Quick question about relay install to fix "Starter Heat Soak" problem...

Treppiede · #1 07-04-2005, 03:06 PM

Good afternoon everyone,
as I mentioned a few weeks ago, I need to fix the starter heat soak problem on my Dad's car with the relay mod you guys wrote about in previous threads.

I have found two posts from Beav and Harvey particularly helpful (thanks guys), however there seems to be a conflict between the two descriptions, and I would like to know which one is the best way to install the relay.

Beav says to connect the relay as follows:

Quote:

#30 - To Battery + , can use the Battery cable at the starter.
#86 - To Ground
#87 - To the Small Terminal on the Starter. First remove the wire already there and place it on....
#85 - This is the 'trigger' for the relay

Harvey says to do it this way instead:

Quote:

The starter has two wires to it, a big battery cable and a small black/yellow wire plugged on to the solenoid. The small b/y wire is removed and connected to terminal 86 on the relay, terminal 85 is connected to earth. A wire (big enough to flow 30 amps) is then run from the large battery terminal on the starter, to terminal 30 on the relay. Another wire is run from terminal 87 on the relay to the spade terminal on the starter solenoid, from where the small b/y wire was removed.

So, according to the above, here's the relay situation:
#86: to small solenoid wire (Harvey) / to Ground (Beav)
#85: to Ground (Harvey) / 'trigger' for the relay (Beav) (<-- ok, trigger for the relay, but where do I connect it to?)
#87: to solenoid terminal on the starter (Harvey and Beav seem to agree on this one)

#30: seems like Harvey wants this on the large + connector on the starter, while Beav wants this to the large + cable that powers the starter.

Guys, I would immensely appreciate if you could shed a little further light on this situation, and tell me which is the better way. I am not very good with electricity, perhaps due to the internal schematics of the relay both ways are correct and I will feel like a moron

, but I would rather get confirmation from the pros.

Also, my relay has a fifth connector labeled "87a". Do I just ignore that since you guys are not mentioning it?

I bought 14ga wire as Beav suggested. Will that be enough also for the power connection?

Regards,

Walter

kuoh · #2 07-04-2005, 03:28 PM

Terminals 85 and 86 are the two ends of the relay coil, it doesn't matter which side is grounded and which side is attached to the starter wire. As for needing a large wire, the starter solenoid doesn't really draw 30 amps so16 ga wire all around should be plenty.

KuoH

dannmarr · #3 07-04-2005, 08:53 PM

Search: starter bypass relay install. You will find my reply on the subject with directions and photos. There is a drawback on this installation though. Read both of my threads. Good luck!

Earthworm · #4 07-05-2005, 04:29 PM

Just don't get the ground/trigger wires backwards! My dad thought it didn't matter...he proved himself wrong!

Beav · #5 07-05-2005, 08:21 PM

Yes, you ignore 87a.

30 goes to battery voltage. That is available at the battery cable to starter stud (just makes a shorter connection rather than running a separate wire back to the battery.)

Yes, 14 ga is plenty for all connections at this relay (actually it is a bit overkill.)

Beav · #6 07-05-2005, 08:23 PM

Quote:

Originally Posted by Earthworm

Just don't get the ground/trigger wires backwards! My dad thought it didn't matter...he proved himself wrong!

I didn't either, why should it?

Earthworm · #7 07-06-2005, 12:03 PM

It made a huge spark like it shorted. Fortunately we didn't cook the relay (which is still working perfectly in my car).

kuoh · #8 07-06-2005, 12:48 PM

Sounds like he got something else wrong in the wiring. The coil will pass DC current equally in either direction, so it doesn't make any difference which side is grounded and which side is hot. If he got a spark, then he likely had some wire errant wire strands from a hot source making intermittent contact with ground. If it were simply a miswire where the hot side was directly shorted to ground, then either a fuse would've blown, or the wires would've just started getting hot until it melted.

