My 93 850 has had this problem for quite a while now. Usually when it stalls I can wait aminute or two and it will fire back up again. I just replaced the fuel pump and its fuse (it was blown, not sure why) and its still having the same problem. At the fuse block I checked all the relays since none of them were identified and they all worked fine but I am not even sure that I checked the right relay since none were marked.

I have both the Chilton & Haynes books but neither has the layout for the relays.

Am I even looking in the right place? Vapor lock mabey? It doesthis year round.

Advice would be greatly appreciated.

Thanks

Revdevil

 

Hi Revdevil,

First thing you need to is to pull (read) codes from the on-board computer; engine ECU:
http://volvospeed.com/Repair/a2.html

If there is an electronic problem, there should be codes. Is your CEL on? If not, the bulb may be burned out. If no code is present, there may be some simple mechanical issue, like tune-up items. No vapour-lock issue has been reported, as far as I know (this was such a problem on earlier Ford Escort).

Please let us know if your car is turbo or NA, as well as the brand name of the fuel pump you just put in. The problem may most likely be caused by the fuel pump relay, if you have not determined its condition, and the relay does fail rather often on 850 with age. If the relay turns out ok, then the fuel pump may be defective.

So, give us a reply and we can go from there.

A list of maintenance tips for 850's:
https://volvoforums.com/m_48928/tm.htm

P.S: A good OEM parts source that many of us here use: http://www.fcpgroton.com/volvo.htm#850


JPN

 

OK. Got the new relay for my 850 yesterday afternoon & it started & I drove it around a bit. This morning (the coldest point of the day) I went to start it for work & nothing.
I want to say that its between cold & hot but it left me stranded the other afternoon at the hottest point of the day.
I checked for codes before I did the relay & there were none.
Any other ideas?

Revdevil

 

Hi revdevil,

When did you find the blown fuel pump fuse? Was this before
you did any work on the fuel pump or after? Has the fuse blown
with the new fuel pump installed?
I think the first step is to determine if you have fuel pressure
when the car will not start (or stalls). Someone else on the forum
may be able to help you with this as I have not worked on my
fuel system yet.
The blown fuse may indicate an intermittent short in the fuel
pump wiring (or the car's wiring harness). It could also indicate
that the pump is locked up and drawing excessive current. I
don't know if a locked pump will blow the fuse on these cars.

Good luck, John

 

Here is the latest. Tonight I Checked the fuel pump with my hand & nothing. Took it out, put it on my bench, put 12V to it and it ran. Put it back in, double checked it for power from the car & it started after a little bitof cranking.

When I went to test drive it down the street it does not respond to throttle much above idle.
If you have it in park or neutral you can rev it up to red line, but put it in gear & it acts normal up to about 2K RPM then it starts boggin & and wont climb anymore.

MAP sensor?
Mass airflow sensor?
(I ruled out TPS because it will work at idle)

I would love to hear some more ideas if you have one.

Thanks,

Rev

 

Oh, & still no codes!

 

Today it started up and I went for a drive down the street. If you accelerate really slow it work OK but the minute you give it gas it boggs & sputters & won't accelerate until you let off & increase the throttle slowly.
Checked my air filter.
Checked the plug wires for cracks.
Compression test is normal.
I did put in 87 octane when I replaced the fuel pump. Could that have something to do with it?

 

Hi revdevil,

You are saying that with the pump in the car it was not running
(before removing it)?
Have you checked the fuel filter? I don't know if an obstructed
fuel line or filter will hydro lock the fuel pump in these cars.
Someone with more experience on the fuel system might be
able to shed some light on this, but with the combination of
symptoms you have described (blown fuse, pump not running
sometimes,car lagging at higher rpm, etc) it sounds to me like you have a problem involving inadequate fuel flow.


John

 

Revdevil,
When is the last time you changed your coolant temp sensor? If I read correctly, the fuel pump works correctly, you changed the fuel relay (red one) right? The CTS is a regular maintenence item and has been know to cause your car to run irradically, miss, and die. Also check your vac hoses.Bestbet it is the CTS.
Check out http://www.matthewsvolvosite.com under repairs database or bay13 at www.volvospeed.com.