2002 S60 base blow back

jquick1 · Post by **jquick1** » 01 Feb 2018, 15:21

Just put this car on the road today February 1. It has a very strange popping sound coming from inside the air filter housing. I know nothing about this car it has 186K on it. I opened the air filter housing and there’s actually air popping back every now and then. Any help? Seems to run fine drove about 15 miles you can tell when it pops back and gets a little hesitation but other Than that I don’t know. Thanks

Post by **abscate** » 01 Feb 2018, 15:58

These cars don't misfire like cars with old cap-rotor-distributor ignition. The one thing to check there is the age on the ignition coils, all five of them.

I would run a compression test to rule out bottom end and valve damage, then from there look over all the vacuum lines for breaks splits holes. While you have the spark plugs out, you can look at them to evaluate each cylinder too. You will need 10 posts before you can put up a picture of them, labelled with a sharpie so you know which one is which

The 2002 are pretty good but everything is 16 years old now, so it will need some TLC.

I believe you got the first year of the much improved Bosch Throttle Body so you did well there.

Post by **abscate** » 01 Feb 2018, 16:08

Start by looking for the Volvo Part Number on the correct mirror.

Im having a flashback to a meeting 10 years ago when a client told me, after shipping us different parts under the same part number

"Nothing in our ISO approved processes says we can't use a given part number for several things"

I ended the meeting immediately by saying "I want you to reflect on that statement for a day, and then come back tomorrow and discuss."

jquick1 · Post by **jquick1** » 01 Feb 2018, 16:17

Appreciate the reply. I would say that the coils are new there is a box in the floorboard with old ones in it and the spark plugs. I would also say the throttle body has been changed(used one)for there is one in the trunk and it doesn’t have the Bosch one.

Georgeandkira · Post by **Georgeandkira** » 01 Feb 2018, 17:42

My '02 base V70 still had the MM ETM. I think the S60's were the same.
These ETM's are married to the car. Many reports on junkyard ETM's failing to work.
How a mismatched ETM acts up is something I do not know.
At least look for gunky dirt in the one in your car now.

Given the old parts on the floor I'd bet the PO was a "hands on" guy. He may also have done the timing belt.
He may have done so incorrectly.
Get a vacuum gauge and see what the legend on the face says.

I concur with doing a compression check.

Post by **RickHaleParker** » 01 Feb 2018, 17:42

The most common cause of intake backfire on a fuel injected engines is a lean fuel to air mix ratio. What happens is the lean mixture burns slow, in some cases it is still burning when the intake valve opens.

I would start by looking for sources of un-metered air, leaks in the intake system, defective MAF ... ect.
If that does not pan out, look for problems in the fuel delivery, low fuel pressure, defective injectors.

Coil Over Plug (COP) can crossfire like the old spark plug wires did if, there is a short in the wiring harness.

Post by **abscate** » 01 Feb 2018, 18:29

George might have nailed it. A 2002 NA will probably have intake CVVT Im guessing, and its really easy to forget to set the CVVT cam one tooth off when installing the belt, especially if you haven't done CVVT before. I missed it last Fall, even knowing about it.

Wrong valve timing can definitely cause popping.

jquick1 · Post by **jquick1** » 01 Feb 2018, 18:59

I will check for leaks, wiring and other issues tomorrow. As for the timing belt I did look at it and it’s old. Thank you guys so much!!

DrDan · Post by **DrDan** » 02 Feb 2018, 00:05

abscate wrote: ↑01 Feb 2018, 18:29 A 2002 NA will probably have intake CVVT Im guessing [...]

True for my 02 NA, B5244S2 engine. CVVT only on the intake side. Also it has the MM throttle body

Post by **abscate** » 02 Feb 2018, 04:53

DrDan wrote: ↑02 Feb 2018, 00:05
abscate wrote: ↑01 Feb 2018, 18:29 A 2002 NA will probably have intake CVVT Im guessing [...]
True for my 02 NA, B5244S2 engine. CVVT only on the intake side. Also it has the MM throttle body

There's quite a few examples of these running 200k miles/300k km. We do tend to read the other end of the curve here, which is a natural statistical bias of a DIY forum. Mine went 137kmiles