Hot Weather Fuel Cuts

1K0 919 051 CL

Since the weather is getting warmer again, some of the older MKV’s may begin to experience failure/overheating of the low pressure fuel pump.  I had this problem last summer. This issue often comes up in hot weather and long distance driving.  The low pressure fuel pump begins to overheat and then cuts out, starving the high pressure fuel pump. Acceleration is completely cut and you have to pull over or slow down.

If you’re experiencing fuel cuts in the heat or during long distance driving, take a look here for some more information. You may need to replace your in-tank fuel pump with the latest version.

Intermittent Fuel Cuts – Low Pressure Fuel Pump

August 17, 2011 Update: 

It seems that the CL part number has now been superseded by 1K0 919 051 DB. I don’t know what the changes are or if the change was spurred by a problem with the CL number. Info from this thread.

As the 5th generation cars begin to age in the U.S., a couple of newer problems are beginning to rise up.  One really annoying problem is the low pressure fuel pump cutting out intermittently.  It leads to the high pressure fuel pump starving of fuel and then the engine loses power for a few seconds.  Utterly annoying and it can be dangerous if you’re traveling at a good rate of speed and happen to slow down in the far left.  It can be difficult to get onto the shoulder.  It tends to happen during a long drive in hot weather.

A newer updated pump (Part Number : 1K0 919 051 CL) is supposed to help with this problem.  This is not located in the engine bay, unlike the high pressure fuel pump.  This one sits underneath the rear seats.  It is easy enough to replace and there are a few DIY’s floating around.  Here’s a good one from the Golfmkv forums – In-tank fuel pump replacement has the best price that I’ve seen so far at $180 dollars plus shipping.

Before changing the fuel pump though, you might want to check whether your thrust sensor has been updated to the latest revision.  This sensor sits on the passenger side of the high pressure fuel pump.  06E906051K is the part number for the newest thrust sensor revision.  If this solves your problem, you’ll have saved around 120 dollars.

06E906051K Thrust Sensor

Post Weekend Updates – Brakes, Sensors and Fuel Pump Edition

I finally got some time to work on the car this weekend.  I was able to do install the speed bleeders, do full flush and bleed with ATE Superblue fluid and finally install the thrust sensor.

Some strange findings on the thrust sensor – I took of the old one only to find out that it was already the updated version.  Dammit.  I hope it was on it’s way out or something.  If you didn’t know already, I was having fuel supply issues on a long trip.  Read all about it here…Click me! I won’t find out until I take another long trip in the heat.

The problem seems to be cropping up in the forums a little more, so at least I know other people have experienced the problem.  There’s still very little information on exactly what is going on.  If anyone knows anything, leave me a comment!

About the speed bleeders… (SB1010S)

They worked perfectly!  That was probably the least trouble I’ve had with bleeding the brakes.  Granted, it would probably be even easier with a pressure bleeder.  These turned out just fine but if you want to spend just a little more, you can get the pressure bleeder and be able to use it with multiple cars.

The ATE Superblue brake fluid is helpful in determining whether you’ve flushed all the old fluid out of the system.  The fluid is, you guessed it, blue.  Once the fluid coming out of the bleeder is blue, you know you’ve flushed all the old crud out.  ATE has an amber colored fluid that you can alternate between flushings to help  you determine if you’ve flushed the Superblue out of the system.  Same specs, just amber.  It’s called Type 200 I believe.  The ATE fluid is a little pricier than store bought but the specs are excellent for a daily driver; 536 degree dry boiling point and 396 wet.

I also re-lubed all the caliper and pad slide points.  I opted to use high temp grease for the back of the pads instead of the tacky silencer stuff.  It might help the pads shift around when they need to instead of tacking them in place.  I’ve been getting an annoying squeal for the past few weeks despite the pads being good still.  Hopefully the the grease will allow the pads to move just enough to eliminate it.  So far so good.

I also did a quick cam follower check to see if anything out of the ordinary, glad to report that after 30,000 + miles on the 2nd cam follower, the DLC coating is barely starting to show some signs of wear, and this is on APR stage 1 software too.  Sweet!

Bah, Sensor Issues!

I took  a trip to Las Vegas recently, (where I promptly lost money) and on the way there, I finally experienced one of the joys of owning a Volkswagen, a beautiful check engine light.  It was glowing, there in my dash, taunting me with its haunting beauty.  (Somewhat long winded story ahead, cut to the chase by scrolling down)

Well, the damn thing started kicking and bucking as I was headed down I-15, maybe 30 miles or so from Primm (now renamed Terrible?)  I couldn’t accelerate smoothly, the throttle wouldn’t respond and the engine just cut out intermittently.  Quite annoying when you’re trying to make it to the side from the fast lane.  I should mention that it was about 106~107 degrees or more outside, that’s really the only time it started doing this.  Basically no throttle and minimal power.  I couldn’t pass this big rig going literally 30 mph without the power cutting.

Anyways, I limped to Primm and was able to let the car cool off.  I needed to scan the car, thankfully I brought a netbook along.  Low pressure fuel codes come up.  Usually it means your fuel pump / follower has gone off the deep end, but I know mine is in good condition.  Another problem that will bring up a low fuel pressure code is the thrust sensor, located right off the high pressure fuel pump.  It’s almost certainly this pos sensor that caused me so much trouble.  There is a TSB out for it so they should fix it under warranty, unless the TSB expired already or you’re out of warranty.

Anyways, once the temperature cooled off a bit, the car never acted up again, until the ride home, where it started losing power around the same area.  Again temps seem to have played a role in this. It was fine the rest of the way.

Short Version:

This is the updated sensor’s part number: 06E-906-051-K

If this sensor isn’t reading correctly it may cause a low fuel pressure code to be set and it may also cause a check engine light to be set off.  You will know if it’s acting up because it will essentially cause a fuel cut.  Very unpleasant feeling I must say.

It is screwed right into the side of the high pressure fuel pump.  I’ll get a picture up when I get the part in.  It is around 36 dollars plus shipping from online dealers and I hear around 50 straight from the dealer.