Earning My Fiat Electrical Merit Badge This Weekend...

[AlexD]

I'm in need of some therapeutic "tinkering time" with my Fiat and plan on immersing myself in all-things electrical. I've been slowly chipping away at smaller items (cleaned all grounds, replaced a rats nest at the two engine bay ground hubs with new ground blocks (inspired by RRoller), cleaned the fuse block contacts and replaced all fuses, cleaned all the exterior light contacts and got them all working, and finally addressed the instrument light rheostat problem that restored my dash lights).

Earlier this week I replaced the voltage regulator on the alternator and will be tackling headlight relays, wiper relays, power window relays (following the lead of @ekstrandt in this thread - http://www.fiatspider.com/f15/viewtopic ... ay#p230563). If time permits and I don't botch something in the interim, I'll replace the dash light bulbs with LEDs (except for the battery charging light as I understand it). I'm excited that the dash lights now but the weak/dim glow is depressing so that's got to be done.

Thanks for all the direct and indirect inspiration, insight, and learning I've absorbed from this group - much appreciated.

Wish me luck and let me know who I contact about getting my merit badge...

[18Fiatsandcounting]

Wish me luck and let me know who I contact about getting my merit badge...

Good luck, and I bow in your general direction! As for the merit badge, let us know on Sunday how things went, and we'll see what we can do.

-Bryan

[AlexD]

Fun fact - I turned 50 this week which hasn't been an issue or concern of mine at all as I've often felt age is merely a number....

.... until I spent the weekend hunched over the engine putting in a fuse block tapped off the alternator, running headlight relays and wiper relays and contorted under the dash putting in power window relays. If ever there was a reminder that I'm not as agile and limber as I used to be, this was it.

That said, fuse block and relay installation complete. Took my time (honestly the longest part was figuring out where to best tap into the existing wiring and then getting up the nerve to actually cut the original wiring/connections and checked everything for function along the way. When all was done:

- The headlights - wow. They're brighter than I ever imagined they could be so night driving is now an option.
- The wipers move for the first time in the year that I've owned the car so no fear of a possible shower holding me back from a drive.
- The windows - holy cow. They pull down and push up with authority. Long gone are the days of leaving just a bit of the window up or removing the door panel so I can grab the window and pull it up. Finally I can fasten the door cards to the door for good.

So for the first time ever, every exterior light works, the dashboard gauges are lit, the wipers work, the windows are amazing, my fuel gauge suddenly started working (BONUS!). Cleaned up and got ready for a celebratory drive to decompress...

...aaannnd the car won't start. Yep... turns over and fires for a quick second (sputtering and choking the whole time) before dying. I can hear the fuel pump and can hear movement at the injectors but it just won't fire. The car started fine each time I checked as I made progress - the last thing I did was remove the relay panel under the glove compartment to try to mount the passenger window relays. Surely I disturbed some ecosystem so will be doing some research this evening to see what I could have knocked loose. It got too late and started getting dark so I decided to regroup tomorrow.

So I learned a valuable lesson this weekend - don't get cocky and talk about earned merit badges or else the Italian electric gods will put you in your place. To the wiring diagrams I go...

[18Fiatsandcounting]

So I learned a valuable lesson this weekend - don't get cocky and talk about earned merit badges or else the Italian electric gods will put you in your place. To the wiring diagrams I go...

First off, Happy Belated 50th Birthday! Second, and this is something all of us have to learn: A Fiat engine is like a mistress. You obviously spent time with other electrical items, so now the engine is pissed. Best to sleep on the couch tonight, my friend... Whatever you do, don't go speaking positively about other cars you might have. Especially Alfas.

My guess is that you disconnected an engine temp sensor wire or the like on that relay panel, so let us know what you find.

A merit badge still awaits you, Grasshopper.

-Bryan

[AlexD]

A Fiat engine is like a mistress. You obviously spent time with other electrical items, so now the engine is pissed. Best to sleep on the couch tonight, my friend... Whatever you do, don't go speaking positively about other cars you might have. Especially Alfas.

-Bryan

That is such a perfect analogy - she was scorned and there was no reasoning. Hoping that we've both cooled off a bit and can make amends today... I'll remind her how beautiful her high beams are and dazzle her with some new spark plugs hoping that she'll let me change her oil again. Otherwise I'll just enjoy the headlights, wipers, and windows until the battery dies...

Will definitely be starting my troubleshooting with the relay panel and working my way backwards. Thanks for the insight.

