idle timing with Holley HP efi
 

Engine is 1400hp procharged Gen7 sitting in a nordic heat Spinning Max 5 34P, the problem I am having is putting it in gear and it stalling........
I watch the idle bubble drop to new fuel cells and it gets rich and stalls.

I am thinking i need to lean those areas out so it doesnt stall. It idles at an afr of 13.2.

I am using timing control for idle,


Anyone have this problem?
https://cimg3.ibsrv.net/gimg/www.off...f35c66ebf.jpeg

I'm not running EFI, but I am using timing for idle control. I have found that by ramping up the timing below your idle set point it works much better than just idle control alone. I ramp up to 36 degrees by the time it gets down to 500rpm plus idle control it works perfect.

Can't you set timing to 30* for 1500 RPM and below? (just for reference)

are you guys running larger cams?

I assume the IAC is still in play? and responding quickly to the controller commands, or with the Procharger has the IAC been replaced with another source for Idle air control?

Just a thought not knowing the details of your engine management setup.

I tuned my 502 with Holley EFI last summer. You can get away from that problem easy. Are your idle timing near 10*? If you have more idle timing, retard it near 10 so you can screw idle air little up. Then watch what route MAP value go on chart when engine stalls and make agressive timing advance to those points, I use 25*. Take ignition controlled idle off from basic ignition setup, it doesn't work on my engine. It have to done straight to ignition chart.
After that tune fuel map right, if you have O2 sensor connected it's easy to adjust AFR to somewhere 12.5-13 when idling on gear, 14 is ok on neutral.

Hope you get some help.

OK yeah that was what i was told. I need to bump timing UP on those cells then look at fuel. I
Are you using timing for idle control? ASM told me to throw out in the entire area 15-18 degrees then timing idle control has a better chance

I do use the IAC i had it on slow but seems best idle is medium or fast

Perfect, I run about 11lbs of boost and a 11.1 to 1 comp motor, race fuel etc. if i run a small prop i never have an issue but the 34 Max5 drives me insane. I also have to take off with tabs all the way down and speed at idle is 6-7mph.....

I don't use idle spark (ingnition controlled idle) it not work with my long duration cam.
My engine is 502 mag efi, that engine iac is so slow that it not help nothing. Late idle timing make engine idle slow, so you put more basic idle air in and engine idle good. When on gear, advanced timing with little bit more air gives more power to idle on gear

I've found that the surge is not always a result of timing that a lot of time is results from the cells being too rich or too lean above or below the target idle speed. Basiclly when the engine senses a change in MAP it will go lean or rich and then you get the surge. The timing can fix it but the real problem is in the big differences in the tables above and below. You can see this when you're in live mode and the green dot is moving all over the place while it's surging. Once you smooth those tables it usually gets better. Takes a lot of patience sometimes.

After each 1/2 hr of tuning efi your keyboard should pour gas on your hands and squirt carb clean in your eyes. Then it would be no different. Lol.

hater :D

does holley have shift anticipation,mefi 4b's do and makes it easy to help control the shift into gear.this along with proper fuel smoothing and advanced timing.

If it does I haven't used it or needed to use it. It does have other Custom Idle Control settings that adjust for load but since it's not made for marine specific so they don't call it shift anticipation. I really haven't had to use it yet though because I didn't have any idle or shift issues on the ones that I've tuned.

you need to tune boats w/ huge props.:D

BINGO BINGO, works perfectly I also raised the Park up to 60,

We got it tuned great this past weekend. I was using a 32P bravo. I am putting on smaller pulley on blower and putting on the MAX5 34P prop for some speed tuning etc.

Bingo? I didn`t understand what Ksalmine was saying, so what did you do? .. more idle air, and or fuel mixture will never act fast enough to prevent a stall, only timing will. so enlighten me please

removed idle spark control, raised timing a few degrees and i set the iac stepper to fast. I also flattened out the fuel in the idle area.

This weekend we are upping boost another 3lbs. putting speed prop on it.

s
So I haven't read each post, so what will the total boost be?

