98 V70 T5 rough idle after warm up, eventually stalls... Topic is solved

[abscate]

That problem will come back. I doubt the pulse damper caused those symptoms.

[valvolvo70]

That problem will come back. I doubt the pulse damper caused those symptoms.

I'm typically a positive guy so I thought sharing what has worked thus far, after trying several other options, seemed to be inline with the overall helpful comments and suggestions on this site. If it goes to hell again, I'll start with your earlier recommendation$.

[yeahyeah]

Did the problem come back? Looking at a similar symptom on a S70

[valvolvo70]

Did the problem come back? Looking at a similar symptom on a S70

Nope...

[misha]

Just replaced the thermostat and ECT...same problems...stumped. Time for a beer.

I found the topic!
So let's go back from a beginning.
Is ECT oem Volvo?
Did you checked connectors for corrosion on both sides(ect side and wiring loom side)?

Is the connector fully 'home"...is it seated properly?

Next....FPR.
'98 T5 (since you have just a damper at fuel rail) is M4.4 and fpr is at passenger's side rear wheel.
Check it's vacuum line for fuel(there should NOT be even a trace of fuel in the vacuum line).Few drips of fuel in the vacuum line are enough for misfiring,sputtering and rough idle.

When FPR is leaking in the vacuum line it's always followed with black smoke from the exhaust.

Disconnect vacuum line,cap the line from the engine side and start the car.Watch for fuel drops from vacuum line from fpr as the car runs...again...there should not be even a trace of fuel.Let it idle for 10-15 min just in case if membrane starts to leak a bit later(it happens).

About evap code....

This time i would check a purge valve which is on driver's side,mounted right besides a radiator and one vacuum line goes directly to intake manifold under the vacuum tree and idle valve(iac).
Remove the purge valve and blow through it.
It's normal state is CLOSED.
It's opened in some conditions when ecu ask for it while the car is running or idling.
So...when removed it must be closed(not able to blow through it).

Cap & rotor.

Are they oem Bosch?

This problem will need detailed inspection.

[valvolvo70]

Just replaced the thermostat and ECT...same problems...stumped. Time for a beer.

I found the topic!
So let's go back from a beginning.
Is ECT oem Volvo?
Did you checked connectors for corrosion on both sides(ect side and wiring loom side)?

Is the connector fully 'home"...is it seated properly?

Next....FPR.
'98 T5 (since you have just a damper at fuel rail) is M4.4 and fpr is at passenger's side rear wheel.
Check it's vacuum line for fuel(there should NOT be even a trace of fuel in the vacuum line).Few drips of fuel in the vacuum line are enough for misfiring,sputtering and rough idle.

When FPR is leaking in the vacuum line it's always followed with black smoke from the exhaust.

Disconnect vacuum line,cap the line from the engine side and start the car.Watch for fuel drops from vacuum line from fpr as the car runs...again...there should not be even a trace of fuel.Let it idle for 10-15 min just in case if membrane starts to leak a bit later(it happens).

About evap code....

This time i would check a purge valve which is on driver's side,mounted right besides a radiator and one vacuum line goes directly to intake manifold under the vacuum tree and idle valve(iac).
Remove the purge valve and blow through it.
It's normal state is CLOSED.
It's opened in some conditions when ecu ask for it while the car is running or idling.
So...when removed it must be closed(not able to blow through it).

Cap & rotor.

Are they oem Bosch?

This problem will need detailed inspection.

I'll run through this list on my T5 and then respond to your questions, thank you for your detailed list!

[valvolvo70]

UPDATE:
Removed purge/EVAP valve and could blow right through it, should be closed. Found a post here on "how to clean EVAP" and sprayed throttle body cleaner until all the black gunk stopped running out each end. Some recommended taking the valve apart, I didn't. Blew through the valve again, it was closed, reassembled valve. Tried to start several times and it only turned over. On the final try there's a loud POP (fire cracker) and smoke billowing from behind/below the engine block, looked like a magic trick in my garage. Oil (spray) was forced from under the oil cap onto the plugs, and after removing the cap, there was smoke inside the block. First thought was I didn't wait long enough for the TB cleaner to evaporate before starting? or......its toast.

I haven't tried to start it again until I here recommendations as to the next steps, if any.