1998 V70| Very Rough idle on start 30 seconds | ~400 K Km

[yanga001]

Hi Everyone,

Car seems to have developed a very rough start under the following conditions:
-its cold out (below 4 celsius)
-some moisture in the air
-can occur on the first start, or sporadically after the engine has been turned off then turned on

The symptoms are the following:
-rough idle, seems like a near misfire
-seems like some smoke is coming from under the hood, i think i have an exhaust leak at the flex pipe
-idle is rough but smooths out after 10-15 seconds
-white smoke out of the exhaust, smoke does not continue to occur once the car has warmed up or is driven. Smoke normally does not return in idle, does not seem to linger like fuel heavy steam

I have had a cylinder 2 misfire code, and sometimes bad upstream o2 sensor codes.

Parts changed recently
-fuel filter
-cap and rotor 30 k km - 40 k km previous
-spark plugs 30-40 k km previous NGK iridums
-Ignition wires
-Coil pack is older maybe 80-100 k km old

Things i am considering could be the cause:
-Head gasket
-bad injectors
-exhaust leak into car warmup system causing incomplete combustion

This is to log as well as gain feedback on what could cause this. Car runs like a nut normally with no issues. I did have a recent issue where a radiator hose popped off, however i caught it before the engine overheated and there was still fluid in the system. No moisture in the oil and no mixtures within the coolant. I have a leaky heater core which drains some coolant, will eventually deal with that.

Smell of the exhaust is not rich nor sweet, smells no different then before.

[scot850]

Check the coolant (ECT) is working correctly and the connector and wires are good at the connector at the back of the power steering pump.
If the ECT is not working correctly. it may not be acting like the choke on old cars and telling the engine to richen the engine on start up and may be making it run lean initially.

Neil.

[yanga001]

Check the coolant (ECT) is working correctly and the connector and wires are good at the connector at the back of the power steering pump.
If the ECT is not working correctly. it may not be acting like the choke on old cars and telling the engine to richen the engine on start up and may be making it run lean initially.

Neil.

I forgot to mention i swapped the ECT from my crashed car into this car. Resistance ranges on the cooler in my car appeared to be better at ambient but the issue persisted prior to changing the sensor and continues to persist unfortunately. Ill test the old sensor to see if it was within operating specs.

[scot850]

It is also possible a fueling issue like a leaking pressure valve. Try, priming the pump before trying to start it by turning the key on and off to Pos II maybe 3 times and see if it starts any easier. Also check the fuel pressure at the rail. Should be around 42 psi.

There are a few other things worth checking:

Check the distributor cap for condensation,cracks, dirty contacts. Also check the rotor arm for wear.

When were the leads to the spark plugs last changed as well as the plugs?

Neil.

[yanga001]

I swapped the leads recently with known good ones and did resistance tests to verify.

Going to try a injector additive tonight to see if it helps any.

I'll check with my scanner when time permits to see if it happens only in open loop mode or closed loop. Will boroscope cylinder 2 after letting it sit to see if coolant is inside.

[yanga001]

Gotta find my compression tester for cylinder 2z. Got a second misfire code on it. Behaviour seems to occur on cold or hot restart of engine when temps below 5C or high moisture. I would be disheartened if it is the head gasket at this point as I was hoping for another two years from the vehicle. it runs and drives great otherwise.

My coolant has not become oily nor has the oil shown signs of moisture mixing. I still get an o2 sensor issue and may have an exhaust leak.

Edit:

Identified a major exhaust leak near the exhaust manifold while running without the radiator cap. The exhaust coming from the engine is not white so I suspect moisture is being pulled in as it goes through the exhaust system. The coolant reservoir is not full of oil either. Will get under the car to see if it needs a new manifold or if it’s a bad weld.

[MrAl]

Hi,

I was having problems like this too and i found it was mostly the fuel pump relay, the electrolytic capacitors were bad. They only last so long and have to be replaced or else buy a new fuel pump relay. If you already did this or "Jumper'd" the relay contacts for the test i guess that's not it.

I eventually found another problem related to that. One of the ignition wires was very bad and had to be replaced.
I'll replace the others too but it's been cold out now that winter hit here in New Jersey. I hope we get a warm day soon.
Strange though, it takes two tries to start the car now it always started on the first try before these problems came up.