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Discussion Starter #1 (Edited)
My 1989 Alfa Romeo Spider has 97,956 miles on the engine. It runs strong with good compression but I am having a recurring problem which has happened three different times. First time: Enjoying a great drive on a 80 degree F. day. Radiator temp. is 175; car is running great. Come to a stop light and idle drops to 0, car dies. I can restart but it runs rough. It will run as long as the RPM's are above 1000 at every stop. Have it towed to my mechanic who says the Fuel Pressure Regulator is bad, puts in a new one and off I go. Second time: Great drive up in the mountains, about 1400 feet above sea level. Leave car parked for about four hours in 85 deg. heat. Try to start car, same problem. Mechanic says new fuel pressure reg. is bad, puts in another for free. Third time: 1800 miles after second reg. put in. Sunny 80 deg. day. Fill up tank with premium gas, drive about 15 miles around town then head for freeway. Car is running great. Come off freeway to stop and go traffic because of road work. Travel about half a mile in traffic, then the same problem. Car dies, rough running on restart, etc. Tired of having car towed. Dream of having a reliable car dashed. Any helpful thoughts would be appreciated. Note: This Forum has been a great help in the past. I would not have kept the car this long without it.
 

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How was it determined all those FPR's were faulty? Typically they fail when the internal diaphragm ruptures. The easy clue is the presence of raw gas at the vacuum hose connection on the FPR (remove hose and sniff).

What is the fuel pressure before and after the FPR? There are fuel pumps that are identical in appearance but some put out way too much pressure. Perhaps this is causing the failure of the FPR's? Or maybe even the actual fault and the FPR's would have been OK?
 

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Sounds like you first need a new mechanic. Check the fuel pump fuse under the rear package shelf. That is probably not the problem, but something to check and replace. Air hose comes loose between air filter and manifold? Sounds like some electrical connection gets hot and loses connection. After the engine is cold again is it ok. On my car any problems have been corroded electrical connections (hot and ground) or leaking vacuum hoses. I have replaced all vacuum and fuel hoses and fuses. Added additional engine ground wire and hot wires from alternator to starter. I did replace my fuel pressure regulator once because it was leaking on the AC compressor and distributor, engine ran fine. Hard to say, their is no one thing every Alfa Spider has a problem with.
 

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maybe it is just the vacuum hose from the FPR to the Plenum....check that for a small split.
(and I'd stick to Bosch, when it comes to FPRs)

could be a failing in-tank fuel pump...? Any odd noises from the under car pump?
 

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Discussion Starter #5
Thanks, I will follow the suggestions. The car has been in my garage for two days. Outside temp is around 60 deg. Tried to start it and was successful. Idle held at 650 RPM's even after engine was up to temp. at 175 deg. and several revs over 3000 rpm's. Normal idle was at 850 rpm's
before problem. Engine is running pretty smooth. Will not trust until I can figure out the problem.
 

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Thanks, I will follow the suggestions. The car has been in my garage for two days. Outside temp is around 60 deg. Tried to start it and was successful. Idle held at 650 RPM's even after engine was up to temp. at 175 deg. and several revs over 3000 rpm's. Normal idle was at 850 rpm's
before problem. Engine is running pretty smooth. Will not trust until I can figure out the problem.
Low idle RPM could be indicative of vacuum leak. With it idling, remove the oil fill cap. If the idle does not change, you probably have a vacuum leak.
 

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Discussion Starter #7
This is a follow up to my original post: I took the suggestion of Sloboy89 to check for a vacuum leak. I know that the car died in stop and go traffic and that I had been using the brake a lot. I discovered that I had both a leaking brake master cylinder and clutch master. Oh Boy! I had brake fluid in the booster so I cleaned it out and attached a new brake master cylinder. I also replaced the clutch master cylinder. Before doing these replacements I removed the oil cap and the idle did not change.
After replacing both master cylinders, I removed the oil cap and the idle became very rough. Progress? Replaced the oil cap, checked the idle and it was still at 600. I then checked all the hoses and the rubber duct that goes across the engine for cracks. I even replaced the oil vapor separator
because when I cleaned it four years ago tons of crud and many pieces of metal fell out.
Time to check the idle, oh @%$#* it is still at 600 rpms. I then slowly pressed on the gas pedal to bring the idle to 900 and held it for about 5 seconds. When I released the pedal, the idle stayed at 900. It held until I brought the rpms to 1500 and released the pedal. Back it went to 600. I did this several times with the same result.
Let the engine cool and tried it again. Idle goes to 600 rpms when the engine is cold. At 175 degrees
It seems to want to hold idle at 900 even if I rev to 1500 it will drop back down to proper idle. I don't know if it will hold when I am driving it because it is still unstable. I am wondering if the AAV could have an effect. I have checked it and it only opens about 1/4 when cold but closes when warm. Never give up!
 

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Thanks for the follow up. That helps everyone else when they search for similar problems.

The AAV's are problematic. They are all getting old and don't want to work anymore (sounds like me...). They usually fail somewhere between open & closed and that messes with a smooth, steady idle. Also, the O-ring in the idle speed adjuster becomes stiff with age (also like me) and no longer adjust properly. BTW, the idle stop screw on the throttle body isn't supposed to be used to adjust the idle speed. Rather is should be set to allow the throttle to close but not jam shut. I set them to about 25-50 rpm above fully closed. And you really can't use the Alfa tach for these adjustments - they are not always that accurate.

The AAV can be replaced by a manual valve (info in the FAQ section). You just have to remember that a manual AAV is self-closing (you have to close it yourself). And the idle adjuster O-ring replaced with a hardware store O-ring. Then, once the idle is properly set make sure the TPS (Throttle Position Switch) is properly adjusted. The TPS tells the computer if the throttle is at idle, wide open or in between. If the computer doesn't know the throttle is at idle due to misadjusted TPS then the idle won't be steady - the computer will keep trying to adjust the mixture instead of following its pre-programmed idle map.
 

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Sounds like you have two very common issues caused by aging. A bad AAV and a vacuum leak, . The AAV is NLA, so I suggest following Eric's advice. The car dying when warm sounds like you may have a third common issue or maybe a third and fourth. 3) Make sure the gas tank is not pressurizing or creating vacuum due to the fuel vapor recovery system in the trunk being clogged. It has two check values if one fails you get vacuum if the other fails - pressure. Plenty on the board about this simple to diagnose and fix issue (drive 15-30 minutes, stop car and open fuel filler cap. Listen). This will create vapor lock or stop your in tank pump to stop. 4) make sure the in-tank fuel pump is working. If your mechanic is not an Alfa guy he may not even have noticed the second pump in the trunk. If the pump is working, it is clearly audible by just opening the trunk and leaning your head in. Any doubts and it is likely not running, but you can listen with a stethoscope or scrap of hose. Again lots of information the board about this pump.
 

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Discussion Starter #10
Final update? I was curious about the last idle test so I connected a tach tester to the coil and started the engine.
The tester showed that the idle was actually at 950 rpms while the tach in the car showed 600. Bad tachometer. I will wait on this repair as I have put enough money into this car already. The final test will be in stop and go traffic. I did take a 70 mile round trip drive up the Pacific Coast. The car ran better than before so I do think that the vacuum leak was affecting performance but I was not paying attention. The Alfa demands attention. Thanks again to everyone who responded. I could not have solved
these problems without your help.
 
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