Help with vehicle staying running and cold starts without throttle aid...

I cannot for the life of me, get my vehicle's tune correct so that it will start on it own without giving it gas on cold starts. It will start without help once warmed up though.

And also after a complete cold start the vehicle will not stay running after gear changes. Idles fine in park at first, then put it into reverse...after about a second it starts dropping rpms then stall saves, then dies. Restart, same thing happens again until I can give it enough gas to stay going for a while. But if it isn't warmed up enough before the next complete stop it will die again.

Then if it isn't completely warmed up but not completely cold its a 50/50 shot that it acts this way.

I've been through all the normal idle threads and tutorials and just can't get these 2 situations tuned out.

I have the right desired air flow, IAC counts, etc.

I am posting my tune below, and help would be GREATLY appreciated.

Thanks

Jeremy

Current Tune:
Attachment 16668

You probably won't wan't to hear this but the usual procedure is to get your VE & MAF dialled in fairly accurately before you get your idle and low speed driveability right. Looking at your VE table and MAF cure they are just not looking very clever currently. I believe they may need a lot more work to smooth them out before you can cure your idle.

If they aren't correct then you may be chasing your tail trying to cure the other issues. Not very helpful but I tend to look at the VE and MAF tables in any tune to see what your working with.

+1 VE and MAF both need work.

Post log files showing RAFIG pids.

Well im not sure what else I can do for ve and maf, ive done calc.maft plenty of times. I guess I can swap to calc. Vet and do that a bunch of times. But I keep getting the same stuff thats already in my ve and maf tables.

You've had this problem since last year. I saw your previous thread on this...

http://forum.efilive.com/showthread....on-cold-starts

I've had a look at your tune, and a lot of the tables don't look quite right to me. Do you have a stock tune to start over with?

Ive since added more mods and done calc.maf after it because of a new maf sensor and intake manifold/tb and have since modified other tables to try and help with initial startup since then with no luck.

Is it worth posting a pic of your inlet setup as it looks like something is causing disruption to the air through the MAF. Do you still have a diffuser before the MAF? You have a ported TB? Not always a good idea that can change the airflow over the IACV port for example and affect the stock tables. The injector table suggests your FPR is vacuum referenced? Just trying to check some basic stuff that affects a lot of the main reference tables.

It's frustrating as I have a very similar setup 224/226 112 cam with a tadge less lift, mine is manual though. I used the LS1-M6 base tune from one of the tutorials and that's served me well. Only slightly tweaking the throttle cracker/follower tables to suit my Edelbrock 80mm TB.

Okay. I think you're better off starting over with a stock tune, but if you want to keep using your current tune then try this...
Set all values in B4105 to 450.
Set all values above zero IAT in B4205 to 35
Set B4206 to Disable.
Add 0.3 to all values in B3701.
Make sure B4001 is correct for your current injector size.
then
Retune your MAF and VE tables.
then
Redo RAFIG/RAFPN

If you find it running too rich or too lean on cold start, then adjust B3632

And, as warlock007 already pointed out to you in your previous thread, with your cam you should idle a bit higher... especially important for cold starts.

VE:
after you redo your VE, you must get rid of any sharp steps/drops/spikes/holes...
large steps/drops/spikes/holes cannot physically exist, so you have to flatten/interpolate these:
i.e. the un-hit cells have to be brought up or down so that they are close to the hit cells
--> I'm talking about only minimal smoothing
ripples of a few percent in one direction are ok) (i.e. not major steps)

MAF:
after you redo your MAF, same thing, you have to bring the un-hit cells into the 4th order polynomial curve;
there is a spreadsheet somewhere on the web to do this, but it can easily be done by hand too;
i.e. the MAF curve must look like a smooth 4 order polynomial (i.e. its slope keeps increasing);
the MAF curve has to be quite smooth (this is how the MAF works), but don't use the smoothing tools, do it by hand.

