Still sluggish at start

difflock54 · Post by **difflock54** » 19 Sep 2013, 18:03

So what did you do to eliminate the fault code for the catylytic convertor?
You mention it has been resolved.
Would be interesting to see if that PO420 code has returned again.

jbjs40 · Post by **jbjs40** » 20 Sep 2013, 15:02

I pulled and cleaned out the cat. The gun that melted together has been removed, now it is just screens in there. re-installed and drove it on the highway and no more code. checked with auto parts store. This idle problem curiously has as many resolutions as members on the site. The first culprit is the idle control valve, (cleaned). MAF, (cleaned). Vacuum lines and hoses, (inspected no visual problems there). Now someone is saying fuel pressure regulator. Another is saying fuel filter, another said fuel pump. I am at a loss because that just about could be any damn thing.

jbjs40 · Post by **jbjs40** » 20 Sep 2013, 17:20

Ok spent the afternoon looking under the hood and driving it around the parking lot. I attempted to let the computer reset so the idle will go back to normal. It tried to stall at every stop and I had to keep the idle up by barely touching the gas pedal. Then I pulled it into the driveway and it idled really low I slowly took my foot off the gas pedal and it was idling at about 200-300 way low. I noticed it was also surging up to 500-600 rpm before falling back down, on it's own. It cycled that way for a good ten minutes. The idle went to 200-300 for a second or two then went up slightly to 500-600 for a few seconds and repeated this cycle. I hope this narrows it down a little. Sorry no codes yet. I tried a couple of auto parts stores and they were not willing to let me borrow the code reader. And I do not have the money to put down while I borrow the tool.

difflock54 · Post by **difflock54** » 21 Sep 2013, 01:43

The variations in idling rpm's could be caused by fluctuations in the fuel pressure. (regulator)

jbjs40 · Post by **jbjs40** » 21 Sep 2013, 13:38

Thanks that is narrowing it down some. I went back under the hood and recleaned the IAC (valve). It did not want to idle. I checked and rechecked hoses and vacuum lines, they are all fine for now. I checked the spark plugs and coils to see if I missed something before they look fine. So I adjusted the throttle linkage up to the point where it would keep running at idle. It took a few turns. So problem is not solved I just cheated a little. The MAF BTW was checked by unplugging it, and the car would not idle and the MAF plugged in the car would not idle so it's not the MAF. But I do not want to drive it with the throttle part way opened just to keep it in idle. I ordered a coolant sensor but now since your advice that is the fuel regulator that makes sense. But at least now I can drive it to the car parts store and get a code read. i'll let you know.

jbjs40 · Post by **jbjs40** » 21 Sep 2013, 14:33

OK codes read. Basically everything.
MAF
Coils
misfires in 1,2,3, and 4 cylinders.
idle control valve
catalytic converter
fuel mixture too light
like I said pretty much everything I touched today.
So getting the codes read led me to nowhere as far as narrowing the problem down. SO I set the throttle BACK to where it is supposed to be. Back to "I don't know" stage.
BTW everything the OBD2 read is fine, there is no misfire on any cylinder, the cat is an older code, the fuel mixture is only reading because I adjusted the throttle cable to partly open the butterfly valve in order to get the car to idle so I could drive it to the store to get it read.
The guy said if it did not idle and if it is not the MAF then it HAS to be the idle air control valve, electrical parts fail and no amount of cleaning will fix it. SO now to hunt down a IAC. BTW did anyone ever replace the IAC and resolve idling problems? I asked a few guys and they said no.

Post by **jblackburn** » 21 Sep 2013, 15:31

It is rare for the IAC valves on Volvos to go bad.

It is not rare for MAF sensors to fail and no amount of cleaning will revive them.

Just thought id throw that out there. Plus you can always return the part.

jbjs40 · Post by **jbjs40** » 25 Sep 2013, 08:14

I cleaned the MAF real good and checked all the tubing after MAF. Car is idling now. It wants to idle really low though. I drove it for a few minutes so the computer can do its thing. I pulled into the driveway and the idle is too high, lowered it to about 800. Is that too high? How high should the idle be on a 2002 1.9t? Anyway I plan on doing the fuel regulator and checking the fuel filter again. Is the coolant temp sensor located on the thermostat housing? If not where is that thing at? My wife's V70 was attached to the coolant reservoir. easy job. But where is it on the S40? Thanks All!

jbjs40 · Post by **jbjs40** » 29 Sep 2013, 19:49

Got the coolant sensor done it was a little frustrating didn't have 19mm wrench so had to cut wire to get socket on it. When I got that the T40 torx fell off the end of the adaptor and went somewhere in the engine sitting on the manifold. I drove the car and eventually the t40 torx fel off and I retrieved it later. Anyway after that adventure, the car is idling around 700-900. it is steady and still drops considerably when I come to a stop. then it evens out. I do not think it should do this. it should drop to a certain point and stay there not drop precariously then even out, what do you make of that? Fuel Regulator still? Or could it be the throttle position sensor?

difflock54 · Post by **difflock54** » 29 Sep 2013, 20:14

My V40 idles smoothly and evenly at 800rpm's. Same year as yours . B4204T3.

Still sluggish at start

Re: Still sluggish at start