'98 V70 Starting issues

[mercuric]

I've yet to have to delve into this portion of fuel delivery, so I got curious about P0442 and looked it up in VIDA. It references P0442 to DTC EFI-612, Leak Diagnostic, Minor Leak. It also pulled up an interesting "Design and Function" piece on the leak diagnostic which explains how the diagnostic is performed and which exact part of the diagnostic fails to set that code.

Leak diagnostic

Vapor which evaporates from the fuel in the fuel tank is routed to and stored in the EVAP canister from where it is introduced into the combustion process via the canister purge (CP) valve and negative pressure in the intake manifold. A leakage diagnostic has been introduced in certain markets to ensure that the fuel tank system is not leaking. This diagnostic is designed so that the system will detect a leak/hole greater than 1 mm. The fuel tank system consists of the fuel tank, fuel filler pipe, roll-over valve, EVAP canister, canister purge (CP) valve and all hoses between these. It now also has a fuel tank pressure sensor and EVAP canister shut-off valve to allow the diagnostic test of the system.
The diagnostic test is divided into phases in which the various components are tested, if a fault is detected the diagnostic test is interrupted and a diagnostic trouble code (DTC) is stored for that component.

The diagnostic test works as follows:
EVAP canister shut-off valve (B) shuts off the EVAP canister, the fuel tank system is entirely closed. Pressure (A) in the fuel tank should be fairly stable, if the pressure in the fuel tank drops this indicates a leaking canister purge (CP) valve (C), and diagnostic trouble code (DTC) EFI-315 (Canister purge (CP) valve, leakage) is stored.
EVAP canister shut-off valve (B) is opened, the tank system is open.
Canister purge (CP) valve (C) is synchronized, and because of the negative pressure in the intake manifold the engine starts to suck air through the EVAP canister. Because the EVAP canister shut-off valve (B) is open, pressure (A) in the tank should drop slowly. If pressure in the tank drops rapidly, this indicates that the EVAP canister shut-off valve is sealed, diagnostic trouble code (DTC) EFI-614 (EVAP canister shut-off valve, flow fault) is stored.
EVAP canister shut-off valve (B) is closed, the canister purge (CP) valve (C) is still synchronized, pressure (A) in the fuel tank should now drop fairly quickly. If the pressure does not drop enough, this indicates a serious leak somewhere in the fuel tank system and diagnostic trouble code (DTC) EFI-611 (Fuel tank system, serious leakage) is stored.
Canister purge (CP) valve (C) is closed, EVAP canister shut-off valve (B) remains closed, there is now a negative pressure (A) in the fuel tank.
The negative pressure (A) in the fuel tank has stabilized, if pressure starts to increase too quickly this indicates a small leakage in the fuel tank system and diagnostic trouble code (DTC) EFI-612 (Fuel tank system, small leakage) is stored.
EVAP canister shut-off valve (B) is opened, the diagnostic test is concluded.

The pressure in the fuel tank system is determined for its various phases by the following factors:
the volume of fuel in the fuel tank.
height above sea level
fuel temperature and evaporation.
The system can calculate this information. Because of this, it is difficult to say how fast or much the pressure can rise or fall in the various phases.

To carry out the diagnostic:
engine temperature must be above -10° C when the engine is started
engine coolant temperature (ECT) must be below +107 °C
there must be no permanent faults stored for the throttle position (TP) sensor, vehicle speed signal (VSS), canister purge (CP) valve, idle air control (IAC) valve, mass air flow (MAF) sensor, battery voltage, fuel tank pressure sensor, EVAP canister shut-off valve, engine coolant temperature (ECT) sensor and the engine must not be misfiring
the engine is idling and load (Tl) must not exceed 2.7 ms (automatic) and 2.3 ms (manual)
speed must be 0 km/h
the concentration of fuel vapor in the canister must not be too high
there must be more than 11 liters of fuel in the tank
the pressure in the tank must not be too high.
fuel trim must be active.
the car must be below 2700 meters above sea level.

The diagnostic test starts at the earliest 17 minutes after the engine has started when all conditions have been fulfilled, and takes approximately 30 seconds. If the diagnostic is interrupted it will try again when all the conditions have been fulfilled again. The engine control module (ECM) makes a maximum of 3 attempts in one journey. If the diagnostic test is interrupted all three times it will not try again until the engine is started again.

Diagnostic trouble code (DTC) information EFI-612
EFI-612 Fuel tank system, small leak

Condition
The EVAP canister shut-off valve is closed, the canister purge (CP) valve is pulsed. When a specific vacuum has been achieved the canister purge (CP) valve is closed. The vacuum in the fuel tank is allowed to stabilize. If it drops too much in a set period diagnostic trouble code (DTC) EFI-612 (Fuel tank system, small leak) is stored.

Possible source
- leaking fuel tank, filler pipe, fuel tank filler cap, EVAP canister, EVAP canister shut-off valve or lines between these components.
- defective fuel tank pressure sensor.

Note the quite specific conditions to actually conduct the test, which probably accounts for the "occasional" nature of getting the code.

Graphic beside leak diagnostic article follows.

[MSLV70]

That's interesting. Thanks for the info.

If the Evap canister had failed, it could cause the issues I'm seeing as the fumes could cause a rich condition under certain circumstances. I already replaced the shutoff valve, but I need to test the canister (if that's even possible). The canister is located in the front driver's wheel well area.

[Klausc]

Unless the cannister is full of liquid gasoline, the fumes will not make much difference. Not enough fumes to change the air/fuel ratio. To check the EVAP system, you need to make a smoke bomb and look for leaks, which can be most anywhere from the tank to the left front wheel. Mine was behind the right rear wheel just under the fuel filter.

[erikv11]

By far the most common leak spots trace to wasted rubber in the J hose on the canister and on the connections at the rollover valve (near the fuel filter). But Klaus is right of course, they can be anywhere.

[MSLV70]

A quick update...

I spent the last few days waiting for parts and then replacing the coolant turbo hose. Luckily it broke as I was a couple hundred yards away from my house. Coasted in to the garage.

I'm still dealing with the starting issue and the P0422 (and now P0455) issue.

My car has the charcoal canister in the front. I traced the line back to the tank where it disappears above the tank. I did find a previously installed check valve in the fuel line (it's next to the line running to the charcoal canister). It's the same one (SUR&R) I have sitting on my work bench ready to install.

Anyways, it looks like I have to drop the tank to track the hose any further back. I've got an emissions test coming up, so I'll have to take care of it soon.

I still don't think the start issue is caused by a bad check valve, but I'll probably swap in the new Sur&R just to rule it out.

[MSLV70]

I believe I fixed my problem with a new set of fuel injectors. I picked up a remanufactured set from CS Performance via eBay for $119.95. Installed them this morning and the car has started on the first crank multiple times.

Apparently the car sat in storage for years with a blown head gasket and I doubt the tank was drained when it was repaired. I imagine the damage was done to 1 or more injectors when the previous owner fired it up after the repair.

-Matt

[MSLV70]

Just closing up this thread. It was definitely the injectors that fixed the problem. I do not know how many of them were bad as it was relatively cheap to get a remanufactured set, so I didn't attempt getting them cleaned/checked.

I've started the car 20+ times since the install and it has started without issue each time.

Hope this helps someone else...

-Matt

[jonesk1978]

Thank You for all the updates I am having the same exact problem I am waiting on a ECT to rule that out first then if that doesn't work I will have my injectors checked thanks again

[MSLV70]

No problem. The car seemed to start most of the time when the outside air temp was cool, so it seemed logical that one or more of the injectors were leaking when warm/hot.

-Matt