VVT solenoid, misfire, lean condition, smell gas

Post by **FireFox31** » 22 Jul 2022, 00:44

I'm in need of help to diagnose a suite of problems with my 2000 V70 with 226k miles. I've got VIDA but need guidance for how to get useful data from it. I've been helping family, unable to fix these problems, and I fear they're getting worse.

For 1.5 years and 20k miles, my car has been a little sluggish (I'll do those recommendations soon). For 7 months and 11k miles, I've had P1672, VIDA's ECM-640A error for the VVT solenoid (camshaft reset valve). Some time in the past 4 months (since my last scan), I got P0301 Cylinder 1 Misfire and P0171 System Too Lean (Bank 1). For a month and 650 miles, I've smelled gas at the back of the car even when it's been off for hours and today I smelled it strongly when idling. For a few days, I've had slightly rough idle, finally prompting me to take action.

To address the misfire, I swapped coils and reset the codes. After a 15 min drive with some hard acceleration, the codes came back. The misfire didn't move with the coil.

My freeze frame data (perhaps during hard acceleration) is:
Fuel Sys 1 - OL-Drive
Fuel Sys 2 - CL-Fault
Calc Load - 10.98%
ETC - 181 F
STFT B1 - 0.00%
LTFT B1 - 49.22%
MAP - 6.50 inHg
Eng RPM - 1809
Veh speed - 39 mph

Could the VVT issue be causing a lean condition and misfire?

As a temporary fix, can I disconnect the cylinder 1 injector power wire to stop spraying gas in the misfiring cylinder? Can I drive a 700 mile round trip like that?

I'd like to see if and how the VVT solenoid moves when activated. Can I unbolt it from the block and trigger it while attached to the car? If I can get access to a 12V source to bench test it, does it matter which pin I use for ground and 12V? This video described solenoid testing.

What VIDA functionality can I use to monitor the VVT, fuel trim, MAF, ETM, O2 sensors, etc? abscate says to watch for STFT <5%, but where do I find that in real time?

Here's a good post and thread about P0171 diagnosis on a P2. Do the same methods work for a P80 V70 with ETM?

I'm going to check the spark plugs for unburned fuel, clean the ETM, test and swap on a used VVT solenoid, look for broken vacuum lines on the air intake, and maybe clean the MAF. Other forum posts I found implicated the throttle position sensor or front O2 sensor.

Thanks for any help.

Post by **abscate** » 22 Jul 2022, 02:00

I got P0305 Cylinder 1 Misfire

?.?.

P0305 should read as cylinder 5 misfire…..soy confuso

454cid · Post by **454cid** » 22 Jul 2022, 04:19

I would pull cyl 5 plug and see what it looks like.... maybe all the plugs.

I would also check fuel pressure. I wonder if you have a leak towards the back, and are not getting full pressure to the engine, and the engine is trying to compensate.... I didn't know LTFT could even get that high.

Does CL fault indicate the car is running in open loop?

Post by **Chuck W** » 22 Jul 2022, 05:48

454cid wrote: ↑22 Jul 2022, 04:19 I would pull cyl 5 plug and see what it looks like.... maybe all the plugs.

I would also check fuel pressure. I wonder if you have a leak towards the back, and are not getting full pressure to the engine, and the engine is trying to compensate.... I didn't know LTFT could even get that high.

Does CL fault indicate the car is running in open loop?

I agree with this. Start here.

Post by **FireFox31** » 22 Jul 2022, 11:01

Sorry, I typed the DTC code wrong. It is P0301 Cylinder 1 Misfire. Edited above.

Regarding fuel pressure, another symptom is that the car kind of stumbles to start when cold. It takes three cranks when warm, but when cold, it can take four to six with the final one being maybe a half crank. I replaced the fuel filter in 2021. I was just under the car trying to trace the fuel smell, sniffing around everything, only detecting a scent where the fill neck connects to the tank.

