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90 volvo 740 Turbo EZK no start no spark

Help, Advice, Owners' Discussion and DIY Tutorials on all Volvo's "mid era" rear wheel drive Volvos.

1975 - 1993 240
1983 - 1992 740
1982 - 1991 760
1986 - 1991 780
1990 - 1998 940
1990 - 1998 960
1997 - 1998 V90/S90

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Endbringer
Posts: 3
Joined: 27 April 2012
Year and Model: 90 volvo 240
Location: Washington

90 volvo 740 Turbo EZK no start no spark

Post by Endbringer »

well I bet you are all sick of the 740 no spark thing but I may have a new twist on it. First off checked for codes found code 4-1-3 took some time to track any reference to this code but what i finally found was EGR temp sensor error most likely would not kill the spark so i began diagnosing.
key on engine off no power to coil, ran a jumper to coil from batt and presto still no spark. so I began checking the power supply to the ignition components. power stage has voltage, TPS testing through OBD was ok, I happen to have a 90 240 that runs grate so i start swapping things out to test with known working and test if the others are still good. CPS from 740 worked in 240 , power stage bosh 124 mod from 740 worked in the 240. next I swapped out the coil from the 240 to the 740 got 1 spark off of the coil and then nothing no spark. so now iv started to suspect power to the CPS and there is nothing coming from the ECU to the CPS, I do not have a working volt meter so test light to ground and no light came on and I am still not sure why there is no power going to coil, I checked the power coming out of the ignition key and all is normal still if that was all a jumper would of fixed it. but if its not wiring then it must be the ecu? all the wires going to the CPS come from the ECU voltage is getting to the ECU pin 5 and 6 but still nothing going to CPS. I rely do not want to spend $175 for a new ECU unless that IS what went dead but a new car is $$$$. Some one out there must know what this Volvo fanatic can do to keep this 740 turbo from joining all the other "it died one day and never started agen" out there.

Endbringer
Posts: 3
Joined: 27 April 2012
Year and Model: 90 volvo 240
Location: Washington

Post by Endbringer »

ok so today I went out and thought since it finaly stopped raining I would try testing everything agen still no power to the coil ran the jumper to the coil and went to start it and she started rite up. so I will now do the tedious and trace the wire back in to the deepths of the maze of wiring and find the brake wish me luck

jimmy57
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Post by jimmy57 »

I recall having issues with coil power supply and I think it was connector problem at the grey connectors cable tied to the strut housing to firewall brace. Inspect those. The relay for coil power supply is also supply for other things as I remember so if it was the relay it would be missing injector power at the green wire. WHen it has no spark does it have injector power?
The suppression relay on the galvanized bracket on strut tower on driver's (or is it passenger side? for turbos that year) can be swapped with the twin relay next to it that is for the auxiliary fan in front of condenser

Endbringer
Posts: 3
Joined: 27 April 2012
Year and Model: 90 volvo 240
Location: Washington

Post by Endbringer »

tracing the wire has proven near imposable with out taking much of the dash apart. I have taken the time to hook up a "Anti theft device" to power the coil and the car runs grate. maby some day when i get crazy ill track it down and fix it properly.

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