1990 740 GL won't start intermittently

woodst · Post by **woodst** » 30 Sep 2009, 15:35

Hello,

We have a 1990 740 GL (non turbo) auto transmission with approx 430,000 km on it.

The issue has happened to us twice. I'll try to give as much detail, just in case it is important.

First time the car started, we drove for approx 30 minutes. Stopped and turned off car for about 20 minutes and when we tried to start it again, it wouldn't. Headlights & indicator lights came on but the engine didn't turn over at all just dead air. Tried in park and in neutral -- no luck.

Just so happens at the time there was a guy across the street that came over to help who brought a metal bar and tapped the solenoid while someone turned the key and the car restarted. His comment was that the car would continue to not start once in awhile because of the solenoid and eventually it would have to be replaced.

We continued to drive the car with no issues with starting until about 3 months later. Car was driven for about 30 minutes, stopped and restarted about 15 minutes later; ran for about 20 minutes and then stopped for about 10 minutes and then wouldn't restart. Same as before, lights on but no turnover at all. Tried several times. (Couldn't tap the solenoid because I was alone).

Next day, tried again and it started first try. Drove it to the mechanic. When he tried to start the car the next day, it started no problem and he said that he didn't think it was the starter because of 'no click' and didn't think the solenoid causes this type of issue. He thought that it was the gearshift not properly engaging into "P" or "N". He said it is difficult to diagnose without it happening to him.

Picked up the car from the mechanic later that day, no problem with it starting.

Any suggestions? I know this is a needle in a haystack...we just hate getting stranded!

Thanks in advance!

Tia

Post by **billofdurham** » 30 Sep 2009, 16:17

I agree with the Good Samaritan with the metal bar. However, there are sevearl things you can do to check that everything else is OK before ripping out the solenoid and replacing it.

The starter is one of the heaviest users of power from the battery, drawing several hundred amps, so all the connections need to be clean.

Start at the battery checking both positive and negative connections. If your radio needs a code make sure you have it then disconnect the battery, negative first and clean the battery posts and the mating surfaces of the connectors. Disconnect the negative lead from the body and clean the area where it connects and the connector itself. When putting the connectors back you should coat them with petroleum jelly or dielectric grease to keep out condensation. This is an old practice which is mostly not done now but I am an old fashioned sort and my cars still get the treatment.

Next move to the starter motor. Check the + wire (the big thick one) connection at the starter. It should be clean and tight. Make sure the bolts holding the starter to the engine are tight - the current goes through the starter and block. You will also find that the engine is earthed (grounded) and there should be a big earthing strap, or you may find that the battery negative terminal is connected directly to the block. Whichever it is make sure the contacts are good.

As you are looking at an intermittent problem your mechanic is correct in saying he can't diagnose the fault unless it presents itself when he has the car. By doing the above checks/cleaning you are narrowing the field down to either the starter motor or the solenoid. If, unfortunately, it should happen again try to listen for a click from the solenoid. If it clicks it is OK and the starter motor is suspect. If it doesn't click it is the solenoid.

To minimize the chance of becoming stranded carry a metal bar and, even when alone, you can tap the solenoid then try to start the car. It may take several attempts but I have done this on more than one car over the years.

Bill.

woodst · Post by **woodst** » 01 Oct 2009, 19:10

Bill,

Once again, thank you for all the help and detailed information you provide in your posts! We will try all your suggestions and hopefully narrow it down.

Cheers!

tia

timshell · Post by **timshell** » 02 Oct 2009, 06:21

tia:

I am experiencing the exact same thing with my '90 740 GL. I am able to turn the key all the way to the right, pop the hood and cross the starter-solenoid with a screwdriver by myself. Not a fix I know and if you do try it alone be sure it is in park!
All the lights radio, etc work fine, just no start and no obvious cause and effect for when it is going to happen: hot, cold, day, night, (except usually when I am in a hurry, arrgh).
Two different shops have told me it is not the starter and one said it is the ignition switch in the dash. Not sure I want to look under there myself and one shop quoted a repair for under $200 so might go that route.
I know this isn't much help except that you are not alone, I suppose. I'll let you know if the ignition replacement fixes mine and if there is a sure fire way to determine that it is, indeed, the culprit.

best of luck, take care,
Steve.

Post by **billofdurham** » 02 Oct 2009, 11:51

timshell, welcome to Matthew's Volvo Site.

Usually the ignition switch in the dash will cause other problems when it is starting to fail, eg radio, panel lights and even main lights.

The attached explains how to test the three components that can cause the problems both you and tia are experiencing.

740 ignition switch check.pdf: (158.69 KiB) Downloaded 179 times

I do recommend that all the contacts be cleaned as in my previous post.

Bill.

timshell · Post by **timshell** » 04 Oct 2009, 00:07

Thank you Bill, All the connections have been cleaned but I will try to test for voltage as the attachment you sent explains.
steve.

Post by **billofdurham** » 04 Oct 2009, 12:02

Steve, when the electrical portion of the ignition switch goes it usually develops play inside so the bits that should connect don't. Usually, when this happens, wiggling the key helps to make contact.

Bill.