Afternoon
1995 940 NA. Driving home doing 75 or so MPH and engine dies. Diagnostics lead me to the in tank pump which I remove and find the negative lead attached to the pump loosely and the connector is melted burned and the male part on the pump has a small scorch mark. Pump reads 0 ohms so I am pretty sure it has a "dead short". This was a brand new OEM Volvo pump I replaced almost exactly 1 year and 10,000 miles ago. So a couple questions, A)Did I nearly blow my ass up(melting/burning in tank)?? B)Why did my 15amp fuse not blow in panel? C)Should I put some sort of a fusible link or such in line prior, and would that help?
Thoughts?

I recently had a similar experience ('94 940). The fuel pump (after-market TRE-340) was in service for about 7 years (42k miles). The car exhibited intermittant no-start. When it would not start, I traced it to the fuel pump. When I pulled the pump, I couldn't believe that the car had just made a 250 mile trip. It looked like all the power was going through a few strands of wire!

Phil Smith
New Bern, NC

Here's a photo...

A. No, the mixture in the tank is too rich to ignite.

B. The cause of the problem was the loose connection, which had high contact resistance. High resistance does not increase current, but actually reduces it. The fuse would hold.

C. No need.

You should re-test that zero ohms you thought you saw. It is highly unlikely. Make sure when using your meter you have a similar known good resistance to compare with, as meters commonly develop a fault resulting in low resistance readings after internal shunt or fuse failure. The pump is probably OK, you just need to tighten the connection to it.
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Art Benstein near Baltimore


You spend the first two years of their life teaching them to walk and talk. Then you spend the next sixteen telling them to sit down and shut up.

The poor connection has a resistance that was dropping voltage across it leaving less for the pump. The pump had low voltage and lower current. You did lose power across the poor connector in the form of heat.
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Paul NW Indiana '89 744 Turbo 175K/ '90 745 turbo 145K

Thanks All, I have truly learned a number of things from this episode. Just got sender back(never easy no matter how many ya do) in and everything buttoned up. She is purring as we speak. I am listening to the delightful trickle of the returning fuel via my ear to the filler tube orifice. Music to my ears. Miller Time.

The poor connection has a resistance that was dropping voltage across it leaving less for the pump. The pump had low voltage and lower current. You did lose power across the poor connector in the form of heat.
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Paul NW Indiana '89 744 Turbo 175K/ '90 745 turbo 145K

Damn, how did I not guess the root cause here would be human(ME). I have done some googling in the last 15 minutes and I was starting to wonder if a loose connection was part of the problem. Thanks Art. I had one of my employers newer techs come over with his fancy schmancy Fluke brand meter, I watched as he tested it and got zero. He then smacked it around a little and retested and got like 2 or 3 ohms as I recall. I am gonna go grab the shop meter and play a bit. How would you make a "better" connection? Drop some solder on the current connector? Clean and burnish? You can just make out the burned spot on the male spade on the pump in this pic. Oy Vay!

Looks like you need to loosen up the hose clamp and turn it away from the connector. Then just pinch the female connector a little with some pliers to make a tighter connection.
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Post Back. That's whats makes this forum work.

I am now getting 3 ohms or so on the motor. Used the shop's cordless battery to apply voltage....she sings. So I guess the question I am left with is, can I solve this by simply reinstalling and using needle nose pliers to make the female part "bite" the spade? What a bunch of extra work I created for myself....

Don't be so hard on yourself. Sure it was a lot of work, but in the end, no money wasted. Just be sure it is clean and tight -- it should be OK.


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Art Benstein near Baltimore

Grandchildren are God's reward for not killing your own children.