Hey everybody, I'm new to this site and I'm so thankful that this exists!!! I have a problem with my 1991 740 that I'm pretty stumped on. I should say that I'm not too car savvy, so stumping me is not that hard.

Anyway, a few weeks ago I hit a pretty big pothole and my car shut off while driving for about 3 seconds. It kicked back on and I thought just a ghost in the machine. About a week and a half ago the same conditions, however the car didn't start again. It would crank but no start. Turning the ignition on, I could hear the fuel pump, which was just replaced with the relay about a year and a half ago. I got it towed home and tried testing for spark. There was no spark from the distributor to the engine. Haven't done a tune up in a while so I got a cap and rotor (plugs and wires comes later because apparently nobody around me has them in stock). Changed that and still not cranking over. Let it sit a few days, tried starting it and it started...
Went about 10 miles before it died on the road again, this time, no trauma like a bump. Still have to change the plugs and wires (at work right now and I'm depending on other people for a ride to get the correct socket for the plugs). It started yesterday and this morning, but I did not drive it in fear it would die on the road again and I'm quickly exhausting my free tows.

Does anybody have any ideas for me once when I get past the tune up stuff? Like I said, I changed the relay switch and fuel pump about a year and a half ago, I just changed the starter last month.

 

Check these few things besides doing the diagnostic testing in the black box that lies under the hood.(read in instr book of your volvo car how you do it,its simple.)
1.Fuel relay has been changed you say,but was it a new one or from the junkyard?
2.Diffuser relay should be changed and its on the coolant container.Causes startfail.
3.Check the relay to the injection valves,its behind the coolant container and the head light and its mounted on the wall.
4.The fuel pump,but you say its replaced.
5.Distributor/Ignition coil/ignitor module,all failures causing spark failure and car dies
6.Impulse sensor is faulty.Just follw a black wire fixed from the back of the motor.It is fixed with a screw there and then is fixed at the other end to the wall below the windshield.Check if the wire is burnt or faulty at both ends.You need to stand on a stool to se it down behind there.

 

Thanks for responding!!!
1. Fuel relay is new and purchased 3 years ago when fuel pump went out.
2. Still need to check diffuser relay.
3. Still need to check the F.I. relay.
4. Fuel pump is new, just as new as the relay so 3 years old. However, I hear the pump hum when the ignition is turned to the on position, so I know the relay and the pump are working.
5. Ignition coil and wire are brand new. Still need to check the distributor and impulse module.
6. Still need to check the impulse sensor.

The car started this morning. It seems it has no problem starting in colder, damper weather conditions, so I suspect there's some problem with conductivity somewhere. I need to wait until it gets dryer and warmer today to check these relays because that's when it's not going to start. I understand that the F.I. relay and the cooling fan relay are the same, so I could swap them, right? Another question is, besides swapping the relays, is there a way to test them to see if they're faulty? Or do you just have to buy 3 different relays at $50 a piece and just replace them and hope that it works?

 

First of all I would suggest you to do the testing at the diagnosis box under the hood.Your car has one,just read the car manual you have and you will learn how it works.You can find the solution to your problem here with the codes you get.And you dont need to buy them relays cause you can borrow them from someone who has a similar car if you know anybody.Can also get them cheap at the junkyard.However,I think your problem is the impulse sensor wire mounted at the back of the motor.Very common problem for this model,especially since your fuelrelay is new..Check it,it could be coroded or something.

 

Yeah I still have to do the testing and I do know how to, just have to have my wife pick me up a multimeter. I didn't have one before so I ordered it. Problem is, without a car to get me there, everything moves sooooooo slow. The impulse sensor...is that the same thing as the Crank Position Sensor?

 

I'd look at that Crankshaft Pos. Sensor, and fuel relay... Just because it was replaced, it may be going bad again.

 

I'm pretty sure the fuel relay is good. I touch it when I turn the ignition on and I can feel it click then immediately hear the fuel pump hum. Right now I can't get my car to NOT start, but I'm still too afraid to drive it day to day because it dies while driving. Will a failing crank sensor cause your car to die while driving or just create starting problems?

 

Sensor
Auto Part #
PC177

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Product Fitment and Detailed Description

1. Genuine Intermotor Quality

Also known as:
Crank Sensor, Crankshaft Sensor, Crank Position Sensor, Crank Angle Sensor






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$49.59

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Additional 1990 Volvo 740 Fitment Information:

VehicleSubmodelAspirationFuel TypeCylinder Head TypeBlockEngineCIDCC1990 - Volvo 740BaseTurbochargedGASSOHCL4 Cyl 2.3L-23161990 - Volvo 740BaseNaturally AspiratedGASSOHCL4 Cyl 2.3L-23161990 - Volvo 740GLNaturally AspiratedGASSOHCL4 Cyl 2.3L-23161990 - Volvo 740GLENaturally AspiratedGASDOHCL4 Cyl 2.3L-2316




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Engine Crankshaft Position Sensor



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1990 Volvo 740 Engine Crankshaft Position Sensor IMC


Auto Part #
802 53043 250

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Product Fitment and Detailed Description

1. Bougicord

Also known as:
Crank Sensor, Crankshaft Sensor, Crank Position Sensor, Crank Angle Sensor







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$50.75

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Additional 1990 Volvo 740 Fitment Information:

Vehicle1990 - Volvo 740






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Engine Crankshaft Position Sensor



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1990 Volvo 740 Engine Crankshaft Position Sensor Bougicord


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W0133-1903829

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Product Fitment and Detailed Description

1. At Flywheel - Engine Speed - Ignition Impulse Sensor

Also known as:
Crank Sensor, Crankshaft Sensor, Crank Position Sensor, Crank Angle Sensor

This is a OEM Product: This Original Equipment Manufacturer part is the same part that was made & installed by the car manufacturer at the factory where the car was produced.






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Vehicle1990 - Volvo 740







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This wire has many names as you will read in that ad.It can cause your car to die while driving as it gets hot

 

Thank you! Sorry, I'm at work right now so I can't check it, but I thought there was a diagnostic check for the crank sensor in the #2 function on the OBD. Does that sound familiar to you?

 

I guess crank position sensor does make a lot of sense. Got a pretty crappy oil leak going on and it's been idling pretty rough ever since. There's a large concentration of oil sitting right on top of the sensor.

 

The CPS would definitely cause a stalled engine, it could also act intermittently... Good place to look...

 

yes,it is true if you have the regina system but dont know what code it sends

 

Quote:

Originally Posted by Valjean

Thank you! Sorry, I'm at work right now so I can't check it, but I thought there was a diagnostic check for the crank sensor in the #2 function on the OBD. Does that sound familiar to you?

See Diagnostic Test Mode 2 on the following site to test the crankshaft position/RPM sensor. And yes, it should set a 214 code if it's not working. Plug into the #6 hole to check ignition codes. This is considered an ignition system problem and is one of the few sensors that does not have a limp-home mode. It will absolutely prevent the car from starting.

Engine and OBD Diagnostic Codes

 

Actually, now that I noticed that you have a Regina system, this might be more helpful. Same principal, slightly different procedure. Go to page 18..
http://www.ohio.edu/people/ridgely/V...Reginabook.pdf