumped a tooth? I'm going to check that tomorrow.

 

[bboyalan]

Very nice improvement! I was always under the assumption that too much timing [especially with piss pump 91] would result in predetonation, but it seems to be working out for you. The small knock counts when you go WOT are probably due to the extra fuel being dumped in that brief moment. Your throttle response must have improved though eh?

 

[decathect]

Very nice improvement! I was always under the assumption that too much timing [especially with piss pump 91] would result in predetonation, but it seems to be working out for you. The small knock counts when you go WOT are probably due to the extra fuel being dumped in that brief moment. Your throttle response must have improved though eh?

absolutely it has improved.

Question though -- the timing that is logged, I assume this DOES NOT include base timing? So to get total timing I should add base timing + logged timing?

Another request - Can someone look at my injector pulse, MAS reading, and the other things that were requested earlier? How do those look, anything else I should fix?

 

[decathect]

For those of you that have been following and making suggestions, thank you.

My inclination was right - the timing belt was off. I am suspecting a bad install last time around. I did the timing belt, and the difference is night and day. The car idles flawlessly, powerband is smooth and improved, and it goes like a raped ape! I love this car.

 

[bboyalan]

Congratulations on resolving your problem! I wasn't aware of your previous post, otherwise I would've replied. You should post a fresh log so that we can analyze it again heh.

Everything looks good for the most part. Where your MAFS shows the "#" sign simply means that your datalogger cannot see/record that high of a value. My MMCD v1.8 doesn't read higher than 1599 . Your voltage reading shows a healthy alternator+battery too.

 

[snakeyes711]

Wait? Whats your preferences set too in MMCD? because it liiks like your running 9-10* of base timing!?....BTW is that stock boost?

 

[bboyalan]

Wait? Whats your preferences set too in MMCD? because it liiks like your running 9-10* of base timing!?....BTW is that stock boost?

He has already stated the following:

This is weird. I advanced the timing. I haven't checked it with the light yet, but its probably 10*-12* BTDC. This is pretty high, right? I feel like I want to advance it more. I'm sure thats what did it. I lost my other datalog before I advanced it, but it was still hitting 43 counts.

car is completely stock other than an axleback exhaust, stock boost, fuel system, etc.

 

[snakeyes711]

Yeah, like so much advance I'd say there is ZERO top end. pull that back thats another thing that'll bring up knock.

 

[decathect]

disregard that information. If you read you'd seen that the timing belt was off, so any information about ignition timing and such before then, can be disregarded as my cams were out of phase and it was just generally acting weird, and I was trying to make it run right.

The car is running great now, have got the ignition timing set to 5* BTDC base.

 

[snakeyes711]

I'm glad to hear you got it sorted out.