New 94' 850 owner need help with codes/stalling

SCain · Post by **SCain** » 14 Oct 2016, 10:22

hello! I purchased a '94 850 off of a friend that had known stalling issues. it will run fine then die occasionally while coming to a stop. I'm handy with a wrench and own a multimeter, but have been unable to pinpoint the cause.

I pulled these codes
A2 121 maf sensor signal, 223 IAC valve opening signal

A7 Ventilation damper motor position sensor open circuit or shorted to 12 volts

I checked for vaccum leaks, couldn't find any. I also cleaned some grounds. my fuel pump relay is red with a Volvo logo, might be original? the MAF is original. the interesting thing is when I unplug the MAF, the car dies. I've seen people suggest you could run the car sans MAF. pretty sure the IAC is original as well.

what do these codes tell you? I'm pretty much limited to $200 in parts and need to get this car going for work. I can't do the usual "throw parts at it and hope it works"

also, I own a Bosch multimeter if there's things I should test. thanks for reading

Post by **bmdubya1198** » 14 Oct 2016, 13:06

The code under A7 has to do with the climate control. The damper motor is probably bad. Definitely not related to the stalling issue.

Even though it dies when you disconnect it, the MAF sensor might still be bad. Have you tried cleaning it with MAF sensor cleaner? If the sensor turns out to be bad, the best cost saving way to take care of that is to grab one from a pull-a-part/pick-n-pull. Probably won't be any more than $20.
The IAC valve might need to be cleaned out as well. That can be cleaned with carburetor cleaner. It's located near the throttle body and vacuum tree.

Also, yes, that is the original fuel pump relay.

Post by **misha** » 14 Oct 2016, 17:44

Replace Maf and clean iac valve.I could bet that when you replace maf....iac valve code will disappear.
Maf MUST be oem.New or used one...it's up to you.
Don't waste your time and money on aftermarket or refurbished MAFs because they will not work properly...if they would work at all.

'94 Maf sensors are different from '95 and after so...they could be a bit harder to find.

SCain · Post by **SCain** » 14 Oct 2016, 20:19

thanks for all the info! really don't want to buy a new MAF but I will to get this over with. going to clean the IAC as soon as I figure out how to get these hoses off without breaking them.

BIG development: I removed the spark plug cover and found a LOT of oil in the crevices, around the coil rubber, and inside the spark plug wells. I pulled the plug and they were all black as ****! and they said Volvo on them.. I hope to god they're not original. there was oil sludge on the outer parts of the plugs too.

would this have anything to do with my problem? replacing the plugs regardless, but if I don't have to get a new MAF, I won't. I just cleaned it, hopefully it solves it

Post by **scot850** » 14 Oct 2016, 23:01

Chances are it is just the seal ring on the oil filler cap has gone hard and is leaking oil down into this area. Seal should be soft and supple and replaced probably ever 2 years or so depending on climate. Clean all the oil off and replace the seal and monitor. Do the rubber glove test on the oil filler hole with the cap removed. If the glove inflates the PCV system needs serviced.

Neil.

Post by **Ozark Lee** » 15 Oct 2016, 07:12

You can try to clean the MAF. Use either MAF cleaner or electrical contact cleaner and just spray it and let it dry. Don't scrub it or even touch it.

I have had about a 20% success rate cleaning them MAF rather than replacing it and the cleaner is way cheap when compared to a new MAF sensor. Also make sure that the connector is clean and well seated. I think it was the early MAFs that had an issue with the connector not holding in tight and many added zip ties to keep it plugged in tight.

...Lee

SCain · Post by **SCain** » 16 Oct 2016, 00:54

I cleaned the MAF, cleaned all the oil out, and will have new spark plugs in. I have some questions

would old and corroded/black spark plugs cause intermittent stalling? pretty sure these plugs have over 140k on them. what about oil in the spark plug wells/wires?

would old spark wires cause my problem?

what does it mean that my car won't start with the MAF unplugged and dies when unplugged while running?

what is the best method of running injector cleaner and intake cleaner ala seafoam? just put some in the gas tank and in the oil filler cap before an oil change? I'm asking because of the spark plugs were black, that means the rest of the inside needs to be cleaned

finally, the fuel pump relay jumper test, if the fuel pump runs when the relay is jumpered does that mean the relay is bad? or the pump is bad?

Post by **abscate** » 16 Oct 2016, 02:46

Don't unplug stuff while running. Unhealthy for electrical stuff and not a good diagnostic.

Fuel pump relays are a common failure point on these cars. If you jump it with wire the pump should run. See if that solves your running problem as a piece of wire is cheap. You can do it with a paper clip but that will get hot.

Bad plugs , wires , oil in plug holes..get that all cleaned up. All of these can stop you cold.

Skip seafoam until you get your fuel running and ignition parts renewed. Black spark plugs mean nothing about the cleanliness of the rest of your engine

Post by **bmdubya1198** » 16 Oct 2016, 07:08

abscate wrote:Don't unplug stuff while running. Unhealthy for electrical stuff and not a good diagnostic.

Fuel pump relays are a common failure point on these cars. If you jump it with wire the pump should run. See if that solves your running problem as a piece of wire is cheap. You can do it with a paper clip but that will get hot.

Bad plugs , wires , oil in plug holes..get that all cleaned up. All of these can stop you cold.

Skip seafoam until you get your fuel running and ignition parts renewed. Black spark plugs mean nothing about the cleanliness of the rest of your engine

+1 to all of this. Clean up that oil real good, maybe get some new plugs. Being that your plugs are black, you're probably running rich, which leads to the MAF sensor again.
Seafoam can be added through a vacuum hose on the vacuum tree, but be very careful and don't stall it out on it. There are a couple threads about it on here.

SCain · Post by **SCain** » 18 Oct 2016, 14:32

what does it mean that the car won't run without the MAF connected? I keep reading everywhere that if you car runs better without it connected, then you need a new MAF; what if it doesn't start at all?

also, who is the oem manufacturer of the MAF?

thanks for all the replies everybody. new spark plugs and fuel pump relay are on the way, I hope it solves the problem. buying a new MAF is the next step if it's not resolved, and I reaaaallly don't want to if it doesn't need to be replaced, is there anything else I can check?