Have you ran any E85 gas in it lately? Sound like maybe your motor is reading high alcohol content . Sometimes causing hard starts . Maybe clean your maf. and throttle body.. Just guessing for things to check... good luck

 

No I've never run E85 through it. Bought it in may with 36k miles on it, but I run seafoam through it regularly usually about every 3rd tank of gas. Do you think that could relate to high alcohol content?

 

2011 GMC SIERRA Rough Start Up

This sounds very similar to my problem

 

Following, I have been having the same problem.

 

Try turning the key on for three seconds then off and do that three or four times before that first morning crank.

 

^^^ +1

 

You putting more than 5w-30 oil in it?

These batteries now a days last upwards of 10 years. So you wasted your money on a new battery as you had at least another 4 to go.

 

You putting more than 5w-30 oil in it?

These batteries now a days last upwards of 10 years. So you wasted your money on a new battery as you had at least another 4 to go.

I've been running Royal Purple 5w-30 full synthetic. Clearly in hind sight a new battery was unnecessary, but I needed a new battery for my boat anyway so it worked out.

 

Try turning the key on for three seconds then off and do that three or four times before that first morning crank.

I tried turning the key on the past two mornings for a good 10 seconds, but did not try turning it off and back on 3 or 4 times. I'll try that next. The only thing that somewhat makes sense is a problem with the fuel pump or an injector. What keeps throwing me off is that it runs fine for the rest of the day after the first start.

 

**UPDATE**

So I've been trying the half start method (turn the key 2 clicks without starting 2-3x) with no luck. Decided yesterday I would clean the throttle body because I hadn't done it in the 8 months I owned my truck. It was admittingly dirty, probably from over oiling my cold air intake filter. Re-cleaned and dried the filter, cleaned the MAF, shined the throttle body up like a new penny and put everything back together. Took it out for a little test drive and it was idling higher than normal, which I expected from cleaning the TB, and decided to let it sit for the night to try the major test this morning. Well... low and behold it's still doing a long startup and hard crank, BUT I did not have to pump the gas pedal this time for it to turn over so there's a slight positive if nothing else.

With all that said what's next on the list?

 

*** UPDATE ***

Good news to those having this similar problem. My truck started normally the past two mornings. I changed my oil Saturday and ran a can of sea foam after doing all the previously mentioned tune ups and it has seemed to finally correct the problem. I think the main take away from this was cleaning the TB and having a clean, but not over oiled, air filter. After cleaning the TB it did idle higher than normal which was expected, but has since finally re-calibrated and is running like normal again.

Hope this helps anyone else and if anyone has further questions, comments please don't hesitate to ask and I'll tell you what I know!

Thanks again for this forum and it's unlimited knowledge and support!

 

Glad you got if fixed and it didn't cost you $600. I may do a preemptive TB cleaning this coming summer.

 

it was probably the sea foam.

 

Haha it was probably the over oiled air filter and dirty TB

 

Need to slack off on Seafoam, i'd say only do about every 25k-30k miles if you want it to be done a good bit of the time.

I would've said coilpacks and spark plugs next. Try some different gas (Shell, Chevron)

 

I took mine in the shop the other day to be checked out, the computer is showing alcohol percentage of 69%. I use only BP gas in my truck. They are getting a tool to measure the alcohol in my fuel before they reset the computer to make sure, that's what GM said to do.

 

I took mine in the shop the other day to be checked out, the computer is showing alcohol percentage of 69%. I use only BP gas in my truck. They are getting a tool to measure the alcohol in my fuel before they reset the computer to make sure, that's what GM said to do.

BP is your problem. Start using someone else. unfortunately BP adds a lot of alcohol to their gas to make it "cheaper". Ive seen a lot of people ruin their engines because of BP gas. Especially if they are not tuned for say E85 (from what I understand the alcohol they use is different than E85). If I remember correctly its from the lack of lubrication that alcohol gives. So your truck is probably correct in the amount of alcohol you have in your gas. Stay away from BP.

as for seafoam use.... Use it every other tank not 30-35k miles or at least once a month. Seafoam eats all the carbon. I don't use it as I DO run E85 in my truck (only problem starting is on really really cold nights). I also use seafoam before any oil change as it helps get all the crap out of the oil (running e85 has eliminated that problem for me).

 

It's either BP or Casey's in my town.

 

I run only Shell myself. I've never run seafoam though...don't plan to either. If I ran seafoam every 2-3 tanks I'd be doing it twice a week lol. Seems a little excessive.

 

LOL that would be excessive... Most people use a tank of gas a week. Me im not most people in that if my kids don't have something going on (like all im doing is driving back and forth to work) I can go 2 weeks on a tank of gas. If my kids are in session (which they are all but 1 month out of the year darn travel sports) then its a tank of gas a week sometimes a tank and a half.

When I had the motorcycle I used seafoam once a month. Miss my bike. had to fill her up every 4 days but a tank of gas on that thing used to be $8. Today it would be $3.

 

Any of you still having starting problems should change your plug and wires. Also clean the maf sensor and throttle body. A lot of times these 5.3 motors need new plugs when they start hard in the cold. Has not happened to my truck since I just replace the plugs at 80g but I've seen it many times. People try and follow the owners manual and change them at 100g and they just don't last that long in most cases.

 

Funny ive seen people drive 150k miles without changing plugs... Plus most don't have wires anymore.

 

There's still wires going from the coil pack to the plug. Last I checked there still calling them spark plug wires lol. I could be wrong if I am show me proof and I will change my wording from now on. And yes they "can" go 150000 miles but come on man. Do you seriously think there burning just as efficiently and as hot as they did on day onE.

Yea sure these plugs hav 150000miles on them my truck still runs. Drives straight down the road. Starts every day. So my plugs must be in good enough shape that I should not spend the 9$ a piece and replace the plugs. Nope there good

 

There's still wires going from the coil pack to the plug. Last I checked there still calling them spark plug wires lol. I could be wrong if I am show me proof and I will change my wording from now on. And yes they "can" go 150000 miles but come on man. Do you seriously think there burning just as efficiently and as hot as they did on day onE.

Yea sure these plugs hav 150000miles on them my truck still runs. Drives straight down the road. Starts every day. So my plugs must be in good enough shape that I should not spend the 9$ a piece and replace the plugs. Nope there good

what part of my post says "your truck runs good until 150k on those spark plugs"? My point was they run all the time over 100k and still function. I replaced my wifes spark plugs (not coil packs) at 106K. Not because I wanted to wait that long but because I am not exactly someone that has all kinds of time to do things. There was no noticeable difference in how the thing drives.

They don't have spark plug wires. Its called a spark plug and coil pack. The wires going to the coil pack are just normal electrical wire.

http://www.ebay.com/itm/like/1814219055 ... ps&lpid=82

The link is for reference only. This is what most newer vehicles now have.

 

Hmm my 2011 5.3 has these
http://m.ebay.com/itm/Spark-Plug-Wire-S ... nav=SEARCH
I believe those are indeed "spark plug wires"