1998 S70 Fuel Pump Relay and MAF

dneume · Post by **dneume** » 04 Sep 2013, 19:16

I am sharing my story because I solved my problem with the help of all the posts in this forum.
HopefullY this post will help someone else.

My wife's 1998 Volvo S70 GLT with 135k miles started cutting out during her ~15 mile morning and evening commute. The car would immediately start again. The car would cut out while idling in traffic and while driving. No codes were being thrown.

I took the car to my independent mechanic, who I trust, but he could not offer a solution.

I suspected a fuel relay failure for these reasons:

1. I had the same issue with my daily driver, a 1993 245 Volvo.
2. The various stories I read across the internet regarding fuel relay failures for S70s
3. My problem occurred intermittently and regardless of driving conditions
4. No codes were being thrown

I purchased a new fuel pump relay and installed it. Now the car would not start.

Since the car would start with the old relay, but not a new relay - I suspected the mass air filter(maf). I purchased an after market Mass air filter(MAF) and installed in in the car.
The car would crank, but would not maintain a consistent idle and would eventually stop while throwing various codes relating to the MAF.

Further reading convinced me that I need to purchase an OEM MAF as the after market MAF tended not to work. I purchased the OEM MAF and installed in the car.

Car started and the problem is solved. The car has stopped cutting out.

My theory is that both the fuel pump relay and the maf were not working consistently but that the ECM(?) was able to compensate. Installing a new fuel pump relay highlighted the fact the maf was failing also.

Post by **cn90** » 04 Sep 2013, 19:32

Not really, Fuel Pump Relay and MAF operate independently. There is no compensation for a bad fuel relay.

Your problem was bad MAF.

Post by **Matty Moo** » 04 Sep 2013, 20:13

I say this....

I bought a case of aftermarket MAF's about two years ago. 24 of them to be exact, they were too cheap to pass up.

When it came time to peddle them my only taker was a shop in Bolivia and I made about $60. Looking back I should have tested them individually in my car and then thrown them on eBay, but it seems like people would buy a junkyard MAF before they buy a new aftermarket unit.

Post by **matthew1** » 04 Sep 2013, 20:22

I did buy a junkyard MAF as a backup 4 years ago. I'm about to put it in because I'm getting low mpg and odd idle lately, airflow sensor cleaner having no effect.

Anyway, aftermarket MAFs -- I don't think I've read of one working. It seems to follow a familiar path: "I got an aftermarket MAF, then I got an OEM and the problem was solved."

Post by **jpr0204** » 05 Sep 2013, 08:31

Good Morning All,

Not that I would ever take sides with the Aftermarket over OEM quality here but I have to say:

Back in 12/2012 at approx. 101,XXX miles I was getting a P1171 and P0172 code. After testing and looking at live data on my scanner I realized the OEM MAF had taken a permenant nap and thats what was causing the hard starts and poor drivability.

I purchased a Cardone Reman. MAF Unit for WAAAAAAAY cheaper than OEM Bosch not becuase I didn't want Bosch but becuase Santa had one hell of a list to fill LOL. Anyhow, it's been in there now for approx. 8 months and 9 months and 9K miles and it works excellent. No issues at all. Best part about it was I was able to buy the Cardone unit for only $63.00 with the core!

Post by **matthew1** » 05 Sep 2013, 11:44

Joe, thanks for the feedback on the Cardone. Good to know.