Fuel Filter Screw Up

[tytypetersen]

I changed out the fuel filter and steel gas and return lines yesterday. Put the filter in the right way but connected the return off the tank to the feed on the filter and connected the feed off the tank to the return. Stupid mistake.

Tired to start the car but off course it wouldn't. Found the error and corrected it.

It started but has a rough idle and hesitates. Check engine light is on. Had an extra fuel pressure regulator and swapped it out thinking that the fuel flowing up the return may have damaged it. Still hesitates and has the check engine light. Don't have a code reader.

What did I bust? Any ideas?

Thanks

[bmwguy325is]

You may just take it and drive it and clear its throat

[jlevie]

While you might have damaged the filter by connecting it backwards, that would have a greater effect when driving than at idle.

It is always a help to know what car it is, in this case specifically if it is one that has the fuel filter in the engine bay as opposed to it being under the car on the left rear. If the filter is in the engine bay my guess is that you've introduced an intake leak while changing the filter or disturbed a connector

[tytypetersen]

It's an 88 325is. Fuel filter in front of the rear driver's wheel.
Thanks!

[DaButt]

It is always a help to know what car it is, in this case specifically if it is one that has the fuel filter in the engine bay as opposed to it being under the car on the left rear. If the filter is in the engine bay my guess is that you've introduced an intake leak while changing the filter or disturbed a connector

Jim, can you speak to this point a little further? I just replaced my fuel filter and it was under the car, left rear. PO had some tiny little NAPA auto parts filter in there. Guy at the DIY place I go to (who used to have the same car- an 85 eta, mine's an 84) told me the PO's fuel filter was in the wrong place. Pointed to a housing underneath the brake reservoir, etc. and said that's where my new one should go... I guess the filter would have fit in the housing.

Not fully trusting him or the Bentley, I replaced it under the L/R as the Bentley states you should.

Did I screw it up?

[u3b3rg33k]

I put a lot of faith in what the vatozone experts have to say.

[tytypetersen]

Ran the car and after about 20 minutes the Check Engine light went out. Still the idle is is a little off. It pulses a little between 500 and 750 rpm. Going to drive some more and see if this clears us as well.

Thanks the help.

[jlevie]

Jim, can you speak to this point a little further? I just replaced my fuel filter and it was under the car, left rear. PO had some tiny little NAPA auto parts filter in there. Guy at the DIY place I go to (who used to have the same car- an 85 eta, mine's an 84) told me the PO's fuel filter was in the wrong place. Pointed to a housing underneath the brake reservoir, etc. and said that's where my new one should go... I guess the filter would have fit in the housing.

Not fully trusting him or the Bentley, I replaced it under the L/R as the Bentley states you should.

Did I screw it up?

While most cars have the fuel filter under the car just forward of the left rear wheel, some early production cars had the filter in the engine bay. Those don't have the filter bracket under the car. I assume your did in which case you did it right.

[DaButt]

While most cars have the fuel filter under the car just forward of the left rear wheel, some early production cars had the filter in the engine bay. Those don't have the filter bracket under the car. I assume your did in which case you did it right.

Actually, there's no bracket where I replaced the filter. There's a pump just above it, in its bracket. I mounted the filter just below the pump. Like I said earlier, that's exactly where the PO had his crappy little NAPA auto parts filter mounted.

Right now the filter is suspended between two pieces of rubber fuel line...

starting to feel like i screwed it up... sheesh. Never thought Bentley would lead me astray.

[phenobarb1]

You didn't screw up. There is another bracket for the fuel filter, but it probably came off your car at some point and wasn't replaced. Just get a new bracket, or clamps, or whatever, and you'll be fine.