Hot start issues with Codes P2177 and P2179 - FIXED

e28jay · #1 02-23-2015, 02:45 PM

FIXED SEE LAST POST. Faulty Hengst fuel filter.

Hi Guys,

I've been battling a hot start issue with codes P2177 and P2179.

When the car is cold it starts fine. Once it is hot, the car just cranks and cranks with no start. I then turn the key off for a few seconds, try again and it will crank for about 5 seconds, then fires up. Idles a little low for a few seconds and then starts to idle fine.

I've replaced the fuel pump, fuel pump relay, fuel filter, cleaned the MAF and the throttle body this past week. Can't see any obvious vacuum leaks. Hose and clamps for the MAF look prefect. Still have the problem. Any other suggestions?

Thanks!

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upallnight · #2 02-23-2015, 03:14 PM

Instead of throwing parts at the problem you need to do some investigation as to what is the problem. P2177 and P2179 mean you have a lean off idle condition. A lean condition can be caused by a bad fuel pump, clogged filter or a vacuum leak. I would determine what type of fuel pressure you have at the fuel rail when you turn the key on without starting the engine. You should be in the neighborhood of 45-50 psi. If you have this type of fuel pressure I would look at a vacuum leak, possibly from the pressure regulator to the engine.

Hopefully when you replace parts you buy decent parts and not cheap parts off eBay or Amazon. There's a reason why the parts are cheap, they don't have a QC program so all their parts made are sold, none are rejected

e28jay · #3 02-23-2015, 03:32 PM

Quote:

Originally Posted by upallnight

Instead of throwing parts at the problem you need to do some investigation as to what is the problem. P2177 and P2179 mean you have a lean off idle condition. A lean condition can be caused by a bad fuel pump, clogged filter or a vacuum leak. I would determine what type of fuel pressure you have at the fuel rail when you turn the key on without starting the engine. You should be in the neighborhood of 45-50 psi. If you have this type of fuel pressure I would look at a vacuum leak, possibly from the pressure regulator to the engine.

Hopefully when you replace parts you buy decent parts and not cheap parts off eBay or Amazon. There's a reason why the parts are cheap, they don't have a QC program so all their parts made are sold, none are rejected

Thanks for the info!

The parts I was replacing were all things on my preventative maint. list anway, we've been slowly chipping away at them. Just bought the car last month so we are going through everything eventually.

I'll need to pick up a fuel pressure gauge. Harbor freight time! Thanks.

upallnight · #4 02-23-2015, 03:51 PM

Unless you want to be a mechanic or just like to own tools, you can rent a pressure gauge at Autozone, Pep Boys, O'reilly or Advance auto. Some offer a free loaner program if you are a good customer with them.

bcredliner · #5 02-23-2015, 03:58 PM

Quote:

Originally Posted by upallnight

Unless you want to be a mechanic or just like to own tools, you can rent a pressure gauge at Autozone, Pep Boys, O'reilly or Advance auto. Some offer a free loaner program if you are a good customer with them.

Autozone charges the cost of the pressure gauge that is 100% refunded when the gauge is returned in good working order.

bcredliner · #6 02-23-2015, 04:01 PM

Cleaning the MAF doesn't always work. Did you spray the wires that are somewhat hidden?
Try removing the MAF connection and see if the idle improves or at least changes.

e28jay · #7 02-25-2015, 02:32 PM

Quote:

Originally Posted by bcredliner

Cleaning the MAF doesn't always work. Did you spray the wires that are somewhat hidden?
Try removing the MAF connection and see if the idle improves or at least changes.

I tried disconnecting the MAF and it did not help.

I sprayed the MAF sensor pretty well.

I forgot to add that I had also replaced the fuel pump relay and it did not help the issue.

I'll be testing the fuel pressure this weekend and will post my results. Thanks for the suggestions guys.

bcredliner · #8 02-25-2015, 04:48 PM

Quote:

Originally Posted by e28jay

I tried disconnecting the MAF and it did not help.

I sprayed the MAF sensor pretty well.

I forgot to add that I had also replaced the fuel pump relay and it did not help the issue.

I'll be testing the fuel pressure this weekend and will post my results. Thanks for the suggestions guys.

The idle didn't change at all?

Doru · #9 02-25-2015, 05:06 PM

Fmugur, a member here had a similar issue a while back with his 1st e53. The injectors were leaking once the car was warmed up, and were flooding. Cold start no problem. Once the injectors were replaced, no more problems. PM him, see what he has to say.

fmugur · #10 02-25-2015, 06:29 PM

Yep, the injectors was the problem in my case but try to rule out the fuel pressure as these guys suggested although why you would have the right pressure when is cold vs. warm.
Can you find the exact pattern start vs. no start?
If you try to start the car within the next few minutes after it was stopped, will it still start?
I believe for mine it was around 20-30 minutes to flood the cylinders. The car would start almost with no issues during the first 20 min or so.

http://www.xoutpost.com/bmw-sav-foru...njector-4.html

The same discussion here:
http://www.xoutpost.com/bmw-sav-foru...d-weather.html

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