First off, let me just state that I'm a complete noob to this car, so if any dumb questions follow any answers given, please forgive me. I've worked on much less complicated vehicles before, so not afraid to get the ol' mits dirty, BUT might need some pointers.

So here goes: bought a near pristine 2001 S40 2.0T with auto transmission about 6 months ago. Car's been lovely, about 210k kilometres on the clock, engine's clean, almost as new in terms of dirt, no oil leaks, nada and stock standard. However, I did notice reluctance to start in hot weather versus ease of start first thing in the morning. In other words, the car would start almost instantaneously first thing, but once it's sat in the parking lot and sun for an hour or more it struggles to take and I've noticed now on a couple of occasions a small puff of black smoke escaping the 'zorst once the engine takes, which in my head translates to overly rich fuel/air mixture in the combustion chamber, but like I said, I'm a noob, so I might be wrong here.

Anyhoo, been coping with this minor problem for a while now, not really having time to look into it. Now of course it's turned around and bitten me in the ****, reason being that I popped into a shop for all of 5 minutes two or three days ago, and when I turned the key to start her afterwards she just cranked and cranked, no dice, no joy. So I figured, okay, let's put a little foot on the gas peddle and aah, there she goes. Nice. Release foot from gas peddle, and what's this? RPM drops and drops until it hits zero and she dies. Huh? Crank her again with a bit of pressure on the gas peddle, starts, release pressure, RPM drops, she stutters and dies.

So I managed to drive her home, one foot on the gas, the other on the brake, an exercise which almost ended in disaster as my left foot is trained for clutch usage when driving manual/stick... You can fill in the blanks for yourself.

Got home, did a quick search on the interwebs for solutions, no dice. Went out, tools in tow, poked around a bit and ended up tightening the throttle cable as a temporary 'fix'. Now she idles a bit on the high side (1300 RPM) but when I put her into drive she drops to about half that, and often I have to massage the gas peddle to keep her from cutting out, although it's better when the engine's warmer. She's never dropped RPM so much when putting her in drive. Hmmm....

So, any ideas folks? Is it a major or minor problem or some component which needs to be cleaned out? Someone mentioned somewhere about cleaning out the throttle body as it tends to gunk up after a while. Someone else mentioned removing and cleaning the MAF, although I have NO clue what the hell that is or where it sits or anything. I've tried using VADIS to self-diagnose the problem, but it keeps bailing on me, hence this post.

Any suggestions/useful how-to links/comments welcome. She drives fine, though I've noticed the consumption has gone up a bit of late. Dunno if that's related to anything, but might mean something to the experts among you.

Thanks a lot and apologies for the lengthy post! Oh, and I'm not getting any error codes or anything on the dash, in case you were wondering. Thanks! Peace.

 

MAF is easy to find - follow the air flow intake on the right side of the engine - midway on top (sorry, too late to take a pic) its a 3-4 inch round part about 3 inches long with a connector plugged in on top, held on by two clamps. what it does is the intake air going to the throttle body flows through the MAF, which has a mesh of fine wires. it measures airflow - but if the wires are dirty (say because your PCV let some oil go to the intake) they will give a false measurement. pop it out by loosening the two clamps, then clean with CRC MAF cleaner (not carb cleaner or gas etc) then reinstall to see if anything changes (takes about 15 min). There's also an idle control valve which lets in the right amount of air at idle that can gum up. That may also need to be cleaned.

Check for some Youtube vids - even for other Volvo models as you'll be able to recognize the part once you see it on the vids.

 

Suggest you check for fault codes with a decent OBD11 reader also.
It may save you time and needless expense on parts replacement that is not necessary.

Inlet air temp sensor could be the culprit causing too rich a mixture when engine is warm/hot. Explains the blackish smoke from the exhaust.

 

Thanks a lot for the quick replies guys. I'll have a look when I have a mo and report back on my findings. And thanks a lot for the MAF function overview and approximate location, appreciate it. Will check for some YouTube vids to get an idea of what it looks like. Cheers!

 

When my 2001 did that I first replaced the Idle Air Control motor which did not fix it. Then the wife found this very forum with the answer: Fuel Pressure Regulator. A 10 min swap and she fired right up. I've been sharing my experience here every since. That was maybe 4 years ago.

 

Thanks Hudini. I'm going to check out the MAF now, clean it out and then see what happens, but that being said you're not the first one mentioning the regulator, so I'm guessing that would be the next stop if the MAF doesn't solve the problem. How much would I be looking at ballpark for a replacement regulator do you think? Thanks!

 

The way you clean a MAF sensor is with MAF spray. You should not touch the MAF sensor element with anything at all.



