R BOOM opinons? pics inside...

[Shocker]

Well finally after a good deal of issues I was able to get my 35r rb25 back on the dyno this afternoon. Sorted out a glitching RPM issue.. "or so I thought" by cleaning out my CAS. Sure enough my car fired right up after this. This issue was a glitch that was being sent to the ECU by the CAS giving crazy RPM readings. For instance while cranking at 300 rpms, it might spike to 16000 rpm or 10000 rpm signal. Causing the piston to missfire at say bottom dead center making it impossible to start. Well I thought it was gone...



anyway. Back to tuning. Car had been running for about 2 hours now, no issues. Tuner was making pulls in 500 rpms increments. Left the timing alone and was doing a/f tuning all at 11.2 +- .1. All was fine. Boost was set to 14psi. Made a 6500 pass no problem and put down 300rwhp.. keep in mind no timing settings were changed yet. So a 7500 pass was up next. Pull sounded fine, loud as **** so our ears are all covered so we might have not heard something... tuner is watching a/f's so he wouldn't have noticed the graph... Car hit redline, idled for a few seconds then shut off and died... Throwing an RPM code.. which was stating the RPMS are fu*ked. So tries cranking cranking, RPMS are spiking like they had been before when the car wouldn't start... Now the graph.. Looks like a mountain not a curve, all is good until around 5000rpms...... after that it seems to be devestation...





Heres what my plugs now looked like. They got so hot that the conductor and porcilin was melted off pretty much all the way. My thoughts are that the CAS started glitching out around 5000 rpm throwing say an RPM signal of 16000 rpm in worst case senerio... most likely caushing some form of predetenation... My tuner thought it was valve float initatialy when he looked at the graph, he had a simillar issue with an SR. But after inspection of all the lifters and plugs we realized that wasn't possible..

compress test goes in 1-6 order, 120 110 110 120 100 60 ... We leak down tested her doesn't seem to be the rings since theres no crank case pressure leaking though... We are concluding that the tip of the plug's are no melted at the bottom side of my valves preventing them from closing all the way... or it might have damaged them.

Anyone ever heard of a CAS doing this type of glitching? and any thoughts on the **** *** compression.. Motor will be removed in a few days for inspection of damage.. not cool for sure. Motor was looking to make about 400rwhp that pass at 14 psi w/o touching base timing.. she will be down for months now.
Modified by Shocker at 5:08 AM 7/13/2007

[eh?]

Did you have to wire the CAS into the microtech ecu harness or was it PNP?

[Shocker]

Did you have to wire the CAS into the microtech ecu harness or was it PNP?

I had to wire it in. Last time while I was trying to get tuned we actually re soldered all the joints for it while there. It was correct.

[l0nestar]

ugh dude. that really sucks. Your plugs look CRAZY! Sorry, nothing really constructive to contribute But I am going to be watching this topic.

So you CAS would just freak and read up to 16,000 RPM while cranking? And you think part of the conductor is stuck or melted to your #6 valve keeping it open? (well, most of your conductors are _gone_ anyways). sheesh. sorry to hear your 'loaf' is going back in the oven

[eh?]

The wiring of the CAS is something I'd look into. Cold joints, poor shielding, etc are going to affect what the ecu sees. You can take apart the CAS but I don't think there's an easy way of checking it. Someone with an O-scope may be able to check it for you.

[Shocker]

The wiring of the CAS is something I'd look into. Cold joints, poor shielding, etc are going to affect what the ecu sees. You can take apart the CAS but I don't think there's an easy way of checking it. Someone with an O-scope may be able to check it for you.

yeah, wiring of the CAS was spliced in 1 place 4 times one for each wire, for on the lt12s loom it comes seperate from the harness. A month back my tuner rewired/soldered it, heat sheilded it, and covered it with sheilding....

testing it is a good idea with the o-scope. wont help much now being my motors partially shot... but might help give me some answers.

[eh?]

I'd def want a conclusive finding before it start it up again. With enough intuition you can bench test the whole harness and cas. Wire battery power to what's needed, hookup the laptop and start jiggling connections, see if you get a spike while you spin the cas.

[Shocker]

I'd def want a conclusive finding before it start it up again. With enough intuition you can bench test the whole harness and cas. Wire battery power to what's needed, hookup the laptop and start jiggling connections, see if you get a spike while you spin the cas.

yeah thats what we did, When you remove the plugs and watch the firing order, when it glitches you might turn the CAS say... 5 degress. No joke the plugs will fire like machine guns when it happens as if its reading some crazy RPM signal. What im saying is that after I opened the denso CAS and blew it out. I put it back on and she fired right up.... Ran for hours before it unfortuneatly came back seemingly destroying my motor during a WOT pull at 5500rpms. Question is how rare is this glitch and have other people had a similar issue?

[Carl H]

are you sure its not something to do with the management?its rather strange that the cas would fail, then work again, then fail again.sorry to hear that something caused motor assplosion, never something you want to hear/see.

