Odd starting issue... any ideas?

[TpaGreenHornet]

I'll be following. Mine started doing the same thing a couple of weeks ago. I already cleaned the maf and throttle body trying to get rid of what feels like a small miss at idle. Which I have read a few other people with the same issue but no cure

 

[domoarigato]

Jake, I think that is a hanging starter or starter related. While no fan of low octane fuels, I do not think that that is your problem in this instance.

I would agree with this, but why would it only hang during the first start of the day and not the rest?

Out of curiosity... where did you get an 89 octane tune? Is it like a custom "Diablew" tune?

My Diablo I2 only has the following "canned" tunes available.

MPG tune
87 tune
91 tune
93 tune

I just flashed the 91 tune for the first time the other day. I cut 2 degrees of timing out at WOT to alleviate a little spark knock that I was getting with 89 octane but I also topped off with a half tank of 93 octane so not sure which one helped.

Hi kbuskill, yes its a custom tune due to fuel availability where I am at (weird I know). Was the 91 canned tune a big diff over the 87?

running some injector cleaner may help I think some other people had a same or similar problem on here and after running some injector cleaner (couple bottles a tank) problem went away, I have like 3 cases of that stuff sitting around so I throw it in often myself.

I will give this a go.

I also tried to prime the fuel pump to see if it was losing pressure, and it didnt fix this issue.

As of now it still exists. Will try the injector cleaner next.

 

[kbuskill]

Hi kbuskill, yes its a custom tune due to fuel availability where I am at (weird I know). Was the 91 canned tune a big diff over the 87?

I guess it is noticeable... my wife drives the truck more than I do so it's not like I am in it everyday. I did notice more spark knock under WOT which is why a took 2° out at WOT.

I don't know where you are but I am in NE FL and 87, 89, 93 are the norm around here which is why I was asking about the 89 tune you have.

You should email me that tune...

Also the fact that your starting issue only happens first start of the morning is why I was thinking fuel pressure... sorry that didn't help.

 

[PG01]

Meh, maybe i did it wrong but 93 canned diablo tune is .....meh

 

[kbuskill]

Meh, maybe i did it wrong but 93 canned diablo tune is .....meh

I haven't tried the 93 tune yet... have you played with any of the transmission settings. I usually leave the torque management alone in the regular setting BUT in tow haul/sport mode I eliminate about 15%... you can take out as much as 20%.

I have kicked around the idea of getting a "Diablew" tune but haven't done it yet.

My guess is it would be about the same as a BBP tune since you send in logs for him to comb through and build you a custom tune... I realize it's not the same as an in person dyno tune.

 

[PG01]

I haven't tried the 93 tune yet... have you played with any of the transmission settings. I usually leave the torque management alone in the regular setting BUT in tow haul/sport mode I eliminate about 15%... you can take out as much as 20%.

I have kicked around the idea of getting a "Diablew" tune but haven't done it yet.

My guess is it would be about the same as a BBP tune since you send in logs for him to comb through and build you a custom tune... I realize it's not the same as an in person dyno tune.

If I remember right, on top of putting 93 tune in, i turned off afm, changed tire size, and made shifts firm at wot which I really don’t like because it really bangs them hard when i get on it.
I really only drive it 1 or 2 nights a week and on weekends and I haven’t had a chance to go back in and change it back but considering i have no idea what im doing i may just put it back to stock before i mess something up.
Im seriously considering putting it stock and getting a bbt.

 

[SLE2013]

running some injector cleaner may help I think some other people had a same or similar problem on here and after running some injector cleaner (couple bottles a tank) problem went away, I have like 3 cases of that stuff sitting around so I throw it in often myself.

I second this... have you tried it yet? any luck?

Mine was doing the same thing, and added some fuel injector cleaner and tier 1 gas, it went away.

 

[bryank97]

My 2007 Tahoe 5.3L does this still. I have started running Lucas Injector/Fuel Conditioner. I have not noticed any change. Biggest factor that effects mine, is temperature. On a 40 degree morning, it is much less noticeable. On a 20 degree morning, its very noticeable. My mothers 08 Suburban, has never experienced this. We buy fuel at similar places all throughout town. My tahoe is flex fuel capable, her suburban is not.

 

[Doubeleive]

do a leak test on the intake in the morning at first start while it is still cold

 

[RED TAHOE LS]

Jake, I know this can be pia when trying everything possible. I know it's all to natural to jump in and hit the key and take off, but try this, turn key ON only, listen for fuel pump running and stop (3 secs.) then start it......NEVER EVER TOUCH THE GAS PEDAL. I know you said you tried priming the pump, just wondering how you did it. My original Tahoe from day 1 has always been started like this @ 202k miles. I know it's different than yours, but give it a try. Good luck.
David g...........