[AlexD]

After another round of my best impression of a Cirque du Soleil contortionist tracing wires and checking relays under the dash, the culprit ended up being the coolant temperature sensor... go figure (but I should have thought of that sooner as I had a small issue last year that I forgot about and never replaced). I doctored up a jumper for the connector and it fired right up. Glad to know that it's an easy fix compared to what was going through my head. Bonus news is that I found the inline fuses all of which were good and the double relay checked out fine. Apparently at some point the PO reconfigured the fuel pump feed so that it's powered with the key in the "on" position which from what i read is a bit of a safety concern so I may need to put in a manual switch somewhere. Add that project to the winter list...

As for the coolant thermal sensor replacement, can I just drain a little bit of coolant from the system before I swap out the sensor or am I looking at a total drain and refill? Since the sensor sits so high in the system I'm hoping to get away with a small/partial drain and top off for the time being.

Thanks as always.

[spider2081]

Apparently at some point the PO reconfigured the fuel pump feed so that it's powered with the key in the "on" position

There is a switch in the air flow meter that can be adjusted so it never opens causing the fuel pump to run as soon as the ignition switch is turned on. Have you unplugged the air flow meter with the key on to see if the pump stops?
If the fuel pump does not stop running when the AFM is unplugged the modification is probably after the dual relays wiring.

[AlexD]

There is a switch in the air flow meter that can be adjusted so it never opens causing the fuel pump to run as soon as the ignition switch is turned on. Have you unplugged the air flow meter with the key on to see if the pump stops?
If the fuel pump does not stop running when the AFM is unplugged the modification is probably after the dual relays wiring.

Thanks for this tip - I wasn't aware of that but will check it out later today!

[18Fiatsandcounting]

As for the coolant thermal sensor replacement, can I just drain a little bit of coolant from the system before I swap out the sensor or am I looking at a total drain and refill? Since the sensor sits so high in the system I'm hoping to get away with a small/partial drain and top off for the time being.

Yes, I think this would work just fine. I'd drain off a little bit of fluid from both the bottom of the radiator as well as the drain petcock on the block under the exhaust manifold. Perhaps a quart of fluid from each.

-Bryan

[AlexD]

Yes, I think this would work just fine. I'd drain off a little bit of fluid from both the bottom of the radiator as well as the drain petcock on the block under the exhaust manifold. Perhaps a quart of fluid from each.

-Bryan

Perfect - thanks for clarifying/confirming. I wasn't even aware of the drain petcock on the block - my learning of the day. Any caution/concern to be exercised (aside from the usual "don't be a gorilla with it") when removing this plug? I don't want to create a complex/major issue when trying to fix a simple/minor one . I'll check to see if there's guidance on torque settings when I tighten it but input here always welcome.

Alex

[18Fiatsandcounting]

Any caution/concern to be exercised (aside from the usual "don't be a gorilla with it") when removing this plug?

Yes, there are some cautions, but it depends on what you actually have. Earlier spiders had an actual petcock with a sort of "four leaf clover" knob. Very handy to drain the coolant from the block, but the handles tended to shear off the shaft. Some later models just had a tapered plug, which is very secure but not very sexy. So, if yours has a handle, be very gentle when removing it, and don't be surprised if the handle shears off...

I can't remember, but I recall just replacing a broken petcock in one of my spiders with a simple brass valve from a hardware store, so it might even have had SAE threads where it screwed into the block.

Anyway, the drain is on the passenger side, under the exhaust manifold, and midway between the front and back of the block. Pretty easy to spot, but if it's never been opened, it might be pretty tight.

-Bryan
PS: If you have the handle type, just tighten moderately tight by hand. If you have an actual metal plug, I'm not aware of a torque spec but I don't think it's that critical. I'm guessing 10 or 15 ft lbs.

[AlexD]

Anyway, the drain is on the passenger side, under the exhaust manifold, and midway between the front and back of the block. Pretty easy to spot, but if it's never been opened, it might be pretty tight.

-Bryan
PS: If you have the handle type, just tighten moderately tight by hand. If you have an actual metal plug, I'm not aware of a torque spec but I don't think it's that critical. I'm guessing 10 or 15 ft lbs.

I've got the tapered plug based on your two descriptions. 13mm based on my test fitting a few minutes ago.



I've ordered the sensor and will plan on draining some fluid out in a few days when the part arrives. Will be sure to go firm yet steady when loosening it - may even hit it with some penetrating oil the night before. I'll give it the "snug it down then give it a little more" treatment when tightening it up.

Thanks.
Alex