1993 940 wagon w/ fuel system issues - Volvo Forums

sleepy_dread · #1 07-25-2011, 02:57 PM

my '93 940 wagon wont start. i think the fuel line may be clogged. i checked the plugs and im getting spark. it tries to start after its sat for a while (a few hours) it kicks a few times then nothing at all. after a few more hours it will false start again. it sound like its just not getting enough fuel. it tries to start after its sat for a while (a few hours) i checked all the fuses and they all seem fine. i just put in sea foam to try and clean the injectors but if its not circulating through the fuel system i dont think it will do any good. does any one have any thoughts on something i might have missed.

pierce · #2 07-25-2011, 05:01 PM

did you check for any OBD codes? see
Engine and OBD Diagnostic Codes
(you want to read the codes from the "A" block pins 2 (fuel injection) and pin 6 (ignition))

to check the fuel pumps and pressure/flow, disconnect the output (back side) of the fuel pressure regulator, connect it to a length of hose leading into a clean gas-safe jug, and jumper the fuel pump at the fuse panel by connecting fuse 1 to fuse 11 for a few seconds, you should get about a half pint a second of gas in your jug (+/- 50%). be careful with sparks around fuel etc etc.

replace the fuel return line on the back of the fuel pressure regulator, and disconnect the vacuum line from the front of the regulator, have a friend do the same jumper thing with fuse 1 to fuse 11, and make sure no fuel comes out of the pressure regulator. replace that vacuum line.

put the OBD jumper into #2 on block "A" and switch the ignition on, then press the button 3 times for a bit more than 1 second each time. This is described as 'DTM 3' on that page on the OBD. the fan should run low speed, then high speed a couple times. then the fuel injectors should go click/clack/click/clack a few times. then the idle control valve (under the intake manifold) should go click/clack/click/clack. and some other stuff, then repeat with the fan. this is a great way of testing these systems.

there's a ton more useful stuff here.
Volvo Maintenance Hints for 7xx/9xx

jupoloopo · #3 07-25-2011, 05:20 PM

Greetings Dread, try unplugging the Air Mass Meter on the accordion tubes:

and see if it starts. if it doesn't start I can't be of much help past this. But if it does start it will go into "limp home mode" and that means you will need to find a another AMM.