Cuts out at 2900 rpm

WeezilUSA · 10-16-2009, 01:18 AM

So tonight Poik and I did a bit more shakedown tuning with vurbo. After swapping to his MSQ (with some req fuel scaling), and finding a potentially hazardous wiring issue... It starts up and runs pretty good. We were able to drive it around a bit (probably 20 minutes or so)... But when it gets up above 2800 rpm, it feels like its hitting a rev limiter (spark cut)... If you push it hard into it, it will backfire, if you push it soft it will just kinda buck. At first it looked like it was going lean when it was getting into those cells... richened it way up, also pulled timing back as it looked like the timing was advancing as it was moving into that cell... no dice.

Tried swapping spark plugs for some colder ones, and the problem still exists. Thoughts? Checked launch control, it is totally off... and rev limiter is set to 6800. I'd post the datalog here, but it doesn't look like my donation has taken effect yet... From looking at the datalog though, there is nothing that really is changing drastically as we are trying to move into that next cell.

Captain Bondo · 10-16-2009, 02:43 AM

The usual questions apply.

Does it rev freely past 2900rpm in neutral?

If not, have you put a timing light on it and revved it to observe the spark?

Definitely need to do that 2nd test.

If it revs up ok in neutral it's a fuel issue.

B-lennium · 10-16-2009, 02:52 AM

I had this problem to, I could not rev higher as 3400, after fiddling with the adjustment pots it worked! 6000rpm!
first turn them all the way CCW, then the middle one 8 turns CW, that worked for me.

I run MSII Extra 2.10 ,36-1 VR pickup.

WeezilUSA · 10-16-2009, 09:54 AM

I haven't tried messing with the adjustment pots... Thats something I'll have to try.

Kenny, It doesn't rev freely in neutral either, it just feels like its hitting a limiter there. Due to the gunshot style backfires that occur if pushed hard on that limiter, it feels like spark.

I'm going to pick up a new timing light, as the one my dad had is spotty at best, and see what its doing on Saturday. Running like this it would be pointless to take it to the dyno, so I had better call them first thing and cancel :(

The other thing is that Poik suggested after we were done last night, was fixing the timing angle and seeing if that changes it vs. running off the map. I did just find that knock detection was turned ON despite me not having a sensor for it, could that randomly be deciding to pull timing back a ton?

Roger-Dee · 10-16-2009, 10:51 AM

Have you checked with a timing light that the timing in MS correspond to the one at the engine ? When I first installed my MS I couldn't get the car to go over 2500~3000 and it was backfiring like crazy. I updated my firmware to the high resolution and the problem went away.

A datalog would be nice too.

Kenny, how one can adjust the latency values ? Only way I can think off is on a dyno with a timing light... ?

linuxman51 · 10-16-2009, 10:04 PM

Quote:

Originally Posted by Roger-Dee

Have you checked with a timing light that the timing in MS correspond to the one at the engine ? When I first installed my MS I couldn't get the car to go over 2500~3000 and it was backfiring like crazy. I updated my firmware to the high resolution and the problem went away.

A datalog would be nice too.

Kenny, how one can adjust the latency values ? Only way I can think off is on a dyno with a timing light... ?

reving in neutral with fixed timing is one way to do it. you're just looking for timing retard over the rpm range, and you increase the latency values to minimize it.

linuxman51 · 10-16-2009, 10:50 AM

adjust the pots and look at the map. if you're loading up on fuel, it'll do that. if your timing is too conservative AND its an ms1 without the latency values set, it can do that as well. taking timing out makes the problem worse, however it usually manifests itself at higher rpms than that.

How much timing? got a datalog? if the rpm is dropping out while it's doing this, you've got your answer.

WeezilUSA · 10-16-2009, 12:31 PM

Latency values for the wideband, or for the injectors?

My timing light's pickup was being really sketchy last night, so it was hard to confirm what exactly was going on. I am going to pick up a new one on saturday and then check that out.

I'll post up the datalog after work. I don't know where Eric saved it on my computer lol.

Poik · 10-16-2009, 01:39 PM

C:\Users\Beaver\AppData\Local\VirtualStore\Program Files\MegaSquirtHR\Car1HR\

The RPM looks just fine in the logs, but we were thinking it could still be missing certain teeth. We need to hold it in neutral and check the timing set to a fixed angle. We couldn't really do that last night at 10pm, the car is really loud.

