Electrical . . but what?

[crafty]

Hi All,
Am hoping that someone has a few suggestions. I was out for a quick run when my 81 spider decided to stop on me. I managed to crank it over and gain 100 metres before she stopped again. I called the road service and he turned up in due course spending an hour on her! (very rare for them to hang around for that length of time) He was able to tell me that there was no power getting to the fuel pump and that the issue may have been in the double relay or even the ignition. I had it towed (very sad sight . . ) and began to trouble shoot some possibilities. I removed the relay and had it tested by a mate in the electrical profession and all was in order. I then provided direct power to the pump and she would kick over, but only for a couple of seconds. Interestingly enough the car will run whilst you have the key in the start position (not good for the starter I know).

Any ideas?

Thanks in advance.

[So Cal Mark]

I'd look at the connector about 6 inches down from the ignition switch. It's common for a loose connection to melt the connector cutting off ignition power. Make sure the fuses aren't loose or correoded either. The fuel pump uses an inline fuse.
After that, it will take a voltmeter to test power throughout the system. It's odd that the pump won't run very long when it's jumped directly to power. It should run as long as it has power and ground.

[rlux4]

The fuse you should look for is an inline one behind the fuse panel. It's on a brown with white stripe wire. I had intermittent problems that I traced to the inline fuse holder, it wouldn't maintain good contact with the fuse. I cut it out and put a normal AGC fuse and holder in it's place and solved the problem.
Have you downloaded the FI diagnostics pages yet?
http://www.wcmotors.com/personal/Fiat%2 ... agnostics/
If you haven't yet, it's and indispensable tool.
Ron

[crafty]

Thank you Gentleman,

I will have a look around and see what I can find.

Mark, I am sorry if I didn't explain myself properly, the fuel pumped worked continuosly when I had it jumped directly to power, the engine just stopped once the ignition switch returned to the running position after starting.

Ron, i downloaded the diagnostics info and will run through it if the fuse isn't the issue.

I'll let you know how I get on.

Thanks again,

Glenn.

[spider2081]

Another few thoughts in addition to those mentioned:
If the car runs in "start" but not "run" it can be the ignition switch itself. You could check for voltage at the coil with the switch in the "run" position.
Have you checked the connector on the Air Flow Sensor if it is loose it might cause the same symptom because in "start " the fuel pump is powered from the fuel relays but in run it is powered from a switch in the Air Flow Sensor.
The large brown wire connector C17, a 4 terminal connector under dash near steering shaft causes lots of intermittent and strange problems.

[htchevyii]

I haven't looked at a Spider wiring diagram, but I know when the afm opens it turns on the pump. Does it have another ciruit that powers it while cranking, or does the cranking engine pull enough air to open it?
Never mind, I just read the post above!

[rlux4]

Trey, you own two Spiders and you've never looked at a wiring diagram for them?!! You must be living a charmed life man.
Ron

[crafty]

Evening,
I had an auto electrician look at the car today. He pinpointed the problem being in my ECU. The issue is when the earth wire returns from the relay into pin 28 of the ECU, it is not being earthed though the unit. He has temporarily hooked up an earthing cable directly from the relay connector so I can get my car home. The electrician said that their were people around who could fix the ECU. Has anyone had any experience in getting this issue repaired or should I just purchase a new one?

At least she is running again !!

Cheers,

Glenn.

[pope]

Pin 28 from the ECU goes to the duel relay and then on to the ignition switch. I think Mark had it pegged when he said to check the ignition wiring.

[launieg]

To re-emphasize what Pope is saying, a replacement ECU will likely not solve your problem. Ground input to the ECU (via dual relay and ignition) needs to be checked. I had to say this, although Pope said it already, cause I had a similar problem, so I swapped in another ECU and problem remained. Eventually solved it, so I now have an extra ECU (nice to have though, for reassurance). As is so often said on this forum, these ECUs rarely fail.

[crafty]

Thanks for all of your responses as i am very naive when it comes to electrical problems.

Where the ground was lost was at the ECU. When we hooked up a temporary earth from the cable running into pin 28 the car ran perfectly.

If pin 28 is for signal input, rather than output, wouldn't the signal already of travelled through the ignition and the relay proving that these aren't an issue? (The electrician tested the ignition at the coil and all was good)

A previous post mentioned the airflow sensor. Could it be possible that the Sensor is triggering the safety circuit which cuts out the ground within the ECU?

As I said I have very little idea so all of your thoughts and pieces of advice are very welcome.

Glenn.

[spider2081]

Great! sounds like you are figuring this problem out. I have a Fiat wire diagram booklet and it states:

" With the Ignition Switch in the "Start" or "Run" position current flows through terminal 86c of the Fuel Injection Relay Set, the coil of the control relay, terminal 28 of the ECU to G7. Ground G7 is attached to the RH side of the intake manifold. Looking at the wire diagram for the ECU it shows pins 16 and 17 go to G7. These are brown wires. There is another ground for the ECU that is on pin 5 and it goes to G8. G8 also attaches to the RH side of the intake manifold.
I don't have a schematic of the internals of the ECU but it sounds like there is a connection between pin 28 and pins 16 and 17 or pin 16 or 17 inside the ECU. You might check wire harness pins 5,16,and 17 to ground and see if they all make a good ground. If they do you might check the ECU pin 28 and see if it checks 0 ohms to ECU pin 16 or 17.
Hope this helps

[crafty]

Hey All,

I sent my ECU away and they diagnosed and fixed the problem. Seems the fuel pump circuit had blown and was the cause of all my problems. I reinstalled it and all was great for the first few kilometres when the temp gauge started to unusually rise. I have now blown the head gasket and will be fixing this as soon as allows. Seems I am the victim of a car that sat too long prior to me purchasing it.

All is good though, I figure that once these things are fixed they won't need attending for a while!!

Glenn.

[adrians]

Glenn,
I know the feeling - that blown head gasket depression ! !

By the way there is another SuperSprint this weekend. Sunday 1/3/09, at Oran Park Race Track. I'll be there with the Spider on the track, Cheryl ( my wife ) is also running in the Silver Subaru Liberty. The Fiat Club boys competed in the Bathurst 12 hour on the weekend, in an Alfa Romeo 147 Diesel, no factory backing.

http://www.alfaromeo.com.au/default.asp ... e&ID=19153

[htchevyii]

Trey, you own two Spiders and you've never looked at a wiring diagram for them?!! You must be living a charmed life man.
Ron

Actually, after I cleaned the grounds on the '82 everything worked! I have been studying the '72 diagrams to see how much crap I can get rid of under the hood. I can't remember what did or didn't work on the '72, I'll see when I get the thing back togeather.