My 83/240 w/B-23 is still running rich, surging at idle. I have replaced the air mass meter, fuel pressure regulator(possible "improvement"), and swapped out the ECU with two other units. I have not replaced the fuel injection temp sensor yet. All four cylinders have consistently shown equally fouled or black spark plugs, which seems to eliminate a faulty injector. Engine seems to run well at high rpm's. Would appreciate advice
RDP.

Hi,

I recently solved a similar problem with a simple fix. I repaired/replaced the 25 amp fuse for the fuel injection system. I was shocked at the condition of the fuse and fuse holder.

Here is a quick run-down on what to do.

Open the hood and look for a 10 gauge wire coming off the + side of the battery to a plastic holder that should be mounted an the inner driver's side quarter panel or wing if you happen to be British. The holder is held to a metal bracket screwed to the body. When you remove the holder it will likely crumble. Pull the fuse and inspect it. The tabs are likely to be nasty. Look inside the fuse holder at the contacts which are likely to be corroded and rusty.

Now would be a good time to disconnect the ground and the positive leads from the battery. The wire from the battery is connected to the clamp by a ring terminal. I cleaned everything up and put a new ring terminal on the wire. I removed the fuse holder and found a lug crimped to the wire which was in good condition. Same for the other side of the wire that connects to the wiring harness.

You can get a new fuse holder from the Volvo dealer for about $7.00 or got one from Radio Shack (30A) and splice it in. I was working on the fly so I did a temp job until the part came in at the dealer. I simply plugged the to lugs from each side of the circuit into a new 25 amp fuse. I crimped the lugs securely to the fuse and wrapped it up with electrical tape so it would not short out on the body or arc across the lugs and bypass the fuse.

When I drove the car I was shocked by the smooth idle, increase in power and improved gas mileage. I still cannot believe it. Total time for the fix was less than 30 minutes.

Now if I can just find a dry day to fix that overdrive wire I will be set!

Chris
'83 245 DL

Chris,
Thanks for the tip. I will definitely check it out and let you know what happens. I pulled off my intake manifold tonight and found the insides of it to be oily. The inside of the idle valve were especially oily. I might add that I believe my problems were brought to a head by a leak in the header to exhaust connnection which allowed exhaust to be sucked in to the preheater hose. Can't figure how oil found its way in to the intake parts, however. Rich running did cause the oil level to increase as gas diluted my motor oil. I have since changed the oil and filter.
Thanks, RDP, Bainbridge Island, Washington State

Hi,

Gas in oil is not good. One cause could be lack of combustion resulting in unburned gas dripping down the cylinder walls.Your plugs may be fouled out as well. Now might be a good time to replace them and keep and eye on them for a few days. Also I was so into my 25 amp post that I forgot to mention my favorite cause of poor running which is a vac leak somewhere. Sounds like you have a good start on solving your problem.

Regarding the preheat hose, I recently watched a thread on the brickboard about disconecting the hose. Mine has never been hooked up so for kicks I did. I came right back off because all I could smell was oil burning the entire time. You may want to do a search on that and read up and see if it is for you.

Best of luck solving your issues!

Thanks
Chris
'83 245 DL

Chris,
I have taken the intake assembly off and in process of cleaning the oily, sooty residue out of it. I will be replacing the idle valve, fuel injection temp sensor, coolant thermostat, preheat air thermostat, and fitting a new fuel pressure regulator just for giggles. Have a Volvo mechanic friend who is supplying parts and advice as I go. I fully expect that all of this will result in a remedy. Plan to also check the fuses as you suggested. I will be posting a rundown soon to describe how my problem ends up being corrected.
Thanks, RDP