I'm still having problems with my 740 wagon. It doesn't start when cold at all. When it does start it runs rich and is missing. After it warms up it smooths out more but still rich. I ran the codes and found a bad air temp sensor. I replaced it and the coolant temp sensor. I had to put in a new intake gasket also. I replaced the fuel pressure regulator also. I know its getting plenty of fuel, if not to much.I have heard the speed sensor could be causing this. I haven't found any new codes. Since every part I have replaced is 17 years old I didn't waste time replacing them. Which goes to show how well these things hold up. Also it has new plugs wires and cap. Any Thoughts?

 

Which coolant temp sensor did you replace? The one or 2 wire sensor?
How good is the wiring harness?

 

I replaced the two wire one. The harness looks to be in good shape. The sensor is the farthest one back by #3 cylinder.

 

Ok thats the right one.
How about the harness?

 

The harness look like it hasn't been touched in 17 years. Its as perfect as can be

 

Is the O2 sensor working properly?

Are you loosing fuel pressure when the car sits for a long time?

 

it seems to keep pressure. I left it sit for a month and had to jump it. It started right up. no wait for the fuel pumps to prime. It seems to be dumping to much fuel. I pulled the plugs I put in this summer and they were black and stunk of fuel. I put new ones in. It ran rough cold then smoothed out after it warmed up. It has been about 5 degrees lately and it won't start. It tries to fire but won't start. Would a cold start valve have anything to do with this? I'm not totally dumb with cars but I mainly know v8s and old vw's. Give me a 65 falcon straight 6 with a three on the tree and I'm in heaven. This newer computer stuff has me bafled.

 

Yes the cold start valve could also be leaking.
If you can unplug the valve and try to start it in the morning and see if it is better.
It should dry up over night.

If it doesn't start pull the plugs and see if they are soaked with gas. If they are the cold start valve might be leaking.

 

My car is a block of ice right now. Hopefully I can get it thawed and out and give it a try. Right nowI can't even get the door open. Did you mean to pull the plug or unhook the fuel line to the valve?

 

Electrical plug from the cold start injector.

 

A bad air mass sensor, or bad cable connection to it, will put the computer into limp home mode. It will run bad when cold, and too rich. I would have a Bosch Jetronic service expert look at it. It's gonna cost ya some bucks, probably.

 

Well finally I got the car in a garage. I did pull the plug on the cold start valve. I also pulled the plugs I just put in and cleaned them fully. I replaced several old crusty vacum lines and a fuel return line. Just to be on the safe side. I also installed the new heater core. Nasty job. So all parts were aircharge sensor, fuel pressure regulator, heater core, new plugs, engine temp sensor, idle control valve and finally a crankshaft position sensor. It finally runs right. I did clean the throttle body and adjust the throttle sensor also. I now have heat and a smooth running car. It took a little to blow the gunk out. Put all the parts but the crank sensor and had no luck. Replaced the crank sensor and it smoothed right out. I replaced most of the parts because I ran the codes. The crank sensor never came up as a code. So here's the total cost $300 for the car, $600 in parts and about 12 hours tinkering. Not bad I think for a good running, clean volvo. If it wasn't for you guys on here helping me, I wouldn't be able to have done this. Thanks A Whole Bunch!!!!!!

 

Congrats glad you got it all figured out.

Pics of the car?

 

I have one in the gallery under 1990 740gl. Its a silver wagon.Black leather and heated seats. I bought it to hall my kids. I got a s10 dropped and it doesn't do well with kids.

 

I know the feeling sold my Toyota 4x4 that wasjacked up about 4 incheswhen my second child was on the way.