The Aspirator · 10-16-2009, 03:27 PM

How sturdy is the VR bracket? That's the first thing that comes to mind, and the cap between it and the teeth. Open up Megatunix or maybe tunerstudio has it, and check out the tooth logger, it'll tell you if there's any problems with the VR sensor reading teeth.

WeezilUSA · 10-16-2009, 04:48 PM

I'm fairly certain that the vr bracket is sturdy enough... Its welded from 1" square tube, with 2 bolt points on the block. The sensor is very close to the teeth. probably less than 1mm, but not touching. I can try to do a datalog from tunerstudio, I have been using megatune, but I have both on my computer, haven't really tried playing with tunerstudion much as of yet.

Come to think of it on the adjustment pots, I had taken the screws out of them at one point when I was doing some work on the MS board, I did put them back in, but they may be way too tight... I don't exactly know what they do, but it would be awesome if that is maybe it.

WeezilUSA · 10-17-2009, 01:54 PM

I'm just going to try those two things today, I'll let you know what happens.

Thanks guys!

WeezilUSA · 10-17-2009, 06:33 PM

No luck yet. What does the NOS w/ Inj Pulsing indicator mean at the bottom of megatune?

WeezilUSA · 10-18-2009, 03:02 AM

Ok... so it was the VR sensor bracket. Turns out it wasn't as stiff as I thought. Fixed the bracket, revved to 6k, and the #1 cyl freeze plug popped out, causing a huge mess. Son of a b. At least it'll be good to go once I get that fixed.

The Aspirator · 10-18-2009, 11:07 AM

Ha! Totally called it. But dammit on the freeze plug man!! Maybe my machine shop just didn't know how to put them in properly? I really trust the guy though, but I had at least 2 pop out on my B23, maybe more. Was it at least on the intake side...err, just looked at the pics, B21's don't have any on the intake side but my B23 does, weird.

For a temp fix those rubber expandable plugs do work in a pinch, but I popped those out too if I revved it too high. If you recall, my solution was to weld those farkers in there for GOOD. I made a big huge thread about freeze plugs a few years ago, there's some great info in there if you haven't read it yet.

WeezilUSA · 10-18-2009, 12:20 PM

I think what happened John, was that they didn't take the freeze plugs out when they worked on it. Doug had JB welded them in, and unless you did it the same way, they looked pretty much the same. I guess hot tanking may have weakened the epoxy, and this was probably bound to happen. My plan is to weld all 4 in, not sure if I should start with new ones, or the ones that I already have. I'll dig up your thread.

Thanks,

Ben

The Aspirator · 10-18-2009, 12:45 PM

Looking at my old pics I can say fairly certainly that the machine shop removed those old plugs and put new ones in, then I slapped new JBweld on top. If you're thinking of welding, definitely read the thread to the end. Mine are still holding great after 3+ years, with only the tiniest weep of coolant from #1 intake side.
http://forums.turbobricks.com/showthread.php?t=73880

WeezilUSA · 10-18-2009, 12:55 PM

Thanks John,

Glad I didn't just impulsively weld it in yesterday.

Poik · 10-18-2009, 03:34 PM

I don't have to work until Thursday so let me know when you want to tune again.

WeezilUSA · 10-18-2009, 04:46 PM

Poik, I'm free Tuesday and Wednesday. I'm guessing it will likely take an evening to get the freeze plug issue taken care of. John, so what do you think I should do for the plugs at this point? I've got a 220v Mig, So was the issue you were originally having that you couldn't get enough heat in there? The other option I'm thinking about is turning some press fit plugs (like my distributor one, if you've seen it).. And have a wider flange than the hole which I could then drill through and either rivet, or tap the block to have a retainer or 2 or 3.

WeezilUSA · 10-18-2009, 05:03 PM

Had another interesting idea when brainstorming with my dad. How about putting the plugs in, and then bolting a piece of flat stock across the face of the freeze plugs, and then maybe threading a bolt hole for each plug to have a bolt pressing against the freeze plug, keeping it from moving?

The Aspirator · 10-18-2009, 05:47 PM

I really like that flat bar idea! You'd have to drill/tap two holes on either side of the plug (into the block), but yeah dude, that'd work great. Or if you're feeling frisky maybe you would weld the flat bar to the block...