Volvo really gouges on the FPR - over 200 bucks. NAPA currently has the complete unit on sale for $147.60. People have found in the past that the NAPA part is a VOLVO OEM part in a NAPA box.

The cheapest way to fix the FPR problem is to buy this part: Volvo Fuel Pressure Regulator (S40 V40) - Genuine Volvo 9404583.

 

Okay, so after getting back from work today I took some time to remove the MAF and have a look at its current state of repair. Took about 5 minutes to get it off, one hose clamp and two torx bolts later. Had a wee squiz at it and apart from some sootiness on the grid located on the side which goes into the air filter box (and which I just brushed away using a soft brush), she was fine. The element thingy located on the inside was still shiny, so I didn't touch it.

In a bid to be what we over here call 'otherwise' (a normal trait for me) I left the MAF off and started the car, just to see if there's any difference. Car started after struggling a tiny bit, but ran fine. Dunno how clever/dumb this was of me, but after switching off the radiator fan kept running, and I was, like, oh... So I hurriedly put the whole assembly back together again (also just wiped off the rubber seal), tightened her up and started Vollie again, and the fan stopped, but then suddenly I had an engine light on the dash. Hmmm... Loosened a battery terminal and reconnected it, cranked Vollie and she started almost immediately. Switched her off, cranked, again started immediately; rinse/repeat about 10 times, same result. Incidentally I made sure the sensor plug which goes into the MAF fit snuggly and also sprayed some Q-20 on the connectors (a very good silicone lubricant we use over here for electrical bits, among other things) before plugging it back in, and the car is starting better than she has been in a long time.

Of course, all being said and done, the engine was still warm after the 20 odd mile drive from work this afternoon, so I'm guessing the real proof in the pudding will be tomorrow morning when she's had a chance to cool down some. Interestingly the major drop in RPM when switching to drive or reverse had also all but disappeared, so I'm hoping it remains as simple as this afternoon's little procedure. If not, fuel regulator here I come (a couple of months down the line, mind you).

Thanks for all the valuable feedback, much appreciated! Will keep you posted. Cheers!

 

Just as well.

The immediate restarts may be because the fuel pressure had no time to leak down. Disconnecting and reconnecting the MAF sensor can help as you're establishing a fresh electrical connection with - in theory - a lower contact resistance.

 

Well, I guess we're playing the waiting game then. I'll know for sure tomorrow morning on first start whether it was my imagination or not, but what you're saying makes sense. If indeed the same symptoms occur first thing then at least I know it's time to look into that fuel regulator. It's a lot of wad, but I guess then I'll just have to carry on as I am until I can afford to replace it. Will post back tomorrow with results. Cheers!

 

You can't expect to buy a 15 year old car, even from your Mum, and not spend any money on maintenance.

As you're in the UK you may have an option. There's a chance VW 036133035A will drop right in. Buy a used one on eBay and try it.

 

I had pretty much the same issue with an 02 S40, 1.9L engine.

I was finally able to fix the problem with help from several members of this forum.

See this discussion - https://volvoforums.com/forum/volvo-...e-codes-69080/

 

Thanks for all the replies guys, much appreciated. Right now it seems that it is the fuel pressure regulator which needs replacing, although I haven't bothered messing around with Vollie again - been too busy with other stuff, but hoping to get something a bit more solid nailed down in terms of an accurate diagnosis of the problem. As mentioned before, I have no error codes popping up on the dash, which would've perhaps helped me further along the right direction.

I did however forget to mention that one of the alu pipes in the engine bay (not sure if it's related to the AC or something else) had somehow been snapped at one of its bends by the previous owner and then basically epoxied back together by same because he was too damn lazy to replace it or just too stingy. So I don't know if this could have anything to do with anything, but I will investigate further and see what pops up. Unfortunately the locals complained about me 'servicing' my car in the parking lot of the security complex I live in, so now I have to find some remote spot to dig around in the engine bay - slightly irritating I might add. Some people are just completely clueless...

I will report back on any further developments/conclusions as I come across them, but as mentioned before, for all intents and purposes it seems to be the fuel pressure regulator, replacement of which will have to wait until the funds are sorted. Unfortunately I don't earn U$, so it'll have to wait for a bit.

Cheers! ;-)

 

Thanks for that slant. As mentioned in my previous post, I've got a mended pipe under the hood, and I'm thinking there might be something worth looking at. I'll have a squiz at it over the weekend, but will be sure to check out that IAC hose as well. Seems like a little hidden bugger, so thanks for posting that link to the related thread! Be sweet if I just needed to replace a pipe, so here's hoping... Peace.