33 1.7 8v No fuel

[SteveHobart]

Hey guys! Well the little Alfa, after being so reliable and bullet prof has come over all Italian and won't fire. She'll crank no problems,  but no fire. I suspect it's not fueling (can sit there pumping the accelerator and it won't flood suggesting it's not getting fuel.
Anyway, I can't find anywhere whether it's a mechanical or electronic fuel pump or a combination of both. Can anyone help? Need the location of the pump and any relay/fuse controlling it.  Thanks!


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[bonno]

Hi SteveHobart
Some simple checks that can determine if it is fuel or electrical related.
Step 1 Fuel : Is fuel getting to the carby? This can simply be done by disconnecting fuel hose/line at the attachment point to carby. Crank the engine for several seconds and check for fuel flow. If fuel is evident, then you have electrical problem go to Step 2 . If not, then could be fuel filter or fuel pump process of elimination.
Step 2 Electrical. Check for spark at the plug.(PS : Need to be careful here as High voltage is generated from coil). Remove a spark plug and attach lead, then suitably ground end of plug and observe for spark. Whist at this point check condition of each spark plugs. If no spark evident, check point gap on distributor to specification and condition of contact points. If OK, then check for spark from coil to distributor. If still no spark, then eliminate the cause of either a faulty lead or coil. If these simple checks do not start the engine then you need to look further into the condition of engine.
Hope this Help

[Citroënbender]

Will it cough and nearly "catch" on a spray of Aerostart?  If so, yes, you have a fuel problem.

If no, then you have either a timing or ignition driver problem. If there is no spark but you can see the cam turning through the oil filler cap hole when cranking the motor, I would suspect an ignition driver module has failed. If the cam is not rotating when you crank, it is not a good look.

Returning to a possible fuel supply problem, is it a fuel injected car?

If so, it's probably got an early Motronic injection computer, and an electric fuel pump indirectly controlled by the computer. If it isn't fuel injected, everything else I say in this attempt to help, is irrelevant. 

You may find a Haynes manual of some use, others call them the "BOL" or Book of Lies.

Electric fuel pumps are switched by a relay, and the current also passes through a fuse of 10A or more. They die, usually (in my experience) of internal corrosion from sitting with stale low-grade fuel inside.

The relay for your fuel pump is "authorised" by the injection computer, when it sees a stable, repeating signal coming from the ignition coil low voltage side. This is a characteristic of early injection computers, newer types operate the fuel pump for a few seconds when you turn the key on, to prime up the system - meaning it starts faster, with less cranking.

[SteveHobart]

Thanks guys. Have already checked the fuel lines at one of the carbies and no, no fuel! Where is the fuel pump on a 8v Twin carb 1.7?


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[bonno]

The model of your car suggest it has a mechanical fuel pump (refer to link below on cost of replacement part). However before you go to all that trouble and expense just check the in-line fuel filter (if fitted) is not blocked. Follow the fuel line back from carburettor to find location.
http://www.ricambio.co.uk/3016-fuel-pump--alfa-romeo-33-alfasud

[Citroënbender]

If it's a mechanical pump, location is upper rear of the motor, passenger side.

Electric pumps in this era are frequently mounted horizontally in a "safe" location just forward of the fuel tank under the car.

[SteveHobart]

Well had some time to have a look today and it's definately not fueling. Disconnect the fuel hose from the Carbie and crank it, nothing coming out. So we either have (a) a blockage or (b) a dead fuel pump.
For the sake of cheap fixes, I'm going to try to pump some compressed air down the fuel line (there is no filter) to dislodge the blockage. If that doesn't work, then it's the pump.
Has anyone put an electronic pump into the engine bay to replace the mechanical pump?


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[Citroënbender]

You may find it's a serviceable type pump with the case upper and lower screwed together, and you can replace failed internal poppet valves with those from a kit or donor pump.  If it's a swaged-together type casing, then yes, a replacement is in order.  To keep the look of engine bay originality you can remove the actuating arm on many units, and the fuel just pushes through with an electric pump supplying pressure from further back in the lines.

