Rough start/idle... CEL flashing

[MrHeavyFoot]

I suspect this is a coolant temp sensor issue, but I thought I'd get some input first.

1. In the past, there have been codes thrown regarding intermittent signal from the temp sensor or something to that effect, but I haven't changed to the green top sensor yet.
2. Temperature light came on yesterday (flashing plus a few beeps) shortly after I started driving home from work, but the car seemed to drive/behave fine. Temp light went out after a couple of minutes.
3. This morning I started the car. Ran very rough for a few seconds then died. Restarted, and gave it a little gas. Car kept idling this time but very rough, CEL started flashing. Popped the hood and the engine was literally shaking.
4. Turned off the car. Took the bus.
5. Haven't had a chance to scan for codes yet. Hope to do that tonight.

If the temp sensor is the cause, will changing it out immediately fix the problem? Or if it was running too rich, is it possible that the spark plugs are now "wet" and will need to be removed/dried before it will run smoothly again?

I ask that because something similar happened last year, except I was never able to get it to refire after it died the first time. At the time, they just changed the spark plugs and all was good, but now I'm wondering if the coolant temp sensor wasn't the root of the problem.

[RobG]

Re: Rough start/idle... CEL flashing

I have had the Beeping and flashing as well, I was told that is only triggered by the low coolant sensor in the overflow, it only happens when its below about -25ish. I'm finially going to switch up the tempsensor for a new one, there is no codes but it reads high through the VAGCOM and the glow plugs don't come on for long enough.

[MrHeavyFoot]

Re: Rough start/idle... CEL flashing

I have had the Beeping and flashing as well, I was told that is only triggered by the low coolant sensor in the overflow, it only happens when its below about -25ish. I'm finially going to switch up the tempsensor for a new one, there is no codes but it reads high through the VAGCOM and the glow plugs don't come on for long enough.

Thanx.

I was going to check the coolant level tonight. Come to think of it, the light did come on while circling down the long counter-clockwise exit ramp in the parkade. I suppose if it was borderline low, that could have set it off. Doesn't explain the rough start/idle this morning though.

[RobG]

Re: Rough start/idle... CEL flashing

Thanx.

I was going to check the coolant level tonight. Come to think of it, the light did come on while circling down the long counter-clockwise exit ramp in the parkade. I suppose if it was borderline low, that could have set it off. Doesn't explain the rough start/idle this morning though.

And is the sensor not on the engine side of the overflow, I'm not sure but I think it is....

[FlyBoy]

Re: Rough start/idle... CEL flashing

Bad MAF sensor can make it run ragged, but wouldn't give you temp light or beeping. Does give you a CEL though.

Maybe you have a bad mix of anti-freeze and it takes a little bit to thaw before it starts flowing. When its cold (say -20 or lower), open the hood, start the car and get out and see if there is coolant going into the expansion tank.

Btw, beeping and flashing of the temp light also happens when the coolant gets up to 120 or higher.

[MrHeavyFoot]

Re: Rough start/idle... CEL flashing

Bad MAF sensor can make it run ragged, but wouldn't give you temp light or beeping. Does give you a CEL though.

Maybe you have a bad mix of anti-freeze and it takes a little bit to thaw before it starts flowing. When its cold (say -20 or lower), open the hood, start the car and get out and see if there is coolant going into the expansion tank.

Btw, beeping and flashing of the temp light also happens when the coolant gets up to 120 or higher.

OK, so now it won't turn over at all, or at least not for more than a second or two. The only codes shown are for mis-fires on cylinders 1 and 2. I suspect that is from when it actually managed to run for a while. I removed a couple of the spark plugs and they appeared wet. Dried them of and replaced them, but no change. So I've removed all 4. I'll let it sit for a while and try tomorrow.

The car is acting very similar to last year. At the time, VW said I had the wrong spark plugs in there. (I had changed to a slightly cooler plug which most sources I read recommended for chipped cars.) But now I've got the OEM plugs in there and the same thing seems to be happening. On both occassions, the problem started on a particularly cold morning.

I'm going to replace the coolant temp sensor, just in case it is somehow related.

Is there any visual evidence when a coil pack goes bad?

Oh... And the coolant level is slightly below the min line, so that might explain the flashing/beeping. Doesn't explain the non-starting though.

[MrHeavyFoot]

Re: Rough start/idle... CEL flashing

Survey says........ spark plugs.

I didn't even put in new ones. I put in the original spark plugs that came with the car and were replaced in summer of 2004. They were sitting in the garage, so I tried them. Fired right up. I suppose I should go get some new ones though.

Now to figure out why I'm going through spark plugs so fast.

[gtimini]

Re: Rough start/idle... CEL flashing

Survey says........ spark plugs.

I didn't even put in new ones. I put in the original spark plugs that came with the car and were replaced in summer of 2004. They were sitting in the garage, so I tried them. Fired right up. I suppose I should go get some new ones though.

Now to figure out why I'm going through spark plugs so fast.

My car has the same cold start problem. But I have never had any problem with with my coolant level and it is still good for -30. I had this problem 2 years ago but that time the car filled the oil pan with Gasoline (about 1L). Funny thing is that VW told me to drive the car to burn all the gasoline out of the oil. Not sure what the problem is so i will wait for the weather to clear up a little more and I will take it home my local dealer to see if they can find the problem. Since the car is still under warrenty I mine as well take advantage of it.

[NeonGTI]

Re: Rough start/idle... CEL flashing

My 1.8t will run like complete poop when it drops below -15. Apply the boost and as soon as it hits 1 bar-ish it will begin to misfire and knock and all sorts of swell things. I have the timing pulled back to timing 1 on the SPS3, which is well below stock, and the boost has been dialed back to HB1. This is on Mohawk 94 gas that, in summer, I can run HB4T5 with no issues and lots of power.

Now that the weather is warmer the problem has mostly gone away and I have been able to really heat the plugs to get rid of any fouling. I am pretty sure I have pooched a plug, or at least damaged it somewhat - replacements go in tomorrow morning.

If your plugs are wet that can often indicate a rich condition which can cause misfires and spark snuffing. The richness / misfires can come from the fuel being too cold and not atomizing well, or there could be a greater percentage of water in the fuel which may have turned in to ice crystals.

Another reason winter sucks.

My car has the same cold start problem. But I have never had any problem with with my coolant level and it is still good for -30. I had this problem 2 years ago but that time the car filled the oil pan with Gasoline (about 1L). Funny thing is that VW told me to drive the car to burn all the gasoline out of the oil. Not sure what the problem is so i will wait for the weather to clear up a little more and I will take it home my local dealer to see if they can find the problem. Since the car is still under warrenty I mine as well take advantage of it.