VEMS 1.8t 630cc coldstart problems

Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 9:21 pm

A value of 30 on the ref dc curve will bring it to about 3k rpm lol

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Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 9:22 pm

I'm going to buy one used and see can I modify the rest position to be slightly more closed.

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Post by **Marc** » Sat Feb 07, 2015 9:41 pm

Urtorsen wrote:I can use it to control the idle but with everything disabled and only using the timing idl control it still won't let me go below 900, it never needs more idle air when warm only less. It's steady as a rock just won't let me go to the 850rpm warm idle setpoint. All I'm using right now after it gets warm is the timing advance iac. The ref dc for iac I drop to zero after it gets to 55 deg

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lower your static timing to zero or so around the idle cells.

Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 10:08 pm

Ok, i was afraid to go below 8 deg or so

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Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 11:25 pm

I brought it down untill I got the target rpm with iac and timing control dissabled and all accessories off. It's down to 3 deg in main block, it's all I had time to do right now, it got to 70 deg coolant and it's steady at target idle. Why would I have to go that much timing retard compared to others??

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Urtorsen · Post by **Urtorsen** » Sat Feb 07, 2015 11:38 pm

I have to let it fully up to driving temps but looks good, is this bad/unusual or a sign of other issues??

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Urtorsen · Post by **Urtorsen** » Sun Feb 08, 2015 3:22 am

Timing mechanically I just checked and it's on the money

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Urtorsen · Post by **Urtorsen** » Sun Feb 08, 2015 3:54 am

This is on a warm engine same settings above
And I just reduced it to zero- still hovering around 910-920

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Urtorsen · Post by **Urtorsen** » Sun Feb 08, 2015 7:05 am

http://www.vems.hu/wiki/index.php?page= ... veThrottle

Just saw this and see a wishlist for a way to have bi directional control over this throttle body. Seems like I'm gonna have to live with it or modify it to close more in rest position and try it like planned

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chaloux · Post by **chaloux** » Sun Feb 08, 2015 9:52 am

My 4k with aan always idled around 1k rpm. Perfectly stable with no IAC/isv or any of that. Very minimalistic setup. I didn't really care, and had idle timing around 15* iirc

Urtorsen · Post by **Urtorsen** » Sun Feb 08, 2015 3:25 pm

Yeah, it's the same on this, 1k and very stable also. Ive a throttle body on the way to play with . When it gets cold here it works fine, like I said the iac ref dc map will give me control until it's warm, it's just so if I can get it down to 750-800rpm with everything dissabled, or when warm, then it will be perfect for me.

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Urtorsen · Post by **Urtorsen** » Tue Feb 10, 2015 8:55 pm

Went reading a whole load over on vems support forums on coldstarts, cranking and warmups , even bought a book to try and get more versed while I'm waiting on lugtronic to get around to it. I'm not going to be messing with power side of things just all the driveability stuff.
Already making great improvement, was a bit off blending the afterstart to the cranking enrichment lol. Started right up and ran without interference from throttle pedal last night, on a cold engine that had been off for about 8 hrs.......temps are going low again this weekend starting Thursday, hopefully I can improve a bit more on it

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Urtorsen · Post by **Urtorsen** » Thu Feb 12, 2015 1:20 am

Started every time first crank after some more adjusting, fkn delighted with it!! Just started and cold idled perfect with temps here in illinois of 18degf....

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loxxrider · Post by **loxxrider** » Thu Feb 12, 2015 2:48 am

Great job. Is the idle still high?

Urtorsen · Post by **Urtorsen** » Thu Feb 12, 2015 11:03 pm

Idle is still hight..... I've got a TB coming to fiddle with to see if I can set the resting point more in the closed position. No matter what I do I can't kill it's air supply any other way. I am going to go through it with a fine comb to see if it's pulling air from somewhere not that noticeable. I've read that a can of brake cleaner sprayed around the possible leak sites at idle will give me a clue as it will race the idle a little.
It's gone below 10f out now and the car hasn't been running since 5:30am , I'm about to go see how it starts right now.

