3 Things to Check if You Have a Cold Start Rough Idle (2023)

Introduction

Welcome!
Here are the parts I used in this video:
Delphi MAF Sensor: amzn.to/3X366kB
Map Sensor: amzn.to/3ZpZvSO
Intake Manifold Gasket: amzn.to/3k1R9jX
OBD2 Reader: amzn.to/3ZuCOwU
Throttle Body Cleaner(might be cheaper in the store): amzn.to/3GXnBgw
Fuel Line Remover: amzn.to/3ZwMLdk
Torque Wrench: amzn.to/3QwFdD6
Orange Grip Mats: amzn.to/3ZmBCvv

I have a Patreon and I would love your support: www.patreon.com/BuildsUnited
You'll have behind the scenes access and more!

Check me out on IG: instagram.com/buildsunited_

I have a website:
AutoMotoNation.com

#BuildsUnited

Disclaimer:
Due to factors beyond the control of Builds United, I cannot guarantee against improper use or unauthorized modifications of this information. Builds United assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. Use this information at your own risk. Builds United recommends safe practices when working on vehicles and or with tools seen or implied in this video. Due to factors beyond the control of Builds United, no information contained in this video shall create any expressed or implied warranty or guarantee of any particular result. Any injury, damage, or loss that may result from improper use of these tools, equipment, or from the information contained in this video is the sole responsibility of the user and not Builds United.

Furthermore, the links posted within the description may or may not contain affiliate links. If used, I trully appreciate the support!

Content

Welcome back to another video.

The Tahoe has been having a rough cold star Idol today.

We are going to figure out what's going on with it.

So first I got a new map sensor.

So how was it old? And in with the new with the map sensor housing, we moved, you got to get a thin flat head.

And your goal is to pinch this tab within the little sliver in the MAF sensor housing.

And at the same time as you press down on that latch, you want to go ahead and grab some sort of pliers and pull the sensor out.

And it should come right out, although faulty map sensors are very common and causing a rough eyewalk.

Hold starts.

That was not my issue.

Here.

I spent a lot of money on that map sensor from Advanced Auto.

So the next common issue would be the map since it going bad.

Luckily, there's a cheap option off of Amazon, it's located, right on top of the manifold.

So since Stone Parts had it didn't fix the issue, let's, go ahead and figure out what the heck's going on to do that.

I grabbed my OBD2 reader, plugged into the OBD2 spot I'm just going to turn the key to accessory.

Because as soon as the engine warms up, I will not have the symptoms anymore.

I'm gonna take my phone out open up the car scanner app connect to the unit I want to check out the live data I'll be checking out the fuel trim levels.

So these numbers should be as close to zero as possible I'm, getting diagnostic because of having won a misfire.

And it is running lean so I'm, assuming it's a vacuum link.

So to test a vacuum link, we got some fluid I've seen people use brake, cleaner, fluid and I'm just going to use air intake cleaner.

So I am spraying where the intake manifold meets up to the block of the engine.

And watch these short-term fuel.

Trim level bank, one go down to zero as I spray it.

So I know, for sure that there's a leak on bank one on the driver's side of the intake manifold, so then I proceed to try out the left side or Bank two.

And we got the same results.

And just like that we have found out that there was an intake.

Manifold gasket, leak got the Tahoe in the garage just received the gasket.

And we got Layla, hey, what's up.

Remember that map sensor? Well, we are going to move that.

Oh, yeah, don't forget to unplug.

The battery the map sensor the vacuum line.

You have an eight millimeter.

Now we need a trim remover tool.

This will just come right off unplug.

The throttle sensor remove the power from the alternator.

Now, this plate, which just unscrews be sure to organize all your screws, because if not and you lose them that would suck get a quick puppy break tab on the back is pull up and you lift up.

Now we need to remove the fuel injectors, that's, four on both sides.

So you just pull up comes right out.

Remove the brake, booster clamp and its hose.

We now need to move this fuel line right back here, you can move it with these plastic pieces.

Or this metal tool is ours, seven zero.

Zero, two, four, this line will be pressurized.

So heel will come out.

So in order to release the pressure, we will come on the left side of the engine.

Take off this.

You want to get a flathead and just press that nipple down the drive is gonna be soaking with gas.

Do not give it to your dog instead, put it away to pull it in and press this tool in you just it'll just slide in, oh, there's still fuel on it.

Do you remember that scene and saw where the girl had to get the key and like this little metal box, and she like stuck a hand through the box and her hand got stuck.

This is basically the same mechanism, except you don't lose a hand if you aren't smart enough to move your hand.

And now we can push all this wiring behind the intake.

Now we have these bolts holding down to intake, they're, essentially all around grab eight millimeter and start removing them.

The ones in the back is kind of tight to get to so you will need a smaller wrench this two way back here on both sides.

So it's gonna be here, hey, squeeze once you break them loose do them by hand and there's one more way back there, that's, the tightest one on the left side to get to far back the plug right here lift at the back it'll, be pushed right out push that through see push down on this lock.

And you pull back that's, at least what the pros say, thank you.

And now it's time to wiggle out the intake, manifold can anybody tell why I had an intake manifold leak when I replace the motor I, just didn't, install it correctly, I know how to install it now and I'll show you, you can definitely tell I've been running lean for far too long.

That means I'm getting too much oxygen compared to how much gas I'm getting.

And you can really tell with the carbon buildup around the uh, the inlets of the heads, the intake Parts holes for the air for the heads head air, head air holes.

We can go ahead and take out all the bolts you just kind of throwing them sideways and come out so don't, lose them.

Just go ahead and clean these surfaces as well.

This is how you properly install an intake gasket.

It literally Clips in wow, isn't that magic.

Why did I not know that when I installed it? The first time this would be a good time to clean these throttle body, I'm gonna use my throttle body cleaner that I use to test the intake, manifold gasket leak.

And now with all that finished, we can sew that sucker back into the engine on the engine on the engine and I'm not going to show you the whole process just do everything in reverse.

And with the proper torque specs on the intake manifold, because if not you can mess things up, so also look up the right crisscross pattern that you'll need to do when you're installing the intake manifold.

Okay, I'll show you the crisscross pattern because I'm a nice person.

Well, I guess, I forgot how an LS should idle, because that definitely sounds a lot more healthy.

So that is hell.

You fix a Refinery I recommend checking the intake first with the test that we did look at those numbers, make sure they're around zero.

If they're way too high, you have an issue because I just simply did not install the intake, manifold gasket correctly, I mean, that's an easy mistake, isn't it.

Everything I use in this video will be linked down below for your convenience.

A rough idle, especially at cold, start can be pretty finicky to diagnose.

But those are three things that you can do to try to fix your rough idle.

Thank you to all my patrons for supporting me.

This is Chris Bill's night.

It always appreciate and respect.

Another I'll, see you in the next video in the next video we are going to detail the Mercedes is filthy and replace a few parts to finally register it.

So I can drive it on the road.