leanin sidewayz

Alright so, I had made a previous post about idle. Got that pretty much squared away.

Now I have a quick question about the CAS.

So I got my engine from a local importer, and had them install it. After driving it for about 2 months I showed it to a friend with an SR. He noticed that they had my CAS turned totally retard to make it idle where it should. I guess that's how they got their 15* when they timed it and handed it to me.

For shits and grins we put it in the middle where it should be. Runs fine other then if I get into boost then come to a stop. Sometimes it will rev to 1900 then dump to 12-1300 in what seems a timed loop. So obviously that's not where it's supposed to be. Leading me to think the CAS is off a tooth?

I now have it back to where they had it, and I may add this thing has no balls whatsoever now compared to when it's set in the middle.

So my question being. Engine out of time? CAS Off a tooth? Or bigger issues?

The only mods it has is a fmic, and a cheap eBay bov, and the boost guauge I have reading in bars.

DennisC

Take then valve cover off to check if the mechanical timing is correct. Then remove the CAS and reinstall it correctly.

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leanin sidewayz

Will do. It's been on the to do list for atleast 2 weeks. But two jobs make it hard to find the time.
What mind boggles me is there's a define mark where this CAS did at one time sit in the middle. I guess I'll never know who did what, and why with this engine considering it came from a car in Japan.

bataangpinoy

generally speaking, timing is pulled to avoid detonation/pinging.

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Croustibat

I think that some JDM SR needed the CAS set at 10° and not 15.

That being said, if they had to turn the CAS fully to one side or the other to get 15°, it means either they did not set it to 15, or the timing chain is out at least 1 tooth.

leanin sidewayz

I don't think they were trying to avoid any detonation or pinging. It has great compression across the board.
I could he wrong though. I've seen so many locals rave about this dealer with no issue.
But then doing that with the CAS makes me suspicious.

@croustibat, can you elaborate why they would go for 10 and not 15? They neverrr told me anytime other then it's in time lol. So I just took thier word for it.

I have had the valve cover off before. But this was not when I was looking into the CAS. I was looking at the cam lobes and checking for slack in the timing chain. Cams look beautiful, no slack in the chain. And it looks almost brand new...

Idk man. I've herd these JDM dealers are sketch dudes who will do anything, and say anything to get you out of the warranty time so they're not liable. The day I picked this car up I took it for a test drive and me being me I got a good straight away and went WOT. Scratched all the way through 3rd (in a good way lol).
Felt funky, found a boost leak in a coupler. Annnnd now I am where I am.

Croustibat

I can't say much more than that. Some engines were set ( = mapped ) for a cas set at 10° BTDC, and that base value is set at 10° in the ECU. Most of them were set for a cas at 15° though.

But one thing i know for sure, if the cas is not somewhere around its middle setting, cam timing is out.

Also, how did they check timing ? Because the only correct way is to use an HT lead between the first coil and the spark plug, and take it from that HT lead. Any other place, like the test loop, usually leads to wrong results on that engine (the ca18det has the same problem).

leanin sidewayz

They never specified on how they checked it. But I'll bet my unborn child they did not use that menthod.

I will note. With the CAS fully retard it sits at 900rpms without a hiccup other then my exhaust leak causing a little flutter here and there.

So here in an hour I'm going to pop the valve cover off and get to the bottom of this CAS and see if it's off and why it is like that. This engine runs awesome. No lifter tick no bottom end noise.

Now what I'm wondering is is my ecu reads 10 or 1 . Its a red top with fins with a 62 ecu I believe.

Also the only means of actual timing we have is a snap on flashlight with a timing mode. Yeah I know. Lame as hel . I've seen a video of the method you mentioned. You can't use, a spark plug checker can you for that method? Lmfao. Yeah I'm a noob know. But we all start somewhere.

leanin sidewayz

Put the CAS exatly where it's supposed to be. Timing was perfect. But NOW once agai . It keeps revving to 1900 then dumping to 1300 over and over unless I move the CAS then put it back.

Any ideas?

Croustibat

Not lame, it should work with that kind of timing light I can't say about the spark plug checker, i never used one.

Again, if it really is at 15° and cas is turned fully to one side or the other, it means a cam is out 1 tooth (at least) .

Maybe your cas is defective. Now that you know how to check the CAS (ie : put HT lead, set idle to 2000rpm, wait for the engine to be hot, THEN set the cas) You can check if the teeth inside the cas or on the AAC are worn out, it causes the CAS to jitter, which can create this. But if it was, you would have a hard time reading the current position.

