Warmup idle dip

Old 08-18-18, 04:02 PM
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Warmup idle dip

I have had an idle dipping issue during warmup since getting the car running but due to various other things it has kind of been at the ed of the list of things to sort. Now the rest of the tune and car are coming together after so long I want to try and sort this out. I have loaded a video onto youtube to demonstrate what happens. It has improved with some recent tweaks I made but may also be helped by the fact idle is currently a bit rich in places as I have not yet fine tuned the water map to my latest settings. What happens is form cold idle is sitting in the 500rpm line 18HG at about 850rpm. as the engine warms up there comes a point where idle rise to over 1000rpm and hence the idle cell shifts to the 1000rpm line. What happens here is when you rev the engine and let the rpm settle back the engine momentarily drops back down into the 500rpm line before it steady's off. However when it does this it seems to create a slightly lean condition which can be seen in the video. This cause the engine to hang there and stumble longer than it should and sometime may even cause it to stall. I added fuel to the 500rpm line but I am not sure if I can keep adding more or if I should in fact be adding to one of the cells to the side instead or as well? as it stands It looks like the current setting will require me to have zero water temp correction by 68 degs which I think usually is expected to zero out at 82degs?? Would that be an issue? I have tried messing with timing but with the microtech it basically done't work as at this point the ecu is detecting idle condition and hence setting default idle timing.
Once the engine warms up fully the idle rarely dips down into that 500rpm line so you don't see the problem. Final idle being around 1120rpm.
Please watch the video and offer some comments if you can.


Thank you
Lee
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Old 08-19-18, 04:49 AM
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Just quickly, what is your target idle rpm on initial startup?
Also are you still running the factory IAC( Idle.Air.Control valve)? the reason I ask is they are prone to getting a bit dirty and then can be slow to respond to adjustment, which can give similar symptoms.
would only take a couple of minutes to check.
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Old 08-19-18, 05:03 AM
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Thanks for reply. Good point but no IAC.. Could not figure the settings.. It is fitted but not plugged in. So idle Rpm is determined by main idle screw and from cold it is where ever the engine is happy. Ignore the lumpy idle.. That is just richness. Smooths out fine when I lean it off.
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Old 08-19-18, 08:15 PM
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add more cold coolant temp pump %.

with microtech, the good thing is, you can usually fix the problem by making it richer. the bad thing is, that's about the only thing you can do with a microtech.
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Old 08-20-18, 03:56 AM
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Thanks for the reply.. As it happens I think I do need to add in some cold pump for when I come on throttle as it still stumbles a little pulling away from cold. I think I have about 10% on the main pump1 and 12% on cold pump. Seemed a lot to me but I have no idea what is normal and adding more seemed to improve it last time. However I don't believe pump will have any impact when coming off throttle which is what I am trying to overcome in the post above. the idle drops a bit low and you see the AFR go into the 13's and it results in it hanging in the 500rpm cell too long. Idle itself does not like going into the 13's much so hence it hangs and sometimes stalls.
I am not sure if I need to add fuel in the 500rpm 18hg or add it in some of the other cells along the 24hg column too maybe? Seems to dip across to the 500rpm 12hg cell sometimes too..
Another reason why I recorded it so I can try and look back over the video and see what is happening?! I just don't want to keep adding fuel in the wrong place and end up with a matrix that doesn't flow nicely or look right even though it might in inadvertently solve the problem! Also I am ware the water map looks like it wants to have zero correction by 68degs and not 82degs now which again I am not sure if this is fine or whether that means something is too rich? Thanks for any pointers or thoughts.

