2007 Chevy Suburban starting problems

[kmcrae1]

When starting vehicle after releasing key from the start position starter and engine contniues to turn over but does not crank. After 2 seconds engine and starter will quit turnover. Have to repeat several times before finally engine will run. I hear no nose out of fuel pump, No codes are set. Replaced battery and ingnition switch. What is causing the issue?

[Meccboy]

The truck continuing to crank is a normal condition. Most newer GM vehicles will continue to crank until it starts, or for 2 seconds after key release.
No fuel pressure is your problem. Will need to check for power at purple wire on fuel tank unit. This is the power feed to the pump.

[Brian]

I have a 96 Chevy Suburban K1500 Gasoline engine. My problem is when I'm driving and stopping around town, the engine will over heat, but when I put it in neutral and rev the engine really high, the temperature goes down. On the highway at a steady speed, it's fine. I replaced the thermostat, the water pump, and the fan clutch. I'm not leaking coolant. I don't know what to do next. Can you help?

[Tommyfan2]

You may have a headgasket problem. Idle the engine and look for bubles in the coolant. If there are, then one of the head gaskets is blowing compression into the cooliong system. Check the radiator for being partially restricted. Some areas would be warm, others hot.

[skmay01]

i just did a topend on my stock 350 suburban, now the engine runs hot when the thermostat is positioned properly , now have to run it with the thermostat upside down ... WHY???

[ProTech]

Well, first of all, putting the thermostat in upside down is basically defeating the purpose of the thermostat itselft. If the truck is running hot with the thermostat in the correct way, are you sure you just don't have a bad thermostat? Otherwise, if it ran at normal temperature before you did the top end work, I'd have to say it's something you did during your repair, or lack of repair so to speak. There is no real reason other than something being messed up. Maybe try a new thermostat, installed correctly, and see what happens. If it still gets too hot, you'll have to recheck your previous repairs.

[skmay01]

I bought the truck with a blown head gasket and full of stop leak. Repairs are by the book. I boiled the new thermostat to see if it was opening correctly, at full boil it opened only about an 1/8 th inch , it is a standard 195 degree t stat , could you tell me if that's typical or faulty?

[skmay01]

I'm also wondering what can go wrong with my gasket job , I'm not trying to be smart , but its a pretty easy job , definitely not my first repair ( or lack of repair ) I'm asking because it doesn't make since to me thermostats open when the engine gets to temperature , if its not opening enough its a problem, but thanks

[ProTech]

I'd be weary of anything that previously had stop leak added to the cooling system. That crap will do nothing but clog up cooling ports in the block and heads.

And there's plenty that can go wrong in an 'easy' gasket replacement....wrong gaskets, debris getting in somewhere, not a good enough cleaning of the deck surfaces, wrong torque specs, etc. Everybody makes mistakes, not saying you did that here, but it's always worthwhile to go over your work. Since I don't know your technical ability, I have to mention all the possibilities, even to the schmucks that can't fix a thing. And on that note, I do have to ask...you are installing the thermostat correctly right? Maybe you're putting it in backwards when you think it's the correct way, and vice-versa, which would obviously cause a problem.

All in all, you've probably got a crap motor.

[tirerob]

hi everybody, i have a 2008 suburban that has a problem at at startup. turn the key, wait for fuel pressure or not and start it will stumble and hesitate until its ran for a few seconds or the throttle is blipped. just yesterday it hesitated at the blip as well. this problem started immediately after installing our rebuilt lc9 5.3l flex(more on that in a sec) and seems to be getting worse. ok..heres whats been done.

as stated, 08 of 07 suburban, 5.3l lc9 vin3 flexer. magnacharger on top, retuned(by magnacharger)ecu/tcu, so no tuner pod. the engine was rebuilt at 144000 because of failed ringlands amazingly enough the cam and lifters were fine, although new now. the factory pistons were replaced with 9.75-1 forged manley pistons and the rotating assembly has been balanced. runs smooth like no chevy i have ever owned, and there is a few. since no cel''s and seems to be a progressing issue there are two things i have been considering.

currently it on key on, fuel pressure is 55-57psi. 60 max on startup but holds 55 running.
bleeds down 20 psi in two hours. over night its down to 25ish

case reset. i havent had this done(didnt know...) all the sensors on the block are new.
fuel pump. booo...but the suburban set with the fuel lines open and dry for probably two months or so while we waited for rebuild and me to finish the install.

there also has been a occasional puff of smoke from the tail, but its a brand new build. if it didnt use a bit of oil id be worried more lol. bout a quart every 1500. well...1-1.5 every 2k id guess. damm thing gets 17-19 on the highway with cylinder dod deactivated hahahha

thanks for the help in advance! also i have a brand new ac delco fuel pump sitting on the shelf, ouch but its ready. i also have a fuel pressure gauge on the rail right now. can post pics and video if you need it! thanks!

[carriedi]

you're probably going to need a scanner with data stream capability. Scan the data stream when you first start it up and see how things are reacting. Idle air control, fuel trims, bad O2 sensor, map sensor, vacuum leak, temp sensor...

coil acting up, plugs or wires going bad...

when you first start up and the engine is cold it puts a bigger load on the ignition system. So the spark will look for an easier path to ground.

If you have a scanner that can graph the cylinder misfires, that may help see if the rough running is tied to certain cylinders. Maybe check mode 6 info.