ok i am going nuts here, i have a volvo 740 and it has developed a starting issue. the car cranks and cranks and cranks and then it starts

things ive done or checked:

replaced spark plugs
check plug wires
checked spark at spark plugs
checked spark at coil
replaced fuel pump relay
checked all fuses
checked all hoses
fuel pump primes when acc on
the o2 sensor is about a year old

the car runs and drives like normal once started,the car pulls with no problem doesnt cut out doesnt lack power ect, car idles fine. doesnt miss or anthing, this just gradually started

what am i missing here i dont know what to do or check

 

there's a one way valve in the fuel line after the pump, that holds pressure after its primed. maybe?

 

is that in tank or outside the tank?

when it cranks it cranks and crank and the dash lights dimly light up before it starts. this is also fluddering the throttle to try and get it started.

i feel like eventually it might not start at all?

 

while this extended crank event You do have good spark then?
Fuel pressure?
Compression #'s?
Engine in Time?

 

yes i get spark from the wires
i get spark from the coil
engine is in time
not sure on compression numbers but i dont believe there would be any reason to suspect conpression

i went out last night for a drive about 2 hours, the car didnt so much as miss,stall or anything, it drives perfectly without any issues. car pulls just fine.

its just the whole when you start it off and go to start it, it cranks and cranks and then start

 

Could it be the radio suppression relay?

 

i just got the fuel filter off, i have a new spare one, the one i got off the car looks to be oem original, when i poured the fuel inside a clear glass the fuel was black.

i tried to get water to go through the fuel filter and it seemed to just collect but nothing came out of the other end, except rust and more black fuel.

i will post back in a hour on a upgrade either way the car definitly needed a fuel filter

 

Coolant Temperature Sensor most likely, the one under the third rail of the intake manifold. It is sending the wrong signal to the brain telling it that the car is warm so no extra fuel is needed. You crank and crank, eventually enough fuel gets in. Once warm all is well, starts fine, right?

 

Actual pressure readings are the only thing that is relevant.

My filter was probably just as bad and never had a long crank....

 

WE need test data not guesses and part changes.

 

well changed the fuel filter and nothing has changed.

how do i get test data im not throwing any kind of CEL?

 

the one way valve is after the main pump (assuming this is a 2-pump Bosch system and not a 1-pump regina, I dunno anything about Regina)

but, the one way valve just makes the difference between a 1 second start anda 3-4 second start.

next time its cranking and cranking and not starting, pull a sparkplug, and inspect it. is it wet? does it smell of gas?

also, what year is this 740? 82-87 were suspect years with bad wiring.

 

what year 740? LH2.2 didn't have any sort of useful diagnostics, OBD-I was introduced with LH2.4 on 1989 non-turbos and 1990+ turbos.

 

its a 1991 volvo 745 Regina fuel system it only has 1 intank fuel pump b230f engine

 

ok, the 91 should have OBD-I, although regina throws somewhat different codes. See this for how to read it... Engine and OBD Diagnostic Codes

 

ok i pulled a couple this is what i got

2-2-3 Signal missing to/from idle valve IAC Idle air control valve
1-2-2 Signal missing or faulty to/from air temperature sensor Air temperature sensor
2-3-2 Self-adjusting oxygen sensor not operating Intake air or fuel system

 

those codes could be quite old. I'd reset it (read the codes until they repeat, then hold the button down for like 10 seconds or something, that page explains exactly what), then drive around for a few more days, and read it again.

 

they are repeating and now im throwing a CEL. i will try to reset and see but something is definitly wrong

i pulled the fuel line to the fuel pressure regulator, cranked it over into a clear cup, there is NO FUEL COMING OUT!

 

the skinny line to the back of the FPR (fuel pressure regulator) is a vacuum line. the input to the FPR is the fuel rail/pipe, and the output is the hose fitting on the bottom, thats the return line to the gas tank.

(note, I'm assuming the regina FPR is similar to the Bosch system, I've never actually seen a Regina).

on a 1989+ (1990+ turbo), the CPR (Crank Position Sensor) generates pulses when the engine is turning over, this goes to the ICU (ignition control unit), which passes those pulses over to the ECU (fuel injection control unit), which switches on the fuel pump relay to turn on the fuel pump(s).

now, if you have spark, then the CPR is working, so the problem is more likely in the fuel pump relay or associated wiring (or fuel pump fuse, if regina has one).

let me dig up the 1991 regina schematics, if I have them...

ok, yeah, your fuel pump is on fuse 11. that fuse is powered via the fuel pump relay, which is getting its power from fuse 1, which is powered directly off the battery. the fuel pump relay, as I said, is told to switch on when the ECU sees the CPR pulses coming from the ICU

 

ok i checked all my fuses ALL are good #1 #11 all of them are good.

i have 2 fuel pump relay's one is a older one another is from 2009. i get the same symptoms with both relay's

i cleared the codes, getting the 1-1-1 so all is clear.

i went and got 20.00 worth of gas which at 4 dollars a gallon only gets you 5 gallons i was thinking maybe my floater might be off..still nothing

i once again took the Main fuel line that goes from under the car which i presume comes from the fuel filter and turned the key and put the hole into A clear cup, still nothing no fuel at all.