MAF cleaner?

[Cheyenne]

My daily driver is a 98 Yukon that we bought in '04. It has about 160k on it and we are the 2nd owner since new. It has a starting issue that it doesn't seem like its getting enough fuel and has a low idle when first started. When I try to start it, if I give it a little gas, it does seem to start a little better but still cranks over too many times. Over the last couple of years, I have replaced the fuel pump, filter, TPS, IAC, temp sender, dist cap, rotor, plugs, and another sensor that is between the air filter and throttle body and cleaned the throttle body but not the MAF.

As I said, I have NOT cleaned or looked at the MAF and wonder if I can clean it with either throttle body cleaner, carb cleaner, starting fluid, acetone, or brake cleaner. Some of the utube videos say to use only something specifically for the MAF. I'll have to go buy some if that's the case. Thanks.

 

[Doubeleive]

yes there is a aerosol can of maf cleaner sold at many parts stores

 

[1BADI5]

Only use MAF cleaner on your MAF............or you might be buying a new onw

 

[swathdiver]

You need this:

https://www.walmart.com/ip/CRC-MAF-Throttle-Body-Single-Use-Twin-Pack-1-Kit/36755294

When BlackBear did my tune, he asked if I'd ever cleaned the throttle body, the plate was at 7-8% at idle. I had not. Eventually got around to buying this and eventually got around to cleaning the MAF and Throttle Body. A couple weeks later my throttle plate is now 3-4% at idle.

 

[1BADI5]

I'd recommend removing the throttle body to clean it correctly

 

[Cheyenne]

That's on my list when the weather gets back in the 50+ degree range. 40's just a bit too cool to mess with it.

 

[iamdub]

As others have said, use MAF cleaner on it.

For the hard start issues, I'd suspect a leaking regulator or failed prime valve in the fuel module as they are both common issues and present similar symptoms. The failed prime valve is especially common with aftermarket fuel modules.

Turn the key on (not start) then off then on a couple of times before turning it to start as usual. If it starts much more quickly or even like normal, then the problem is likely the primer valve. Hooking up a fuel pressure gauge to confirm would be the next step.

If the regulator is leaking, the fuel system loses it prime just the same, only the fuel is leaked into the intake manifold instead of back into the fuel tank. This essentially floods the engine upon startup. When you say you "give it gas" (pressing the pedal), you're not actually giving it gas (gasoline). You're giving it air. This extra air helps to lean out the mixture to help the engine run well enough until the extra fuel is burned off and the fuel/air mix can be monitored and adjusted by the PCM.

 

[east302]

If the regulator is leaking, the fuel system loses it prime just the same, only the fuel is leaked into the intake manifold instead of back into the fuel tank.

@iamdub

Hey,

I have a question on how these leak.

In the regulator, can fuel only leak into the top chamber where the spring and vacuum port are (and then spill out into the intake) or can it also leak into the return line - the diaphragm seal either being damaged or the spring not holding it seated so it never really closes with spring pressure and bleeds past into the return.



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[RED TAHOE LS]

That's on my list when the weather gets back in the 50+ degree range. 40's just a bit too cool to mess with it.

Just curious, is your avatar Camaro a real DZ engine car ? Years back I had an original 68 RS MO engine Z 28......MISS IT.
David g...........

 

[iamdub]

@iamdub

Hey,

I have a question on how these leak.

In the regulator, can fuel only leak into the top chamber where the spring and vacuum port are (and then spill out into the intake) or can it also leak into the return line - the diaphragm seal either being damaged or the spring not holding it seated so it never really closes with spring pressure and bleeds past into the return.



Sent from my iPhone using Tapatalk

How/where they leak I don't know for sure. I personally have never dealt with a leak but I know where the regulator is (inside the IM) and a leak there would dump fuel into the plenum. If the regulator was just leaking the fuel into the return, then this would cause a loss of prime, but not flood the intake with fuel.