Hello and allow me to introduce myself as Volvoholic02. Moving right along, my daughter has an '02 S40 with about 167,000 mi. Recently, I had to replace front brake hoses and pads. My friend took it for a test drive to evaluate brake job and noticed a misfire and puff of smoke from exhaust when he "got on it" just a bit. The engine kinda "choked and puked" during misfire but afterwards seemed to return to running fairly acceptably when driven easily. The check engine light came on at the time of misfire but has since disappeared.

I know y'all hate these 'vague' engine problem descriptions but I have little else to share except.....the car, prior to the 'misfire' mentioned above, seemed to have a moderately loud sounding exhaust noise. The noise is something that has developed over the past 12,000 miles of ownership.

I have NO idea if the exhaust noise is a leak or if it is related to the exhaust system/process. Also, since the 'misfire' and other than the 'noisy exhaust' sound', I've driven the car and it seems to run 'decent' when 'babied'. In other words, driving it as though a tennis ball has been stuffed under the accelerator pedal...at relatively low speeds (< 50 mph).

A day after the misfire, I took the car to our local auto parts store and asked them to connect their hand-held computer to the car and read the check engine code that was most recently displayed. They told me unless the CEL was currently being displayed, their 'computer' could NOT retrieve any code that might be stored in memory. So.....I'm at a loss of where to start. I don't have the money to take the car to the dealer for diagnostics. Any thoughts???

p.s. i was willing to try replacing the spark plugs as a reasonably inexpensive first step to finding the problem. i can also tell you that according to the owners manual, ALL scheduled maintenance has been performed prior to 155,000 mi as evidenced by the dealership service department stamp shown in the scheduled maintenance section of the manual. once again, do you have any thoughts on what could be wrong or what you would you do???

 

I would replace the ignition coils and spark plugs with NGK Iridiums. If the plug wires are original I'd replace them too.

My 2001 did what you described at about 105k miles. I had previously replaced the plugs at 100k miles. I ohmed the ignition coils and they were within spec so I looked elsewhere. I removed and cleaned the injectors, cleaned the MAF, cleaned the throttle body, changed air cleaner and fuel filter. Still had a miss under load. Frustrated I replaced the plugs and wires. Still missed under load. Now I'm really frustrated. Out of desperation I bought 2 new ignition coils and the problem went away.

Turns out the plastic piece that connects the plug to the coil up top can leak voltage which arcs to the head. You cannot see it with the coils in place and it only becomes an issue when you need the plugs to fire correctly under boost.

If you replace the coils check Autozone. Last I checked they had genuine Volvo ignition coils inside their brand Duralast boxes. They had the lowest cost at the time also.

For the exhaust leak is it the classic sewing machine sound? Mine would do that when cold but get quieter as it warmed up. It was simply a loose nut on a exhaust manifold stud above the turbo. It happened several times until I secured it with a stop nut in July.

 

Hudini
I want to replace my plug wires, coil wire, coil, cap, rotor. Would you use Autozone Duralast for these? Thanks! I changed the plugs, all other prts are original, 13 yrs old!

1998 C70, 2.3, HPT, coupe, 37k miles

 

the exhaust noise is like what you'd expect to hear if a muffler was about to die. i wouldn't describe it as 'sewing machine' or high pitched, rather, it's a deeper pitch i'll describe as 'throaty' or to put in musical terms, it's definitely in the bass tones. it sounds like a leaky muffler??? the vehicle has NEVER sound so bad BUT it was doing this before the misfire that occurred under 'heavy load' or otherwise while 'getting on the gas fairly heavy'. it's funny, the car seems to idle smoothly and run OK while driven 'easily'.

the engine misfire MAY or may NOT have anything to do with the loud exhaust. the misfire could just be a 'final warning' that is telling me to DO SOMETHING. as i said, autozone could not help me since they said my CEL had to be ON...which it currently is NOT. it did, however, come on while driving at the time of the misfire/puff of smoke.

i'll look into the ignition coils as you've suggested and check prices. the last thing i want to do is throw MAJOR money at the vehicle buying parts unnecessarily. if that were the case, i would be better served paying a volvo dealer to diagnose and find the error code that was thrown and move forward.

 

I too hate throwing parts at cars rather than diagnosing them. The coils were about $45 each last I checked so not overly expensive considering you can change them yourself. If you want to spend a whole bunch of money then definitely take the car to a Volvo dealer.......

The loose nut on the exhaust manifold on mine was not very loud or deep so I'm guessing as you that it's the muffler or something else further on down the line from the engine. Guess you gotta crawl up under there to see.

 

PM sent

 

for the 1.9t (2002 s40), can I get some opinions on which plugs i should buy??? is there somewhat of a consensus on this subject or is everybody doing their own thing? i really don't want to spend $12.00/plug when a $6.00 plug would be perfect. after all, i'm not even sure what the problem is with the car but i'm willing to start with new plugs. thanks!

 

You can't go wrong with the Volvo plugs. They are very good quality. What you described sounds like plugs and/or coils / wires. If they are the original coils and wires with that many miles it is likely that they are in need.
Stan

 

As with anything, everyone has their favorite. Last time I used the NGK Iridiums. I used the Volvo plugs before that. I would also consider the Autolite Iridiums in the future. Just pick your favorite, gap them properly, use anti-seize on the threads and di-electric grease on the plug boot.

 

Ordered & received OEM plug wires, coil wire, coil, distributor cap & rotor, replacing this weekend. Keep old for spares. Next timing belt!

1998 C70 2.3 HPT Coupe Auto 37k miles all original but tires & plugs!

 

The cap and rotor threw me for a sec, then I realized you were talking about a '98 C70. Wow, that is low miles.
Stan

 

Just replaced original tires, 2 rims, canisto, curb damage & original spark plugs, original fuel filter. After replacing plug wires, coil wire, rotor & cap going to replace transmission filter & power flush transmission & coolant. Timing belt & water pump in the spring. Like to find front end bushing replacement package to replace all in the spring if available. 14 yrs old, sometimes noisey turning right. 37kmiles.


1998 C70, Coupe, 2.3 HPT, Auto. Have SC900 & SC901 radios with CD cassetts, (with codes), both work perfectly.