2001 V70 T5 Rough Start in Morning

stringmonkey · Post by **stringmonkey** » 27 Sep 2016, 11:43

Hi all, I've got something here that started a couple months ago and I really should take initiative to do something about it before it truly gets cold here in Wisconsin...

Nearly 100% of the time when I start my '01 V70 T5 up in the morning it has about 2-3 seconds of "rough idle" before it finds its place. Sometimes it seems like it's going to totally die out before it steadies itself. Really feels like a misfire or something like it. Once the engine finds it's idle after that initial few seconds it is perfectly smooth for the rest of my day. I could start/stop 20 more times throughout the day and never once have this condition repeat until the next morning.

I feel like this is one of those issues that could turn into a wild goose chase if I just started haphazardly throwing parts into it so any advice or suggestions would be much appreciated.

I've got 116k on this one and all maintenance has been very well kept up to date.

Post by **kcodyjr** » 27 Sep 2016, 12:43

Is the CEL coming on?

Always move #1: check it for codes. Even if the CEL isn't lit. If you can find someone with a VIDA set, great, but in a pinch, borrow the scanner from AutoZone. It'll tell you all the really critical ones.

stringmonkey · Post by **stringmonkey** » 27 Sep 2016, 14:08

No CEL. Nothing else going on really. I have an OBD II scanner and show nothing on that either...

Post by **kcodyjr** » 27 Sep 2016, 14:11

How is it on a hot start? Does it do it? Or is it only on the first cold start of the day?

Post by **kcodyjr** » 27 Sep 2016, 14:13

Sorry, you already said that. Just the cold start. Let me think...

Post by **kcodyjr** » 27 Sep 2016, 14:18

Possibilities that come to mind:

Fuel pressure regulator might be internally marginal and allowing fuel to drain back into the tank as it sits?

Vacuum leak in the charcoal canister, causing a lean condition when it burns off the vapors?

Bad SAS check valve, allowing unintended exhaust gas recirculation?

Slow internal coolant leak, leaving water in the cylinder after it sits?

Do these models have spark plug wires? Condensation collecting on weak wires, causing a temporary partial short to ground?

Is there any smoke out the tailpipe when it's sputtering?

stringmonkey · Post by **stringmonkey** » 27 Sep 2016, 21:00

Thanks for the reply.
1- Fuel pressure regulator... not familiar with that, any way I could test that or diagnose that?
2- Vacuum leak in charcoal canister... would something like this correct itself that quickly after startup? I mean literally we're talking 2-3 seconds of rough idle.
3- Bad SAS check valve. Again not familiar with that but again as in #2 would that correct itself that quickly?
4- Slow internal coolant leak... This one seems more plausible to me. I've owned the car about a year now and had to add a splash of coolant over the summer. This also seems like a condition that would be corrected once it was displaced which in my mind could happen very quickly after startup.
5- No plug wires... coil on plug for this one. I lazily and cheaply did plugs a few months ago and didn't to coils... Not sure if a bad coil would produce this type of symptom though. In my experience it seems bad coils act up more once they're hot or under heavier load. Then again I'm not a mechanic.
6- Haven't noted any smoke when its sputtering/rough but I'll keep a closer eye on that.

Thanks again!

Post by **abscate** » 28 Sep 2016, 02:24

My T5 is a bit lumpy on startup for 2-3 seconds. I think this started being noticeable at 120k or so. Now at 180k.

I think this is safe to just monitor. If you are really rich, replace all the coils. If you are moderately rich, just replace one, and move it one cylinder each weekend to see if it improves

Post by **kcodyjr** » 28 Sep 2016, 09:41

Hm, no, I'm pretty sure the evap canister purge and the SAS system run for more than 2-3 seconds.

Search around the forums for the fuel pressure regulator. I haven't had to replace one. One way to test is, when you're expecting a rough start, press on the Schrader valve on the fuel rail, with the car still off. You should get a little spit of fuel. If not, it lost pressure and fuel drained back to the tank when it was sitting, so now it has to re-fill the line. Pockets of air in the fuel line would explain your behavior.

Yeah, when an electronic primitive like a coil gets hot, its resistance increases, so it should get worse. An incorrect spark plug gap could be a possibility. It would start to behave a little better when it warmed up. Did you regap them before you put them in?

A similar possibility to an internal coolant leak, is an internal oil leak. If you've got a bad valve stem seal, oil leaks down into the cylinder as it sits, and then has to burn off when you start it. But, that should smoke like a chimney.

Was there any sign of fouling on the old plugs?

stringmonkey · Post by **stringmonkey** » 28 Sep 2016, 10:21

Before the first start this morning I did the test on the Schrader valve and got a squirt of fuel so that's good.

As far as spark plug gap I did a once over with that but the rough start didn't really seem better or worse after new plugs. I will say that the image uploaded below does look like a bit of a fouled plug to me. I can't remember if any others were like that or which one that was but it thought that was ugly enough to snap a pic of and send to my friend.

I'll keep an eye on the coolant level... its just below the minimum level and I'm almost positive I topped it off early this year.

Quick update, this morning I didn't get a rough idle on the first start (of course it didn't because I had a friend come to observe). I had also asked any of the other drivers in my household if they have been noticing it and nobody has. I couldn't imagine how this is possible but the only time they move my car is if it is second in the driveway. When it's parked second in the driveway it's more level. So maybe it has to do with what angle its parked at. If its in the front of the driveway its parked at more of an angle and that's when I seem to notice the rough start more. I'm going to keep trying to park it level and see if this keeps helps.

One other bit of info that's probably worth mentioning now that I think of it....The vehicle came with 2" thick of maintenance paperwork/history. Basically everything has been done but the one thing I haven't found info on is the PCV system clean out or replacement. A few weeks back I had a rear cam seal go which I replaced. That cam seal failure could have been caused by a plugged up PCV or just random failure. I did the PCV self diagnosis tests and it seems fine even revving up to 2500 rpm but maybe it's all related?