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Discussion Starter #1
My Alfa 87 Quad has had constant problems with completely losing power all of a sudden on the road. Intermittant problem...feels like a complete cut off of gas to engine. I have to leave car for about 1hr to cool off in order to drive again.
This prob has been occuring for 4 years now and I service it a one of the more reputable Alfa centers in NY. They have already replaced: fuel pump, fuse under back seat at relay, brake cylinder and hoses, O2 sensor, and even added a power relay at ignition and nothing has solved the problem...very expensive and frustrating.

I called a reputable Alfa parts dealer this morning and they suggested looking at the flywheel sensor connections, and testing fuel pressure and spark with hot engine. They think it might be either: a connectivity issue, spark problem, or fuel delivery prob.

Any thoughts here? Thanks for your help
 

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When you lose power is everything dead? Lights, instruments, etc? If so, there must be an iffy connection somewhere in a main power supply. Check battery connections and the negative cable's connection to the body (it bolts to the floor of the trunk near the battery. Also check the engine to body ground strap - from the right side of the bell housing to a tab of metal in the transmission tunnel. Clean and tighten the connections at the starter motor and the connection point on the left inner fender (black box with 3-4 red wires and a pair of green wires).

Checking the flywheel sensors is a good idea and relatively easy. See the link to L-jet Spider diagnosis in my signature block for details.

Testing fuel pressure would be useful too but that is not as easy. You'd need to tee in a fitting and hook up a gauage to read fuel pressure up to ~50+ psi (correct fuel pressure is in the 30's to 40's IIRC).

How old are the fuel hoses? A fellow BB member had a devil of a time with his Spider losing power. He finally found a fuel hose with an internal fault. A flap of rubber would act like a one-way valve/restictor. It'd flow fuel at a slow rate (if he drove sedately) then block fuel if he floored it. After sitting for a while the pressure would bleed off and the restriction would open. He did the fuel pressure testing like I described above. When the pressure would drop he assumed he had faulty fuel pump. Not so - it was the faulty fuel line (a relatively new one, too, IIRC!
 

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Can you describe the symptoms with more detail? When it loses power, does the engine cut out completely, or does it just run at low power, as if it's starved for gas? Does it idle fine, and only lose power when you lean on the accelerator? Are there any other symptoms or indications?

Tim
 

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Discussion Starter #4 (Edited)
thanks for the responses....

1) all electricals are on when I lose power...no disco warning lights flash..instrument panel is fine.. tach keeps working

2) engine seems starved for gas...when I broke down the other day, as engine was coughing and I was chugging to a dead stop, I floored the gas pedal to see if tach responded and it didnt...it stayed at 900 idle...no increased rpm at engine either...just coughing

3) per above, it stayed at 900 idle for a few seconds and then dropped to about 550 when I stopped giving it gas

4) three sensations I feel when this happens: a) a sudden and complete loss of acceleration; b) feels as if brakes are being applied and wont let car move (changed brake hoses/fluid) two days ago and 1 hour later broke down again
c) frustration!!!!

5) I have owned for 6 years...I never changed fuel hoses (changed outside pump 2x and change filters 1x/6 months). I use high-test unleaded and an occasional STP fuel injector cleaner

6) I need to let car sit for 1 hour on side of road before I can even attempt to go again, and then I can usually get it home as symptom dissapears until next time

Thoughts???

thanks
 

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....Throwing darts while wearing a blindfold....
I'm still learning about Alfa's, but have you checked to see if the fuel tank is venting appropriately? If the fuel is being pulled from the cell faster than air is coming in, it'll can create a vacuum. After sitting for an hour, the car can "catch its breath".

Like I said, still learning, and it's just a guess.
 

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One thing that you should rule out is an intermittent ECU. These have been known to "die" when hot, not uncommon with electronics of that vintage. Having gone the tough route that you have, I'd borrow or buy a FI ECU, try it, so that could be ruled out.

In tank fuel pump has not been mentioned by you. Another possible culprit is the ignition switch, not uncommon.

Best regards, Elio
 

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Discussion Starter #7
thanks for additional responses:

1) in-tank fuel pump has been ruled out by my shop as I always keep fuel well above 1/2 tank and have been told that the in-tank pump only is only utilized below 1/2 tank capacity...also humming of pump is heard in tank

2) Fuel filters have apparently come out clean on inspections, so my shop doesnt think it is worth dropping the tank to see if there is corrosion getting in to fuel line.....although I have mentioned a number of times to them that I was the owner of a '74 TR6 and had the exact same problem...my shop then dropped the tank, found corrosion and all problems were fixed.

Also, one other thing I have yet to mention: all of these problems started just one month after the cylinder head was rebuilt by the same shop. I had never had any of these problems before the head was fixed.......could there be a straight line from the head to this problem?

I am not a car mechanic, so I need to leave diagnosis and fixes to others.......

Thanks to all for your help
 
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