2001 V70 T5 mt starts and dies...SOLVED: MAF was root cause Topic is solved

[93SCMax]

Original owner, 158k, had been running well but I am putting few miles on the car these days. I do not have VIDA but do have a good Craftman OBDII scanner.

What I've done:
- New Interstate battery installed 2/14/2023. Old Volvo OEM battery was 87 months old and wouldn't hold a charge.
- Started car Sunday morning and the idle was very rough, totally uncharacteristic. No codes. Idle is normally smooth and steady. Turned the car off. Came back later that afternoon, started right up, all normal. Did a test drive, all normal.
- Started the car the next day. Very irratic idle then it dies. Tried a few more times, always died a few seconds later. Can't even keep it running long enough to get it into the garage. Still no codes. Disconnected the new battery for two days hoping it's an ECM glitch.
- Started again multiple times but won't stay running. Feels like it's fuel pressure or electronic control/sensor related. Still no codes.
- Searched the forum for similar experiences. Lots of posts. Battery, clogged fuel filter, PEM, FPS, ETM/ECM connectors, etc.

Analysis:
- I feel the battery isn't an issue as it's 2 weeks old and measures 12.4 V with the car off. I can't keep the car running long enough to check whether the alternator is charging it.
- My fuel filter was last replaced with a Volvo OEM filter on 6/2012, about 50k ago. I don't really think I have a clogged filter, but I ordered a new one and will change it out when it arrives.
- I don't think it's ETM related since I installed a newer version ETM from a junkyard S60 T5 about 2.5 years ago. My original ETM developed the standard failure mode and threw the Orange triangle on the dash. No triangle now.
- I'm really thinking its either the PEM or FPS. Both should be original. I don't have a fuel pressure guage to plug into the rail. Can someone direct me to a "how to do this"? Also, exactly where on the fuel tank is the PEM? Since the car is in the driveway on a slight slope, it will not be easy to jack the rear and get under it.

So I'm thinking, new FPS unless I can check the rail pressure, and/or junkyard PEM, unless I can remove the current PEM and clean it.

Any advice on the most efficient, least costly way to solve this would be appreciated? Am I missing another common root cause?

Thanks for any/all input.

[deano1]

Did you say you checked fuel pressure? You can hear fuel pump cycle when you turn key to position 2?
I don't think 2001 had PEM, just old style FPR. I may be wrong on that though.

[93SCMax]

Thanks for your response.

No haven't checked fuel pressure...would need a guage and "how to" procedure.

Funny, after watching Youtube videos concerning the PEM, I can't find one in the standard location. Tell me more about FPR?

[abscate]

Did you say you checked fuel pressure? You can hear fuel pump cycle when you turn key to position 2?
I don't think 2001 had PEM, just old style FPR. I may be wrong on that though.

Righto for deano, no PEM on a 2001

Check robert DIY Volvo channel for fuel pressure check video

[deano1]

Fuel Pressure Regulator just bypasses extra pressure back to the tank. Nothing real fancy but it works, where as then PEM varies the speed of the pump to match engine needs at different loads.
So I would start by listening for the pump to cycle at key position 2. It will only do that for half a second or so then you should check at the schrader valve on the fuel rail for pressure.
If pump doesn't cycle On/0ff then we have to suspect fuel pump. But before pulling the pump make sure the pump is getting power when it's suposed to.
Cheers

[93SCMax]

Thanks for the responses.
I was questioning whether I had a PEM. Confusing that the Volvo parts sellers (IPD, FCP Euro) list a PEM that fits my model and year.

Where is the FPR located?...hopefully not in the tank. Per another video I watched, I'd like to see if the FPR vacuum hose causes a change.

One other relevant fact. Volvo did a safety recall for "a potentially" leaking fuel pump. I declined multiple offers to have mine changed because the car ran great and I had no leak. I didn't want to potentially introduce another problem. So...the fuel pump is original.

I'll try the cycle test and also try to do a pressure test at the schrader valve.

I appreciate the help.

[93SCMax]

Update:
- 15A fuel pump fuse #33 good
- Fuel pump relay CMI12 exchanged with known good relay CMI11
- Key on position II generates 2 sec whirling noise from the fuel pump. Multiple on/offs confirm activation so it appears the fuel pump has power.
- Car still starts, won't idle and dies a few seconds later. No codes or error messages.

Researching fuel pressure guages as the next step to check rail pressure when starting.

[volvolugnut]

There are multiple part failures possible. Start troubleshooting.
Check fuel pressure - it should be about 55 PSI. Check with a gauge at the end of the fuel rail. A 0-100 PSI air pressure gauge and short rubber hose of correct size to fit on the Schroader valve will work for a fuel pressure test. Just remove the internal valve inside the end to allow fuel flow to the gauge. Hose clamp everything to prevent leaks.
Does your scanner read recorded engine parameters? Check for throttle position reading and inlet air temperature. At idle throttle should be about 10%. Inlet air temp should be about ambient temp. Coolant temp should be some reasonable temp. If any of these are weird you have a sensor issue.

Plug wires all connected? Any loose wires you may have accidently bumped?

Is the turbo pressure hose in place and tight? This will prevent running.

volvolugnut

[93SCMax]

Volvolugnut,
- my scanner does record engine parameters. I will check them.
- no wires disconnected or accidently bumped. The only work done on the car recently was putting in a new battery in the trunk. Only other work under the hood was to see if critters ate a wire, and to check fuses and relays. I think everything looks normal. The car had been running well except for the drained battery when not run regularly.
- I double checked the turbo pressure hose and it's secure on the turbo. I'll have to double check at the ETM end.

The car not being inside the garage has created a few problems for me.

Thanks for your advice.

[93SCMax]

Well I seem to be making progress thanks to the help provided here.

ETM hose is on solid.

I can eliminate the fuel pump. Pressure is 51 psi at key on, 55-57 while cranking, and around 50 psi 30 minutes after key off.

I also disconnected the MAF, and was able to keep the car running at idle, although it ran rough. I swear I had done this earlier during troubleshooting and the car would not run at idle with the MAF disconnected. In the past, if I had a MAF issue, it always threw P0100. I did have a spare junkyard MAF in the garage, so I changed it out. The car now runs and doesn't die with the "used" MAF, but runs extremely rough at idle, like a cylinder is missing. The rpm's jump around from 790 to 835 rpm (manual transmission). I don't know if this because the ECM now needs to relearn (battery disconnected for two days), or whether I haven't completely addressed the root cause. Previously, the car ran and idled perfectly.

Other scanner data at key on, cold engine: ECT=66F, IAT=68F, TPS%=19.6, O2SB1 S2=0.430V, O2SB1 S1= -0.007, EQ Ratio 11 = 1.000.

Now that the car will idle, I should be able to capture data if that will help troubleshoot. I may also try to procure another MAF.

I'll disconnect the pressure gauge and let the car idle for awhile. I may attempt to take a short drive around the neighborhood. If nothing else, I can now move her into the garage for further troubleshooting.

I'm still baffled that I haven't thrown a code. I wish I had bought VIDA/DICE 20 years ago.

Any other advice?