Could the LTFT have been high because I was really hard on the throttle when the CEL was triggered? Previous freeze frame data for the misfire, recorded at an unknown time, was:
Fuel Sys 1 - CL
Fuel Sys 2 - CL-Fault
Calc Load - 34.12%
ETC - 140 F
STFT B1 - 21.09%
LTFT B1 - 10.16%
MAP - 13.88 inHg
Eng RPM - 841
Veh speed - 1 mph

I'll spend some time learning about the fuel data in freeze frame and VIDA so I can diagnose it further. I'll try to obtain a fuel pressure gauge today to get a reading.

Post by **abscate** » 22 Jul 2022, 12:04

Lets take some STFT on a warmed up engine, Closed loop, at idle

STFT (R=850) = ???

STFT (R=3000) = ???

LTFT at end of test = ??

to see how bad your vacuum leak is..

Post by **FireFox31** » 22 Jul 2022, 22:47

I did not get to test fuel pressure because I don't have a tester. I order one soon.

Fuel trim data with engine warm according to VIDA:
Idle - 880 rpm, STFT 1.13, LTFT 1.49, front O2 lambda 1.08
Rev - 3000 rpm, STFT 1.07, LTFT 1.08, front O2 lambda 1.00
Idle after rev - 850 rpm, STFT 1.24, LTFT 1.49, front O2 lambda 0.99

: Idle after rev; PXL_20220723_012032596.jpg (428.44 KiB) Viewed 7820 times

I had cleared the codes before running this test. After running it, VIDA reported:
ECM-250A Long-term fuel trim - Upper limit
ECM-3502 Misfiring - Cyl.1

While at idle, "ECM-Misfire counter 1" constantly incremented until it hit 255, stayed at max (presumably until it hit 512), then reset to 0 before beginning to increment again. Yet when driving around town, the misfire counter reset and stayed at 0. The following image is from a short drive around town.

: Misfire only when idle; PXL_20220723_022610026.jpg (257.31 KiB) Viewed 7820 times

While testing at idle for so long, I had my windows up and cabin fan off. When I turned on the fan, it smelled like exhaust. Inside the engine bay smelled a little like exhaust too. I don't hear an exhaust leak but I mention it since we're talking about air leaks.

I pulled my spark plugs and they looked decent but a little black. They're 1 year and 16k miles old. Plugs 2 and 3 had oil on their threads though the PCV and filler cap are not leaking. I swapped the misfiring plug 1 with 3. The misfire remained on cylinder 1.

: Plugs too black?; PXL_20220722_193035038.jpg (336.57 KiB) Viewed 7815 times

I checked my intake VVT solenoid with a multimeter and it read 78.2 k Ohms. The spare I have read 4.3 Ohms. I couldn't install the spare because it has the new style wiring (the adapter is available separate from the kit from, parts 9441560 and 30656680).

The sensor in my thermostat may be damaged from coolant dripping down from my loose coolant hose. A multimeter reading across its pins read 1.537 k Ohms. VIDA has reported " CCM-135 Engine coolant temperature (ECT) Signal missing " for four months. My dashboard thermometer works fine and VIDA seemed to report temps accurately. Since summer heat started, my engine fan occasionally runs for a few minutes after stopping the car, typically after short drives when the engine is warm, not after five hour highway drives.

: ECT with coolant drips; PXL_20220722_205945400.jpg (188.13 KiB) Viewed 7820 times

Post by **abscate** » 23 Jul 2022, 01:49

Fuel trims are fine. Probably getting the long term trim fault due to misfires. Plugs look fine.

Did you try moving the coil to isolate the fault?

See look up table for 1999- on style ECT ( they glitched the formatting a bit and shifted the columns one box over)

454cid · Post by **454cid** » 23 Jul 2022, 02:20

I'm confused..... you got a lean code, but the O2 is showing around 1 volt, which is rich. It should be pulling fuel, but your fuel trims are under 5%???

Post by **FireFox31** » 23 Jul 2022, 10:14

I got the lean code while accelerating hard on the highway. I'll record that run on VIDA and see how it looks. Can anyone recommend which sensors I should be recording to get helpful information?

I'm baffled by the misfiring only at idle. I swapped the plug to one cylinder and the coil to another, but the misfire stays on cylinder 1.

Thanks for the ECT data. I'll check mine more closely before installing the one I just bought from FCP.