1986 240 DL Fuel pump fuse bypassed?

mhgreen · Post by **mhgreen** » 05 Jan 2015, 17:46

Hello all. Thank you in advance for your guidance here.

I was attempting to replace the fuel filter on my 240. I removed the main fuel pump fuse (#6), and waited for the engine to stall…only it didn't, and wouldn't after 10-15 minutes of running. I purchased this car used (very used), and I have no knowledge of previous service, shortcuts, bypasses, tricks, etc. that have been done on the car. Am I correct to assume that the fuel pump fuse was bypassed? How can I know? Can I change the fuel filter without shutting down the pump this way?

Matt

93Regina · Post by **93Regina** » 05 Jan 2015, 22:33

mhgreen wrote:I removed the main fuel pump fuse (#6)

Remove fuse #4 next time; #6 thru #10 are hot all the time.

Post by **rgk** » 06 Jan 2015, 02:42

Yes, if I remember correctly, the right side of the #4 fuse terminal goes to the main pump, and the left side of the #4 fuse terminal goes to the primer pump, or vice-versa. It's weird.

mhgreen · Post by **mhgreen** » 11 Jan 2015, 21:36

How long should the car take to stall once the fuse is removed?

Post by **rgk** » 12 Jan 2015, 09:54

Less than ten seconds.

mhgreen · Post by **mhgreen** » 12 Jan 2015, 18:25

And if it doesn't stall…?

lummert · Post by **lummert** » 12 Jan 2015, 18:46

mhgreen wrote:And if it doesn't stall…?

Then your fuel pump relay wiring may have been rewired.

Post by **rgk** » 14 Jan 2015, 11:26

Would this also apply to having a different year/model's relay connected?

Post by **rgk** » 14 Jan 2015, 11:27

Try removing fuses 4 and 6...

93Regina · Post by **93Regina** » 14 Jan 2015, 11:31

rgk wrote:Would this also apply to having a different year/model's relay connected?

Really getting off topic on this topic...a relay is required, unless one wants to fry their ignition switch.

Now, does OP know where relay is found, or even have an understanding of relevant electrical circuits?