Delayed start when cold.

[clarkerussell]

Hello all,

I have an odd situation that I wanted to get a second opinion on... After sitting unused for about 6 months, my 1998 S70 GLT developed a delay when starting the car in the mornings. When I turn the key to start, I hear the solenoid engage, but the started doesn't turn over. If I hold it in start position for about 5-7 seconds the starter will engage and the car starts right up. Generally if the car has already been running, it'll fire right up with a fraction of a second of delay. Although it was still holding a good charge, I proactively replaced the 5 year old battery but the symptoms are the same.

I have tested the voltage at several points and here is what I get:

+ terminal to - terminal on the battery 12.3v
- battery terminal to the + post on the starter solenoid 12.3v (no voltage loss in the cable)
- battery terminal to the + post on the other side of the solenoid 0.0v without key turned, 12.2v with key turned to start

11.91v to the ignition wire on the solenoid when the key is turned to start
With the key off I am getting 3.75v to the ignition with on the solenoid (seems odd that there is any voltage there, is that normal?

I'm thinking it's the starter causing the problem, but I wanted to check with you guys prior to spending the time and $$ replacing the starter. However, the starter is original and the car is 20 years old with 285K miles on it, so it's likely due for a new one anyway...

Any thoughts on this would be greatly appreciated!

[scot850]

It could be a few things. While not able to answer your question on the voltage issue there are a few issues I could suggest, especially with the mileage and the car sitting for so long:

1) Check all the engine earthing cables and the grounding on the starter motor.
2) the starter motor is possibly the issue as it may be the solenoid is bad or the motor itself is sticky and hence the delay.
3) The ignition switch may be on its way out.

Neil.

[misha]

Voltage drop test MUST be performed while engine is running and when everything is warmed up(after about 30 min.of driving) and without turning the engine off.
Btw...fully charged battery should read 12.6-12.7v,especially if it is fresh and new.
12.3v indicates that it's at around 70% of charge.

After a voltage drop test result we can go further.

[clarkerussell]

Voltage drop test MUST be performed while engine is running and when everything is warmed up(after about 30 min.of driving) and without turning the engine off.
Btw...fully charged battery should read 12.6-12.7v,especially if it is fresh and new.
12.3v indicates that it's at around 70% of charge.

After a voltage drop test result we can go further.

Thanks, yes, the battery has been sitting in the car now for about 1.5 weeks so I expected it to be down a bit.

Regarding the voltage test, I will get the car warmed up and repeat the tests (assuming I can get the car to start, of course).

Thanks!

[clarkerussell]

Quick test, after about 5-10 minutes of idling...

Starting voltage on the battery was 12.3v (It had charged a bit from earlier this evening due to idling)

13.86V at the Starter + post while running
13.62V at the + post on the battery

basically a .25v drop between the battery and starter.

[misha]

https://www.aa1car.com/library/voltage_drop_testing.htm

Voltage drop test MUST also be performed under load(headlights,rear demister and heater blower)...and on both sides..positive and negative.

[clarkerussell]

https://www.aa1car.com/library/voltage_drop_testing.htm

Voltage drop test MUST also be performed under load(headlights,rear demister and heater blower)...and on both sides..positive and negative.

This is great, thanks you! It's raining now, but I will be sure to do this test tonight!

[dj_v70]

Ultimately, the only voltage that matters is the voltage that the starter sees, and you have to check it under load because starter draws significant current ...

You are not measuring the voltages at the critical place. Measure voltage between starter large terminal and engine ground (ie. starter housing) while key is turned to position 3. If voltage is greater than 12v (and your solenoid has clicked, meaning that solenoid terminal has 12v also) and starter isn’t turning, replace starter. If you are not getting 12v plus, need to look at wiring/grounding.

[abscate]

Delayed cranking is often the result of a bad pigtail between the solenoid and starter

You have to remove the starter to diagnose.

[clarkerussell]

OK, I did some testing and I think it's just a bad positive cable. I started by removing the battery cables and giving the ends and the battery posts another through cleaning. The battery was a little low due to testing earlier, but it was sitting at 12.05V with no load.

I unplugged the lead distributor wire to keep the car from starting and I recorded the following:

Battery voltage (post to post) while trying to crank was 10.98V
Voltage between the starter battery terminal stud and the starter case with load was 9.56v

That's a pretty large drop in voltage so I tested between the positive battery terminal and the battery terminal on the starter and recorded about a 1 volt loss. I hear there should be less than .2 volt loss, so that seems pretty bad...

The negative side tested good with about a .23 volt drop between the negative battery post and the starter case, so I think that is still good.

Right now I'm thinking I should just replace the positive cable and go from there.