I have a Lingenfelter 100mm mass air flow sensor slot style so no it does not have a diffuser any longer I have a 92 millimeter fast throttle body drive by cable and a TrailBlazer SS intake radically ported for the sake manifold

also the IAT sensor reads off on this computer because I cannot adjust the i-80 scalar so I unweighted the IAT sensor because of this

Okay then, do the rest... just ignore changing B4205.

Put your MAF table back to the Lingenfelter specified curve before retuning your MAF table.

OK I was trying to decipher your tune file name!

With the slot style MAF they can be sensitive to placement to around the circumference of the tubing if there's any disruption to air flow immediately upstream i.e. sharp bends. Not always so easy to relocate of course.

Using the same information as I had in the previous file but with smoothing the VE and MAF tables here is my 11th OL iteration file:
Attachment 16679

Here is the Ling. MAF info for the curve, which is almost the same except I have more airflow until u get very high in frequency:
Attachment 16678

My Calc.MAFT shows almost exact same data every time for VE table and MAF curve, other than the fact that the weather keeps changing from 40 to 80 every other day here in Louisiana.

Also my desired idle speeds are in b4603 and are up to 900 rpms when it is cool, settling to 725 at 80C...so it doesn't seem like idle speed should be the issue on cold starts. Unless they need to be 1200 or something...

Also here is a partial RAFPN warm up log:

Attachment 16681

Can you do a cold start log, and log the following;

SAE.TP
SAE.MAF
SAE.RPM
SAE.ECT
SAE.MAP
SAE.SPARKADV
GM.AFR
GM.IAC
GM.KR
GM.IBPW1

Start logging before before you start the engine. Do a start without any throttle aid and then a start with throttle aid. Then do a small cold engine drive and log a stall and restart (if you still have the stalling issue).

Here are a couple cold start attempts with and without throttle aid, with stalling after starting going from Park to Reverse to Drive, etc.:

Attachment 16700

Attachment 16699

Current Tune running, while the above logs took place:

Attachment 16698

Also take notice that I increased all idle speeds by 75 rpms and have since retuned for that but am having the same problems anyway.

Okay, I've looked at your logs and it looks like your engine is bogging down when cold (too much fuel). I've modified your tune a bit. Flash in this tune and do another cold start log the same way as you did the last one... and logging the same pids.

Quote:

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Originally Posted by statesman

Okay, I've looked at your logs and it looks like your engine is bogging down when cold (too much fuel). I've modified your tune a bit. Flash in this tune and do another cold start log the same way as you did the last one... and logging the same pids.

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Here are 2 sets of cold start logs after loading in your modified tune:

Attachment 16706

Attachment 16707

Other than not starting without throttle aid, do you have any ideas on how to fix the surging and dying that are shown in these logs as well, once started?

Okay, I've looked at your logs and I noticed something that I missed last time. Your problem is not enough air when cold. Your IAC is maxing out. I'm guessing that you haven't drilled or cracked your TB yet. You've got an IAC count around 125 hot... should be 30-50. You need to get your IAC counts down. We'll probably have to put a bit of the fuel back into your cold running, but you need to fix your air first.

Quote:

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Originally Posted by statesman

Okay, I've looked at your logs and I noticed something that I missed last time. Your problem is not enough air when cold. Your IAC is maxing out. I'm guessing that you haven't drilled or cracked your TB yet. You've got an IAC count around 125 hot... should be 30-50. You need to get your IAC counts down. We'll probably have to put a bit of the fuel back into your cold running, but you need to fix your air first.

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When its hot the iac counts are right at 40, it doesnt get to that until ive been riding around for 20-30 mins tho.

The default IAC is set to 310, should that be changed maybe before opening up the tb blade some and ending up with higher iac counts once actually warm?

For Example:

Attachment 16709

I'm switching to an LS7 card style MAF myself on an E40 ECM. What I have learned as you mentioned the IAT output is not compatible and needs to be re-scaled. Since this table is not available I'm switching to a separate IAT that is compatible. Isn't a lot of the cold start fueling based on coolant and intake air temps?

