Optical vs. Hall Effect

[turboglenn]

Okay, well this is a continuation of my RPM based ignition problem thread ( can't rev past 7200)

I've replaced every single part of the ignition including the CAS with new parts and still have the same issue of the ignition breaking up over 7200 RPM.

What I'm starting to think is that there's too much electrical field interference (EFI noise) going on screwing up the CAS's signal to the ECU. I've shielded all the wires by making tin-foil wraps along with copper shielding wire wrapped around the foil shielding and all of it's grounded, and I'm still getting the same issue.

So the point of this thread is. Right now I'm using a Hall Effect (black top) CAS. These are still based off a magnetic signal but have internal circuitry to convert the signal to a square wave form. But being that it's based on Magnetic fields, I'm starting to think it could be falling prey to the electrical noise in the engine bay. My thought is that the green top CAS being of an "optical" type would be a bit less accurate, but less prone to electrical noise. Anyone have any thoughts or experience on this matter? I've never had this issue before except when we had some bad grounds on a couple customer cars, and I've fixed and added more grounds than you can count on mine with no luck.

I just want to get some input before i hack the wiring off my last green-top sensor just to test the theory. I try and keep a stock of known good CAS's around for customer cars when doing a stand alone install or a 6bolt swap. And since the green tops have an actual wire harness and plug on them instead of just a plug like the black tops have i thought I'd ask before cutting it up and making it appear "hacked up" or "rigged" and harder to sell to a customer.

If i had an oscilliscope this would be easy to pinpoint and easier to fix, but i don't have the spare 500 bucks laying around just to test my car. I recently shut down one of my businesses to work for the post office and i'm not getting a good amount of hours right now, so the budget is being watched a lot closer, especially after spending 3k on a trans a month or so ago

[danl]

I went through ignition issues last year. A friend of mine and me thought my issue was my stock 90 CAS. So I bought a used known good 91 green top CAS. It didn't help. Then I got a known good black top CAS and that also didn't help.

What did help is replacing my lash adjusters with new OEM ones (not top lines). I haven't had a problem since doing this.

I also overhauled my whole fuel system as I had problems over 26psi in the past but never tested it with the new lash adjusters. I haven't had an issue with 28psi on pump gas with the new fuel system.

I also added a dynatek ARC-2 ignition and the car pulls much stronger when in heavy boost.

I have ran to 8000 rpm's numerous times now with my stock 90 CAS. It has no intentions of misfiring as high as I can rev it, but with a stock bottom end I'm stopping at 8000rpm's for now.

[turboglenn]

By lash adjusters do you mean lifters? I put a new set in when i put my cams in(big hole 3g type), so i don't see that being an issue, but I do have 3 spare sets just in case.

[danl]

Technically DSM's have lash adjusters and V8's with pushrods have lifters. Just saying.

Anyways I am saying "lifters". Check your cams for chatter marks. Mine had chatter marks on the zero lift portion as the lash adjusters collapsed on ramp up and then the valve seats slammed the seats during the ramp down portion of the cam as the lifters were collapsed. I had nice little chatter marks that let me know woah sumptin ain't right here ! Put in new lash adjusters and did two 24-25psi pulls and all was fine............

BUT! I'm not totally convinced that I didn't also have a fuel issue, hence replacing the fuel pump, adding an inline, 8an feed, aeromotive regulator (I was running stock), fuelrail, etc. I believe it may have been a combination of both.

So check your cams for chatter marks. Also check for floating valves. If you put cams in did you upgrade your valvetrain? A floating valve will cause similar misfires.

[turboglenn]

Originally Posted by danl

Technically DSM's have lash adjusters and V8's with pushrods have lifters. Just saying.

Anyways I am saying "lifters". Check your cams for chatter marks. Mine had chatter marks on the zero lift portion as the lash adjusters collapsed on ramp up and then the valve seats slammed the seats during the ramp down portion of the cam as the lifters were collapsed. I had nice little chatter marks that let me know woah sumptin ain't right here ! Put in new lash adjusters and did two 24-25psi pulls and all was fine............