12.5-13.2 depending on if i stop at 6k or 5700

Remember the motor has 11.1to1 compression

I disable the Timing control also , Bring idle timing down to about 10-15*. Open throttle blade so IAC is Barely open ( 5-10ish Counts )
Make sure you do a TPS reset ! Holley wont kick in the idle till the TPS says 0 .
Then in the Timing Table , say if you idle at 900 rpm, in the break points below say 750-800 rpm , Ramp up the timing to 30ish.
That way when you pop it in gear and the rpm drops , the lower rpm timing kicks it back up to your Target Idle Cells ,
Tuning your optimum AFR at Idle is a bit of a guess , that low of exhaust flow will actually give you a false reading.
I just try to find what it likes by idling around the water in gear and moving the fuel table up and down in the idle cells .
Till I get it good and clean .
Also make sure you dont have any fuel adders messing with your tables at Idle.

good advice. Going from a 4 blade to a MAX5 34P creates a bunch of shock. I can realistically keep my idle at 950.......what numbers do you use in your park settings?

I have the Parked at about 90% till it hits 60*F then ramps down to 65% @ 100*F .
Hold Position is about 30% . You can play with your settings , this was on a 572 with a Whipple.
The Throttle body injection is a bigger ***** to get to idle good.

Do you suffer from prop shock? what prop etc are you using and what boat.

Damn, I won`t let my 8:5:1 engine see anything past 9psi.Seen way too many blow up past 11psi/low compression
Let us know how long that engine lasts.

So you disabled the thing that makes the idle stable and that worked.. interesting.

https://cimg1.ibsrv.net/gimg/www.off...be524e928.jpeg
it will take 18-20. Amazing motor

this is a new PSI block forged crank ultra rods etc. its thicker and bigger.

https://cimg0.ibsrv.net/gimg/www.off...503088b41.jpeg
https://cimg7.ibsrv.net/gimg/www.off...3d93f1d7e.jpeg
This is Big Blue

Id be more worried about detonation. What octane fuel?

One issue I had , was the one holley iac harness i had, was wired for a chrysler iac. Well, plugging that into the LSX style IAC I had, everything seemed fine. Problem was , the ecu was commanding iac, and giving feedback, but the iac pintle was simply not doing anything. I couldnt figure out why the hell i was getting significant rpm drop when putting in gear. Chased my tail on that for a minute. It was a matter of swapping two pins to fix.

I run 110
engine temp is 125, oil temp on full boost and 5000-6000rpm is 235, this block also oil squirters under the pistons.

yes I can with my ecm. No need to though

Your effective compression ratio is 21.5:1
Good luck with that in a marine endurance motor .

if it ended like that I’d say thanks, but effective compression isn’t the end. Cam timing, lift and duration also affect that number. I’m pretty sure my builders know a bunch more than anyone here. We did a tear down in January all was perfect. 35 hours on it and in perfect condition.

https://cimg3.ibsrv.net/gimg/www.off...84d52ec0e.jpeg
That’s Jim Shofner, owner of Arizona Speed and Marine. He actually designed and built that intake and continues to manufacture all blue top motor intakes. He is currently designing a wiring harness that will convert any Holley ecm to work with just about any mercruiser engine.

https://cimg9.ibsrv.net/gimg/www.off...02059d726.jpeg

Yet youre here seeking advice.....:party-smiley-004:


Thats a bold statement, theres quite a few really sharp guys (and builders) on this thread offering help. Not the first "1400hp" procharged build we seen here over the years.

I think he is out west running that setup at elevation.

Another know it all ... We`re all idiots cause the 100 year old tuner knows more than anyone of us.
At $9/gallon I bet the thing don`t get run for extended periods so maybe that`s what`s saving your a$$.
Never once heard a good thing about Speed and Marine, quite the opposite.
Good luck, ask your builder any questions from now on .

I didn't come here to diss any of you or even listen to you guys call out a "100 year old tuner" etc. thanks for your input. check yourself or bring your bada$$ boat to Havasu or the Lake Powell Challenge and lets square up. Id rather ask you guys here to engage in some chat about idle tuning and learn than anything else. Good luck fellas.

I've got no dog in your tuning fight, but did notice this PSI mentioned in your other thread awhile back.
Never heard of them.
Do you know, is this who he's using for base engines or blocks? https://psiengines.com/

Otherwise, I missed it in the 1st picture with the crossover in place.
Anyone else seen big block heads with water ports for a crossover?
Answered my own question. A Gen 7 thing. Never knew.