P0172, P0302 & P0410

blacklistedbully · Post by **blacklistedbully** » 18 Oct 2019, 11:00

Hi all. Recently found this site. Awesome! Here's my issue:
Daughter's '98 C70 2.3L turbo recently showed codes for misfires in all 5 cylinders and P0172 (Bank 1 rich) Can't remember the rest, but I did replace the MAF which seemed to work. No more rough idling...car ran great. Cleared codes. This lasted about 2 weeks, then back to rough idle. Codes read P0302 (cylinder 2 misfire) & P0410 (Secondary Air Injection System). All spark plugs seemed in good condition, though the gaps were not checked. Compression good.

Had her clean the old MAF with MAF sensor cleaner and reinstall, sent the Delphi AF10311 MAF back for refund. Car seemed to run a little better, but for less than 1 day. Back to the rough idle. Had her clear codes to see what would happen. Got:
P0172, P0302 & P0410. Freeze frame info only on P0302, and is as follows:

Engine speed - 840 RPM
Calc Load - 1.6%
Coolant - 210 F
STFTRM1 - -.8%
LTFTRM1 - -6.3%
Veh Speed - 6 MPH
Fuel System 1 Loop - Closed
Fuel System 2 Loop - N/A

My thoughts include:

Check cylinder 2 spark plug gap
Might it still be just a bad MAF, and the Delphi replacement was a dud?
Check wires, caps & rotors
Have replaced some vacuum line connectors/elbows that were obviously leaking, but thinking another leak may be the problem. Get a smoke test?
Possible air pump failure?

Money is tight at the moment, so I'm hoping to avoid falling into a money pit, only to find this car needs more $ than it is worth.

Any suggestions would be greatly appreciated!

Post by **misha** » 18 Oct 2019, 16:51

These cars will run ONLY on OE and OEM sensors.In this case...it's Bosch.
Delphi(aftermarket) will not work.
It's better to use oe sensor from junkyard than any aftermarket ones.

Maf connectors on these cars are prone to failure....even if pins in connector looks ok you will need a small precision screwdriver to minimize gaps on all pins in the connector.

Connecting and disconnecting the actual connector a few times should help to determine if it's bad.
If car runs ok untill next re-start after re-seating the connector....it's not the maf.

Also....if car runs better with Maf disconnected....then it's bad(or the connector is bad).

blacklistedbully · Post by **blacklistedbully** » 20 Oct 2019, 18:31

Misha, thank you. I'll give it a try. In the meantime, I found notes of previous codes. They were P0300 (random multiple misfires), P0303 (misfires in chyliner 3), P0304 (misfires cylinder 4), P0305 (misfires cylinder 5), P0172 (Bank 1 rich) & P0455 (gross leak in Evap system).

Also, on her last visit home, right b4 she left I had to quickly replace some rotted vacuum line elbows & connectors. I noticed the air pump check valve was disconnected from one end. Like a dummy I removed it to inspect it, not paying attention to which direction it was going. It's 1/2 white, 1/2 black, and comes from a hose that appears to extend from the front of the car, by the radiator towards I assume the air pump.
https://www.eeuroparts.com/Parts/8406/C ... e-9135666/

Anybody know which side faces the pump? Is it possible having this check valve either failed or installed backward is causing the problems and/or has led to an air pump failure that is in turn causing the problems?

Post by **abscate** » 20 Oct 2019, 19:36

Blow through the valve. One way will flow the other won’t. Draw an arrow with sharpie in the direction it flows

Point the arrow away from an air pump

Point the arrobw towards a source of vacuum

blacklistedbully · Post by **blacklistedbully** » 20 Oct 2019, 20:16

abscate, thank you!

Post by **abscate** » 20 Oct 2019, 23:52

...welcome!

Don’t forget to post back the white black convention here for reference!

(Oh my God Karen! You can’t just ask why purge valves are white!)

blacklistedbully · Post by **blacklistedbully** » 24 Oct 2019, 00:37

New developments. No new codes, but daughter reports the car would not start on first two tries this morning before starting on the 3rd. Also said drive back home felt like engine "stumbled" some during acceleration on the freeway. AC, lights, radio, etc. working.

Her BF is guessing bad ignition coil. But no codes for running lean...in fact, running rich in bank one. Plus, still only showing misfire in cylinder 2. Correct me if I'm wrong, but on a '98 C70, doesn't the ignition coil serve multiple cylinders, and if so, would a bad coil be likely if only cylinder 2 is misfiring?

Post by **abscate** » 24 Oct 2019, 06:01

From another car make I found that the check valve convention is flow is enabled from white to black, blocked from black to white.

So

Air pump ..........white/black ........air injection

Engine vacuum........black/white.........purge valve or other vacuum motor

blacklistedbully · Post by **blacklistedbully** » 24 Oct 2019, 18:46

misha wrote: ↑18 Oct 2019, 16:51 These cars will run ONLY on OE and OEM sensors.In this case...it's Bosch.
Delphi(aftermarket) will not work.

FCP Euro lists a Bremi as OE. Any idea if that one works?

Post by **abscate** » 24 Oct 2019, 20:32

blacklistedbully wrote: ↑24 Oct 2019, 00:37 New developments. No new codes, but daughter reports the car would not start on first two tries this morning before starting on the 3rd. Also said drive back home felt like engine "stumbled" some during acceleration on the freeway. AC, lights, radio, etc. working.

Her BF is guessing bad ignition coil. But no codes for running lean...in fact, running rich in bank one. Plus, still only showing misfire in cylinder 2. Correct me if I'm wrong, but on a '98 C70, doesn't the ignition coil serve multiple cylinders, and if so, would a bad coil be likely if only cylinder 2 is misfiring?

Correct. On a -1998 a misfiring single cylinder is cap, rotor, wire,plug,or engine mechanical.