Universal 5432 on E 38 dies at mid to high RPM

[Geoff Nelson]

Cruising along at 1800rpm/6.5 kts in open ocean (10mi from shore) my normally very steady running engine starts to "hiccup". A small drop in RPM and then it comes back to where it was. 20 mins later, the same thing but slower to recover. Then again 10 mins later. And eventually it dies. Pop in neutral, restart and it fires right back up immediately. Runs for a bit, another drop or two and dies. Starts right back up. Does this all night for two more hours. Runs cool (180deg). No other variations from normal operation. Sees to die more at 2000rpm and seems to run fine at 1300rpm (every now and then a little drop but only for a second then comes rightback). Seems like a fuel flow issue. I have a half tank fuel (~20gals). The Dahl seems fine (a little sediment in the bottom but no different from the past). The fact it starts right back up after dying really is throwing me.

Thoughts?

Thanks in advance.

G-

 

[Tom Metzger]

All of the usual suspects

As you suggest, it sounds like a fuel problem, leaving all of the usual suspects: Clogged or crimped vent line, fouled filter, fouled fuel line, fouled fuel line valve, fouled pick up tube in the tank, etc.

I would start by checking the tank vent for spiders and such, and then blow out the fuel lines.

A week or so ago crud built up in a fuel line ball valve stopped a Tartan at my marina.

 

[e38 owner]

fuel

A friend of mine had a similar problem had a pinhole leak in the fuel line

 

[kevin81]

Geoff:
I had he exact same symptoms on my E34 with a Universal XP25 two years ago. After having the primary and secondary fuel filters changed, the problem started. I finally had another diesel mechanic work on it and he eventually found a small piece of plastic (plastic wrap) had found its way into the fuel line between the primary and secondary filters. The only explanation I arrived at was when the filters were changed the first time, a piece of the filter's package was stuck to the filter and was then "pumped" into the fuel line. After blowing the line clean (also after several hours of troubleshooting) the problem disappeared.
Kevin

 

[jkm]

Though I have my original A4, both my truck and car are diesels.

The most common problem that you describe comes from debris in the fuel tank, clogging your supply tube.

Diesel fuel is not well filtered like gasoline and the turnover in tanks is not good. Fresh diesel is essential.

Next week Califronia will start selling low sulfur diesel, which is a cleaner fuel. As it will be lighter, one friend has stated that the debris found in so many storage tanks will actually become heavier vis a vis the fuel and such we may not experience the "foul fuel symptom"

I do know that if you run out of fuel with a diesel, the engine is very difficult to restart because of the debris in the lines. FWIW .01 or .02

 

[Geoff Nelson]

Fuel pump question

So I have checked the vent line and all is good there. Both the Dahl and the Primary are in good shape and have only had like 70 gals run through them. I have replaced all the fuel lines (10' from the tank to the Facet lifting pump to the Dahl to the primary filter). Now I can't get the eninge to start as the fuel does not make it to the return so I am thinking it is the Facet lifting pump that is bad. It clicks away like normal but I would think that if the engine is not running, there should be fuel returning to the tank and there is none when I take the return line off.

I can't find an exact match to the Facet 12V pump that is in there... anyone have any other suggestions on pump type to use?

 

[CaptnNero]

Walbro ?

...

I can't find an exact match to the Facet 12V pump that is in there... anyone have any other suggestions on pump type to use?

I don't know how the specs match but I've heard that Walbro pumps are a good way to go now. Here's a link http://www.autoperformanceengineering.com/html/6000_pump.html

You'll need to find out if that kind of flow rate is acceptable. Our Universal M25Xp consumes only about 1/2 gallon per hour but I don't know how much more is supposed to be returning to the tank. I think the smallest Walbro does 36 gallons/hour !

 

[chaco]

Fuel Pump Internal Filter

Found out this weekend while inspecting my Facett Fuel Pump that it has an
INTERNAL FILTER! Fulled the little bugger out....full of GUNK
Probably not cleaned in 20 years. Cleaned it with a toothbrush and diesel fuel.
Finished up with carb cleaner. What a LUCKY find
I was in the process of Commissioning my fuel system for delivery in to the
new Beta BD 902 using the fuel pump to flush hoses and purge air.
The fuel pump would not work until I cleaned the filter. All that gunk would
have headed for the new engine
Check your Fuel Pump Filter before you buy a new one.

Good Luck

 

[Geoff Nelson]

Facet pump and internal fuel filter

The Facet pump I have looks like a sealed system... I don't see how you can get at the guts to get to the filter- or did you just back-flow the cleaner?

 

[chaco]

Facett Fuel Pump Filter

The bottom unscrews on my Pump to get at the Filter.
You can see the Pump on the "Magical Fuel Pump SetUp" Thread posted today. Maybe your Model IS sealed. Then she is shot, as you are not getting
a STRONG return back to the Tank. Run it without the filter in to a container
to verify that you have no blockage.