1998 v70r vacuum leak

dcmike · Post by **dcmike** » 04 Apr 2019, 10:17

My V70R threw a p0172 code and I found a vacuum line broke, but I don’t know where the other end goes. It’s the other end of the white line. Any help would be great.

Mike

Post by **RickHaleParker** » 04 Apr 2019, 11:01

Follow the hose marked with the Red arrow until you find the nipple on the metal pipe.
It is on the side closest to the engine block

: V70_Vac.jpeg (272.13 KiB) Viewed 2370 times

dcmike · Post by **dcmike** » 04 Apr 2019, 16:19

Thank you for the help.

I replaced the hose, but the car still has a code P0172. I reset the CEL twice and the car still has a rough idle and code. Any Ideas of what could be causing the code?

dcmike · Post by **dcmike** » 04 Apr 2019, 19:45

I just went out and drove the car. The car has no power and smokes a lot. the code is also still there. I checked everything that I replaced and it is all back together. Now I am very frustrated.

Post by **erikv11** » 04 Apr 2019, 20:02

To be clear, the white line connects to the fuel pressure regulator behind the engine, down low close to the firewall. Look for a small metal line back there. My preferred way to fix this line is to just get a length of rubber or silicone and get rid of the hard white line and elbows.

Any time you have p0172, first place to check is the nipple on the passenger side of the intake manifold. Get a flashlight and peer in there, between the manifold and the thermostat housing. Otherwise check all the vacuum lines and/or try using starting fluid etc to search for vacuum leaks.

Post by **erikv11** » 04 Apr 2019, 20:03

Also, take a look at this post, go over the routing of all the vacuum lines: viewtopic.php?t=63615

dcmike · Post by **dcmike** » 05 Apr 2019, 19:42

I looked at the elbow and it was still on the nipple on the intake manifold. Does this line go to the PTC? If so, could a bad PTC cause the MAF problem? I will do more with the car tomorrow morning.

tardcart · Post by **tardcart** » 05 Apr 2019, 19:52

you cant loose enough vacuum on the line to the PTC to upset the MAF. It may cause some idle roughness but no code. Check all the turbo connections between the MAF and throttle body.

Post by **RickHaleParker** » 05 Apr 2019, 19:59

You might try cleaning your MAF sensor with MAF cleaner only.
Check Oil condition and level.
Check fuel pressure.

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P0171 = EFI-231 Long-term fuel trim, part load
P0172 = EFI-232 Long-term fuel trim, idling speed

Diagnostic trouble code (DTC) information EFI-231, EFI-232

Condition
The engine control module (ECM) receives information from the heated oxygen sensor (HO2S) about the fuel/air mixture in the idling and partial load ranges. If the fuel/air mixture deviates from λ=1 the short-term fuel trim will compensate for this by adjusting injection time so that λ=1 is achieved. When the short-term fuel trim makes an adjustment, the integrator median must be adjusted by the long-term trim. If adaptation needs to adjust to close to its maximum diagnostic trouble code (DTC) EFI-232 (idling range -0.48 ms - 0.40 ms) or diagnostic trouble code (DTC) EFI-231 (part load range factor 0.773 - 1.227) and the status message Upper limit (lean fuel/air mixture) or Lower limit (rich fuel/air mixture) will be stored.

Substitute value
none.

Possible source
Upper limit:

defective mass air flow (MAF) sensor
low fuel pressure
air leakage
faulty pulsation damper
faulty sensor signals.

Lower limit:

defective mass air flow (MAF) sensor
high fuel pressure
leaking injectors
leaking evaporative emission (EVAP) system
contaminated engine oil
oil level too high
faulty sensor signals.

Fault symptoms
can result in high fuel consumption
may result in poor performance

tardcart · Post by **tardcart** » 05 Apr 2019, 20:06

If that disconnected line was to the fuel damper, it would run rich with high fuel pressure ( smoking), but the line is usually connected to the throttle body tree.