BUT! I'm not totally convinced that I didn't also have a fuel issue, hence replacing the fuel pump, adding an inline, 8an feed, aeromotive regulator (I was running stock), fuelrail, etc. I believe it may have been a combination of both.

So check your cams for chatter marks. Also check for floating valves. If you put cams in did you upgrade your valvetrain? A floating valve will cause similar misfires.

I'm starting to think more and more that this is valve train related. I am on stock springs and retainers, the head was just rebuilt and freshened before i put it on, but the components are all stock except for the FFWD 264/272 cams. As soon as i can afford srings those will be next in line for replacement. I think i'll change wires first just in case there's an issue at one of the boots letting spark escape and grounding things out. They tested good, but that only means they'll transfer spark energy, it doesn't say they won't leak it. I looked under the hood at night and didn't see anything, but if it's happening under the area where they seal to teh VC i wouldn't see it happening.

The min reason i haven't put much focus on the wires is that wire realted issues are usually load dependant, meaning that the more boost and load you put on them teh sooner they'll mis, but this happens at 9psi just as bad as it does at 25psi. Oh well, i'll keep on plugging away untill she's fixed i guess.

I'll pop the valve cover and check for chatter marks when i change the oil this week.

thanks for helping out

[danl]

Summit is selling the NGK wires for $36. I just picked up a set because they are so cheap, but my 3 year old NGK blues are doing just fine. Its worth a wire and plug change but that is not your problem.

You can't be running cams with stock springs/retainers/keepers. Even mild cams won't work too well. I'm not sure what "264" etc... means these days, different people make cams of the same duration that act completely different. What I can tell you is that I had problems with stock cams and the problems grew WAY worse when I got cams.

You need a good set of duals and some titanium keepers. I really like the Supertech duals. I run them and a friend of mine runs them. We got them from FP with the viton valve stem seals that you should have so that you don't have clearance issues. Also make sure they are shimmed correctly so that the install height and/or seat pressure is correct. Call up FP and they will explain if you can't get it from reading on their site.

[turboglenn]

I plan on going to beehive springs, as Daren at ffwd highly recomended them and said he uses them quite often with these same cams. 264 is supposed to be intake cam duration and 272 is exhaust ( but i'm sure you knew that.. i'm only specifying for people that search the forums)

By fp i take it you mean forced performance? I don't do too much online shopping so i don't hit all the vendor websites, that's the main reason i ask.

I forget where Daren told me to order the springs from, so does anyone know who makes teh "beehive" springs and where's a good place to get them for a decent price? The only thing that makes me not want to replace them is if i'm doing it and drop a valve making me have to pull the head to get it back out.

[bane3d]

Quick search and found kiggly sells them Kiggly Racing - kigglyracing.com (although they are currently out). $450 a set with a real cool video included. http://www.kigglyracing.com/parts/im...ive_Spring.avi

d

[danl]

The kiggly beehives are probably the best springs out their yes.

THe magnus stuff is good no doubt, but lets just say that the Kiggly stuff is good to at least 11,000+ rpm

Thats why I suggested the FP duals (AKA Supertech duals). They are good enough for 95% of the DSM'ers.

Forced Performance: DSM High Tension Dual Spring Kit

Call FP on monday they will explain it all for you.

[bane3d]

From reading on some other threads I've also seen good recommendations on the magnus set. It's $600 but claims that it's good to 11000 rpm while the kiggly set was never quoted an actual rpm limit, it is comprable according to kevin. Now magnus has them in stock while kiggly doesn't. It's worth a call if you can't wait just to make sure.

d

[turboglenn]

Man, 600 bucks..that might have to wait, i've spent close to 5k in the last few months on upgrades and repairs. I'm not looking to take another big hit for a little while yet because i have to pay my insurance on 3 vehicles and get the bikes up and running here in the next month or so too.

