2001 Volvo S40
110K
Maintained to spec.
Replaced fuel pressure regulator last winter to address cold start problem.

We're into our 100F (38C) days here. The car starts and runs fine from cold. However, if you drive a bit on a hot day, then stop and come back to restart the car within about a half hour, the engine stumbles and hesitates upon restart. It settles down within 1 minute and runs fine again. A/C on or off makes no difference.

The check engine light comes on occasionally after this problem occurs. It is logging P301-304 cylinder misfire detected (duh) codes. No other codes are being logged.

The problem is similar to a vapor lock on a carburetor engine.

Anyone had and corrected this problem?

Thanks.

 

Sounds similar to issues I had (2002 v40). Occasional rough idle on hot start and hesitation. Would also sometimes start happening if sitting in heavy traffic on hot days. Would get various misfire codes. Over time, changed plugs, wires, coils, FPR, cleaned throttle body and AIC. Problem persisted, but so occasionally that it was hard to pin down. Finally, got very bad and finally threw codes for Mass Air Sensor and MAP (manifold pressure sensor). Replaced both and problem seems to be fixed with better take-off performance as well. MAP sensor is mounted on the fuel rail.

 

The MAP sensor is cheapest, so I shall start there. I'll let you know if it helps. Good thing the cars are equipped with lots of sophisticated onboard diagnostics, so we don't have to GUESS at repairs.

 

hi, do you have any update? my 02' S40 also has the long starting problem, which occured after long parking, especially after sitting in the sun.

 

I replaced the MAP sensor a couple of weeks ago. Since then, the weather has been reasonably mild, with the hottest day hitting 95F. No stumble problems with the car, but I don't know of it's a result of dlk1's brilliant suggestion and my mechanical abilities or the lack of 100+ temperatures.

 

The long crank time problem is most likely going to be the FPR. Common and widespread issues on these cars. This is a different problem from the rough start and stumble that BRB describes and I had. Car would start fine but idle was rough, would have bad hesitation, etc.

So many people have so many of the same problems with these cars that at the end of the day, I find myself thinking;

"I love my Volvo, I love my Volvo, even though I know it's a piece of ****, I love my Volvo...."

 

Buy a VW, then you'll know what a problem car is.

 

Thanks very much for your clarification, they're 2 issues, I got it.
But now I'm facing an urgent case as following link, could you please provide some suggestion?
https://volvoforums.com/forum/volvo-s40-11/emergent-situation-about-fpr-removal-33783/
thanks

 

Don't know the price difference to just buy the internal guts without the plastic housing and hose, but I think that's the way you should go; buy the whole unit. It comes with the 'S' shaped hose attached and swapping out the part is a breeze. Not aware if you can just buy the hose; 'TECH' may know....

$180.00 at 'My Swedish Parts':

http://www.trademotion.com/partlocat...layCatalogid=0

 

The housing is difficult to be removed (cause the screw driver can't work straightly), and the price is double. So...
Thanks for your reply!

 

I've placed the order, $172 for the full FPR (with housing and S hose) and O-ring.
Before placing order, I tried, but found it's hardly possible to insert the metal part into the housing while keeping the fragile filter part of the internal safe. On the other hand, the obstacle (to deal with the bolt, which is connecting FPR with fuel rail) has been removed. Don't need to remove the hose first, as described in Mr 1warhelion's processes. Before that, I was worried about how to remove the hose to make room for screw driver and how to install it back.
Thanks again.

 

First hot day this year and the problem is back. Looks like the MAF is next. AIP Electronics lists a replacement for $144 on eBay. Swedish Parts is at $250 and up. Anyone have any experience with AIP?

 

If you go with the troubleshooting like this it will be expensive.What makes you think that the MAF is bad?Did you get a code for it being faulty?What you should invest is a fuel pressure meter and see if the pressure gets build up if its low just before you start the engine.Before I replaced the pump it took 3 times to turn the key and wait until the pump shuts off to get the pressure up in the rail.

 

Good idea. What's correct pressure?

 

3Bar/44PSI by Haynes manual but the FPR has a mark of 309KPa which comes out 44.8PSI.Pressure also varies with vacuum/boost in the intake manifold.There is two different kinda tester.One is for lower pressure up to 15PSI this is for the engine with a carburetor .You wanna get the one says for injected systems measuring up to 100PSI.You can leave it on overnight.I have this one.
http://www.sears.com/shc/s/p_10153_1...&blockType=G14

 

Thanks. Will check it and post results.

 

Finally got the car and the tools all in the same place. The results are:

Fuel Pressure: 46psi, no leak down in the 10 minutes I watched it. I left the tester hooked up for the day (car is parked).

Engine codes. Along with the expected P0301 - P0304 cylinder misfire codes I got a new one, P0107 MAP/BARO Circuit Low Input. Based on other posts, the chief suspect is the MAP sensor under the fuel rail. Agreed?

If agreed, got a part #?

 

Out of curiosity, is your CEL light on when you're checking codes?

I'm getting regular misfires at idle in my '02 S60, but I get no CEL, so I don't know which cylinder to look at. I have a code reader, but I'm not sure if I can pull stored codes with it (if there are codes stored).

I've done all of my regular maintenance items (timing belt, alternator, battery, PCV system, spark plugs) hoping to cure the problem, but it persists. I'd love to at least know which is the problem cylinder.

 

I've pulled the codes with the CEL on and off, so the codes get stored. In most cases, the CEL will go out after three or four runs if no further problems occur. I believe they remain stored until cleared using an engine code checker.

 

Update: No further problems with hot restart to date. No more codes logged. Haven't made any changes or replaced any parts. Probably would be a good time to sell it...