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Discussion Starter #1
Hi

I have a fuel problem on my 75 Turbo.
The car starts and drive, but sometimes (more than half of the times I drive de car) it has all sinptoms of not having fuel, and sometimes when I still insist with it just stops.
If I start the car it will start fine, but continues with the problem.
Some people told me that the 75 TS and the turbo have 2 fuel pumps, the normal outside the car (below the right rear passenger), and one inside the fuel tank. Is this correct?
 

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Hi

I have a fuel problem on my 75 Turbo.
The car starts and drive, but sometimes (more than half of the times I drive de car) it has all sinptoms of not having fuel, and sometimes when I still insist with it just stops.
If I start the car it will start fine, but continues with the problem.
Some people told me that the 75 TS and the turbo have 2 fuel pumps, the normal outside the car (below the right rear passenger), and one inside the fuel tank. Is this correct?
I think it would be a safe bet to say that all of the fuel injected 75's had the same basic fuel system lay out of in tank pump and outside high pressure pump.

Sort the problem out before a lean condition under boost makes a mess of your engine.
 

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Discussion Starter #4
If one fails, does the car still work and drive?
 

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But Mad North-Northwest
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I think it would be a safe bet to say that all of the fuel injected 75's had the same basic fuel system lay out of in tank pump and outside high pressure pump.
The V6 cars do not have an in-tank pump, only the external pump.
 

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no, it will run only poorly .The external one will suck the fuel throught the one in the tank
but going around cornering the fuel will run out went the fuel movers in the tank.
you will have no fuel on fast take offs and hard cornering .

also look at your fuel line for damage.
"went my car was panited the joker squashed the line went he jacked in up"
 

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Discussion Starter #8 (Edited)
Today I drove the car to work.
I unpluged the electrical conection from the tank pump and the car didn´t stop. It is working because it has a loud buzz and when you disconect it, it stops.
So the tank pump is working, and because the car still works with it disconected the external pump is also working.
Still I have a car that drives jerking, seams it has low/no fuel.

Last saturday I also drove the car and I was driving fast (with turbo load), when in a second it "cut", the engine braked the car, and the next second it backfired loud (very loud on the exaust of the midle of the car, I thought something breaked).
 

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Discussion Starter #10
Went was a new fuel filer last fitted ?
I bought the car 3 years ago, but drove some 2000Km until now, so I never replaced it.
I saw it today and it looks good on the outside.
But maybe you are right, and is a good idea to replace it now, because it could be blocked.
 

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Have a look at the Pierburg safety relay (a tall relay) next to the battery. If this malfunctions due to dirty contacts or vibration, it will cut the fuel as you describe.
Jim K.
 

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Discussion Starter #12 (Edited)
Have a look at the Pierburg safety relay (a tall relay) next to the battery. If this malfunctions due to dirty contacts or vibration, it will cut the fuel as you describe.
Jim K.
As I rebember, there are 4 ou 5 replays near the battery.
What does that relay do?
You say "safety relay", but what does it do/protect?
 

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It is a safety feature of the system. If it does not receive pulses from the ignition coil, it removes power from the fuel pump and fuel injectors. It's also called 'speedometer relay' (!?) in Alfa technical manuals. I had an intermittent failure of this device in my car and took a while to isolate! Its the tall relay with 9 contact pins underneath.
Jim K.
 

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Discussion Starter #14
It is a safety feature of the system. If it does not receive pulses from the ignition coil, it removes power from the fuel pump and fuel injectors. It's also called 'speedometer relay' (!?) in Alfa technical manuals. I had an intermittent failure of this device in my car and took a while to isolate! Its the tall relay with 9 contact pins underneath.
Jim K.
Mine doesnt have a Pierburg.
It has a blue Bosch with only 7 contacts.
The socket/female has 9 holes but my relay only have 7 contacts.
The Pierburg you say should have 5 big contacts and 4 small ones.
On my relay it doent have 2 smalls. It has 5 bigs and 2 smalls.
When I remove it with the car runing the engine stops.
When I move the key to the position before starting the car it clics and I hear the pumps starting to work.