As for welding, the first pics in the thread were with my little 90amp flux core and the welds cracked right through, all of them. Then I took the block to John Lane's house with his 220v Miller and zapped the crap out of em. I don't know how much juice he used, but it was definitely enough, the beads are FAT. No pre-heat for the cast iron, no fancy prep, just judicious attacking with a wire wheel and lots of brake kleen, then zap zap zap. Thanks JL!!

WeezilUSA · 11-30-2009, 01:22 PM

Ok so just a little note here... I reinforced the VR sensor bracket, and then made the brace for the freeze plugs... Issue with cutting out occurred again. Matt Cramer from DIY autotune suggested I try a 10k ohm resistor in my VR signal, to help cut down noise. Well I put it in, and voila... Worked like a charm! No more cutout, just revs revs revs! FYI I put it in the Negative signal right next to the MS box.

The Aspirator · 11-30-2009, 05:16 PM

Isn't that weird, how one stupid little change can completely eliminate a huge problem? Adding caps did it for me.

WeezilUSA · 12-01-2009, 02:22 AM

Yeah, it is strange how it was such a small thing... But I guess after you do ALL of the big things, it is bound to come down to something small right?

What AFR should I be shooting for at idle? I fouled my plugs and killed the car (had to get a ride and go buy some new ones as I forgot to carry my spares), just from idling while trying to warm it up when leaving work today. Also Its sputtering out a bit of black smoke after idling for a while. I'm seeing between 13-15 afr's at idle around 900 rpm.

I did get my first taste of boost on the freeway though, I only let it pull up to about 4k rpm, and I think the wastegate is a 6psi gate... Lets just say, I think this car has potential to be scary.

Also, I need to wire up my windshield wipers and turn signal reminders... both were issues on the drive home.

10-16-2009, 02:52 AM	#3
B-lennium Board Member Join Date: Aug 2005 Location: Holland	I had this problem to, I could not rev higher as 3400, after fiddling with the adjustment pots it worked! 6000rpm! first turn them all the way CCW, then the middle one 8 turns CW, that worked for me. I run MSII Extra 2.10 ,36-1 VR pickup. __________________ Volvo 164e B30e, KG-17 cam & Isky valvetrain, Megasquirt MSII extra, EDIS6, Polaris. Follow my work in the project tread. Project 164

10-16-2009, 10:51 AM	#5
Roger-Dee is DeeWorks.ca Join Date: Aug 2006 Location: Sherbrooke, Qc	Have you checked with a timing light that the timing in MS correspond to the one at the engine ? When I first installed my MS I couldn't get the car to go over 2500~3000 and it was backfiring like crazy. I updated my firmware to the high resolution and the problem went away. A datalog would be nice too. Kenny, how one can adjust the latency values ? Only way I can think off is on a dyno with a timing light... ? __________________ 94 944T - 16v turbo - 12,14@122 www.deeworks.ca

10-16-2009, 03:27 PM	#10
The Aspirator It's a girl! Join Date: Apr 2003 Location: Vinemount, Ontario CANADA	How sturdy is the VR bracket? That's the first thing that comes to mind, and the cap between it and the teeth. Open up Megatunix or maybe tunerstudio has it, and check out the tooth logger, it'll tell you if there's any problems with the VR sensor reading teeth. __________________ '83 242 '95 T5R '98 S70

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10-16-2009, 01:18 AM	#1
WeezilUSA Fair Enough... Join Date: Nov 2002 Location: Vancouver WA	Cuts out at 2900 rpm So tonight Poik and I did a bit more shakedown tuning with vurbo. After swapping to his MSQ (with some req fuel scaling), and finding a potentially hazardous wiring issue... It starts up and runs pretty good. We were able to drive it around a bit (probably 20 minutes or so)... But when it gets up above 2800 rpm, it feels like its hitting a rev limiter (spark cut)... If you push it hard into it, it will backfire, if you push it soft it will just kinda buck. At first it looked like it was going lean when it was getting into those cells... richened it way up, also pulled timing back as it looked like the timing was advancing as it was moving into that cell... no dice. Tried swapping spark plugs for some colder ones, and the problem still exists. Thoughts? Checked launch control, it is totally off... and rev limiter is set to 6800. I'd post the datalog here, but it doesn't look like my donation has taken effect yet... From looking at the datalog though, there is nothing that really is changing drastically as we are trying to move into that next cell. __________________ R-Sport International Customer Service For all RSI related messages, please email me (no PM)... Thanks! ben@r-sport.org

