volvo1975
can some 1 ,,,please please help me ive changed my leads ands plugs ,,,fuel filter,,, crank sensor,,, radio / fuel relay, and added fuel injector cleaner ,,,and still my volvo 740 still gets a miss, it has been a bit erratic when cold until warm but it can still do it when warm as well?? but not as bad just faint... any 1 know what it could be,, pressure regulator??
Tigabu
@Vee_Que @volvodriverman @egads @Angus242164
egads (she/her)
Distributor cap changed?
Ex850R
No expert but what fuel do you use? 95 ? E10 or not?
volvodriverman
I'm chasing something simular with my 740t, as yet I haven't found the cause but I suspect a fuelling issue. Mine won't start first time then fires right up, it is hard to get it mobile until warm. I don't have a miss though. I'd be guessing at cap & rotor but its certainly possible. Also check the connector & wiring for the hall sensor.
volvo1975
thanks u guyz ,,,volvodrive man how is your radio supp relay drivers shock tower it controls the fuel injection as well,, can cause a total car stop.... keep a spare very important and check or renew the crank angle sensor
volvo1975
snoopy ,,, i only use 91 unleaded NO E10 its strange it can run so good then it starts its crap,, its truly a nice car but im getting nervous,,,,
volvo1975
egads...thank you....... no havent changed it but that will be next job!!
volvodriverman
volvo1975;12957 wrotethanks u guyz ,,,volvodrive man how is your radio supp relay drivers shock tower it controls the fuel injection as well,, can cause a total car stop.... keep a spare very important and check or renew the crank angle sensor
Relay is good, swapped for a known good one. I'm on lh2.2, I'm guessing you're lh2.4 by the crank angle sensor comment? If you are there's onboard diagnostics. (well there is for 2.2 but meh)
volvo1975
im bit dumb what is lh 2.2 lh 2.4,,,,, mine was reving up and down all over the place,, changed the sensor starts gr8 now.... mine is 2.3 ltr 89 mod
nickm
Injector seals? If fuel. Coolant temp sender for the ECU?
A logic probe is handy for diagnosing injector and hall sensor problems.
I had a heat sensitive issue with the LH2.2 hall sensor.
You can plug the probe in at the ECU and watch the pulses. If there are issues here.
This is for the Fuel ecu.
EK117Z
nickm
One other question. Is the car in open loop when this occurs and changes when in closed loop?
volvodriverman
That's awesome info, cheers. I had a dig under the fuse panel as the rear demist & lighter aren't working & the main earth block has a wire which is burnt up badly, suspicion is nothing is earthed properly. A lot of stuff earths through that area so would explain some gremlins...I hope
volvo1975
thanks gr8 help,, see what happens must be something small,, i hope
Vee_Que
Sounds like the idle motor is causing the idling up and down. Have you cleaned the throttle body and idle air control valve?
Mine doesn't always start first time. I don't stress about it. It probably is the angle sensor in the distributor, the wiring is old and should be replaced all the way through I think too.
Angus242164
Fault description is a bit vague, is the car misfiring?
It's difficult to offer more than a guess without being there to see/drive it in person, it could be anything from a worn distributor cap/rotor, to damaged engine wiring harness insulation, to a blown head gasket.
volvo1975
Thank you Angus, its not doing it all the time, just now and then BUT it shouldnt be doing it at all, im replacing the cap and button asap, i really thought it was a lead problem, its not misfiring it just has a hesition for a split second about the 5th time its happened and also starts not at full capacity the (revs arent stable) when cold...thanks again karl
ive replaced - fuel filtter , leads , spark plugs,radio/fuel relay, crank angle sensor,
volvo1975
gr8 news i took disy cap off and the condition was black crap all over,, the contacts were covered goin for a good run now fingers x thanks u guyz
Ex850R
Get new one and rotor and replace the wires inside.
