Be careful when doing the LCR Mod on your PD lift pump... Use stiff tubing

Be careful when doing the original LCR Mod on your lift pump... I did this and ended up with some major power loss and studder issues.. I chased this problem for a long time... Was thinking at first something wrong with the tune, then with the fuel filter, then the lift pump.. was even considering changing out the injectors and the injector harness.. .Turns out the problem most likely was the kink in the green hose I installed ...

When I changed out the PD lift pump with an new unmodified Lift pump, the problem immediately went away.

After my initial test drive with the new lift pump, I examined the just removed LCR modded lift pump and I believe I may have identified the cause of the studder... A kinked hose ...When I first put this lift pump in, I did the original "LCR Mod" to it... i.e. added a check valve and bypass circuit in case the pump went bad ... however by looking at the green hose I have there, it clear that there is a good kink in it. Hose may have not long enough or not stiff enough.

Bottom line... If you do this mod, be careful how you run the tubing... Make sure you get stiff enough and long enough tubing so it will not kink. ...

DanG144 shows the tubing running much longer on his Lift pump mod DIY than I did mine so that method would be much better IMO. Mine was based on the original LCR mod and It was fine for a long time and I think the tubing originally kept it's rigidity and smooth trajectory. My theory is that over time, it got weaker and instead of staying stiff and making a smooth flow, it kinked and caused a major fuel flow restriction.

P

What improvemts does this mod to the pump make??

If the pump fails it stops it from cutting the fuel
Not all lift pumps need this mod I believe?

Right, this mod is only needed if you have the "new style" pump, and then only if you wish to have the backup limp home ability to pull fuel through the assembly when the electric motor fails.

BEW style lift pump thread, with links to Left Coast Resident's mod thread.

New style lift pump with mod completed

new style lift pump with mod completed

Original style lift pump

original style lift pump

I think a much superior way to handle this is to replace the electric motor for the original lift pump, with the (presently $90) one from the TDIWAGONGUY. He supplies hard plastic corrugated hoses that will never fail.

replacement electric motor/pump that goes inside the BEW lift pump assembly

replacement electric motor/pump that goes inside the BEW lift pump assembly

Though I must admit, I have YET to see the new style pumps fail at all, and they have been the only ones available for years now.

I would add as well to use a very high quality hose clamp with a rounded edge (if you use hose clamps) on them, as the VITON material is not tough and the slightest nick will cause it to crack and break. I had one cut itself on a sharp edge of the original plastic barb, where I had cut the original hose off and raised a ridge, and I have had one cut itself on a cheap style hose clamp. Good quality hose clamps

The hose you use is always the weak link in the project, as far as I can tell. It tends to crimp or simply break off. though it is an elegant idea, and a sound idea, weakness in execution (even using the best materials I can presently locate) make this questionable to do. I am concerned that we actually reduce reliability, rather than increase it.

I have had three lift pump mods fail that I am aware of, but I am not aware of any new style lift pump failures.

thank you Pierre and DanG for this info. I was going to start collecting the parts for the mod, but I think I'll just throw it in as is.

Now, to collect the wiring parts, since the 'kit' from idparts cost went through the roof after VW jacked up the prices..

kiva822 said:

thank you Pierre and DanG for this info. I was going to start collecting the parts for the mod, but I think I'll just throw it in as is.

Click to expand...

+1 Thanks you two for the info. I did the LCR mod to the lift pump I installed in my previous Golf, which got totaled, so I never got to see if the mod was worth it or not. Like kiva822, I will just throw it in there as is if I add a lift pump to the current Golf.

Why not just use some high quality fuel line hose for the bend around in the pump? It's available at most auto part stores and it shouldn't collapse under strain.

Only real disadvantage is price, but for the peace of mind it might be worth it. Anyways you don't have to do the whole thing in it just along failure points/bends, curves, kinks, etc.

Fuel hose kinks with the tight bends, and most of it is not rated for being immersed in fuel. You might be surprised at what happens to a hose put in diesel or B5; biodiesel is an entirely different animal.

Check the hose chemical ratings. VERY few hoses are rated for both diesel and biodiesel.

If you can come up with a method that works reliably (mod failure rate should be lower than base fuel pump failure rate by 50% or more), then please share it. Several of us have had decent success, but I still think we likely raised the overall probability of failure too much.

I have several years and tens of thousands of miles on my PD pump with the LCR mod and haven't seen any issues whatsoever. I did use a long section of line for the curved part. I think I'll pull it out and check it just in case (once my tank gets lower) but I don't think it's restricted at all.

Reviving this thread,,, I have always been curious if the lift pump installed in an alh either external or PD, work continuously once you run your engine why not just hook up a wire directly from IP solenoid to the pump instead of doing all the hook up wires going through a relay?

Don’t rob voltage from the solenoid or it may not open fully

ok thxs Justin it was a curiosity only I have always used relays when wiring these suckers

The long answer is the the gauge of wire running do the OE solenoid is spec'd only for the current to drive that relay. If you draw a higher load on that same gauge wire, the voltage drop from the wire's resistance causes less power to be able to be supplied. Since the solenoids are voltage devices, if that voltage drop is too great, the solenoid can/will malfunction.