I'd suggest any electric pump be rear mounted, fuel lines on many older cars are good at siphoning if split in an accident...

There are many suitable "universal" pumps, from the NZ made sealed units with plastic bodies, to the Facet style ones, SU replicas if you want that ticking sound, I don't recommend Holley or similar pumps from the go-fast crowd, you would have to regulate fuel pressure with a return style regulator. 

An electric pump needs not just an ignition switched (from the "run" position) feed with inline fuse, but also a means of emergency self-shutoff.  The safest way to do this is with a tachymetric relay, which does two things.  First, when the ignition is turned on, it operates the pump for about five-ten seconds, allowing some fuel supply to be generated. Second, once the car is cranking or running, it senses the ignition pulses from the coil and resumes power to the fuel pump.  Soon as the ignition coil signal stops (when your engine stops turning) the relay drops out, stopping the pump.

You can buy such relays as "LPG" safety relays in brands like Peel, they are about $45 new.

[bonno]

In addition to Citroenbenders post, you need to fit a blanking plate and gasket to were the mechanical pump is currently fitted. Be mindful that the cost for this conversion would be in excess of $300 just for the parts alone, whilst the mechanical pump is considerably cheaper and should be available locally refer to  Alfa Romeo club sponsor in your state.
cheers
bonno

[SteveHobart]

Thanks gents. I did a mechanical to electronic fuel pump conversion on a GQ patrol before but that's when the new mechanical pump was $250 for a new one. Just ordered a replacement Alfa one for $55 from EBay! Lol Thanks for the advice!


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[Citroënbender]

Excellent score on the $55 fuel pump.

Bonno, I'm not sure that one needs to spend so much as the $300 you suggest.

The Fuelflow 015 or 015L is about $65 and can be readily mounted in a discreet underbody location: https://www.onlineautoparts.com.au/products/Fuel-Pump-Piston-Type-1-4psi-Fuel-Pump---Electric-Universal-FuelFlow/ZPN-01623

A Peel switch fetches about $45-$50 new: http://bluelpg.com.au/shop/lpg-safety-switch-peel

You can buy an underbonnet inertia switch from a scrapyard, the Peugeot one is common and cheap, with a "tail" of wire attached it will be $25 or less.   

An inline fuseholder (weatherproof) like the Narva 54406BL at about $12 is the last specific item, the rest is wire, terminals, cable ties, sheathing etc.  Say $45 for all that.

Unless the mechanical pump diaphragm is ruptured (the sump would be evidently and appreciably diluted with fuel) you don't need to blank off the pump mount, just remove the pump, drive out the actuator pivot pin, remove actuator, refit its pivot pin and reseal the pin ends - then reattach the pump to block.  You're in for $200 max, plus your time - which leaves $100 more for petrol.

Getting back to the failed pump, I have seen with my own eyes, the result of rubbish fuel being left to sit - in this case, in an approximately 10 year old Corolla driven by a "little old lady".  The fuel, which presumably had a portion of ethanol in it, had oxidised to a vinegar solution over several months of disuse and corroded right through the internals of the original fuel rail pressure reg. Almost unbelievable - had I not personally seen this I would dismiss it as nonsense.  So there is a bit to be said in favour of both good fuel and fuel stabilisers for the occasionally driven brigade! 

[bonno]

Hi SteveHobart
Good news as I see from your new post that the replacement fuel pump fixed the problem and the car is now back on the road.
cheers
bonno

[SteveHobart]

Amazingly quick delivery on that pump! And yes, working great now!


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[SteveHobart]

Damn! Thought everything was going well and now every fuel line upstream of the new pump is leaking! Lol Old cars hey!


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[bonno]

Steve
If it is leaking just around the hose joints try tightening the hose clamps. If this fails, new hoses and clamps are in order at a cost of $20 at your local spare parts dealer.
cheers
bonno