Volvo 740 no spark
#1
Volvo 740 no spark
Heyy people,
Ive searched other threads but i didnt find the solution yet, so that's why this thread.
Okay so ill start in the beginning,
at first my Volvo 740 GLE with the b230k engine only stopped working when i cleaned it with high pressure, after a few days "something" dried up and it worked again normally, but the last time it didnt so i started searching, at first i had a spark and fuel but it woudent start, so i thought okay i guess thé timing has to be off, there must be something wrong with the timing sensor
(i didnt know anything from this engine, but i really wanna learn so please, no judge for the simple minded way i did this) so i got myself a new one, wanted to install it but broke the housing of the distributor becaus of the steel revets
I bought myself a new distributor, installed it and started the engine and it worked for like half a dayAfter that it just stopped in the middle of a ride after i adjusted the angel some times to get it going until i could do it properly
So i dragged it home and now i don't even have a spark anymore, i tried another Coil my friend had lying around, becaus i got 12 volts on it and it didnt spark, but now Ive read something that the ignition module shoud make it spark and not just the distributor, so now im trying to measure the right volts on the module, but i don't really know what to expect
and im pretty sure my module is ok, since it's also a new one, said they guy i bought the car from.
Does anyone know what to exactly expect for the signal? And maybe on which wire on the module i shoud expect it?
or do you guys know what coud be wrong?
Everything i measures for now is:
2 times 12 volts on my Coil with just contact on8 volts when cranking
2 times 12 volt on my module1 Time 8 volt while cranking (i think this is the signal)
12 volt on the hall effect sensor
8 volt on the signal and the +
BTW im sorry if my English is bad, im from Belgium and never had lessons!
Ive searched other threads but i didnt find the solution yet, so that's why this thread.
Okay so ill start in the beginning,
at first my Volvo 740 GLE with the b230k engine only stopped working when i cleaned it with high pressure, after a few days "something" dried up and it worked again normally, but the last time it didnt so i started searching, at first i had a spark and fuel but it woudent start, so i thought okay i guess thé timing has to be off, there must be something wrong with the timing sensor
(i didnt know anything from this engine, but i really wanna learn so please, no judge for the simple minded way i did this) so i got myself a new one, wanted to install it but broke the housing of the distributor becaus of the steel revets
I bought myself a new distributor, installed it and started the engine and it worked for like half a dayAfter that it just stopped in the middle of a ride after i adjusted the angel some times to get it going until i could do it properly
So i dragged it home and now i don't even have a spark anymore, i tried another Coil my friend had lying around, becaus i got 12 volts on it and it didnt spark, but now Ive read something that the ignition module shoud make it spark and not just the distributor, so now im trying to measure the right volts on the module, but i don't really know what to expect
and im pretty sure my module is ok, since it's also a new one, said they guy i bought the car from.
Does anyone know what to exactly expect for the signal? And maybe on which wire on the module i shoud expect it?
or do you guys know what coud be wrong?
Everything i measures for now is:
2 times 12 volts on my Coil with just contact on8 volts when cranking
2 times 12 volt on my module1 Time 8 volt while cranking (i think this is the signal)
12 volt on the hall effect sensor
8 volt on the signal and the +
BTW im sorry if my English is bad, im from Belgium and never had lessons!
#3
#4
No i haven't actually, and it's only 12,09 sometimes but now i have it on a loader all thé time and then it Gets to 14 volt, but is it possible that it has enough power to crank the engine but not to start it?
and the distributor is at the back, but yesterday i tried to measure my signal from the hall effect sensor and i do get 5 volts but no Hertz, but that could be thanks to my cheap instruments, im gonna try to get a scope to get a better sight on it! Or if you guys know a good method to make sure it works properly? Becaus that scope aint gonna be too easy im afraid!
and the distributor is at the back, but yesterday i tried to measure my signal from the hall effect sensor and i do get 5 volts but no Hertz, but that could be thanks to my cheap instruments, im gonna try to get a scope to get a better sight on it! Or if you guys know a good method to make sure it works properly? Becaus that scope aint gonna be too easy im afraid!
#5
I tried to start it with cables to another car and that didnt help mutch and it's a rear distributor
but now recently i tried to measure the signal from the hall effect sensor, but i didnt get a signal on thé Hertz setting, but i don't know if i did that part right, i tried to measure the frequency like i woud measure volts so om not sure if that's the right way, i put the tool on thé signal wire and a mass Point on my doorframe
Does anyone know a better way to test it? And if that's the right way, im asking myself wy the new sensor woud die so quick, i tested the wires for ohm and didnt see too mutch resistans so coud it be in the computer?
but now recently i tried to measure the signal from the hall effect sensor, but i didnt get a signal on thé Hertz setting, but i don't know if i did that part right, i tried to measure the frequency like i woud measure volts so om not sure if that's the right way, i put the tool on thé signal wire and a mass Point on my doorframe
Does anyone know a better way to test it? And if that's the right way, im asking myself wy the new sensor woud die so quick, i tested the wires for ohm and didnt see too mutch resistans so coud it be in the computer?
#6
The only way that your timing coulda changed...enough to matter, is a broken T-belt.
You need 3 things to run:
Gas...at the right time, and right amount. You could dump some in the intake..... half a cup and see if it fires off and then dies. If you have the correct spark, this will verify no gas.
Spark, same thing, at the right time. They make a spark testor, that you can get at Autozone. Or you can just use an old plug. But, the testor you can screw in and out and change the gap and get a rough estimate of how much Voltage your system has....it has markings on it for dif volts.
Compression....look at my 1st sentence. loosen the top 2-3 bolts on the timing cover, pry it out, and see if your belt still goes roundy-round (a technical term). Or if your car has a dizzy...the rotor should turn roundy-round (probably the easiest way to check....assuming that it hasn't jumped a tooth.
You need 3 things to run:
Gas...at the right time, and right amount. You could dump some in the intake..... half a cup and see if it fires off and then dies. If you have the correct spark, this will verify no gas.
Spark, same thing, at the right time. They make a spark testor, that you can get at Autozone. Or you can just use an old plug. But, the testor you can screw in and out and change the gap and get a rough estimate of how much Voltage your system has....it has markings on it for dif volts.
Compression....look at my 1st sentence. loosen the top 2-3 bolts on the timing cover, pry it out, and see if your belt still goes roundy-round (a technical term). Or if your car has a dizzy...the rotor should turn roundy-round (probably the easiest way to check....assuming that it hasn't jumped a tooth.
#7
Thé spark really is the problem since there isn't any but im starting to think my ECM is broke, i get power supply, have a new ignition module and a new distributor, i don't get any loss of voltage over the cables and with the new distributor i also got a new sensor so the signal should be okay too, i don't know what else it could be?
and when i try tot start thé voltage on the Coil Drops tot 8 - 10 volts?
Or is that normal?
and when i try tot start thé voltage on the Coil Drops tot 8 - 10 volts?
Or is that normal?
Last edited by Boeckx; 03-28-2021 at 02:41 PM.
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