First post on the board, very nice resource! I didn't find what I was seeking with the search function so I figured I'd ask a question.

I've got a 2001 Volvo V70 that has a "first start of the day" problem. After the car has sat for at least 12-18 hours it will start and run rough for about 5 seconds, then smooth out and run normally.

The car went to the dealership for this problem last year and they were able to duplicate it. They claim it is losing pressure on the fuel rail after sitting for a period of time. They wanted to replace the fuel filter and the fuel pump.

Well, time goes by and I replace the fuel filter and the intank pump, however, it did nothing for the problem at all. Still, the first start of the day leads to rough running and then it clears out and runs just fine.

Has anyone else experienced this issue? The car has had the throttle body recall performed and done, has new Volvo plugs, good maintenence, etc. Solid car, we like it (bought it used in 2001, 7k on clock, has 85k now) and plan to run it for at least four more years, just would like to get rid of this little issue as well as a couple others.

Thanks much,
Ron

 

Do you have access to a fuel pressure gauge?
If so connect it and let it sit and see for yourself if the fuel pressure drops.

Maybe the fuel pressure regulator is bad. You can also pull the vaccum line on the regulator and see if it has gas in it.

 

Hey Ron. Welcome aboard. Is this the first issue you've had in 6 years? I'm jealous. Hope you get your 4 more years out of it. Sorry i can't help you with your starting problem tho. But someone will.

 

Yep, I have fuel pressure gauges and can easily check the pressure.

However, I don't think it is fuel pressure related. When you turn the ignition key to position 2 the fuel pump is on. It'll pressurize the fuel rail. So, many times I've turned the key to position 2, sat there for varying periods from a few seconds to half a minute, and then started the car. Same thing, runs rough on the initial start of the day.

As far as problems this is not the first one I've had with the V70. I've had the strut plate issues, leaking power steering reservoir, and a few other common V70 issues. I've fixed them all myself except for the tbody issue as that is mostly parts, but this rough starting one I don't have a good clue yet as to what to go after. I do a lot of car work - build motors, race cars, etc. but I'm unfamilar with Volvo ECU systems.

R

 

But when you turn the key on once if all the fuel lines are empty it won't prime all the way to the rail. It will take turning the key 3 to 4 times to prime all the lines.

 

I can certainly try that as well, and monitor fuel pressure. This week I'll put my gauge on it and leave it there so that it can be monitored after sitting.

 

On second thought, I'll ceratinly try it but if it shows and issue on pressure with key on once then it behaves differently from every other rail fuel injected car I've owned and messed with.

Everything else I've worked with is fully pressurized within a few seconds of pump being on. The pump is definitely on in the 2 position, so it should acheive working pressure (not sure what it is on a Volvo, I'd expcet 35-45 psi or so) more or less immediately.

I'll slap a gauge on it.

 

Yes but if all the lines empty. The pump only runs for like 5-10 seconds then turns off if the car isn't started.

 

Most likely a a fuel issue in this case , Though I had a similar rough running on cold start problem with my S70, 5 fresh sparkplugs cleared it up.

 

It isn't fuel or spark plugs. It has new plugs, and the problem has existed for over a year on various fuels.

I forgot one piece of info that is very important:

The problem does not exist when outside temperatures stay below 65F. So, if the night before the startup is cool, around 55-60F, it won't happen. Sorry about leaving this piece of info out.

R

 

If that is the case I would be looking for a faulty coolant temp sender. It will cause start problems also.

 

Good idea. That is simple to check out, simple to replace too as I recall.

R

 

Maybe a coolant temp sensor issue. Or thermostat.

 

I have replaced the thermostat to no avail. And the fuel pressure is quite okay, even on leak down overnight.

Have to look for a engine coolant sensor, and, does the V70 have an air intake temperature sensor that might be malfunctioning? Maybe it is reporting air temps colder than actual, resulting in a fuel enrichment for a predicted cold start that does not exist? I would think that handled by the engine coolant sensor but I don't know Volvo ECU strategies.

Ron

 

On yours the Mass Flow sensor and coolant temp sensor work together for the cold start.

 

Resurrecting an old thread. What ended up being the problem? I am having the same issue - but mine doesn't appear to be outside temp related.

 

My Volvo has the exact same issues any of you around ten years later to say what the fix was?

 

I'm running into the same issue, although the issue is consistent regardless of temperature outside. The car (2002 V70 XC) will crank over multiple times and either stall out, or eventually start, leading me to believe either a sensor is causing it to not get enough fuel when starting. New battery, new coils and plugs. New alternator, new fuel filter. Once running, it will randomly idle low (~500RPMS) but then will kick back up to the 675's. When pressing the gas and driving, no issues. I also recently (12 months back) put in a new Manifold Pressure Sensor. Did anyone ever figure out the fix? I'm going to try replacing the Coolant Temperature Sensor as a hail Mary attempt. But don't really want to unknowingly replace all the engine sensors without some kind of clue.

 

The best way here is get a scan tool or borrow one and you can just read the engine temperature directly. When the engine is fully cold you can easily conclude whether you agree with it or not.

 

I should also note, no codes on my reader. I'll check the temp when cold per your suggestion regarding the CTS, in my experience with this car (purchased in 2010) odd sensors failing seem to cause (what one would assume) unrelated symptoms.