Quote:

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Originally Posted by ACCLR8N

Isn't a lot of the cold start fueling based on coolant and intake air temps?

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He has his after-start IAT enrichment zero'd out, but it will still have a serious impact on his temperature blending... which determines fueling. It would probably be a good idea if sac811 switched to a separate IAT, which is compatible, like you are doing.

Quote:

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Originally Posted by sac811

When its hot the iac counts are right at 40, it doesnt get to that until ive been riding around for 20-30 mins tho.

The default IAC is set to 310, should that be changed maybe before opening up the tb blade some and ending up with higher iac counts once actually warm?

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No, leave your default IAC. I've modified your IAC table. See if this helps.

Quote:

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Originally Posted by statesman

No, leave your default IAC. I've modified your IAC table. See if this helps.

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This is the start with your new file before performing rafig rafpn:

Attachment 16711

I will have a start attempt with same file after rafig later today.

Here is my cold start log after rafig/rafpn:

Attachment 16713

It seemed like it may have wanted to start better, but it definitely ran better than in the past with less surging and dying.

Quote:

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Originally Posted by sac811

It seemed like it may have wanted to start better, but it definitely ran better than in the past with less surging and dying.

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We're making progress... that's a good thing.

Can you post your new tune with your updated airflow.

Quote:

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Originally Posted by statesman

We're making progress... that's a good thing.

Can you post your new tune with your updated airflow.

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Newest tune file:

Attachment 16716

By what method are you correcting VE and MAF tables...?

Quote:

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Originally Posted by joecar

By what method are you correcting VE and MAF tables...?

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Calc.maft

Your desired airflow table looks better now.

Okay, here's Mod3. Only small changes, but should reduce the surging.

Post a log when you've tried it.

Quote:

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Originally Posted by joecar

By what method are you correcting VE and MAF tables...?

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Does something look wrong to you?

Quote:

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Originally Posted by statesman

Your desired airflow table looks better now.

Okay, here's Mod3. Only small changes, but should reduce the surging.

Post a log when you've tried it.

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So im just doing another start up log like ive been doing correct?

Yes, same as you've been doing, same start up log... same pids. I altered your startup spark as well, so I want to see if it's more inclined to start now.

Quote:

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Originally Posted by sac811

Calc.maft

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Quote:

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Originally Posted by statesman

Does something look wrong to you?

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I'm sanity checking on the procedure...

sac811,

are you using wideband only (I see trims/CL disabled in the log)...?
if so, what pid are you using to correct the VE table (CALC.WO2BEN)...?

Just sanity checking

( if you use CALC.SELBEN, this will have flat 1.00 spots from LTFT's being zero due to trims/CL being disabled, and this will mislead your efforts )

stateman has you on the right track :cheers:

Quote:

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Originally Posted by joecar

I'm sanity checking on the procedure...

sac811,

are you using wideband only (I see trims/CL disabled in the log)...?
if so, what pid are you using to correct the VE table (CALC.WO2BEN)...?

Just sanity checking.

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Yes wideband only and calc.wo2ben

Quote:

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Originally Posted by sac811

Yes wideband only and calc.wo2ben

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Ok, cool... carry on with statesman's instructions.

3 cold start attempts this morning (they didn't want to act right as the same file for some reason):

Attachment 16722
Attachment 16723
Attachment 16724

The last is it running for a bit after throttle aid start.

This is a successful start without throttle aid at 40C and the ride home afterwards:

Attachment 16725

Mind you, the cold starts in the previous thread were without proper rafig/rafpn for that cold of a start, since the temperature just went from 80 degrees F yesterday to 40 degrees F this morning...hate these weather changes up and down in Louisiana.

Unaided start at 40C is good. You will need to redo your RAFIG/RAFPN for those colder temperatures.

Okay, here's Mod4. A few changes in this one. I think you'll see a good improvement with these changes.

Quote:

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Originally Posted by joecar

I'm sanity checking on the procedure...

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Always good to have an extra set of eyes doing some sanity checking. :cheers: