94 850 T5 Stalling....

Japedo · Post by **Japedo** » 26 Jul 2008, 09:04

Hello there, just wondering if anybody has any ideas on how i can troubleshoot my car issues. 94 850 T5 470 kilometers
It just started stalling lastnight while on the Highway. THe car lost power and the tachometer dropped a bit "not completley" I was able to get a bit of power out of the car if I put the throttle to the floor but it was still very intermitant and if i slowed to a stop it would stall out every time.
However it restarts without hesitation every time, but once the car idles up and back down like it normally does when started, it'll idle rough and stall within 20secs. If i give it atleast half throttle it'll continue to run but not very well and their is some backfireing for sure but once at idle it'll stall.
I checked the fuel pressure at the rail following a stall and there is deffinentley fuel. Their are only 4 codes in A2 and all in relation to the front and rear o2 sensors "these codes are not new" I can't seem to get socket A6 "ignition" to do anything. The car had a new distributor,rotor, plugs, wires and airfilter installed lastweek. I also swapped a different MAF sensor and IACvalve on just for fun, but the symptoms persisted. I cleaned the throttle body lastnight and removed the throttle position sensor as I haven't had the tps off the car in the past 4 years that ive owned it. I am a bit confused and my next attempt will be swapping the tps off my parts car tomorrow to rule that option out. I believe it could be the TPS as the fual millage callculator isn't showing excessive fuel consumption even though im haveing to hold the pedal to the floor just to make it move. Boost/vacume levels are normall and PCV was also checked lastweek.
Sorry for such a lengthy question just though i'd add as much info as possible. I really don't want to bring this to the dealer as I know it is somethin stupid that i can fix with a bit of help. THanks

Japedo 94 850 t5 470 kms
01 V70XC 112 miles

Post by **MadeInJapan** » 26 Jul 2008, 09:14

Check all of your hoses, even your hard to see turbo hoses for leaks...sounds like this might be it if you've swapped your IAC and MAF. You're getting unmetered air in there somehow. Otherwise, you could actually have a bad front 02. Oh, by the way, the same exact signs were apparent with my S70 and I found that my intercooler was cracked. Drove fine with the MAF completely unplugged, so you might try that- it puts the ECU into a limp mode, allowing the car to run with even the biggest air leak- doesn't necessarily mean the MAF you got is bad (although it could be if the leaks and front 02 don't check out).

Japedo · Post by **Japedo** » 26 Jul 2008, 09:23

I forgot to mention that this started lastnightr and on the way home it started acting normall for about 5mins. then back to barely running. I am almost positive that both 02 sensors are shot as they have never been replaced since my ownership and have been throwing codes for atleast 2 years, But the car gets good millage so i haven't replaced them " no catalatic converter either"
I'll deffinently check the lines for leakage especially since I had the line off that goes into the turbo while servicing the PCV last week. But do u think there is any chance it could be the TPS????

THanks for such a fast responce

Post by **MadeInJapan** » 26 Jul 2008, 09:39

A TPS should give you a TPS code.

Japedo · Post by **Japedo** » 26 Jul 2008, 09:47

ya, good point. however and i didn't mention this yet but Their are TPS codes thrown in relation to the tranny. TPS signal to high, TPS signal to low. in socket A1.
I also had a cracked intercooler last year and it ran exactly like it does now but it wasn't showing boost on the guage then. and was burning fuel like crazy!!! Unpluggin the MAf stalls the car imediatley. I guess it could be a few different things and i'll be sure to add my findings tomorrow. Thanks again

Japedo · Post by **Japedo** » 27 Jul 2008, 07:30

Well I thought I had made some progress thismorning when I found I had a vacume line disconected between the boost control valve and the intake hose going into the turbo. But this didn't change the stalling issue. Ive checked all the hoses as best as I can and have not found any other problems yet. I find it odd that it starts perfectly and if I give it throttle within the first 20 secs of running it'll bulid revs smoothly and idle down properly, and at aprox 20 secs it idles terribly and stalls.
I ran the system test 1 on the car and it wasn't registering the TPS.
procedure i followed
"wire in socket A2 press led button twice briefly once flashing LED illuminates wide open throttle gives code 3.3.3 throttle move to or from idle code 332 transmission control module when gear selector moved code 124"

THe only one that checked out for me was the transmission! Ive never done this test before but all the other self test procedures checked out to be fine. anyways i don't have a tps hear right now but am gona try later today..

Japedo

Japedo · Post by **Japedo** » 27 Jul 2008, 07:40

http://www.volvoclub.org.uk/tech/servic ... ertion.pdf

This is a better explanation of the self tests i performed if anyone is interested. I did a quick search and didn't see this link on the site. Probably hear somewhere though.

Post by **MadeInJapan** » 27 Jul 2008, 08:42

Yes, it is in the free download of the 850 Service Manual (in pinned section).
Very good find though! Bits and pieces of the service manual are all over the net but you can download the entire thing in the location I mentioned.

Japedo · Post by **Japedo** » 27 Jul 2008, 19:53

well, the TPS didn't solve any problems for the car. Although it registers the tps while doing the self test now. Even though their is still fuel at the rail afer it stalls out could it be possible that the pressure just isn't high enough for it to maintain idle after the startup? I replaced the fuel filter last fall but never the fuel pump. The car is even misfiring today on cylinder 2 which sucks as I replaced wires,plugs and distributor last week! Im almost ready to send it to the stealership for a diagnosis.. which sucks as it's only been there once in the past 4 years.

Japedo

94850 T5
01V70XC

Post by **Ozark Lee** » 27 Jul 2008, 20:45

I replaced the fuel filter last fall but never the fuel pump. The car is even misfiring today on cylinder 2 which sucks as I replaced wires,plugs and distributor last week! Im almost ready to send it to the stealership for a diagnosis..

You can buy a fuel pressure gauge for around US $30.00. Fuel pumps normally fail in an all or nothing mode. You can beat on the bottom of the tank and get yourself home sometimes but once they quit they well and truly quit.

Fuel pump relay failures are a tad more intermittent but you can jumper the socket positions associated with pins 15 and 87 on the number 103 relay and bypass the relay. If the car runs fine with the relay jumpered then you can either repair or replace the relay.

...Lee