S70 idles and dies

Fisherman S70 · Post by **Fisherman S70** » 04 Jun 2012, 10:41

98 S70, 220k miles. This is my moms car. Car stalled a few days ago. Limped home. Figured it needed a tune up. Changed the plugs, gapped at .028. Changed the fuel filter, was nearly completely clogged. Figured that was the main source of the problem. Verified the filter was pointed in the correct direction. Just for grins I checked the gap on the old plugs. .050! Battery was disconnected for about 30 mins. while I changed the filter. Tried to start, nothing. Continued to try, eventually it started acting like it wanted to start. After about 30 minutes, finally. But would only idle for about 20 seconds, chug and die. If I touched the gas at all it would die. As time went on, it seemed to improve. After an hour, frustrated, I took 3 of the plugs out (the easy ones to remove) opened the gap wider, tried to start it and it fired right up. Figuring I had bad info on the gap, I then gapped the 2 remaining plugs. It seemed to run beautifully. At this point I could step on the gas, it would rev up nicely, I was thinking great, problem solved.
Took off for a test drive, seemed perfect, for about 6 blocks. Started to chug, then died. Barely made it back home.
Got some MAF cleaner, cleaned that out, no change. Rented a OBD2. (Check engine light has been on this whole time)
Plugged it in, I got nothing. The unit powered up fine, it was a brand new unit. I'm stumped. Took plugs back out, reset the gap to specs under the hood, noticed that the new plugs had a new light brown residue on them now. (AC Delco plugs) Was able to start, but only idle for 20 secs. or so, then die as if it ran out of gas. Half a tank of gas is in the car. I'm a Chevy guy, this is my mom's car, she's 75, hard to get good info on her interpretation of what the car was doing. She's on a fixed income, so it's up to me. Thanks
to find a solution, since she can't afford it.

Post by **jblackburn** » 04 Jun 2012, 10:48

Welcome to the site. First, I'm surprised the car ran at all on .050" gaps.

Unplug the mass airflow sensor entirely and see if the car will stay running around the block. If that works, you'll need a new sensor.

If that doesn't work, look the the fuel pump relay. The upper fuse panel near the windshield has a few Torx screws around the edges of the cover. Remove those and remove the cover. Remove relay #103, and stick a jumper wire between pins 15 and 87. Start the engine and see if it will stay running this time under load.

If this is a turbo model (t5 or GLT), also check any of the turbo hoses to make sure they have not blown off the clamps at the metal pipes. Tug on all of them and make sure they're not loose - this is actually quite a common occurrence.

Hope that gives you some starting points.

Fisherman S70 · Post by **Fisherman S70** » 04 Jun 2012, 11:40

Thank you for your response. This is not a turbo. I cleaned the MAF sensor, no change. I did unplug it entirely, wouldn't start.
I will take your advice on the fuel pump relay.
Thanks again.

Fisherman S70 · Post by **Fisherman S70** » 04 Jun 2012, 15:06

Thank You jblackburn! I used a jumper in place of the relay and it ran like a champ! Got a new relay in no time and put it in.
Solved the problem.
Thanks so much for your expertise!

Post by **jblackburn** » 04 Jun 2012, 15:12

Woo! Glad it was something simple.

bistrohenry · Post by **bistrohenry** » 04 Jun 2012, 15:39

Same relay on a 96 850? The search result is a bit voluminous...

Post by **jblackburn** » 04 Jun 2012, 15:46