[Coolwhip]

why denso's

however, sorry to hear that as well on about the motor

[Shocker]

are you sure its not something to do with the management?its rather strange that the cas would fail, then work again, then fail again.sorry to hear that something caused motor assplosion, never something you want to hear/see.

not sure, It shouldn't be.. but then again you never know. I just got it back it had a burnt out coil drive from a coil pack arching itself.. And they said everything was fine. I just don't understand why after I cleaned it out she fired right up....

[blurrbosi]

I'm crying FOR you my friend. This sucks.

[Shocker]

I'm crying FOR you my friend. This sucks.

thanks.

I talked to Jon at Microtech he confirmed that there is no way it was the ECU's fault. For all it does is receive the signal from the CAS and then goes from there. It by no means has anyone of "making up" an rpm.

He suggested most likely it is the cas's fault, wiring issue "which I doubt since it was actually complimented then re-done by a professional" or it was getting RFI from either the altnerator or starter..

Whenever it may be that I start her up again, prolly a year from now... He said to make sure I have new leads, new cas, new wiring loom for the CAS and insure the wire is well away from the altnerator ect...

[Carl H]

that has got to be some massive interference to toss the cas signal out like that.

[Shocker]

that has got to be some massive interference to toss the cas signal out like that.

see thats exactly what my tuner and I initial thought over a month ago when I was down there to get tuned the first time. It was glitching out then, we thought the Quest Alt might have been messing with it since it was only a few inches away.

Thats when we rewired the CAS sensor, and moved the wire outside of the compartment basically so it ran down the fender, then down the rad support into the CAS.

It was the same deal after that. It wasn't until I took it apart cleaned it out a bit and reinstalled did it finally work properly but only for a few hours as it was back after/during that last pull.

[Carl H]

hrum.i know you've talked to microtech but a buddy of mine had serious issues with his not too long ago.bought it brand new in box for installation on his turbo fc and when all was said and done it wouldnt work right.for some reason it would put its self into test mode constantly and then when you got it into normal mode it would flip back into test mode.if you have ran the cas wire that far away from any interference device then there has to be another problem.ive had my cas wire dangle down before near the alternator and never had the pfc hiccup once.

[Shocker]

yeah, seems crazy if it was the Microtech unit, I just got it back from servicing/repair of a burnt out ign output from an arcing coilpack, was tested and said to work fine.

thats why I'm leaning to my CAS to be faulty, would been nice if I had had another to verify with.

[matafied]

man that stinks did any of them spark plug debris make it to your turbin??
Modified by matafied at 2:29 PM 7/11/2007

[Shocker]

Well ripped her apart today.. and ripped her down...... pulled the head and observed.. #6 cylinder is the one with the chip in the piston, its what concerns me the most. #6 and #2 on the head are a little mashed up from the exploding spark plugs.. You can see the white from all the predetanation.. Now there really is zero scoring a tiny bit on the #6 and #2, its hardly noticeable. The headgasket was toasted all the way down the block... Valves are all fine as well.

heres the pics, any opionons.... Im half considering throwing a HG on her fixing the CAS and just driving her till she dies. I plan to rebuild over the winter.... Figure it might not hurt to bad after I clean it up a bit. I dont know all I want is to drive my freaking car.before I ripped her apart......... plugs arnt in line I know... was from tuning day.

[l0nestar]

Crikey! Seriously. Fix the HG and CAS, and drive it till you plan to tear-it down and rebuild it again. Although those pistons don't look too healthy...
Modified by l0nestar at 1:53 PM 7/13/2007

[Shocker]

Crikey! Seriously. Fix the HG and CAS, and drive it till you plan to tear-it down and rebuild it again. Although those pistons don't look too healthy...

Thats what I'm thinking to. We finished the tune for low boost only 14psi, around 400rwhp I'll prolly just leave it there.. less stress. I mean, couldn't hurt.. she breaks she breaks. Either way it needs rebuilt this winter. To do it right I just don't have the cash at the moment...

#6 is the only one that is really messed up.. but nothing I cant smooth out a bit with a brillo and light file.

[Darius]

It looks like you were detonating so badly that it broke your spark plugs and then got the pieces between the piston and quench pad on the head and chewed the $hit out of everything. I'm surprised your other pistons look as good as they do. The material in the other cylinders must have escaped through the valves before getting caught off to the sides of the cylinder.

The part that I would be most concerned with is the quench area on the head. In order to salvage the head, you are probably going to have to deck it about 2 mm which is a hell of a lot. Another thing you want to check are the valve seats to make sure pieces didn't get caught half way between the valve and seat when the valve closed.

Wasn't someone watching the knock output while tuning or was it something that happened so fast that you couldn't catch it? Also, what temp plugs were you running? Stock or colder?

[Darius]

I am new to tuning cars myself, but I just thought of something. If your CAS was giving a faulty signal of say 16,000, wouldn't that be off of the fuel/ign map or peg the far right column of the map? I couldn't see the map extending past your redline.

Isn't this how it happens, the ECU reads the signal from the CAS and MAF to determine the cells that hold the injector duration and ignition timing and fires the injectors and spark accordingly? I'm thinking that the RB with the PFC base map, like most, tends to have a little too much timing advance up top which causes huge detonation in a very small window and can catch a person off guard if they aren't paying attention.