I just tested bouth pumps.
When I put 12V to the one inside de tank it works and give little quantity of petrol. When I give 12V to the outside it gives a lot of petrol.
Is ti working the way it should?
With the quantity the one outside deliver I doubt it is fuel quantity problem.
I´m lost... :(
 

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If the relay is ok, is it possible to connect a fuel pressure gauge (0-6bar or 0-10bar) and monitor that while you drive? If yes, you will immediately see if the cutout is fuel pressure related. I assume all your electrical connections to the pump, starting with the fuse, are all clean and tight?
Jim K.
 

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Discussion Starter #16
If the relay is ok, is it possible to connect a fuel pressure gauge (0-6bar or 0-10bar) and monitor that while you drive? If yes, you will immediately see if the cutout is fuel pressure related. I assume all your electrical connections to the pump, starting with the fuse, are all clean and tight?
Jim K.
I dont have a fuel gauge, so I cant test that.
But I´m going to replace the extrenal fuel pump and the filter for one that I have at home and that came from a 75 1.6ie.
The fuel pump has the same size, but the filter is smaller. But I think its almost the same thing for what I want, to test if it is a weak pump.
If with this pump I have the same problem, what should I test?
 

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If you temporarily connect a pressure gauge like I propose, you will not have to change fuel pumps and filters. It will also show you how the regulator is working. You can really test the fuel system like this. If this tests out ok, I think your next step will be to check if the signal to the injectors is somehow intermittent and causes the problem. It is worthwhile to check and clean all injection harness pins and connections before continuing, making sure nothing is loose or corroded. Start with the main ecu connector. It may be a good idea to spray some contact cleaner and use a toothbrush for the connector pins.
Jim K.
 

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Discussion Starter #18
If the relay is ok, is it possible to connect a fuel pressure gauge (0-6bar or 0-10bar) and monitor that while you drive? If yes, you will immediately see if the cutout is fuel pressure related. I assume all your electrical connections to the pump, starting with the fuse, are all clean and tight?
Jim K.
Where is the fuse located?
The problem is not fuel.
I tested with an old bronken tire compressor gauge. It showed arroud 2.5-2.6 bar with the original pump and filter. Showed the same with another 75 pump I have spare. It had diferent electrical contacts, but I made an adapter with wire.
So if it has fuel pressure it must be electric/electronic.
I changed the coil and the electronic ignition module, checked each injector removing the conector with the car working, cleaned all contacts I found, cleaned relays (contacts), checked the first ECU (passenger feet) and cleaned the conector (but it looked new), opened the distribuctor and cleaned its insides, cleaned the Hall sensor conector.
Everything was cleaned with quality electronic contact cleaner, the one that doesnt have lubricant. Some seconds later its cleaned and completily dry.
But nothing changed.
Now the car even failed when reving from idle and not moving.
The last thing I did was change the rotor (dont know if this is the right word) of the distribuctor. I did it after all cleanings and al tests.
I dont know if it is a coincidence, but after changing it to an old spare I have here, I did 2km with the car and it didn´t fail. I even drived with a little of turbo bust, and it when sooth.
But it can be coincidence.
Is it possible that a f#$%ing rotor can be the reason for this malfuntion?
 

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Hi Carlos.

I had a very similar problem to you... very erratic as to when it would stop. Check all relays, fuses and connectors and even replaced the fuel pump with a new one.

In the end I think I traced the problem to a bad feed from the MAF unit.

The ECU is directed to start the fuel pump when the engine is cranked over but I understand that the ECU will stop the fuel pump if the MAF unit is not detecting air flow e.g if then engine stalls. (But I might be ill informed on this... Can anyone else confirm this?)

I had some issue with the MAF wipper unit not providing a good enough signal when idling so the ECU would shut off the pump. So the "wipper" and "contacts" inside where cleaned with contact cleaner and the problem went away.

However to resolve the problem temporarily, I just hard wired the fuel pump to the ignition until I had time to find and fix the real issue.

Regards
Phil.
 

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The rotor has caused many problems of this type, as it deteriorates over time. Sometimes everything goes back to normal when you replace it.
Another reason for erratic running/stalling is an intake air leak, after the afm. If air enters after the afm, it is not measured and there is no fuel for a correct mixture. Inspect all tubes and pipes for leaks, hidden cuts and loose/failed clamps, everywhere between the afm and the intake manifold. in the 1.8T there are many air connections to be checked.
Jim K.
 
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