98 S70 Stalls with no CEL

styoung94 · Post by **styoung94** » 06 Oct 2014, 08:37

Yesterday as I was driving my S70 the rpms started to drop and the car stuttered for 20 seconds and the died. After that it would not start, my battery was too weak. I then got a new battery and the car would start up and run but after a short time, ~2 min, it would drop rpm, stutter, then die. I ended up having it towed back to my home.

I have not tried pulling any codes but when I initially start the car up there is not a check engine light. Chances are I'll just end up taking it into a shop but does anyone have any ideas as to what would cause that? The abs light has been on for awhile so I assume the module is bad, but that has been on for 5 months no and no problems, aside from abs not always working.

Post by **erikv11** » 06 Oct 2014, 10:18

Fuel pump relay or fuel pump itself are both very likely suspects.

Post by **rspi** » 06 Oct 2014, 10:23

styoung94 · Post by **styoung94** » 06 Oct 2014, 14:18

Can I test the fuel pump with the line still connected? It won't flood the engine or anything right?

styoung94 · Post by **styoung94** » 06 Oct 2014, 14:36

Just tested it following the method in the video. I could hear the fuel pump when I jumped the wires. So I tried it again with the relay installed and also heard the fuel pump.

I then started the car with the relay installed. It idled fine for a minute, then stuttered down to ~200 rpm, came back to idle by itself. I then gave it some gas and it died.

Still possible that its the fuel pump or fuel pump relay?

Post by **erikv11** » 06 Oct 2014, 14:49

I don't know what is in that video but a very common way to test the relay is to make a jumper wire and install it in place of the relay. Then do those same tests. If it no longer dies, then you have found the cause (relay) but if it still does, then cross the relay off the list and move on.

Be careful and sensible about making a jumper wire, you don't need a fuse inline but you need reasonably heavy gauge wire and to know that it may get hot, too.

Post by **rspi** » 06 Oct 2014, 15:11

Some people install the jump wire, drive the car around for a few hours or a day. If the problem is gone, they replace the relay.

Better yet, if you have no record of the relay ever being replaced, just replace it. I replace mine every 10 years.

styoung94 · Post by **styoung94** » 06 Oct 2014, 15:12

It still stalls out even with the jumper. So it doesn't seem like its the relay. It was unable to idle as long as it did with the relay installed. It was also harder to start with the jumper.

Post by **erikv11** » 06 Oct 2014, 16:33

That is weird behavior for the jumper, was it really skinny wire? Do you know the gauge?

styoung94 · Post by **styoung94** » 06 Oct 2014, 16:45

I'm not sure of the gauge. It was fairly thick solid copper wire that holds its shape. It was larger than a typical speaker wire.