Fuel Pump + Sender - Rusted in tank??

[tonytiger 0]

 

It's been a while since I've posted anything on here - Corrado hasn't been on the road for a few years, but I'm finally trying to make some progress.

As ever - the car is having none of it (it's a vr6).  The fuel pump has packed up, which was rather unexpected being as it had a brand new one this time last year.

Annoying as that is, what I'm really surprised at is that the metal on the pump housing and the sender arm are rusty.  I don't understand why that would be.   The pump has been fully submerged in petrol.  The car hasn't moved or even been started in 10 months or more.  If there was any water in the tank it should have been at the bottom?   

When I removed the pump yesterday I put the petrol from it in a jar to see if any water separated from the petrol but can't see any water at all.

 

The pump I fitted last year was a brand new Johns pump (having read the help thread on vr pumps) - to replace the original Pierburg.  Looking back at my photos of the old pump, I can see the housing didn't have any metal work on like the new pump, but I can also see that the sender arm wasn't rusty either.

The VDO sender was brand new too.  Could just about understand a cheaper pump rusting but not the sender arm as well.

Has anybody else experienced this, or have any suggestions as to why the rust has occurred?   

 

 

Edited August 31, 2020 by tonytiger
Added photos

[blue95 0]

Wow that is rusty, not seen that before, you may have picked up a bad batch of contaminated fuel (containing water) remember reading up on a few incidents 

 

 

Edited August 31, 2020 by blue95

[1xshaunx1 27]

Agree with blue, very strange. I only put Shell in mine if I can help it. 

[Keyo 47]

Will be water ingress by the looks of it or somehow the cheap pump has caused this erosion- the thread actually recommend to get the more expensive OE VDO pump to be fair. Is that any  could be a mixture of not been fitted correctly and seals not doing their job-  hopefully your fuel filter has done its job and this crud getting into your block  ? 

Edited August 31, 2020 by Keyo

[Dox 22]

Electrolysis maybe?

 

petrol floats on top of water so there’s need to be a lot to cause corrosion there?

 

Chineseium alloy would be my guess 

[tonytiger 0]

Thanks for the replies. 
yes, I can’t understand why the pump housing has rusted at the top as any water (if there is any) should be at the bottom of the tank.  And it’s fair point about a cheap pump and the metal being of poor quality - but the sender arm is bad too and that was a brand new genuine VDO item.  
 

Looks like I’ll have to drain the tank fully to see if there is any sign of water in there, and fork out for a new pump.  ☹️
 

[tonedef 8]

Mine did exactly the same when it was laid up in the paint shop for a couple of years. The pump was rusted solid and had to be replaced, I managed to get the sender working again with a bit of TLC though.

[Keyo 47]

Might be worth checking that the filler cap has the o ring seal - is an odd one . I think once the pump started to rot into carried onto the sender . 

Edited September 2, 2020 by Keyo

[fendervg 29]

This might the significant price difference between the VDO/Bosch units and the cheaper copies - it could well be that the grade of metal being used is inferior. Still, corrosion shouldn't really happen without water in the petrol.

[tonytiger 0]

Just an update on this.  Dismantled the pump fully as shown in the photos.  Bit of a mess! I’m actually pleased I didn’t fit a VDO pump last year as I expect the same would likely have happened to that. Have ordered a VDO unit this time though - should have arrived this week but it’s delayed so hopefully will arrive early next week. 
Tondef - interesting to hear that you had this problem when laid up, I normally would start the car every couple of months, but that just didn’t happen this year.  
 

I’ve been draining the fuel, not much left in there now and can see the bottom of the tank probably needs cleaning so I’ll tackle that before I fit the new pump.  Still no sign of water in the fuel from the samples I’ve set aside, but I think I read that ethanol mixes with water? 
 

Will be going with Esso super unleaded as a precaution which is supposed to be ethanol free, as the car still won’t be getting used much for a while. 
 

Cleaned up the old sender and think that will be fine. 
 

Good shout on the fuel cap - the o ring is still there but might be worth replacing regardless as a precaution. 

[fendervg 29]

Ouch - that looks well nasty - I see you had to get the hack saw out! That looks very different to the insides of a VDO pump btw.

[1xshaunx1 27]

Can’t see that working again 

[Keyo 47]

I was expecting a chinese gold fish  gulping. 

[tonedef 8]

On 9/11/2020 at 8:58 AM, tonytiger said:

Just an update on this.  Dismantled the pump fully as shown in the photos.  Bit of a mess! I’m actually pleased I didn’t fit a VDO pump last year as I expect the same would likely have happened to that. Have ordered a VDO unit this time though - should have arrived this week but it’s delayed so hopefully will arrive early next week. 
Tondef - interesting to hear that you had this problem when laid up, I normally would start the car every couple of months, but that just didn’t happen this year.  
 

I’ve been draining the fuel, not much left in there now and can see the bottom of the tank probably needs cleaning so I’ll tackle that before I fit the new pump.  Still no sign of water in the fuel from the samples I’ve set aside, but I think I read that ethanol mixes with water? 
 

Will be going with Esso super unleaded as a precaution which is supposed to be ethanol free, as the car still won’t be getting used much for a while. 
 

Cleaned up the old sender and think that will be fine. 
 

Good shout on the fuel cap - the o ring is still there but might be worth replacing regardless as a precaution. 

 

 

 

 

I started mine regularly when it was at home but at the paint shop it was sat for the best part of two years. Another thing to look out for if the fuel has deteriorated to the point the pump has rusted in it is the injectors, when I came to get it started only two of them were actually firing, I had to have them serviced to clean out all the crud.