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Urtorsen · Post by **Urtorsen** » Fri Feb 13, 2015 12:00 am

Had 10f on the dash and started right up again. Have to adjust the afterstart enrich again but it's going well.
I'm convinced there's something wrong with this TB. The revs were t dropping with the iac ref curve as it should have. I hadn't noticed before but the TPS % was at 5% on Vems. I tapped the throttle pedal slightly and it let go to 0% and the rpm dropped to where it should be following the curves. There's two pots in the TB for the TPS and iac, something's hanging up me thinks.

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Urtorsen · Post by **Urtorsen** » Fri Feb 13, 2015 12:00 am

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SEStone · Post by **SEStone** » Sun Feb 15, 2015 4:12 pm

FWIW, that engine idles around -5 to 5deg timing stock depending on loads and such. Running such little timing gives a large 'torque reserve' as Bosch calls it, and really slows down response to help stabilize idle control.

I've tuned a handful of cars with 034 using open loop GPO-controlled idle using the idle motor plus the closed loop ignition timing control. Works a treat.

Urtorsen · Post by **Urtorsen** » Tue Feb 17, 2015 12:31 am

I'm waiting on lugtronic to get back to me so I can get the knock control enabled(instructions per vems seem straightforward and easy to follow though) and to sort out the ign table. I'm not confident enough to go playing with the ign tables so much but retarding the idle blocks is ok I suppose, so after changing those blocks to 3 deg I will have surrounding cells at 14-15 deg , is that too much of a jump??

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Urtorsen · Post by **Urtorsen** » Tue Feb 17, 2015 12:40 am

I still have the P,I,D set to zero. Is there a default to start from with the 1.8t? I raised the freq for the iac to 200hz, I read something about it running at 400 or something with oem. it was at 25hz and was clicking alot, that stopped when I raised it.
Coldstarts are pretty decent now, I had it parked all night in 6f temps and it started first turn, the cold/warmup idle was hunting for the first 10 secs not sure why but lowering the ref dc tables slightly lessens it. I didn't think I'd have to be doing all this stuff but I suppose it's a good way to learn as long as I'm carefull and don't get ahead of myself

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loxxrider · Post by **loxxrider** » Tue Feb 17, 2015 1:49 am

Actually, this kind of thing is what takes the most time with tuning if you aren't used to it.

The valve is still clicking, just much faster so you can't hear it the way you were at 25 hz!

If you don't have PID tuned on the IAC, then it probably isn't doing much. I made a nice post here about tuning PID systems. If you use it, you should be able to get that thing working properly. Let me know if you have any questions about it. Even though it refers to boost control the whole time, you can apply it directly to the idle control valve or any other PID system.

http://theprojectpad.com/viewtopic.php?f=28&t=1252

Urtorsen · Post by **Urtorsen** » Tue Feb 17, 2015 5:15 am

Yup, I read it and it really is a great write up, I'm going to tackle it this week sometime hopefully. I will be re-reading it again before doing it.
The vems guide : Set the ref dc table so there's a steady idle around 200 above target, in all temps ,
the PID to bring it to control/correct it smoothly and quickly whenever there's a lot of variance and let the idle ign adv control take care of the smaller quicker changes.
What I don't understand is what brings the idle back down the 200rpm to where I want it after setting the ref dc as above?
All that will have to come after I get the timing idle corrected to bring the rpm down to in around the target 850, it's tough to get time but I'm enjoying learning none the less.

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Urtorsen · Post by **Urtorsen** » Tue Feb 17, 2015 5:32 am

Is enabling the P I D going to bring it (back down 200rpm)to target. Then it will Be taking away or adding to the ref dc as required to correct my idle in different conditions if the ign adv control doesn't get to it first??

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loxxrider · Post by **loxxrider** » Tue Feb 17, 2015 6:47 am

Attach your config so we can take a look.

Urtorsen · Post by **Urtorsen** » Wed Feb 18, 2015 1:58 am

Ok, I'll try and get time using my phones hotspot or when I get home later

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