Idle issues whAt am I missing?

I have an idle issue when just touching the accelerator, pushing in the clutch from speed. If catch it with the pedal I can let off slowly, and get the ecu to catch it.

Specs

Id1000. Scaler set at 890. And latencies as per t1's Subaru specific.

 

Cams:

crower xxxx91-4

INT/EXH - Dur @ .050” Lift: 220°/220° RR: 1/1 Gross Lift: .400”/.400” LSA: 114° RPM: 1000 to 7500 Redline: 8000

 

Intake is stock.

Vaccum at idle is -7psi

 

Watching maf, throttle plate angle, total timing, afr and rpm.

 

I notice when it is happily idling at 750, the throttle plate angle is 5.2deg, timing 17-20, maf 5 g/sec. And afr swinging from 14.5-14.8

 

Now if I touch the throttle, the plate angle dips to 2.14deg and engine dies.

Stab it then slowly let off the throttle it hits 3.2deg runs @ 400 rpm then once the ecu takes over it dips to 2.14 then climbs to 4.98, then 5.2 where it idles happy again.

 

If I give it a vacuum leak ie pull off the bov vac line, it gets better, still dips bu does not stall.

 

I wish rr had more tAbles, like initial throttle plate angle, defco resume ect.

 

What do other people see for throttle plate angle, maf at idle?

 

Mike

Nobody?

adjust your requested torque table such that the value corresponding to just touching the throttle maps to a point in the throttle position table slightly less (start with 0.5 deg less) than the throttle angle that causes a stable idle. then smooth the rest of the table corresponding to larger requested torques.

 

if you set the value a little too low you will get the behaviour you have now. if you set it a little to high you will get surging when returning to idle, especially in the cold.

The problem is you have cams and really high manifold pressure at idle. You built a race motor, don't expect it to work like a stock motor.

 

Race motors idle over 1000 rpm.

adjust your requested torque table such that the value corresponding to just touching the throttle maps to a point in the throttle position table slightly less (start with 0.5 deg less) than the throttle angle that causes a stable idle. then smooth the rest of the table corresponding to larger requested torques.

 

if you set the value a little too low you will get the behaviour you have now. if you set it a little to high you will get surging when returning to idle, especially in the cold.

 

This sounds really promising. My car behaves a little bit like fredraud's right after a reflash, but it learns to return to idle after it's had some practice. I'm going to try your suggestion just to see if it allows me to skip that post-flash learning phase.

 

Fredraud, I've heard of people with bigger cams getting more stable idles by tuning their cars to idle rich (like 12.5:1 - 13.5:1). That's something else to look into, if bugblatterbeast's suggestion doesn't fix the problem.

Weiner.. Didn't your mother tell you that if you have nothing constructive to say, then STFU? I have no problem getting it to idle @ 500 rpm in open loop. I would not consider 14inhg high manifold pressure, at my elevation of 3600ft. Stock this engine ran 16-17inhg at idle

 

At times I do respect your opinion, but the cams are truly on the conservative side. I don't know what kind of race motors you build or have built, but 106-108 LSa with 270-280 duration cam is what I consider race.. Not 220 on 114.. It's not my first rodeo. I have no problems getting this motor to idle at 750 or even ( 400 with a slight lope)

It's the ecu taking it from pedal dbw to ecu Idle control. And frankly, if I have to pull old skool and rev eng where initial throttle angle and defco are I will..

But I thing I will try the other poster's suggestion first

 

Mike

Nsfw, I tried playing with timing, but I found that the more range I gave it, the more it loped. Ie set min to 5 deg, and it jumped 10-22. Up and down like a yoyo

i read it as -7inhg not psi

 

that's good vacuum for cams

on a side note, I also hate this idle issue right after a reflash/reset. I've found that doing a 3rd gear pull seems to expedite the learning process. I reset my ecu last night and on the way home did some pulls, started it up this morning and it doesn't dip and rough out.

 

Since you're saying that you have mild cams, I'd suspect the vaccum to be a bit higher than that no? -7psi is only ~-14inHg, that's pretty low eh? For reference, -19 to -21inHg is stock, I wouldn't think mild cams should drop it THAT much. Though, you are at 3500ft, lol

Thanks bugblatter!

That helped tremendously. Will post a log. No stalling even after a reset.

 

I'm also getting pending misfire codes on all cylinders simultaneously. Then blinking check engine light.

 

I also have an issue with a lean spot and stumble at about 3500-4000 on lightly reving it up..

When I had a significant vac leak I had misfire on all cyl and a lean code.

Found it the damn inlet tube ripped

http://tapatalk.com/mu/325d2a8a-a89d-7d85.jpg

 

Are my only options oem?

Or are there aftermarket ones?

Bingo. There are a lot of aftermarket ones, http://www.fredbeansparts.com

There is at least one brand that doesn't have the correct zig-zag where the inlet goes around the TGV housing to meet the turbo compressor. Stay away from those, get one that has the right bend. It's basically just the last inch or two before it meets the compressor. It's obvious if you see pictures of both types.

Personally I like the OEM 08-09 inlet. More robust design.

Personally I like the OEM 08-09 inlet. More robust design.

 

Have a part number?

stocker rubber inlet requires removal of intake manifold

 

aftermarket silicone ones can be squeezed in without unbolting the IM

ATP's can be removed/replaced without removing the IM too... just barely.

 

Did it today. Didn't enjoy it one bit.

Well how did you get all the parts and screws that fell onto of the engine, and under the intake??

 

 

I took my stocker out as well without removing the intake.. But I figured it would be easier to put the new one in with it out of the way... Plus I had to get at those parts... Btw what is the dooey that has a connector on it that goes to the pcv system just before the turbo inlet..??

It is plastic.. And the damn magnet no pick it up

I did lose a 10mm nut when I was putting things back together. I removed it from a t-bolt clamp on the end of the inlet pipe (the one that holds the silicone zig-zag) and fumbled while putting the clamp back together.

 

Then again maybe I'll find it in my driveway tomorrow, I forgot to check for it when I was done.

 

If it was a white plastic fitting, it's basically just an elbow and the connector's job is to verify that it's still attached to the car. And I am not making this up. But I'm not sure which part you're talking about... I re-arranged my PCV system and removed a few parts while I was at it.

This part http://tapatalk.com/mu/325d2a8a-c031-4318.jpghttp://tapatalk.com/mu/325d2a8a-c07b-2471.jpg

I think it's the same part, but mine was white. If you look closely, there is exactly one piece of metal in that connector - it forms the two prongs.

 

If you pull it out, and you end up with a C-shaped bit of stamped metal, you can just stuff it into the electrical connector that used to plug in there, to keep the ECU happy. Then you have one less part to complicate your PCV system.

 

But take a close look at the thing before you do tear it apart. If you pull the prongs out and you end up with a tangled mess of broken sensor stuff... that's your problem, not mine.