Maybe your IACV gets stuck, or you BOV is leaking (if you have one, they do leak) ?

leanin sidewayz

We cranked the engine by hand until we had the crank mark up top where it was supposed to be and the cams as well. They sat like looking like this < >

We then reinstalled the CAS with it centered and it also met it's mark. And man I'll tell you this thing never ran so smooth. Let it get warm (started doing it's dumping thing then stopped with a bit of throttle), I took it around the block and got on it a bit. Best powerband I've felt from it. Turned it off, went inside, and when I went to drive home. No dumping idle.

So to answer your question, yeah either my IACV is stuck, or shot. Or not doing it job correctly. My bov? That pos could very possibly be leaking. It's very cheap lol.
Now I know the ecu has it's own means of an idle after it gets warm and closed loop stops. I believe it reads from the o2? I have an opportunity to buy a Freddy Intake with a IACV included. I may take that route since getting to the IACV that's crammed behind the stock intake seems near impossible. I herd of a way to set your idle via revving your car to 2k for 2 mins with the TPS off then putting it back on and adjusting your idle screw? I'd have to look that one up again.

Lastly, the freind that's helping me do all this built his SR from the ground up. His does the same exact thing with the dumping idle. So either it's HIM f'ing up somewhere. Or we both have a similar issue. But his always goes away with bleeding the air from the coolant in the waterneck. Not mine though. Today's weather is garbage. So the time I will have to look into anything will be pretty minimal.

Javi802

You did make sure the crank pulley lined up at the second notch (0 degrees, aka Top dead center) from the left, correct?

leanin sidewayz

Forgot to note his does this as well. But that clown doesn't have his coolant lines running to his IACV.
So I'm kind of leaning towards that. Or its a 20 year old engine with a faulty excessory, running mods it's never seen, with all the emissions deleted, and running pretty much a 3" straight pipe to a hollow fart can (cheap exhaust came with the car. Living on pennys taking on a car that wants dimonds)

Buy a 240 they said... It'll be reliable they said.. Lol it's worth all the struggle though I love the s chassis.

leanin sidewayz

Yes sir. I'll be double checking that if I don't get to the bottom of this. But I'm almost positive of that. There's no play in the timing chain at al . So for it to be off a tooth would shock me.

Croustibat

BOVs get pulled open by vaccum, creating an intake of unmetered air, leading to lumpy idle and stalling (unless idle is set high) when coming to a halt.

There are 3 ways to clear the problem:
1/ use map + iat instead of MAF (long, expensive, not worth it)
2/ recirc the BOV (cheap, efficient, only "downside": no more wooosh sound)
3/ remove the BOV (needs blocking off the BOV hole on the piping)

If you can easily try 2 or 3, by all means try. I don't think it will solve all the problems here, but at least it will remove one of the list.

The ECU tries to adapt AFR with the closed loop system, but it does not change timing. It will change timing if the engine is near stall, which might be what you are noticing. Timing changes your idle speed. The ECU has an internal target idle rpm, you should adjust this and set the IACV to match that idle. Of course, you can change the IACV setting to match the idle you want without changing the target idle in the ECU, but then the ECU may start doing weird things, like considering it is too high and pulling timing to get it lower, then adding timing because it is near stall.

leanin sidewayz

Very very helpful Input, and much needed. I will either be trying to recirculate it. Or dish out more money for a better BOV.

Then I'll make sure my IACV is still doing it's job. I'd say it is. I drove all over today in 37 degree weather, and did not get that idle dumping I was mentioning. I sat at 900 with small flutters. Which is probably the damn bov, or exhaust leak. It's not a bad leak. But with the SR being as sensitive as it is. I wouldn't put it past anything in the slightest to cause a flutter. Everyone says these engines almost never idle perfect.

I'm satisfied kinda. But my ocd, and mentality drives me to set, and make everything %100 on this engine.

Hell everyone says I care, worry, and try to hard to make things smooth with my car . But I pay them no mind.

Croustibat

Even a quality BOV will leak. The ones that leak LESS have a double chamber/piston design, like the HKS SSQV ones, but there are so many fakes that the chances of getting a real one are very slim. And they are expensive. If it is worth less than 200$ it is a fake. If it is worth more ... well it can be a fake too.
Recirculating is fine really, even with a leaky BOV. It does not make that woosh sound, but then people get so surprised NOT to hear that sound when getting left in the dust that you will grin a lot