01 S60 intermittent hard start

[rbodor3]

Looking for advice what to check next.

For about a year, I've had a very intermittent hard start.
ALWAYS
-After about 30 seconds of key Pos2, starts fine.
-Fuel Pump Relay (in CEM) clicks on/off at a very regular interval. As soon as it's done clicking (~30s), starts fine
-Car has been sitting at least 1hr

SOMETIMES
-In key Pos1, Tach swings all the way to red, sometimes it jerks back-and-forth between 0-red

NEVER
-Appears to have nothing to do with temperature or rain
-After starting, there are no P-codes

Throughout this journey, I've tried everything I can think of. In chronological order:
1) Discovered starter batt+ cable loose
2) Discovered AC (FMI1) and horn (FMI2) relays intermittently not activating; replaced
3) Windshield washer pump relay (FMI3) not activating; replaced
4) Replaced alternator (swap-nostics)
5) Replaced ECM relay (FMA2) (swap-nostics)
6) Replaced starter relay (FMA4) (swap-nostics)
7) Replaced starter (swap-nostics)
Discovered FP relay (CMI12) was clicking intermittently; replaced
9) Replaced fuel pump (swap-nostics)
10) XeMODeX CEM replacement
11) Discovered taillights not turning on; replaced relay (believe CMI7, but didn't record)
12) Discovered windshield wipers intermittently not working; replaced relays (FST1, FST3)
13) Intermittent misfire while driving <30s. Intermittent misfire at idle. Replaced COP #3 & #5
14) Replaced crank and cam position sensors (swap-nostics)

[jonesg]

Replace the mechanic !
Seriously, try more diagnosis, do a fuel pressure test .
Have you run vida on it ?.

[br0dy519]

Are you sure that clicking you hear after 30 seconds isn’t the throttle body calibration?

You’ve replaced about a thousand relays, I’ve never had a single one fail. If your car is actually frying relay after relay, you’ve got a more serious issue on your hands… follow jones’ advice and get this thing on a VIDA read immediately.

[rbodor3]

I erased all faults, then restarted and recorded the following codes:
CEM-1A61, Comm w/ TCM missing - I manual-swapped the car in 2013, had the ECM tuned, and removed the TCM. This DTC is always active.
CEM-3F03, Shift lock signal - low - DTC always active due to manual swap
DDM-0025, Mirror motor - signal missing - Driver's side mirror motor replaced ~2015, used motor was failed, and wasn't connected
DDM-0030, Rear view mirror potentiometer - faulty signal, red
DDM-0032, Rear view mirror potentiometer - faulty signal, red
PDM-003E, Control module - signal too high, red
CEM-1C02, L-signal - signal low, amber - L-signal reports <0.2V at pos2, >0.8V engine motoring

Prior to changing the fuel pump, priming pressure (key pos 2) was low. I pulled the rear seats and couldn't hear the pump priming in Pos2, and replaced w/ new Bosch OE pump. Pump still not priming, which is when I discovered the FP relay CMI12 was clicking intermittently.

I have the CEM out of the kickpanel and can touch the relay, so I'm 100% certain the FP Relay is the clicking sound

[rbodor3]

Fuel pressure = ~50psi primed
=~60psi running
=~45psi after 30min

[jonesg]

CEM-1C02'
check the small signal wire at the alternator, pull the spade connector and inspect for green gremlins.
Signal low is often "signal missing."

What voltage do you get across the battery terminals as it idles, should be 14v+

a lot of problems may have been caused by that loose power cable.

you're gonna have to catch it when it won't start and do some quick troubleshooting, a noid light on a coil connector to make sure they are firing, listen to the injectors with stethoscope as someone cranks it.

[rbodor3]

Signal wire at alternator checked fine. Battery at idle shows 13.5-14VDC.

While investigating wire harness for any potential shorts, I discovered the VVT solenoid wires had cracked and were intermittently shorting! Digging further, found significant damage across all the ignition wiring back to the main trunk. I checked all wiring back to the ECM to confirm no damage elsewhere. I replaced all this wiring w/ that from Prancing Moose. A few of the IPD HD coil packs showed signs of cracking/failure, so I replaced all w/ Bosch OE.
I'm not sure how long the VVT sensor wires were intermittently shorting, so I disconnected and measured resistance along that entire circuit:
VVT solenoid = 4.2 Ohm (3.7 spec)
EVAP canister valve = 22 Ohm (28-32 spec) <-- replacement purchased
PTC valve = 9.6 Ohm (cannot find a spec in Vida)

I confirmed no other short-to-low/high anywhere else in the harness, and buttoned it all back up.

Intermittent no-start still continues. I'll update once the EVAP canister valve is replaced, but I suspect that is a red herring.

[abscate]

That’s had a massive short to ground and needs inspection all the way on the wiring loom. Ooof, that’s bad.

Resistance measurements on solenoids are guides and not to be taken too holistically as diagnostics. I’ve found 50%-100% variation on solenoids in good operating condition, from Volvo specs

[rbodor3]

In order to pass emissions, I've been driving the car every day for a week to get it to go show OBD Readiness. No failure recurrence.
Last night it finally showed "Ready". When I started the car this morning, the failure recurred. I left the key in Pos2, and after ~10s (as always) the failure stopped (relay stopped clicking) and I started the car. It's now "not ready", has high idle and rich AFR (which always occur after failure).

My next steps are:
-Replace EVAP Canister Purge valve, which I'm still pending delivery from IPD - although I doubt this is the cause.
-Inspect the internal circuitry of the ECM for any damage due to the shorted COP/VVT wires. I doubt I'll find anything because visual inspection would likely only reveal a truly catastrophic failure (rather than my intermittent fail).

[rbodor3]

Discovered the PTC heater wiring leads have exposed wires & corrosion right at the connector. You can better see this in the photo after I cut the connector off the main harness. I suspect this was causing a short, and shares a common ground w/ the ETM, and common power to the TCV. Since the corrosion was so close to the connector, I decided to repair:
Sprayed w/ QD Contact Cleaner
Dabbed w/ Starbrite liquid electrical tape
Slipped heat shrink over each lead
Re-soldered to the main harness (w/ heat shrink), and new loom

Again, it's running fine. No fault set at any time.