V40 misfire, won't run, and P102

Pluis · Post by **Pluis** » 03 Apr 2010, 08:42

I have a 2003 V40 with about 190000KM.

Honestly I have haven't done anything to her in the last 100000km.

Recently it's been getting harder for her to start in the morning. she'll turn over for a bit and then start.

We'll the other day she gave up and refused to start. she turns over but wont start.

Since then I've:

A)Replaced the fuel filter
A)Replaced sparkplugs

I have one of those code readers and I'm getting misfire on cylider 1 & 4 and P102 MAF mass air flow.

I was told that it isn't the mass air flow sensor because it should still start but run in what they call is limp mode.

My next plan of action is to replace the 2 ignition coils.

Any thoughts would be greatly appreciated.

Thanks

Post by **matthew1** » 03 Apr 2010, 10:36

You're jumping ahead, let's go slower. Your car needs three things to run: air, fuel, spark. After those basics, there are degrees of each: you need a certain fuel pressure, a certain air flow that is properly metered, a spark that is robust.

You can check spark by removing the sparkplugs from the wells, one at a time, and watching to see if the spark arcs to the block. Search the forum for more on that before you do it! You need to be careful when you do this.

You can check fuel by testing the fuel pressure. I don't know how to do it on S/V40s, but it's a basic car maintenance thing that you can do or have a mechanic do.

Check for vacuum hose leaks letting in unmetered air.

Joe Hurless · Post by **Joe Hurless** » 04 Apr 2010, 22:29

Try this: pull the engine cover and start the car. Pull the connections to the coils one at a time and see if pulling one causes the engine to run a little rougher. If it does, the coil is working properly, if nothing happens to the engine idle when you unplug it, the coil is bad. If your issue is intermittent, this will not help much because the coils may be working properly at the time of testing. If this is the case, Swap the coils around to see if the problem follows the coils in question. If so, theres your problem.

Pluis · Post by **Pluis** » 08 Apr 2010, 09:41

So I replaced one of the coils because I was getting very little spark from it.

The only way I can start the car is to kick down on the throttle and start it up.
If I can keep her from stalling by varying the pressure on the throttle and when she finally gets up to normal operating temperature, I'll be able to start her again just by turning the key with no foot on the throttle.

Thoughts?

Joe Hurless · Post by **Joe Hurless** » 09 Apr 2010, 02:45

Well that sounds like a couple of things. First of all, Check your air hoses. You could have a rip in an intake hose causing your car to sputter and die. Another thing to consider is if your car cranks for a long time before starting you could have a bad fuel pressure regulator. These are your quick, cheap checks. If everything looks good, which I am thinking it will, your issue is probably your air mass meter.

Pluis · Post by **Pluis** » 26 Apr 2010, 10:07

So the only way she was able to start for the past week in the morning was if I had the accelerator pressed all the way down while I turned the key. I would have to hold the accelerator for a bit before she would idle on her own.

She would start fine for the rest of the day. The next morning, same thing all over again.

Well yesterday I tried starting her in the morning and she would start with me holding the accelerator but holding the accelerator for an extended period of time she will not idle on her own.

Any help would be appreciated.

Thanks,

Paul