I will try and get the video rotated too! I thought it had done it! Clearer to watch on youtube or full screen either way.
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Old 08-20-18, 08:13 AM
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Finally managed to sort out a correctly rotated video!
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Old 08-20-18, 08:16 AM
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Last edited by Leeroy_25; 08-20-18 at 08:28 AM.
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Old 08-24-18, 12:34 PM
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To get things moving a bit.. Can anyone comment if it is acceptable for the water temp correction to zero out before 82degs with 875cc primary injectors and 1100rpm idle speed?
Thank you
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Old 08-25-18, 04:09 PM
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Yea. That's fine. Double or triple the pump, and if it helps, fine tune it from there.
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Old 08-25-18, 06:11 PM
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Thanks for reply. I will try going heavier on the coldpump for pull away issues when warming up. Starting to wonder if in fact it has gone to far and. Getting too much fuel causing it to stammer the misfire. Will play around. Maybe zero out cold pump and wind up pump1 to see if that resolves issues during warmup. At least I am just tinkering with one setting then.
Could be I need to delay the Trigger point a bit too maybe. Another thing to look at. Annoying thing is I only get a few minutes to try and fix thus each time I take the car out! Then it warms up and drives like fine! We have kind of drifted a little off topic. The idle dropping below desired idle and lingering when lifting off the gas was the main issue to resolve. I kept adding fuel to the 500rpm line and it seemed to have no impact and possibly make it worse. I took some out and it seemed better. Almost back to where it was. Not sorted but a bit better. So totally confused here! Only other option might be richer idle cell which I don't want. But short of figuring out the settings on the IAC I might end up having to love with this?
On a slight side. Stickman, please can you post a pic of your matrix table and confirm primary injector size. Anyone else reading please do the same. Might really help me spot the error I my matrix/settings. So annoying. It can only be a handful of cells and I cannot seem to get it figured.
Something just came to mind.. Should the throttle dampner plunger touch the throttle lever to slow the throttle shut off? Or is it quite common they don't. I am Pretty sure mine does not.
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Old 08-26-18, 01:31 PM
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One thing I learned over the years is keep your post short if you want a concise answer hehe. People reading on Forum have attention span of a fruit fly unless you actually happen to have a prev relationship with a particular person or you are the one asking the question.

I don't have the Microtech anymore. I went to halTech a couple years ago. I posted my Matrix and the entire setting here a few years ago when I was in your shoes. I'm sure you can dig it up if you look.

Fyi you will never get the car to run like stock with Microtech. Just be happy that the car is running and you can do some wot pulls. That is it. If you start focusing on little quirks and chasing after them, knowing what I know now, you'll be chasing after that Dragon for the rest of your life with microTech. Microtech just cannot do this unless you're willing to pull up tuning table every time you start the car.
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Old 08-26-18, 01:35 PM
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Lol! Thanks Stickman. The Microtech does kind of have me drawn in!
Will hunt out your post.
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Old 08-26-18, 01:36 PM
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You can also increase timing at negative vacuum just below where the car likes to Idle. You can match that with the little more fuel on the table. When I had the wobble at idle, it was because it was lean, drop rpm, and it will recover bc 800rpm cell had more fuel. Your situation may be different. You have AFR gauge. That should tell you which way you should go.
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Old 08-26-18, 03:01 PM
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Thanks for extra post.. AFR points to lean but IIRC adding too much fuel can cause it to stumble too which will then also show as lean right? I will try again next time I get to drive it. How much timing can I add in the higher vac cells. It is already a bit higher. Shame that adding timing into the rpm table doesn't work as the TPS trips into idle mode before Rpm has recovered!
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Old 08-26-18, 03:29 PM
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Any idea what thread you posted your maps in. I just spent the last hour reading threads you started and cannot find anything. Plenty of good info in them which I have spotted some before!
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Old 08-27-18, 11:39 AM
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You can add High timing as long as you're in vacuum. It will not hurt anything. I think mine was way over thirties if I remember correctly. If you search my post with keyword like map or Microtech, it should pop up?
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Old 08-28-18, 02:16 PM
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Will get back on the search!
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Old 08-30-18, 06:20 AM
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Here are my timing maps in case they prompt any suggestions.


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Old 08-30-18, 10:57 AM
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i think your timing is way too low in low rpm.

try to increase t_rpm map to 15 adv at 500rpm and 10* adv at 1000rpm.

also post your idle map if you're having idle problems.
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Old 08-30-18, 10:59 AM
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it's been awhile, maybe idle map was only fuel. not sure if microtech had separate timing map for idle. let me know how that works out.
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Old 08-30-18, 02:05 PM
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Thanks for the reply. So this is what I planned to try. I am pretty sure I did it already and the result is idle timing goes up to 15degs. I.e the default timing for idle is set by the 500rpm line even though idle is over 1000rpm!? I will double check though. No other table for idle timing by the way. That is what I need to be able to do though I think.
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Old 08-30-18, 02:15 PM
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If the trim adjustment doesn't work. Then I could try adding a bit more in the map table under vac maybe? Only issue is I think tps might detect idle before engine hits the dip and therefore map table becomes irrelevant too!
Did you resolve your idle dip in the end or not?
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Old 08-30-18, 03:58 PM
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One other point. In the t_map the timing stays low at 1500rpm.. Why.. Is there a reason this is not somewhere more central to the 2000 Rpm value? Like 12degrees? won't help idle issue just curious!?
I will post idle map later. But in matrix mode unlike timing idle appears to follow the cell being highlighted?! I. E it does not default to the 500rpm line. You can see the matrix or roughly how it looks now in the YouTube.
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