Mechanics

COLD START ISSUE

1993 Volvo 850 • 5 cylinder 2WD Automatic • 240,000 miles

Can anyone tell me what the fuel pressure should be before start-up & if it is supposed to increase or decrease after start up. I am reading around 43psi before start-up & around 40psi while running.
Thank you in advance!
Avatar
1989hawkgt
March 9, 2011.



Fuel pressure good is there a running problem?


Docfixit
Mar 9, 2011.
Car will not start up if under 60 degrees, tries to start then dies. Seems like no fuel enrichment. If over 60 degrees & engine is cold there is no fast idle drops right to 700/800 rpms.


Tiny
1989hawkgt
Mar 9, 2011.
Most likely faulty coolant temp sensor not signaling ECM off cold engine and not riching fuel mix


Docfixit
Mar 9, 2011.
That was my initial thought. I just replaced it yesterday


Tiny
1989hawkgt
Mar 9, 2011.
So did it help? Have tried a good fuel system cleaner?


Docfixit
Mar 9, 2011.
To your 1st? No, replacing the coolant temp sensor did not help. Engine will eventually run & it does drive, just hard to get started if outside temp is low. At first try idle jumps to around 1800 rpm then dies. If you wait 20 seconds or so it will do the same thing over & over again until the heads get some heat then it will keep running & drive fine. I guess some fuel injector cleaner couldn't hurt but just doesn't seem to be what's causing the problem.


Tiny
1989hawkgt
Mar 9, 2011.
Has Idle air controler been removed and cleaned? Has MAF been cleaned?


Docfixit
Mar 9, 2011.
I will clean IAC. It seems to move freely. Mass airflow sensor has also been replaced. I can't get to it right now due to pouring rain but I will get to it asap. Anything else you can thing of would be appreciated & I will tackle them one at a time. Thanks & you assistance is greatly appreciated. I am trying to fix this for an elderly couple whom don't have any extra money to get it fixed. I am paying for parts myself. Thanks again!


Tiny
1989hawkgt
Mar 9, 2011.
Have tried diagnostic test unit for possible codes?


Docfixit
Mar 9, 2011.
Don't know of anyone whom has a tester for that old of a car. I see there is a DLC in front of the computers, how is that used. Looks like a place to test several different functions.


Tiny
1989hawkgt
Mar 9, 2011.
Page 1 of 3