10-16-2009, 09:54 AM	#4
WeezilUSA Fair Enough... Join Date: Nov 2002 Location: Vancouver WA	I haven't tried messing with the adjustment pots... Thats something I'll have to try. Kenny, It doesn't rev freely in neutral either, it just feels like its hitting a limiter there. Due to the gunshot style backfires that occur if pushed hard on that limiter, it feels like spark. I'm going to pick up a new timing light, as the one my dad had is spotty at best, and see what its doing on Saturday. Running like this it would be pointless to take it to the dyno, so I had better call them first thing and cancel :( The other thing is that Poik suggested after we were done last night, was fixing the timing angle and seeing if that changes it vs. running off the map. I did just find that knock detection was turned ON despite me not having a sensor for it, could that randomly be deciding to pull timing back a ton?

10-16-2009, 10:50 AM	#7
linuxman51 ARRRRHARHAR Join Date: Dec 2002 Location: mont, AL	adjust the pots and look at the map. if you're loading up on fuel, it'll do that. if your timing is too conservative AND its an ms1 without the latency values set, it can do that as well. taking timing out makes the problem worse, however it usually manifests itself at higher rpms than that. How much timing? got a datalog? if the rpm is dropping out while it's doing this, you've got your answer.

10-16-2009, 12:31 PM	#8
WeezilUSA Fair Enough... Join Date: Nov 2002 Location: Vancouver WA	Latency values for the wideband, or for the injectors? My timing light's pickup was being really sketchy last night, so it was hard to confirm what exactly was going on. I am going to pick up a new one on saturday and then check that out. I'll post up the datalog after work. I don't know where Eric saved it on my computer lol.

10-16-2009, 04:48 PM	#11
WeezilUSA Fair Enough... Join Date: Nov 2002 Location: Vancouver WA	I'm fairly certain that the vr bracket is sturdy enough... Its welded from 1" square tube, with 2 bolt points on the block. The sensor is very close to the teeth. probably less than 1mm, but not touching. I can try to do a datalog from tunerstudio, I have been using megatune, but I have both on my computer, haven't really tried playing with tunerstudion much as of yet. Come to think of it on the adjustment pots, I had taken the screws out of them at one point when I was doing some work on the MS board, I did put them back in, but they may be way too tight... I don't exactly know what they do, but it would be awesome if that is maybe it.

10-17-2009, 01:54 PM	#12
WeezilUSA Fair Enough... Join Date: Nov 2002 Location: Vancouver WA	I'm just going to try those two things today, I'll let you know what happens. Thanks guys!

10-17-2009, 06:33 PM	#13
WeezilUSA Fair Enough... Join Date: Nov 2002 Location: Vancouver WA	No luck yet. What does the NOS w/ Inj Pulsing indicator mean at the bottom of megatune?

10-18-2009, 03:02 AM	#14
WeezilUSA Fair Enough... Join Date: Nov 2002 Location: Vancouver WA	Ok... so it was the VR sensor bracket. Turns out it wasn't as stiff as I thought. Fixed the bracket, revved to 6k, and the #1 cyl freeze plug popped out, causing a huge mess. Son of a b. At least it'll be good to go once I get that fixed.

10-18-2009, 11:07 AM	#15
The Aspirator It's a girl! Join Date: Apr 2003 Location: Vinemount, Ontario CANADA	Ha! Totally called it. But dammit on the freeze plug man!! Maybe my machine shop just didn't know how to put them in properly? I really trust the guy though, but I had at least 2 pop out on my B23, maybe more. Was it at least on the intake side...err, just looked at the pics, B21's don't have any on the intake side but my B23 does, weird. For a temp fix those rubber expandable plugs do work in a pinch, but I popped those out too if I revved it too high. If you recall, my solution was to weld those farkers in there for GOOD. I made a big huge thread about freeze plugs a few years ago, there's some great info in there if you haven't read it yet.

