Hi,
I've recently bought an 1998 S40 with the 1.8GDI engine. I noticed an intermittent hesitation at different speeds where the engine would feel to slow down and the surge a little off and on. Well it's been to Volvo who checked the computer, said they checked the coils, throttle body cleaned and lubricated, etc. and eventually changed the plugs all for £179! £90 labour £58 for the plug + VAT.
I've only driven it home since so don't know if it's fully fixed. If not, what else could it be? They said if it was the coils it would have shown up in their test, is there now grey area in this? Could it still be the coils?
If I still have a problem, I can't afford to take it back to Volvo at those costs!

Also I cant even see the plugs when I take the top cover off the engine, where are they? Are the four black boxes on the top the coils or are they injectors?

Thanks,
Adam.

It is possible it is the coils.They normally act up when the car is hot.Then when you accelerate hard the car starts missfiring.

Once you remove the black cover on the top of the engine the coils are under the cover.The injectors are under a smaller cover in the front of the engine.

I am used to the U.S. cars which are 2000 and newer S40's.The 2000 cars have 2 coils and 2 plug wires.One coil for 2 cylinders.

You can remove the coil and pull down the boot and look at the plastic if it is cracked it might be missfiring.Most of the time when they crack they go bad shortly after that.

From my experience they last about 30 to 40,000 miles.

hey ajag22, did the issue get resolved? i have the same car, with the same problems!!! 1.8 99 Vreg (UK) gdi that also has the exact same problem. it tends to struggle past the 3krpm then shoots of after that, very annoying hesitation upon acceleration, feels like a lag, and that somethings blocking the fuel etc. ive had a full service done which made it alot smoother but the problem is still there. took it to a tuning clinic, guy did a rolling road test, put some oil in ma engine then revved the hell out of it, but this hasnt resolved it either!

tech, is replacing the coils expensive to do?

ajag22, if it hasnt resolved then you should take it back and they should keep trying to fix it as youve paid them innitially and told them wot the problem is so they shouldnt give you any excuses or charge you more.

The coils are somewhat expensive but you can replace them your self.

Hi, well I haven't fixed it yet... but still have to try the coils/or thinking maybe the LAMBDA sensor. Trying to get hold of a haynes so I know where the sensor is located but given it's operation this could be causing my problem. No idea what a coil costs and there's four of them so I'll try and find a scrap yard with one in and buy a couple. I'll swap two over, try it for a bit, if no luck swap the other two out and put the old 2 back.

I'm not taking it back to Volvo as they'll just suggest something without dianosing the fault, as the said the plug change was the 1st step in trying to rectify things and I should be able to do the above two jobs myself.
Adam.

Your car has 2 O2 sensors there is a cover at the fire wall black and is about a foot long the plugs for the O2's are under there.
The sensors can be seen from under the hood at the exhaust manifold.

I have the same problem on a 2001 s40. I changed the fuel filter, put gas treatment, and changed the plugs. The next thing I will try is the coils.

If it chugs or misses on acceleration then most likely the coils.

Right,
I've now changed the air filter, 2 of the coils (and swapped the other two for the replaced ones when I was still getting symptoms), O2 sensor, fuel filter, plugs. I am still hetting some stuttering occasionally!

What I have noticed is that the lights will dip occasionally and the fans go quieter for a second or two every so often, could this be the cause? A bad earth somewhere or something shorting out?

Thanks,
Adam.

Could it be the MAF giving up once and a while, I think this would give the symptoms I'm experiencing, but how do I diagnose the MAF?

Thanks,
Adam.

I boubt it is the mass flow.

Do you have any codes in the system?

I don't have a device to read the codes from. Is there any way I can read them manually or do I need to buy a device? Also my alarm is always going off which is quite annoying, Just wouldn't stop goin off this afternoon.

Thanks,
Adam.

If you have an Auto Zone near you they will pull codes for free.
If not then you will need to buy one or send it to the shop.

ORIGINAL: ajag22

Right,
I've now changed the air filter, 2 of the coils (and swapped the other two for the replaced ones when I was still getting symptoms), O2 sensor, fuel filter, plugs. I am still hetting some stuttering occasionally!

What I have noticed is that the lights will dip occasionally and the fans go quieter for a second or two every so often, could this be the cause? A bad earth somewhere or something shorting out?

Thanks,
Adam.


Could be an electrical fault causing interruption to fuel pump and/or spark. I'd start at the battery, alternator, alternator drivebelt & main earth point(s). Worth checking wiring & earth to climate control/aircon, fault might occur only when this kicks-in?

Sounds annoying! Good luck.