s70 2.0 NA strange ignition/miss issues Topic is solved

Post by **hausmeister** » 13 Oct 2016, 12:49

Hi

For a few months I have had a strange problem with my s70 (1998 2L na with MAP sensor). During Summer I'm driving the T5-R so I didn't care much.
Symptoms are like this:

mostly happens in Cold/moist weather (aka winter

):
Car starts and runs perfectly. I go shopping, and when I try starting the car again it will barely start, I have to go WOT to get it to catch. After that it mostly idles ok. But when you put load on it, in the lower rpm range (below 2k) it stalls and misses like crazy. Also reving the engine from idle to 2k it misses in between without load.
It is very difficult to launch from a standstill, I have to keep rpm above 2k.
If I drive for some time after that it again runs perfectly.

At first I suspected moisture in the engine bay/cables, because I noticed it after washing the car. But really, there is no water getting into it directly. I also sprayed some water on the cables, it didn't care at all.

I have already replaced all igniton cables, ignition coil. Distributor and Plugs have about 6k miles on them. I will replace them again just to be sure.
Battery is ok, on board voltage is a steady 14v when running.

I just don't know what to look for...

Any help appreciated

Post by **scot850** » 13 Oct 2016, 13:03

The fact that the car would appear to have 'developed' the fault after you washed it, do you mean you washed the outside of the car or the engine bay?

If it was the engine bay then the first place I would look is the distributer cap if you car has one. They do not like to get water in them and will short out as they don't always loose all the water and it stays damp in there.

I suspect though you may have externally washed the car and since had problems. First thing to do is to remove the plastic catch try and wiper arms below the front windshield and make sure the drain tubes are not blocked. There are 2, one either end, and there are also 2 from the catch tray (4 in all). If they block when it rains or the car is washed they can back water but to the fuse box below the windshield.

I'd also pull all the fuses and check they are not corroded if water has got into there.

You car may have what we call a B+ cable that runs from the battery to the fuse box. These are known to cause problems.

Lastly, water may be getting in around the windshield seal and sunroof (again if you have one make sure the drain tubes are clear) to make sure water is not getting into the dashboard. Lift the carpets and check under them to make sure they are dry.

Lastly check all the earthing cables in the engine bay are good and clean and that the cables are not corroding internally as well as the battery cables. They can increase resistance as the car warms.

Last place to check would be unrelated to all of these would be the ignition switch electrical portion if this has never been replaced.

Good luck!.

Neil.

Post by **hausmeister** » 13 Oct 2016, 15:52

It is not 100% directly related to washing or water... I can't explain it. I mostly noticed it if eg. it rained the day before and everything is damp. But then again not always. (not washing the engine bay, just the car)
Also the engine bay does not really get wet. I was wondering if there is water somewhere that evaporates when the engine warms a bit and then the mist causes issues, but I don't see how.

I had similar issues before where a marten damaged one of the ignition cables... but I replaced the cables, added protective sleeves and double checked them... It might have damaged some other wires, but nothing I could see.

Could the injectors cause this in some way? I don't think so, but the car has been standing some time.

Post by **hausmeister** » 14 Oct 2016, 14:57

Just had the same problem, but today it is dry and also a bit warmer.
So I'm not sure if moisture and temperature are really factors...
Think I will take a look at the injectors when I have the time. What bugs me the most is that the car runs great at first. Mostly then when I shut it off after a short drive and start again it has the issues. After a few minutes of driving it seems fine again.
I have a holiday coming up, will check when I get back.

Post by **misha** » 14 Oct 2016, 17:26

Is that 2.0 20v or 10v?
Vacuum line from map sensor ok?

You said that you replaced distributor cap...but what about rotor?
Any codes?

Post by **hausmeister** » 15 Oct 2016, 10:04

it is the 10v. I replaced most of the vac. lines, at least all I could find. I have owned this car for 10 years and it has been well maintained...
Yes, replaced the whole shebang

At least no CEL, checking codes is on to do list.

Post by **misha** » 15 Oct 2016, 10:20

Are cap,rotor & ignition coil oem Bosch or aftermarket?

Again....Vacuum line going to Map sensor....is it ok?
Are plugs properly gapped if they are not oem Volvo?Check them visually...i once had brand new NGK spark plug on Xm which was cracked at ceramic part same day when it was installed.

Post by **hausmeister** » 15 Oct 2016, 14:23

Everything oem/bosch. Plugs are volvo original 3 pronged(didn't gap them or anything).
I think the MAP sensor is above the cooling fan? Then yes, I replaced that line.

Currently I'm looking for some other possibilities that I can look into

I had a bad Ignition cable once. And while the stuttering/misses were similar it only happened when the engine was hot and @ low rpm, but always reproducable. Then I had the marten damage; misfires were pretty much constant and went away when I replaced the cables.
This seems different... the engine runs like new other then in these special cases...

I tried to look for some videos of injector issues, but not much luck. I have filled it up with premium high octane and added an injector cleaner. I'l be out of country the next 2 weeks, and then I'll look at it again.

For now thanks for the suggestions!

Post by **misha** » 15 Oct 2016, 14:45

Triple prong oem Volvo spark plugs should be for 20v na cars ONLY.They should have 1.2 mm gap right out of the box and it's NOT adjustable.
I think that that's your problem because 10v cars should have a single prong spark plugs gapped at 0.6-0.8mm.

Read "item description":
http://m.ebay.co.uk/itm/291906143122?rm ... noapp=true
Also....2.0 20v cars should have different gapped spark plugs....if i remember corectly.
Can you post a picture of that map sensor?

Post by **hausmeister** » 10 Nov 2016, 14:50

Was able to capture it on video today. From what I can tell I got better with the injector cleaner... but it happens more often If I don't drive the car much.
It started perfectly, I drove ~ 2 minutes and went shopping. Came back and this happened. It won't start without WOT.