KuoH

Quote:

Originally Posted by Earthworm

It made a huge spark like it shorted. Fortunately we didn't cook the relay (which is still working perfectly in my car).

Earthworm · #9 07-06-2005, 04:01 PM

We were testing the relay directly to the battery.

oab_au · #10 07-06-2005, 06:09 PM

The polarity of the relay winding depends on the type of relay that is used. Some modern relays contain a diode across the winding (85 to 86), to prevent an inducitive spike from damaging the electronics that switch the winding on/off. If this type is connected the wrong way, it will short and blow the diode. The relay will still work, as the winding is still intact, just the diode gone. (sounds like Davids result

) This type of relay usually has a dia. of the diode connection on the side.

Terminal 87a is a duplicate of 87, used if the relay is switching two headlights, or twin horns.

The current draw by the starter solenoid can approch 30 amps. Becides pulling the solenoid armiture in and starter gear into mesh, it also passes current through the starter motor itself, to start the gear rotating so that it will mesh with the ring gear, and not just hit teeth end on and not mesh. If it was only the solenoid winding, that pulled current, we would not have the trouble.

Sorry for the confusion Walter.
Harvey.

Treppiede · #11 08-21-2005, 03:21 PM

Guys,
sorry for disappearing but bad-weather (sunshine state my a$$) and schoolwork (Summer-B finals anyone?) have prevented me from installing the relay on my Pop's SVX.

Anyways, thanks to all of you for the replies and follow-ups, which allowed me to get back to it today and try connecting everything... which brings me to my new story:

- I proceed to connect the Relay as recommended (Dannmarr's pics were very useful, thanks man).
- I ask my Old Man to start the car, but she doesn't start.
- I remove the relay, and the car is now back to stock.

I believe I did everything correctly, however there is one connection that I was unsure about, and I am hoping that it is the cause of my failed installation:

1- The cable that comes from Relay pin #87 is supposed to go to the LARGE connector on the starter, right? Now what I wanted to ensure is that I connect both the large connector and the new wire connected to #87 to the starter bolt, right?

2- The small spade terminal I crimped on the cable connected to #85 goes into the small plug I took out of the bottom of the starter, right? Now, am I supposed to connect something to the spade that is hanging from the starter, or just leave it like that?

If you guys could shed some light on the above questions, it would be great.

Thanks again for the help!

Walter

oab_au · #12 08-21-2005, 05:26 PM

Quote:

Originally Posted by Treppiede

Guys,
sorry for disappearing but bad-weather (sunshine state my a$$) and schoolwork (Summer-B finals anyone?) have prevented me from installing the relay on my Pop's SVX.

Anyways, thanks to all of you for the replies and follow-ups, which allowed me to get back to it today and try connecting everything... which brings me to my new story:

- I proceed to connect the Relay as recommended (Dannmarr's pics were very useful, thanks man).
- I ask my Old Man to start the car, but she doesn't start.
- I remove the relay, and the car is now back to stock.

I believe I did everything correctly, however there is one connection that I was unsure about, and I am hoping that it is the cause of my failed installation:

1- The cable that comes from Relay pin #87 is supposed to go to the LARGE connector on the starter, right? Now what I wanted to ensure is that I connect both the large connector and the new wire connected to #87 to the starter bolt, right?

2- The small spade terminal I crimped on the cable connected to #85 goes into the small plug I took out of the bottom of the starter, right? Now, am I supposed to connect something to the spade that is hanging from the starter, or just leave it like that?

If you guys could shed some light on the above questions, it would be great.

Thanks again for the help!

Walter

OK Walter, using Dannmarr's wiring connections,

Once again, here are the connections;
#30 to the battery + or where the big battery cable connects to the starter
#86 to ground connect to the engine block
#87 to the starter solenoid this relay terminal is connected to the little spade terminal on the starter, that the little wire was removed from
#85 to the wire that was removed from the starter solenoid the little wire that was unpluged from the starter, is now connected to this relay terminal.

87a is not used.

Harvey.