[Shocker]

I am new to tuning cars myself, but I just thought of something. If your CAS was giving a faulty signal of say 16,000, wouldn't that be off of the fuel/ign map or peg the far right column of the map? I couldn't see the map extending past your redline.

Isn't this how it happens, the ECU reads the signal from the CAS and MAF to determine the cells that hold the injector duration and ignition timing and fires the injectors and spark accordingly? I'm thinking that the RB with the PFC base map, like most, tends to have a little too much timing advance up top which causes huge detonation in a very small window and can catch a person off guard if they aren't paying attention.

whoa, your thinking would be right If I was running a MAF with the PFC. I have a microtech lt12s, that has a 3 BAR map sensor. There are no knock sensors for the unit itself. Only way to find out if the CAS was spiking would have been if someone was datalogging the RPM signal on the computer. However, since we had made about 7 pulls prior without a hitch there was no concern.

The crazy signal only displays on the microtech laptop itself, it does not transfer to the in car tach. It will be fine, then just spike, and be fine again, then spike. And with the smooth I6 its hard to even hear a missfire if its on one cylinder. Not to mention when the DBB is screaming, the open wastegate is roaring, and all of our ears are plugged.

The tuner is watching the A/F's, I was watching boost, other guy was checking oil pressure. Sorta tricky to watch it all. If we had datalogged and had someone watch the screen it could have been done. Like I said tho, there was no concern at the time since all was well.

Yeah I understand about the quench area. Im going to bring the head down to my local shop have them take a look at. I wouldn't try to save it on a rebuild Id just buy a new. It's only ****ed on #2 and #6 like in the pics the rest of the cylinders are pretty good. So Im thinking just have it decked, clean the hell out of the tops of the pistons and mating surface's. Get a new headgasket on, and compresson check her. If its half way decent. She goes back in.. If not well 8 months from now I might have start up...

Also Darius you are right about the metal electrodes a good deal of fine particles were shot out of my wastegate onto the ground along with a pile of sludge seemed to be a mix of oil and coolant and fuel.

[l0nestar]

... a good deal of fine particles were shot out of my wastegate onto the ground along with a pile of sludge seemed to be a mix of oil and coolant and fuel.

That would make me want to cry... and then say 'bad words'.. and then just stare puzzled and ... ?

[Shocker]

That would make me want to cry... and then say 'bad words'.. and then just stare puzzled and ... ?

lol crying solves nothing, same with being pissed. You can't get mad because it changes nothing. **** happens its part of building a car. You learn more and more as you go in and unfortunetly I had a major issue that went unnoticed.

Put it this way at least most of those particles went out a 300 dollar wastegate that is surprisingly unscaved rather than a 1600 dollar turbo. Which lived as well. Things can always be worse.

[matafied]

man that stinks did any of them spark plug debris make it to your turbin??

Modified by matafied at 2:29 PM 7/11/2007

good to know the turbo made it ok

[Darius]

Sorry I got confused with another thread. I can't believe microtech wouldn't have an input for knock sensors. How do you know how far you can advance your timing and pull fuel without them? Can you add them to your datalogging as auxiliary inputs? I totally agree that you can't tell if the car is knocking at all until it goes KABOOM. It's not like it is a pronounced sound with these motors unless you're at idle. That's why it is so important to have knock sensors IMO.

This is a minor setback. You're right, just mill the head down until all the quench areas are smooth again and clean up the pistons. New HG and you're ready to go. Actually, I have a head gasket (OEM) if you want it. I was saving it for cdorhout, but he is going to want to go with a metal head gasket when he blows his up. I'm sure the mix of oil fuel and coolant was because of the head gasket $hitting itself, so don't even sweat that. I bet you gave the rings a run for their money though Have you turned the motor over by hand to see if it still pumps smoothly?

[Shocker]

Darius, OEM headgasket sounds great, I was just about to order new set, but if you have one, let me know the price. email: [email protected] Thanks man!

Engine is extremely smooth, honestly it feels like it always has. Freaking RB power standing up to that abuse. I was extremely surprised on the condition of the internals. I feel the motor might have been completely saved by the spark plugs exploding since they got on the quences and most likely helped press the head up allowing the HG to blow and quickly before the rings took all the abuse..

As for the knock sensor's I actually search on Microtech forum and also talked about it with an admin on there. They really don't believe in them since most modified motors are running large lift cams, solid mounts, heavy clutches that chatter, all types of vibrations that can trigger knock sensors. There for they have no way of running them yet... Although I'm not as seriously built as other cars, I think they might have helped.. but I gotta live with what I have. People have been putting down serious power without them so I'm sure they know what they are talking about.

Also anyone have an proper working oval plugged RB CAS for sale? I have an rb20 one thats square... just nicer If I have the proper plug for my harness. email is [email protected] if you have one. thanks.

[Shocker]

actually scratch that Darius, I would buy it but I need the exhaust and intake one as well.. for the price on ebay I might as well get all the gaskets. Lol

thank you though.