Excessive Cranking/Transmission Issue

[MackAttack]

Hey guys, Mack again with more problems with his truck haha

I have a 2009 Chevy Suburban with 164,500 miles, and I’m having a couple of issues. Issue one I am having is with her cold starting. Every morning when I start her, she cranks like crazy for Atleast 8+ seconds, starts a tiny bit, then dies again, while shaking like hell. Rinse and repeat 2 times and we’re in business. After I start driving though, I could feel the car shaking back in forth as if it’s struggling for fuel for a little bit, then it’ll fix itself and it will start right up normally if you start it within an hour. Do you guys think it’s a fuel pump?

Second issue I am having is that when I am coming to a stop, I can feel something a little to the front of under me going “clank”/“clunk” paired with the car feeling like it was slightly rear ended. Sometimes I’ll just hear the clank with no shaking. In my honest opinion, it sounds like The transmission is downshifting too late. The reason for me thinking this is when I take my foot off the gas while driving, and put it back on, sometimes the car will Snap/Jult forward and snap your head back, I think it might be in a higher gear than it should be. I just serviced the trans fluid about 3K miles ago

Please help! Mack

 

[strutaeng]

On your first question: please purchase a fuel pressure gauge and hook it up to see what pressures are. It's the only way to determine if it's a fuel delivery problem.

The nicer gauges have a long hose you can tape to your windshield and see what the pressures are while driving and engine under load.

Sounds like you are starting to have transmission problems as well. :-(

 

[OR VietVet]

The first problem sounds like classic examples of fuel delivery problem. The long crank part sounds like a fuel bleed off, either by the pump or a leak somewhere, like an injector. Need to get a fuel pressure gauge attached and with a long enough hose, bring out the back of hood and tape to w/s and watch the pressure while driving.

The second problem does sound like a transmission problem but hopefully a transmission tech will chime in. @rockola1971 or @NickTransmissions .

Question, did both these problems start happening at the same time?

 

[MackAttack]

On your first question: please purchase a fuel pressure gauge and hook it up to see what pressures are. It's the only way to determine if it's a fuel delivery problem.

The nicer gauges have a long hose you can tape to your windshield and see what the pressures are while driving and engine under load.

Sounds like you are starting to have transmission problems as well. :-(

Alright awesome OMW to auto parts shop right now. Which brand do you recommend?

 

[MackAttack]

The first problem sounds like classic examples of fuel delivery problem. The long crank part sounds like a fuel bleed off, either by the pump or a leak somewhere, like an injector. Need to get a fuel pressure gauge attached and with a long enough hose, bring out the back of hood and tape to w/s and watch the pressure while driving.

The second problem does sound like a transmission problem but hopefully a transmission tech will chime in. @rockola1971 or @NickTransmissions .

Question, did both these problems start happening at the same time?

That was something Chevy told me a while back, but they wanted 350$ just to look at it, and god knows how much to fix it. The fuel pump issue started maybe 2 months ago. The transmission acting out was about around the same time, if not maybe a month older? When I first bought the truck from my father in February, I had complained that when I shift from P to D, the car jults sometimes. It has just gotten progressively worse, and now the issue that was concerning me was that it’s starting to act up while driving

 

[strutaeng]

Alright awesome OMW to auto parts shop right now. Which brand do you recommend?

I've had a few of the ones from the local parts store, but the short hose eventually deteriorates and leaks.

Last one I got was the HF Maddox brand with the longer hose. I haven't used it much, but seems decent. IIRC it's like $50. Money well spent for diagnostics.

 

[MackAttack]

I've had a few of the ones from the local parts store, but the short hose eventually deteriorates and leaks.

Last one I got was the HF Maddox brand with the longer hose. I haven't used it much, but seems decent. IIRC it's like $50. Money well spent for diagnostics.

Alright awesome I’ll grab that puppy. I’m a Atv mechanic hobbiest so I’m sure I can use it for my off roaders as well

 

[MackAttack]

About the tranny, how hard would that be to fix? I know transmissions are no joke to disassemble lol. I believe I have a 6L80 since that’s what came standard with these guys. I have a few friends that own shops, but I doubt any of them can do such complex things like transmissions

 

[iamdub]

No CEL? Does it have any modifications at all? K&N drop-in filter?

The problems could be related, and an electronic issue at that. A quick/free test would be to unplug the MAF sensor and see if there are any changes to the symptoms.

 

[MackAttack]

No CEL? Does it have any modifications at all? K&N drop-in filter?

The problems could be related, and an electronic issue at that. A quick/free test would be to unplug the MAF sensor and see if there are any changes to the symptoms.

as in modifications to the engine, there is nothing. I just replaced the water pump, thermostat, thermostat housing, radiator, all fluids, coolant temp sensor (which I have to replace again since it is freaking out on me). If you mean aftermarket, everything is about the same except for the inside of the truck. No check engine lights, Zero rust on any surface of the truck (California vehicle it’s whole life) not even a tire pressure light. I can ask my friends who work at orilleys which I’m about to go to to run a OBD2 Port scan

Edit: I meant to mention, I do have aftermarket electrical systems inside the truck but nothing aftermarket with any mechanical parts of it. I have a high end audio system with subs head units speakers amps but It has nothing to do with anything with the tranny or anything. Chevy refused to look at my truck when I brought it in for a whining sound lol. They’ll sell you a new truck but they won’t fix the current one haha