Bench testing fuel pump relay???

[MyVeloce]

How can I bench test whether the main relay for my fuel injection system is working?

The relay is a Bosch (p/n 0 280 230 001) seven prong spade relay. The numbers for the connections are 1, 15, 30, 31, 50, 87, and 87B.

My car stopped runnnning as if it ran out of gas. Both fuel pumps work outside the car and neither are receiving power. All fuses are intact. This relay is the larger one connected to the housing of the Bosch fuel injection controller housing on the shelf behind the passenger's seat.

Thanks

Tom

[alfaloco]

What model year is your car?

The standard relay configuration is:

coil -- terminals 85 & 86
norm. open contacts -- terminals 30 & 87

So if you apply 12VDC across 85 and 86, you should close 30 and 87.

[alfaloco]

Sorry- I see in your heading you have an '82 Spider. Let us know about your relay function. International Auto Parts stocks these relays.

[MyVeloce]

Quote:

Originally Posted by alfaloco What model year is your car? The standard relay configuration is: coil -- terminals 85 & 86 norm. open contacts -- terminals 30 & 87 So if you apply 12VDC across 85 and 86, you should close 30 and 87.

[Davy13]

I know you said that all fuses are intact, but I thought the same thing, until I actually broke open the glass fuse behind the passenger seat to reveal a break at the base of the fuse, instead of where it normally breaks... So at the risk of insulting your intelligence, PLEASE check for current at the fuse holder. Or replace the whole glass fuse doo-hickey with one of those fuse holders for the flat style fuses... I was in a similar situation not two months ago in my '83...

-Dave.

[MyVeloce]

Quote:

Originally Posted by Davy13 I know you said that all fuses are intact, but I thought the same thing, until I actually broke open the glass fuse behind the passenger seat to reveal a break at the base of the fuse, instead of where it normally breaks... So at the risk of insulting your intelligence, PLEASE check for current at the fuse holder. Or replace the whole glass fuse doo-hickey with one of those fuse holders for the flat style fuses... I was in a similar situation not two months ago in my '83... -Dave.

[alfaloco]

Actually, you can get a replacement relay at a NAPA store which will work. The Bosch relay is a standard automotive configuration as far as the socket and terminal layout. Take the old relay to NAPA and have them match it. I cannot imagine $67 for a common automotive relay, honestly.

This past summer I troubleshooted a fuel pump problem in my '91 Spider, and when I checked the suspect relay by substitution, I pulled an identical relay out of the fuse box of our 2000 Dodge Caravan.

Using a 12VDC source (your car battery or two 6-volt lantern batteries in series), carefully clip the positive and negative wire leads to terminals 85 and 86. It helps to have test wires set up with small alligator clips for this kind of thing. The relay should click indicating the coil has closed the contacts. Take a multimeter (VOM, or volt-ohmeter), turn to the resistance ohm scale at 20K ohms, and touch the leads to terminals 30 and 87. If the meter goes to zero, you have continuity through those contacts. Remove a battery lead from either 85 or 86, and the meter should read "1", indicating the contacts have opened again.

One caution here, and I say this because I've been mistaken before when I assumed something on an '82 or '86 Spider was identical to our series 4 Spiders (it wasn't!). Check the socket where the fuel pump relay plugs in. If there is only one wire lead off terminal 87, that is to say terminal 87b is not used, then a standard relay should work. I believe it is the main Motronic relay on ours which uses both no. 87 contacts (DPST for you EE's out there), and you need to know that when sourcing that particular relay.

BTW- I have heard it is very worthwhile to replace that inline fuse also with a newer type ATC fuse and holder, since they are less prone to corrosion than the old glass tube style. It may not be your problem right now, but you could easily eliminate it occuring in the future, right?

[papajam]

Another thought would be to check the inertia switch, which if tripped, will cut the power to the fuel pumps. I think it's located on the rightside firewall by the washer bottle.

[MyVeloce]

Quote:

Originally Posted by papajam Another thought would be to check the inertia switch, which if tripped, will cut the power to the fuel pumps. I think it's located on the rightside firewall by the washer bottle.

[papajam]

This is from the '82 Spider L-jet book. Not word for word mind you but the operation is the same.

The submerged pump operates when the ignition is on. The main fuel pump operates when the key is in the start position and, thru the inhibitor relay, when the key is on ONLY after the engine is running.

So, here's two questions for ya. Is there battery voltage at the fuel pump relay terminal #50 (I think) when the key is in the start position and is there spark at the sparkplugs.

[papajam]

Here are the ISO code number descriptions on your fuel pump relay;

1 - low voltage (ignition coil, distributor)
15 - switched positive output from battery, ignition switch
30 - input direct from battery positive
31 - return direct to battery
50 - starting motor control
87 - relay contact for brake contact and transfer contact, input
87b - second output

And what I think they mean in English

1 - coil negative terminal (tach signal, engine running signal)
15 - battery positive, switched
30 - battery positive, unswitched
31 - ground
50 - engages the starter
87b - output to fuel pump
87 - beats me but I'll guess it's the input signal from the inhibitor relay

[MyVeloce]

Quote:

Originally Posted by papajam This is from the '82 Spider L-jet book. Not word for word mind you but the operation is the same. The submerged pump operates when the ignition is on. The main fuel pump operates when the key is in the start position and, thru the inhibitor relay, when the key is on ONLY after the engine is running. So, here's two questions for ya. Is there battery voltage at the fuel pump relay terminal #50 (I think) when the key is in the start position and is there spark at the sparkplugs.