I have a '92 745 B230F that I have been getting a cold no-start with lately.

Some history:

1) Occasional high idle only when fully warm (e.g. when coming to a stop after freeway driving). Turnoff engine and restart immediately and it's back to normal. IAC motor is clean a a whistle.

2) Occasional no starts when hot in the past, but rare.

3) Recent cold no-starts.

Once started this thing runs great. Like a swiss watch. Passed CA smog with flying colors yesterday. Good power curve and fuel consumption. Good cap/rotor/wires. I can hear the fuel pump pressure up when the ignition is switched on. It just doesn't want to start. I will occasionally hear it barely start to fire but it just doesn't do it. Sometimes I can go back to it the next day in the same spot and it will fire right up.

I've read and read and I'm at a loss. Anyone have any ideas?

Thanks!
Tom



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'92 745 B230F

Thanks to everyone. Uncle Olaf was correct. The shielded wiring harness for the Crank Position Sensor was cracked. This was at the firewall where it ran through a factory cable tie with several other wires, just a few inches before the connector plug.

Sadly, I sold the car ('92 745) last week. It was my first Volvo and I put a lot into her but it was time to let her go. And so I keep my '95 850 sedan as my daily driver. I'm happy with 20 valves. Life could be a lot worse.
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'92 745 B230F

For no-starts, which are constant, go to www.stepbystepvolvo.com for free guide to 740 no-starts.

When it won't start try checking the voltage at the injectors. With the key ON you should have 12 volts to ground at one pin and zero on the other. Some say you need to disconnect all 4 injector plugs to get a reading. No 12 volts and it's the "radio" relay or connector plug.

Hey Tom,



I would take a look at your impulse sensor. If its wires are frayed, its toast. They cost about $ 30. I would also check the fuel pump relay and the radio suppression relay. The FAQ shows to repair them. Its really easy if you have a little experience soldering. Another thing to check is the ignition coil/power stage which is a combined unit with Regina injection.



Regards, Jon 'Uncle Olaf'

Thanks for replying, Unc'.

I assume the impulse sensor would be the crank position sensor on my '92? I hate just replacing sensors without knowing they're the culprit, but logic points this direction.

I already soldered the FI Relay (and the OD relay) and can hear the fuel pump cycle on for a second. The radio suppression relay looks a little tougher to crack open than the FI relay....almost like it's glued together with black rubber.

I have a Bosch ignition.
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'92 745 B230F

Howdy,

I just had a very similar problem on my wife's '92 240 with Bosch ignition. Replacing the power stage (a.k.a. ignition module/amplifier) seems to have solved it. On the 240's, it's mounted on the inner fender, between the battery and the driver's side headlight. Not sure exactly where it is on the 740's.

I hear you about not liking to replace parts (sensors especially) if they're not definitely bad. On the power stage, however, from reading the Bentley, it seems that there isn't really a test for just that one part. More like "if you test everything else and it all checks out okay, then maybe your ignition power stage is faulty."

I was about to start a separate thread about this, due to some contradictory test values for the coil in the Bentley manual and the Brickboard FAQ, so there'll be some more detailed information about my car's symptoms in there. They're not exactly like yours (no high idle), but very similar. Test your coil as per the Bentley (and/or FAQs) too. A marginal coil will knock out a power stage and vise versa.

Incidentally, I replaced the Crank Position Sensor on my wife's car last year. If your's is original, take a real careful look at it as Uncle Olaf suggests. Secondly, have you checked for fault codes stored in the ECU/ICU self diagnostics? When my '92 was acting up it never threw codes, so if you're seeing a fault code or two it might point you in a different direction.

Good luck and have fun!

Best,
Afton

'68 122, '87 '88 & 92 240's, all stick shift station wagons

Hey Tom,


I am indeed referring to the crank position sensor. Its mounted to the bellhousing. Sorry for any confusion. Glad to hear you soldered the fuel relay, takes a potential issue of the list.


Regards, Jon