71 Spider - backfiring, bucking and stalling - please help

[71veloce]

Thanks to everyone who offered such good advice on the problems we were having with our "new" 71 Spider - after over a MONTH (!!) at the local mechanic, she's running nicely - a few tweaks still needed (high idle needs adjusting, and new master cylinder will be installed next week) but we got her back last week and what a joy to drive!

We'll post a picture after the final work is done - thanks again for all the help.

[Farace]

Congrats on getting her running. I'm looking forward to the pictures.

[Kipp]

Tell us what the last shop did to get it to run after it is warm???
It is great to here you are having some fun driving it.

[71veloce]

I've gotta admit, there was no scientific testing on the part of the mechanics - it would have been nice if they'd checked the problem after each part was replaced. They replaced the points and condenser, a new V belt, and a new rear fuel filter - which was clogged SOLID. I was convinced the problem was the TA but apparently not... stupid question but why would a rear fuel filter issue be problematic only after warmup? Assuming THAT was the problematic part...

[Farace]

It might just be that the rear fuel filter was the big problem, barely letting it run cold, and that the engine ran just a bit more poorly after warm-up, enough so that it wouldn't run at all.

[71veloce]

I dunno, Bob... it would start up fine, sound great at first - and it was the same whether we just let it idle in the driveway for 15 minutes or drove it for 8 minutes - if driving: after a few minutes you'd feel the engine dogging a bit, then the hesitation, then the bucking and backfiring. Never drove it long enough to find out what would happen if it was pushed farther than that. Idling, it would start fine, then start catching, then sputter, then just die after about 10 or 15 minutes.

And certainly replacing the fuel filter fixed the issue of the fuel pressure light being on all the time!

Once we get the brakes and idle taken care of, we can start working on the cosmetic issues. That'll be a relief!

[MrT]

I can give one scenario: rear filter mostly plugged, but passing (almost) enough fuel to make pump happy and keep fuel pressure to runnable conditions. Loose rust in tank/lines running to fuel filter and clogging it with big flakes that don't stick in the filter matrix. Perhaps the flakes are in the in-tank pump (present in '71 cars?) and plug it up. Sounds like you should at least inspect the tank. It might be in rather poor shape internally. The rust plugging the rear filter came from somewhere. I think we all know where.

[agiyo]

I had a very similar problem recently on my newly assembled Berlina. The culprit turned out to be a late Spica engine compartment filter gasket installed in my '73 filter housing. It would run fine until heat built up, or we gained altitude, at which time it bled off fuel pressure and sucked air.

Spica is an incredible system, but ya gots ta check everything and know what *right* looks like.

Joe

[Farace]

Quote:

Originally Posted by MrT Perhaps the flakes are in the in-tank pump (present in '71 cars?) and plug it up.

[AlfaRomeo1750]

Hello All,

Wow what an ordeal! I am glad to hear you found a somewhat experienced shop to get you back on the road and smiling.

I have a 71 Spider, early on in my restoration I encountered the same problems you have had. My filters were clogging with tank rust from the car having sat a while before I had my hands in it.

I would go through a filter every few weeks, which made the car useful only for short trips. To solve this problem, I found a local welding/tank, Radiator shop who would take apart my fuel tank... Sand blast it, and then coat the inside so that it would not rust.

I just thought I would mention this to help you get on the road with out worry of tank rust clogging your new filter. Changing filters are not fun from underneathe, and gas doesnt feel too nice in your hair.

I am glad to hear you are on the road again.

Best of luck

Martin.

71 Spider Veloce
81 GTV6
87 Quadrifoglio
93 164 S

[71veloce]

Martin, thanks so much for the advice - we've now been through THREE shops: the first were a bunch of idiots, the second were experienced but seemingly afraid of working on the car (the owner said "oh, gee, there's not a lot of information on this car, I'm not sure we can do it" - after we handed him the Spica manual, and about fifty pages of printouts from this BB and other sources! This is a guy who fixes Ferraris, Porsches, BMWs, etc. - there's a Mangusta in there right now - but he's afraid of a 71 Alfa??)... and the third guy, who's doing the brake work, is a dream mechanic - one of those people who just LOVES cars, especially old ones, and talks about "listening to what the car has to say to him" - also knows how to read manuals!

I'll talk to him about coating the gas tank and see if he can do it or if we'll have to find someone else. The pointer is much appreciated!

[Vivace]

Ahh, you have found he who is one with your car...this is good. He will place his hands on the hood and sense the conflict...

We had a Volvo mechanic in Seattle...Odvar! From Norway, white beard and ponytail down his back, swore like a sailor, no sign or advertising but every old Volvo in town was there. And he could fix cars - he just knew. He often fixed things I didn't ask for and said, "You're not going on a trip with those in THAT condition, G-- d--- it! Pay me when you can."

Drove a V8 Studebaker, a perfect 544, and a 242 with a Ford 289! He would never say "nice car" when I came by in the Duetto, but he'd look it over and nod.

Good luck with your Spider!
MG

[71veloce]

Vivace, sounds like they are made from the same mold - our guy Andy has the grey beard and ponytail as well, and goes nowhere with shoes on or without his Portuguese Water Dog, Nemo, at his side. Unfortunately I can't get anywhere near topping "ODVAR" (!!) as a name. He too is the local Volvo guru, and where I live, that's the car of choice. A conversation with Andy is just as likely to veer into the metaphysical as the mechanical, but always comes back to what's going on with the car. Gotta love that holistic view.

Hopefully we'll be picking the black beauty up again next week for some quality late summer driving!

[Vivace]

I hope you'll put up some photos sometime - I love the clean-lined '71, and black is sharp on a Spider!

Mike