10-18-2009, 12:20 PM	#16
WeezilUSA Fair Enough... Join Date: Nov 2002 Location: Vancouver WA	I think what happened John, was that they didn't take the freeze plugs out when they worked on it. Doug had JB welded them in, and unless you did it the same way, they looked pretty much the same. I guess hot tanking may have weakened the epoxy, and this was probably bound to happen. My plan is to weld all 4 in, not sure if I should start with new ones, or the ones that I already have. I'll dig up your thread. Thanks, Ben

10-18-2009, 12:45 PM	#17
The Aspirator It's a girl! Join Date: Apr 2003 Location: Vinemount, Ontario CANADA	Looking at my old pics I can say fairly certainly that the machine shop removed those old plugs and put new ones in, then I slapped new JBweld on top. If you're thinking of welding, definitely read the thread to the end. Mine are still holding great after 3+ years, with only the tiniest weep of coolant from #1 intake side. http://forums.turbobricks.com/showthread.php?t=73880

10-18-2009, 12:55 PM	#18
WeezilUSA Fair Enough... Join Date: Nov 2002 Location: Vancouver WA	Thanks John, Glad I didn't just impulsively weld it in yesterday.

10-18-2009, 03:34 PM	#19
Poik Backwards Turbo Join Date: Feb 2005 Location: Göteborg, Sweden	I don't have to work until Thursday so let me know when you want to tune again.

10-18-2009, 04:46 PM	#20
WeezilUSA Fair Enough... Join Date: Nov 2002 Location: Vancouver WA	Poik, I'm free Tuesday and Wednesday. I'm guessing it will likely take an evening to get the freeze plug issue taken care of. John, so what do you think I should do for the plugs at this point? I've got a 220v Mig, So was the issue you were originally having that you couldn't get enough heat in there? The other option I'm thinking about is turning some press fit plugs (like my distributor one, if you've seen it).. And have a wider flange than the hole which I could then drill through and either rivet, or tap the block to have a retainer or 2 or 3.

10-18-2009, 05:03 PM	#21
WeezilUSA Fair Enough... Join Date: Nov 2002 Location: Vancouver WA	Had another interesting idea when brainstorming with my dad. How about putting the plugs in, and then bolting a piece of flat stock across the face of the freeze plugs, and then maybe threading a bolt hole for each plug to have a bolt pressing against the freeze plug, keeping it from moving?

10-18-2009, 05:47 PM	#22
The Aspirator It's a girl! Join Date: Apr 2003 Location: Vinemount, Ontario CANADA	I really like that flat bar idea! You'd have to drill/tap two holes on either side of the plug (into the block), but yeah dude, that'd work great. Or if you're feeling frisky maybe you would weld the flat bar to the block... As for welding, the first pics in the thread were with my little 90amp flux core and the welds cracked right through, all of them. Then I took the block to John Lane's house with his 220v Miller and zapped the crap out of em. I don't know how much juice he used, but it was definitely enough, the beads are FAT. No pre-heat for the cast iron, no fancy prep, just judicious attacking with a wire wheel and lots of brake kleen, then zap zap zap. Thanks JL!!

11-30-2009, 01:22 PM	#23
WeezilUSA Fair Enough... Join Date: Nov 2002 Location: Vancouver WA	Ok so just a little note here... I reinforced the VR sensor bracket, and then made the brace for the freeze plugs... Issue with cutting out occurred again. Matt Cramer from DIY autotune suggested I try a 10k ohm resistor in my VR signal, to help cut down noise. Well I put it in, and voila... Worked like a charm! No more cutout, just revs revs revs! FYI I put it in the Negative signal right next to the MS box.

11-30-2009, 05:16 PM	#24
The Aspirator It's a girl! Join Date: Apr 2003 Location: Vinemount, Ontario CANADA	Isn't that weird, how one stupid little change can completely eliminate a huge problem? Adding caps did it for me.

12-01-2009, 02:22 AM	#25
WeezilUSA Fair Enough... Join Date: Nov 2002 Location: Vancouver WA	Yeah, it is strange how it was such a small thing... But I guess after you do ALL of the big things, it is bound to come down to something small right? What AFR should I be shooting for at idle? I fouled my plugs and killed the car (had to get a ride and go buy some new ones as I forgot to carry my spares), just from idling while trying to warm it up when leaving work today. Also Its sputtering out a bit of black smoke after idling for a while. I'm seeing between 13-15 afr's at idle around 900 rpm. I did get my first taste of boost on the freeway though, I only let it pull up to about 4k rpm, and I think the wastegate is a 6psi gate... Lets just say, I think this car has potential to be scary. Also, I need to wire up my windshield wipers and turn signal reminders... both were issues on the drive home.