V70 2000 2.4T Hard to Start After Sitting Overnight – Need Help Diagnosing

[d3xter]

Hi everyone,

I'm having an issue with my 2000 Volvo V70 II 2.4T. The car doesn't want to start after sitting overnight. The starter cranks, but it only fires up on the second or third attempt, and then it struggles to stay running. After another try and once the engine warms up a bit, the problem goes away, and everything runs smoothly. When the engine is warm, I can turn it off and restart without any issues.



I have the VIDA diagnostic tool, and it's not showing any misfire codes. I've tried running the car without the LPG, but the issue persists. The LPG is set to start at 35°C (95°F).

Here's a list of recent repairs with dates:

• June 2021: CEM repair, LPG injectors replaced

• July 2022: Throttle body cleaned

• August 2023: Exhaust system replaced, including the catalytic converter

• January-May 2024: Replaced VVT sensor (third one), with a new gasket, camshaft seal, fuel cap, spark plugs, oil service with filters, and intercooler pipe with two sensors

• July 2024: LPG regulator refurbished

• A while back, all the ignition coils were replaced, the VVT pulley was swapped, and the throttle body was refurbished.

The car feels low on power, likely due to the ECM-6806 error, but that’s not my main concern. The longer the car sits, the harder it is to start. After sitting for a week, it wouldn’t start at all, not even a misfire. I tried push-starting it three times, but the engine wouldn’t catch. Eventually, it started when I turned the key. The wires and hoses under the hood look intact with no visible cracks. The wiring harness going to the coils is in bad shape; the plastic sheathing has deteriorated, leaving some wires exposed, though the engine runs smoothly without any noticeable issues like fluctuating RPMs.

Where should I look? Is there anything I should check with VIDA to track down the problem?

[abscate]

The engine coolant temperature sensor, or ECT, is a common cause of this. It’s a 1999-2000 only part

You can test it with an ohmeter to resistance specs which are in these Fora pages. I’ll try to link

[d3xter]

How can the ETC prevent the engine from starting properly?

I replaced the VVT sensor. Which of these operation graphs looks correct, 1, 2 or 3? I’ll check tomorrow morning to see if it helped.

• 1.

before.jpg (60.35 KiB) Viewed 755 times

• 2. (without 4000 rpm)

old_too_still_before.jpg (64.78 KiB) Viewed 752 times

• 3.

after.jpg (59.21 KiB) Viewed 755 times

[jonesg]

"How can the ETC prevent the engine from starting properly?"

if the coolant temp is being reported off .

is fuel pressure priming up at key on.?

[d3xter]

The ETC is working correctly; I checked it with a multimeter, and it shows the proper values. Replacing the VVT valve caused an incorrect reading for adaptation camshaft opening. I'll try another sensor, but this time I'll disconnect the battery terminal before replacing it.

[d3xter]

My wife refueled with gasoline yesterday, and today the car started up normally! I don't remember when it was last refueled... Where could the problem be? In the quality of the gasoline? In the fuel tank? I used to fill the tank completely and could go 4 months without refueling, and the car would start normally.

[jonesg]

fuel pressure.?
if the pump is marginal , the full tank creates a lot of head pressure to assist the fuel pump.

also, if the temp sensor in the pass compartment is off it can affect the start mixture.
i think its located in the passenger mirror.

[d3xter]

The fuel was definitely the problem, I bought a fuel system cleaner additive, and later I'll replace the filter. The car is working fine now.