Crumpler

Good Morning Gentlemen, I had a quick question in regards to new FP.
Current unit is functioning fine but not new, could even be original.
I am replacing as a preventative measure. I feel like I got the HP covered, now the long game is an attempt to make the car as reliable as I can...

I have new Bosch unit and check valve in hand.
Are there other wearable parts to change out WYAIT.
More specifically 893 906 093, labeled as retaining valve in PET?

Thanks ahead of time.

joejoe

That is the check valve. Make sure to change the crush rings, and it is surprising how tight these need to be to not leak.

Crumpler

Ahhhhhh.
Now I get it.

It looked like a separate component (in addition) to check valve on PET.
I might need glasses.

Thanks JoeJoe, Did you crack open those computers yet?

docmirror

Ever heard of infant mortality? Do you know that the part you're installing is better built than the factory Bosch part that came with the car? Yes, I know it's old.

joejoe

Not yet on the chip change yet. The grey car is running better than it ever has, so will do the chips after sharktoberfest and perk up the other '86.5.

Crumpler

So Doc that is a valid point.
The short answer is no, I'm not sure.
I did assume the new OE unit was good.

Sounds like I should confirm.

My thoughts:


I could jump the unit in the box, but I recall reading that you are not supposed to run them dry, even for short amount of time?

I could jump relay and measure the amount of fuel pushed in a certain amount of time on new and old unit to see if in spec.? More labor, but can be done.

Switch units and compare performance? Doesn't mean new unit won't fail at a later date.

Abort and wait until old unit proves faulty?
(I was kind of hoping to avoid chasing my tail or a ride on a flat bed down the road).

Looking for advice.
Thanks.

docmirror

Well, it's an age-old question whether to replace a working component based on hours or performance, or wait until a failure presents itself.

There's no one perfect answer. Of course, things wear, and the pump that came from the factory new wasn't designed for Ethanol, but the counter-argument is that the current batch of Bosch pumps are no longer made in Germany with strict production and quality control. So - all I'm pointing out is it's a crap shoot. If you don't change it, the pump might fail on the next drive. If you do change it, same result possible.

For a car like this, if it gets driven regularly I would have the new pump handy but not replace until performance issues or failure mode presents. I think the pump is rated at about 30 gallons/hour so it's putting out plenty of fuel to the rails. The excess is returned to the tank so it's a long way to go before you will see any performance degradation. But - they do fail from Ethanol swelling, as does the internal fuel line.

I guess what I'm saying is I might get the pump and line out of the tank and inspect the line and maybe replace that with an ethanol approved hose. This could quite possibly save the pump from getting a fragment from the line stuck in it and save you the pump failure. But - I wouldn't replace the pump. In the case of the fuel line, it's a known problem with a known better solution(Ethanol safe fuel line). In the case of the pump, my opinion is that the current batch of fuel pumps from Bosch are an unknown quantity, and I would trust the old pump over the new. The only test I might do is a current draw test to see if the old pump is taking excess current.

<edit: Of course, there is a risk to the gland nut seal in the fuel tank if you decide to take the pump off too. Nothing is perfectly safe! lol >

Crumpler

Thanks Doc, I appreciate the help.

I was not aware of these quality concerns, and it does have a Czech Republic stamp on it now that you mention it...
Is this now a concern across the board with Bosch, or just the FP's?

I like the concept of a draw test, if I can validate that the old pump is still within normal spec., then I could probably just put the new one in my travel box with all the other doomsday supplies.

I'll work on that and see what I got.
How many amps should I see on the draw for a "good" FP?

The Fixer

Hey Dave,
I doubt that pump is original,
My car is on it's 4th.
I'd do as Doc says and leave it until it shows signs of failing.
As far as amps, i replaced mine about 600 miles ago because it was pulling 20 which is too much.
I'd have to go out and check what the new one uses but someone here probably already knows that.
take care

Crumpler

Thanks Matt.
That gives me a good yardstick to go by.
What have you been upto buddy?
I figured you either have something big that you are going to roll out, or getting some rest.

Crumpler

I had a chance to run out to the garage and do a draw test on the old FP.

Consistent reading between 6.1 - 6.3 Amps.

I'm feeling ok about that, it seems consistent with some other FP values I came across in my research...but what do you guys say?

docmirror

Sounds like a good number. Those pumps move a lot of fuel. run it, enjoy it, keep your pump handy in case.

The Fixer

Hey Dave,

I was wondering the same about you.

I bet your Porsche is running great with that new chip set.

Crumpler

Doc thanks again for the help.

Hey Matt, the S3 runs like I always thought it could, it only took four years (and an unknown amount of receipts that I never want to tally up)....

I do believe I would not be where I am with the car without the help of everybody here.

Regards.

jpitman2

6A is good, mine was similar. If/when you need to change the pump, remove the whole pump/filter assy from the car, rebuild on the bench , then refit. Have access to a new S pipe - these are consumable - my local wrench keeps them in stock because its very easy to distort them while fitting a new pump or filter. The relay is probably more likely to fail than the pump.
jp 83 Euro S AT 55k