New 740 GL Owner with starting problem

[My91Wagon]

Hello RWD Volvo Fans,

I have loved boxy Volvos since Junior High and I have finally bought one as a daily driver project early this year. Picked up a 91 740 wagon GL (Regina and auto) with about 140k. About two days ago I began having a starting problem. The car would crank and almost start but would not start. If I would crank the car about 2 or 3 times in a row it would start eventually but just barley. I have done some research and thought it may be the fuel pump relay….I check mine 1st and even though I could feel the click on the relay I went on and changed the relay. Now it starts but it still takes a bit of cranking to do so. Please help me? Could it be the radio suppression relay?

Here is the work I have done on the car already:

Air Mass Sensor
Spark plugs
Distributor Cap
Distributor Rotor
Fuel Filter

FYI, I do hear the fuel pump right before I start the car.

THANKS in advance!!!!

[billofdurham]

Welcome to Matthew's Volvo Site.

Have you checked for fault codes using the On-Board Diagnostic (OBD) unit in the engine compartment? This is a first step in diagnosis. Instructions for its use are pinned at the top of the forum.

On the Regina system with an intermittent no-start problem check the following:
Crank sensor;
Interference relay aka radio suppression relay;
Fuel pump relay;
Wiring to cold start injector.

Bill.

[My91Wagon]

Thanks for the welome Bill!

Okay, I will check the OBD and then check back in...

Thanks again!

[Vtech]

Hello , did you see if the injectors are clicking , listen with a screwdriver on the injector and your ear on the handle while someone cranks the engine . If no clicking , disconnect one injector connector and see if there is power at the green wire when cranking , if not the radio supression relay is likely bad . There may be an identical relay under the hood used for the electric fan you can swap with to verify . If injectors are clicking - see if you have spark to the spark plugs , if not , I would suspect the engine speed sensor on the back of the engine at the bell housing . Did you say you heard the fuel pump humming when the engine is cranking ?
Larry

[Thinker]

I spent many hours reading different forums over and over for days before taking any action. One of the most common culprits mentioned for hard starting was the cold start valve. OEM replacements are pricey, therefore, probably one of the last things people do to correct this hard starting issue. Besides a lot of, "Where the heck is this thing?". One commonality was poor eletrical contacts. (wire connectors). I looked under the intake manifold and found two, very obscure, connectors. Carefully jostled them to make sure of a good connection and voila', car starts like a new one every time. Check your sensor connectors. Didn't touch any of the other suggestions. This fix nailed it!

[My91Wagon]

Wow! Thanks for all the tips!

I was able to find the diagnostic unit. From there I placed the connect cable into the space labeled “2”. I turned the ignition to on, pressed the button on the diagnostic unit only once for what I thought was 1 second then watched the codes. What I got was a flashing code of 3-2-1???? When I pressed the diagnostic button twice (with each depression being held for 1 second) all I got was a rapid, repetitive blinking??? I was thinking that perhaps I didn’t understand how to transition from the first level of testing to the second.

[Vtech]

code 321 From socket #2 is for cold start injector circuit . below around 58 deg f pcm gives a couple sec ground to cold start injector under intake . supression relay supplies bat+ to injector . as Thinker said loose connection can cause your problem , should still start fine above 60deg f . cold start injector is awkward to get to , but necessary to test , injector windings should be about 10 ohms ,gray/blk wire is ground when temp below 58deg f , blue grn wire is bat+ from supression relay . also at diagnostic plug check codes at pin #6 for ignition system . You are getting there , Larry

[My91Wagon]

I first want to thank you all for your knowledge. This board is GREAT!

Ok the car no longer has any starting issues since the weather has gotten warmer. So I assume it is safe to say that the culprit is in fact the cold starter valve. I did look for loose connections but did not find any, but I will look again as I am not POSITIVE I know the exact location of the cold starte valve. I did search for pictures but to not avail. From searching there seems to be several ways to fix this:
Replace it
Clean it
Change the wiring

I am looking for a write up that addresses this...any one know where I can find a write-up?

Thanks

[billofdurham]

The cold start injector or valve (CSI) is located on the underside of the intake manifold, right where you can't get at it. It is very close to the coolant temp sensor, near cyclinder #3, intake side.

Switch off the ignition, disconnect the cold start valve and check, with an ohmmeter or multimeter, between terminal 1 on the connector, right hand side as you look at it. You should get infinite resistance if it is earthing (grounding) OK.

If that test is OK check the cold start valve itself with an ohmmeter between the two terminals on the valve. You should get 10 ohms. If you don't get 10 ohms the cold start valve is faulty.

If you get 10 ohms switch on the ignition with the sensor disconnected and check from terminal 1 on the connector and earth. you should get battery voltage.

Let us know what you find.

Bill.