I have a 1990 Volvo 740 GL Wagon Non-turbo. I purchased it a few weeks back. It had been sitting for 3 to 4 months but started/ran and drove fine prior to. I assumed it was probably gas or a fuel pump. I changed the fuel out. I changed the fuel filter. I changed the plugs and wires, as well as, the rotor. I have replaced the Map Sensor, Air Temp sensor, Cleaned the throttle body. I replaced the Throttle position Sensor. Air Filter, valve cover gasket, Injectors etc. I Checked the fuel pressure and it checks good. All fuses are good. The injector relay and fuel pump relays are good. It is a regina rex system. With some coaching I can get the car started. It runs and jumps between 700 and 1000 rpm’s constantly. It revs and unrevs to do this it seems. In park at times I can rev it up and take the rpm’s up and then it normally dies out. Under load(in Drive etc.) when you give it gas and it dies out. I pulled a plug and the new plug is black and dirty, which indicates it is running rich and flooding out. I am out of ideas…..when its running at idle it runs smooth at times. Any suggestions before I send this one to the bone yard? I really want to get it running because the body is in great shape and it seems like a fun car but I do not know what else to do.

 

The Regina system is a damn solid setup. You have a couple of issues going on it would seem. Does it hunt idle when cold and hot? Is it worse cold or hot? Have you double checked all your vacuum hoses? Your idle air control valve? It sounds like the iac can't find idle. The glaring oversight I see is you do not mention the O2 sensor. Before you consign a perfectly good Volvo to the bone yard (as so many others have done) invest in a multi-meter and at least a Haynes repair manual. Check the O2 sensor...I'll bet it's either dead or extremely lazy. With all the sensors and valves under the hood, the lowly O2 sensor gets overlooked all the time. It is the rear guard; the only sensor that tells the ecu if the input from under the hood is actually working.

 

Well it does not matter if it is hot or cold it runs the same. At times it will idle fine. I was going to check the o2 sensor but it is stuck on so I will have to get a tourch to remove it. I can understand an o2 sensor causing a vehichle to run rich or lean but to have a hard time starting and die with any accelleration I do not see an o2 sensor causing this. I could be wrong though. I have checked for vaccum leaks the best I can but I have had a difficult time finding a solid diagram. I have a alldatadiy online manual but no dice there. The IAC is good.

 

A bad crank angle sensor will cause the symptoms you are describing. You might not be getting proper spark...if you are getting perfect fuel pressure than only other thing it can be is spark. You have fuel dumping in and probably intermittent or weak spark hence the flooding...hope this helps...good luck!!

 

I have the same cold start and idle problems in my Regina Rex 1990 non turbo Volvo 740 Wagon. We have replace near everything, but still get the shakey idle and poor start on cold days. Did you find an answer?
I have posted my problem on the forum today, and was hoping to find someone who ended up solving it.
Thanks for any help

It is nice to hear that the Regina system does work...eventually.