fuel pressure to injector pump

My Passat has been lurching and sometimes quitting lately and I've noticed the clear supply line to the injector pump from the fuel tank is not full when it's running-almost looks like air in it but most likely a weak stream. Is that normal for a 96 and what pressure should the supply pump be delivering at the injector pump? Is there a port on the injector pump that I can check supply pressure? Filter is new.

Is the thermostatic T yellowed and old? If so, it's also probably crackjed and in need of replacement. Don't worry too much about the o-rings on the filter. They are new, every time you change the filter.

Tony

Your Passat does not have an external fuel pump. Your injection pump has a vane pump inside that sucks the fuel from the tank so everything before the IP is under vacuum. You have an air leak somewhere. Most commom spot is the thermo-tee in the fuel filter.

I'll check that out.thanks.

That tee is black but i don't see any leakage unless it just leaks air in under vacuum. It has the permanent clamps so should I just replace it or better still bypass it since the 5th injector has been eliminated?. Wouldn't an air leak anywhere outside the tank leak fuel out and at least show a wet spot?

50harleyrider said:

Wouldn't an air leak anywhere outside the tank leak fuel out and at least show a wet spot?

Click to expand...

It wouldn't necessarily leave a wet spot. You are more likely to see bubbles in the clear fuel lines.

Tony

I'll go ahead and replace it. Where is the best place to buy one? Are all years the same? What is the best location to vacuum the air out of all the lines and the IP? I hope the IP isn't damaged.

IP life is hard to measure. Generally if you are getting IP related codes, particularly for the QA, it likely need to be replaced. But, that's after trying a LOT of troubleshooting.

For the thermostatic T, try the following:
idparts.com
worldimpex.com
1stvwparts.com
metalmanparts.com

Tony

I got my thermo-T from Idparts and a bosch fuel filter from another vendor. When was fuel filter last changed? GL

Filter is new. Corey doesn't show in his IDPARTS catalog but I'll call him

There are different thermostatic "T's" for different fuel filters. I had a crack on mine once and had to replace it...about $25 from World Impex. Just give your vendor the fuel filter part number as well as the year, model, vin and build date of your car to get it all matched up....never assume the right filter or "T" is in there already!

Thanks for all the help. A simple tightening of all the worm gear clamps stopped the air leak. Now back to my limp mode issues...