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Discussion Starter #1
I have been searching for the reason my Alfa starts slowly and has to build to idle speed, either cold or hot. I have been through everything at least three times and I still have what I call "a slow start and building to idle level. It is not the "start syndrome" associated with l-jetronics systems. Once started and warmed up, car runs great and pulls through the Revs with authority.

I have not been running the car since winter season is here. Today I warmed her up and took both wet and dry compression. Prior compression tests taken last year where across the board at 125psi each. The one today shows #4 at 50psi,, and the rest at 125psi. taking the compression wet everyone of them registered at 150psi.

Possible potential valve problem on #4.

Could a sticking valve or air leak when dry or wet cause the engine to start slowly and then build to idle?

The start problem happens either cold or warm. It is just that the problem is slow starting and seemingly having to touch the throttle pedal for more fuel to achieve good idle when starting.

Clear as mud???

I think I had better run the car and keep track of the compression history for clarity and eval; but, slow starting is what really bothers me. My 914-Sixer (3.2 Motronics) starts right now with authority and spot on idle. I hope to get the Alfa in this same condition.

Any thoughts and ideas?

Steve
 

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when a wet compression test shoots up like that, it points to bad rings....not valves.
 

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I am having difficulty trying to explain the unusual low compression measurement followed by a seemingly normal reading after adding the oil. Yes, low compression improved by adding oil makes the ring seating suspect but the improvement you're reporting is not typical. Perhaps the low reading was due to the compression gauge not fully seated?

Have you confirmed all parts of the Spider's Cold Start System are functioning properly? The CSS is not under computer control - it's a stand alone system with the ThermoTime Switch, Cold Start Injector & Aux Air Valve. And that the fuel injectors are all functioning properly? A weak injector or a leaky injector (or more than one) could certainly affect starting. The engine would then run fine once running. A place like OK Injectors will test the injectors for spray & leaking. They then clean them with solvents & ultrasonic baths and re-test. Leaky injectors & uneven spray volumes are common.
 

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Discussion Starter #4
Thanks for the comments and the correction on sealing the rings with oil.

I kept coming back to the cold start system prior attempts at finding the cause. I have changed cold start valves, aux. air valve, etc. but not the thermal switch. I have put new cost start valve in twice, two different aux. air valves, and even have done Greg's manual replacement for the aux. air valve. The problem still prevails.

New fuel injectors were replaced last year. I even have a set of Greg's matched flow ones on the shelf; since Eric mentioned injectors I will be putting in the best ones from Greg.

I have not touched the Thermal switch. Could this be a possible cause?

The low compression in #4 cylinder means the car needs to be run more and not set as it has for the past ten years. This is something to watch but the car runs fine when once started (both cold and hot). I am not going to try to understand why the compression difference occurs at this time. Have not overhauled an engine in years, but Alfa deserves the best. The engine is such a beautiful design.

I am still looking for air leaks but I do not think this is a probable cause.

The car did leave me once when I thought I had everything solved, but the coil turned out to be bad, some obsolete parts not working, and updating. Mechanically, the car should be ready for the road except for the "soft starting problem". Idle should be right there when the car starts but alas mine does not have it. It will start without foot throttle and then increase rpm achieving a good idle; if it seems to hang at times a little foot throttle gets it over the hump to achieve idle. Immediate restarts are fine; wait 15-20 "soft start to idle".

I am going to follow the comments listed on this thread, change the injectors to matched flow ones I have from Greg, look at the thermal switch, and run the car watching the compression. Document cause and effects and keep everyone informed. I think I will look at the aux air valve and cold start injector items again.

Thanks for all the input.

Steve
 

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71 Berlina 74 GTV 17 Giulia Q4
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If the compression is as low as 50 it will not start with the same authority as will one with all four cylinders at tip top compression. I'm not saying that is your problem, no one can definitely say what the problem is from far away but it's something to consider.
 

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Hi Steve,
If, as you say, "stepping on" or "pumping" the throttle pedal a couple of times gets the car to idle properly, I wouldn't rule out a problem with the throttle linkage (or its adjustment).
 

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A leak down test can pin point the source of low compression (if true). A proper leak down tester measures how well the cylinder being tested can hold air under pressure. It is usually reported as a percentage. A new, properly broken in engine will show leaks in the 3-10% range. A used but good engine will show 10-20%, a worn engine 30% or more.

Even simpler one can use an adapter to pressurize each cylinder with air at 50-80 psi and then listen for escaping air to see where the weak points are. Listen at the intake plenum & exhaust pipe to check for leaking valves (should be no hissing). Listen through the oil fill for leaking rings (some hiss is normal - compare the best cylinder to the questionable one). Listen at the adjacent spark plug hole for a faulty head gasket. And also look for air bubbling in the coolant to check the head gasket.

Note that the cylinder being tested has to be positioned with its valves closed - typically at TDC. And that when you apply the air pressure the engine can suddenly turn - so be careful!
 

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Discussion Starter #9
Thanks for the comments; everyone has possibilities. I am afraid the path may lead me to the #4 cylinder and the problem of low compression. If that is the case, the car will be fixed the correct way. In the time being, I will follow all the excellent suggestions making sure I am solving the problem(s) of the car.

Thanks, back at you later,
Steve
 

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Yo Steve,

Do not rule out the possibility your continuing issues stem from failure to include a signature line with your posts :). 411 in the subject line don't count :).

Alfa BB gods act in mysterious ways... They are customarily lenient on the first post.

Fine name you got there!

All the best, and we'll be looking forward to developments.
 

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Discussion Starter #11
Steve, gave a good laugh and good advice! I completely missed the security check at the very end.

Every Alfa presents different set of "LEARNING EXPERIENCES" and the people on this board provide great support and advice. It is always a great pleasure to associate with Alfa people. We do not have problems but great learning experiences!

Over the last forty plus years I have had about 15 Alfas and they have provided great hobby of being involved and a caretaker for them. Some have been rare (1966 GTC) and some have been parts cars (101 Spider) and various driver types inbetween.

The present car I am working on is for my nephew which he will get in few years. It is providing with a completely new learning experience so I can pass on to him the "Alfa Romeo Sickness"!

Steve
 
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