P0171 System Running lean

zippy83 · Post by **zippy83** » 03 Feb 2019, 19:01

HI All,

I am back hammering at this issue. So I took some carb cleaner again and went to town. From different angles spraying around the intake manifold I noticed that the engine wants to stall during the heavy spray. Please see video below.

[youtube] [/youtube]

So my question would be, shouldn't the RPM go up when I spray the carb cleaner (co-worker of mine told me I should see increase in RPM) if there is a vacuum leak?

Once I took off the intake manifold I was able to identify that some of the carb cleaner got in. I have some gaskets on order but I was wondering about my question above..

Thanks
Zip

Post by **RickHaleParker** » 04 Feb 2019, 11:43

Depends on the chemical composition of the carb cleaner you are using. Ether (starting fluid) is better for finding leaks in the intake system.

You video is not working, it will not play.

zippy83 · Post by **zippy83** » 04 Feb 2019, 12:10

I am not sure why it wont play on this site

here is the link

zippy83 · Post by **zippy83** » 05 Feb 2019, 07:30

I fixed the issue. Actually it was a bad gasket on the lower intake facing the cylinder head.
Off to the next issue...

KArthur1 · Post by **KArthur1** » 05 Mar 2019, 19:45

I have been chasing this same code. I build a DIY smoke generator. The only leak I found was where the emissions line plugs into the push-lock fitting. The fitting is right there on top of the intake between the mass air flow sensor and the firewall. The push-lock fitting is red. I sealed it with self-adhesive tape, but I still get the code from time to time.

This is the connection.

The bad gasket that you found, is it the one that you are spraying in the video? I think that is #5 intake (the one closest to the mass air flow sensor).

zippy83 · Post by **zippy83** » 05 Mar 2019, 20:32

The bad gasket that I found was on the air intake that faces the engine block. I was spraying the upper section which some of that cleaner got into the lower section and started to act up. The code went away and has not returned since.

In your case when the code comes back how long does it stay on?

KArthur1 · Post by **KArthur1** » 05 Mar 2019, 21:14

My code stays on until I clear it with my scanner. It will come back almost immediately. I am still trying to figure out where your leak was. Was it in # one or # two of this image.... or a different place? Can you point to it?

zippy83 · Post by **zippy83** » 06 Mar 2019, 06:40

Well in that case the code never goes away, the only reason it goes away is because you have cleared it manually but it comes back within minutes. You still have a leak somewhere.. Looking at the picture above mine was in the lower section. Your Air gets sucked in through the upper intake manifold (the big plastic peace) then goes through the lower intake manifold the (Iron made manifold) seen in this picture

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That connects to your engine block (against the cylinder head) In order to remove that peace you will need to carefully move the fuel rail out of the way so you can re-install the new gasket, if that's what's bad. you will also need to remove the Air Box and to remove the air box easier without braking anything I had to remove the vacuum pump as well. From the picture below you will also notice that I have removed the battery as well..

Put is all back together and here are some torque specs

Intake manifold (lower section, against cylinder head): Torque to 19 Nm
Intake manifold (upper section): Torque to 10 Nm

Also worth mentioning is that your lean condition could also be caused by clogged PCV system. Have you inspected the PCV breather hose that connects to the crankcase from the Oil Trap? Also while you have the lower intake manifold off you can inspect couple hoses that are in the area that could also be a suspect. No 1 in the picture bellow.. inspect that elbow and make sure it is not cracked anywhere. No2 in the picture is the PCV breather hose that goes from the Oil Trap to the crank case.. (mine is out of the way) Make sure that on the OIL Trap it's tight. there is a small hose clam on there..

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