I'm looking to maybe spend around 300 or so, but if i can't get anything good in that range i'll just wait till mid summer.

[turboglenn]

Originally Posted by danl

Thats why I suggested the FP duals (AKA Supertech duals). They are good enough for 95% of the DSM'ers.

Forced Performance: DSM High Tension Dual Spring Kit

Did you say you have to get certain valve seals with those springs to avoid clearance issues?(i would assume they are the one's listed on that page) Also what are you talking about shimming? The lifters or what? The lifters are the only thing i've seen in my head that gets shimmed and that's just with the FFWD cams. But then again i usually don't do the heads. I'll put cams in, but if they need springs or anything i send them to the machine shop so they can be checked, cleaned and have everything else freshened up at the same time, so my machinist usually just gives me back a bolt on head.

[Drift_SM]

I think your theory on electircal noise could be very accurate.

Try coverings the parts of the wiring harness near your intake manifold with wire loom and lots of electrical tape.

Also do you still have the little tiny noise reducing thing that sits on the right side of the manifold? Its silver and cylinder shaped with one black wire going to it.

You can see it here...left bottom corner of the brake reservoir cap.

http://members.shaw.ca/dsm.1000q/Eng...rakemaster.htm

also in this pick (top right corner of intake manifold.)

http://members.shaw.ca/dsm.1000q/Eng...kemanifold.htm

[turboglenn]

Originally Posted by Drift_SM

I think your theory on electircal noise could be very accurate.

Try coverings the parts of the wiring harness near your intake manifold with wire loom and lots of electrical tape.

Also do you still have the little tiny noise reducing thing that sits on the right side of the manifold? Its silver and cylinder shaped with one black wire going to it.

You can see it here...left bottom corner of the brake reservoir cap.

http://members.shaw.ca/dsm.1000q/Eng...rakemaster.htm

also in this pick (top right corner of intake manifold.)

http://members.shaw.ca/dsm.1000q/Eng...kemanifold.htm

Yea, that's still on there. Do you have the page from the service manual that shows how that's actually wired in? Or what it's called by Mitsubishi would be helpful because I've wanted to replace it but can't think of the name of it when i call the auto parts store. I thought it was a capacitor, but they don't list a capacitor for the ignition system at o'reillys



EDIT: here it is, it's a capacitor but Mitsubishi calls it a "condenser" I think if i can get a wiring diagram for it that I'll swap a new one in with all new wiring.
http://members.shaw.ca/dsm.1000q/Eng...econdenser.htm

Anyone have that page for a 2g on how many there are and where they are? Also a part # or specs on it so i can replace it with one from an electronics store would be great if some one had it!

[JFZERO ECLIPSE]

That little metal barrel is a capacitor...Real name is a noise capacitor

in the FSM page 43 on the electrical part....

Page 54 says A-64 (1-B) Capacitor...Wire is black

Page 55 give you a generic diagram

Hope this helps...I hate electrical so this 1 is all you glenn

[turboglenn]

Originally Posted by JFZERO ECLIPSE

That little metal barrel is a capacitor...Real name is a noise capacitor

in the FSM page 43 on the electrical part....

Page 54 says A-64 (1-B) Capacitor...Wire is black

Page 55 give you a generic diagram

Hope this helps...I hate electrical so this 1 is all you glenn

Any chance you could scan that page on your PC and either host it up and post the link here or just email it to me as an attachment? PM me if you'd rather email it and need my address.

[JFZERO ECLIPSE]

I have the FSM on cd, and it was a total pita to try to get it into paint format....

But finally got it too work hope this helps...







A64 is the top rightmost line....have stuff written above it but too small....basacally stating the its a black wire and only has 1 pin inside the connector....

[Black95TSIawd]

How do you get that little capacitor thingie on a SMIM?

[JFZERO ECLIPSE]

I should be part of the main harness...Just unclip/bolt it from your stock intake manifold. and find a bolt that it'll fit on the smim...maybe the throttle cable bolts seeing as how their 10mm