Xc70 won't start after changing MAF sensor

BenL · Post by **BenL** » 04 Nov 2016, 19:25

I put a new MAF sensor in my xc70. When I tried to start it it didn't catch. After a couple for tries and no start I put the old MAF back in thinking the auto parts store sold me the wrong one. Still no start. I read the engine codes and got U0073. Any suggestions?

Post by **abscate** » 05 Nov 2016, 01:20

Try feeding it some ether, sold as starting fluid, into the air cleaner to see if you have a fuel or spark problem.

Ignition on P2s is reliable, sounds like fuel to me

Post by **shiloh51933** » 05 Nov 2016, 12:02

BenL wrote:I put a new MAF sensor in my XC70. When I tried to start it it didn't catch. After a couple for tries and no start I put the old MAF back in thinking the auto parts store sold me the wrong one. Still no start. I read the engine codes and got U0073. Any suggestions?

Why did you buy a new MAF sensor?
If you were having issues with starting b4 replacing MAF did unplugging MAF seem to resolve this issue?

BenL · Post by **BenL** » 05 Nov 2016, 12:37

Abscate, thanks for the suggestion. I was heading to get ether and decided to try again. It started right up. I'll still get some ether for when I put the new one back in.
Shiloh51933, the xc70 had been shaking when accelerating over 55mph. So I took it to my mechanic. He got codes related to the MAF and cleaned it. It ran well for a couple of days then started shaking again wed. and thurs. I called asking for things I could do at home. The MAF was one that came up so I'am trying that.

Post by **shiloh51933** » 05 Nov 2016, 14:59

BenL wrote:Abscate, thanks for the suggestion. I was heading to get ether and decided to try again. It started right up. I'll still get some ether for when I put the new one back in.
Shiloh51933, the XC70 had been shaking when accelerating over 55mph. So I took it to my mechanic. He got codes related to the MAF and cleaned it. It ran well for a couple of days then started shaking again wed. and thurs. I called asking for things I could do at home. The MAF was one that came up so I'am trying that.

You sure the shaking was related to the engine performance and not the front end or unbalanced tires?
An MAF code can come up if somebody simply unplugged the MAF sensor from connector while your XC70 was on/running. Just a suggestion, you don't want to get into the habit of throwing parts at your vehicle.

Post by **oragex** » 05 Nov 2016, 16:37

BenL wrote:Shiloh51933, the XC70 had been shaking when accelerating over 55mph. So I took it to my mechanic. He got codes related to the MAF and cleaned it. It ran well for a couple of days then started shaking again wed. and thurs. I called asking for things I could do at home. The MAF was one that came up so I'am trying that.

What exactly is shaking, the steering wheel, brake pedal, gas pedal?

This is typical for unbalanced wheels, easy to just put the front wheel back see if something changes. Other causes, worn/chinese axles, broken engine mount, coil pack, worn front control arms, stuck piston rings (had this one, the gas pedal would shake around 50mph), warped brake disks (or uneven tight wheel lugs)

BenL · Post by **BenL** » 06 Nov 2016, 02:27

Thanks for all of the advice. The new MAF sensor is in and the car is at the grocery store. I started it a few time. It ternates between working perfectly one start and the next time it will start oddly, high revs or up and down revs, then surge. The last time it started and then stalled. I don't know what to do next. The new sensor looks a little different than the old one. Could that cause issues? I thought maybe the odd performance was the computer sorting out different readings from a new sensor and would go away.

Post by **abscate** » 06 Nov 2016, 03:49

This is a turbo car, so the induction path of sir hoses between theMAF and the throttle body is critical. No loose clampsleaks, splits. You have to remove each part and inspect out of the car to eliminate this,though, about two hours of labour.

BenL · Post by **BenL** » 06 Nov 2016, 09:13

Thanks abscate. I'll check the hoses. The visit before last my mechanic mentioned that the turbo was leaking a bit and would have to get replaced in the future. When I just had it in for the shaking I asked for the turbo to get a close inspection. I assumed that they had, though there was no mention of it when I picked the car up. Could a bad turbo cause bad shaking?

Post by **abscate** » 06 Nov 2016, 23:22

Not really, and the turbos on these cars are replaced about as often as hens teeth.

A leak in the turbo is a gasket or fitting problem and rarely means turbo replacement.

This car has a coil over each plug and they start going bad at about 100k miles. Pull all the spark plugs and look for one misfiring, easy at home fix. Replace plugs if they are over 30000 miles old