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Yet another "My Alfa 75/Milano won't start" thread

4K views 25 replies 5 participants last post by  Phantom Italian 
#1 · (Edited)
My Alfa Milano cranks but won't start

Hello all!

So my 87 Milano suddenly decided it won't start. I've been fiddling with it over the past few days and this is what I've found. Bear with me as this car is still very new to me. It cranks and won't turn over, so first I checked the fuel delivery system and the infamous double relay. Both are in working order. I can hear the fuel pump and I opened the little hose on the front of the engine attached to the fuel rail, the name escapes me, and tried starting it and gas spurted out. So I'm fairly confident that it is not the fuel delivery system. Next I checked all of the grounds and they are all very clean with no corrosion. Next I went to the ignition system. The whole distributor was replaced around 9 years ago and the car has had maybe 2,000 miles since then. So I'm fairly certain it's not that. So I went to the ignition coil. I tested it for the same voltage as the battery and it tested positive. I then checked the air intake hose from the air filter to the throttle body and followed this guide L-jetronic Fuel Injection Technical Troubleshooting Article . I removed it and cleaned it. I could not find any holes, though maybe I was checking it wrong, so I used shoe goo on the accordion section and all of the parts where the other hoses connect, let it dry thoroughly, and put it back. After letting it sit for 24 hours to make sure it dried right, I tried starting the car... IT STARTED!...and then immediately died. I tried again and it wouldn't start again. Still cranks, but won't start. Am I right in thinking that, at this point, it's probably one of the vacuum hoses? They haven't been replaced for at least 10 years so that very well may be it. After that, the only thing I can think of is to check the spark plugs. Any opinions and or advice will be greatly appreciated. Thanks in advance for any of the aforementioned comments!
UPDATE

I checked the spark plug wires for spark today and they are sparking well when I try to start the car. I then checked the cold start injector as I have read those can be troublesome. That checked out ok as well. Only thing I noticed was that the wire for the engine temperature sensor is disconnected. I would suspect it but it was neatly wrapped around the surrounding wires which leads me to believe it has been that way for a while. Is there anything else it could be? Do I have a vacuum leak?
 
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#4 ·
Sorry, just noticed that you actually mentioned that in your original note! When you say your engine temperature sensor is disconnected you mean the one that is shown in the guide that is supposed to be disconnected, not your CTS (coolant temp sensor), correct?

First make sure your battery isn't too low after all the start attempts, anything below a certain voltage (I can't remember exactly but 10.5v comes to mind?) and it won't start, ideally you have at least 12v.

Try disconnecting the connection to the cold start injector and see if the car starts (maybe it is spraying too much fuel), if that doesn't work then leave it disconnected and try starting in "flood clear mode" by pressing the gas pedal all the way down while trying to start the car, it may take a few cranks, if the car starts then let off the gas right way. Don't try starting with a partial throttle or by pumping the pedal or you might blow your plenum off. Pressing all the way down when starting tells the ECU to pulse the injectors.

Kevin
 
#5 ·
The coolant temperature sensor must be connected and in working order for the Fuel injection to work properly. Go back to the guide and determine exactly which sensor is disconnected. There is also a ground wire on the thermostat housing and that also must be connected.
 
#6 ·
I took a look and it is the one that is supposed to be disconnected. I have yet to check that and the thermos time switch. I checked the voltage on the cold start injector yesterday and it checked out ok. I'll try seeing if it squirts today and, if it does, if maybe it's too much. Didn't know about the ground wire. I'll look into that as well. I also checked for spark from the wires and I got plenty there so ignition is good. The last thing I thought to check was the AAV. I put it in the freezer for 25-30 min and it didn't seem to open much at all. I just finished cleaning it and I'll see if that makes any difference. Probably won't though considering I am in Texas and it doesn't get very cold here. Thanks for the input. I'll update later today if I can.
 
#9 ·
So I took off the auxiliary air valve and found it wasn't opening very easily. I stuck it in the freezer for around 30 min. two times and it barely opened. I tried cleaning it but to no avail. I tried starting the car with the vacuum hoses attached to a piece of copper tubing instead and voila! she started like a dream and idled. idled high but idled which is more than I've been able to get from it. Is this normal? Should the AAV be preventing the car from starting?
 
#10 ·
ghnl has posted about replacing his AAV with a manual valve. I read that this Bosch AAV was copied and improved on some Japanese cars - maybe Datsun Z cars. The engine needs more idle air when it is cold. Alfa switched to a motorized PWM valve for idle air control on the 164,
 
#11 ·
Check for injector pulse first. Use a Noid Light

First things first. Put a Noid light on the #1 injector connector and see if it flashes while the car is cranking. If you don't have a Noid light you definitely need one. If your Noid light doesn't flash then you have no injector pulse.

Also get yourself a remote starter switch, so you can start the car and watch the light at the same time
 

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#13 ·
Normally when these cars start and then die immediately, it means that the main injectors are not firing but the cold start injector (CSI) is. The CSI which is not controlled by the ECU, squirts in enough fuel to start the car, and let it run for a few seconds.

The CSI only runs when A, the motor is cranking AND B. engine coolant is cold.
 
#14 ·
UPDATE
So my most recent check yielded an interesting result. I had forgotten but one of the comments above recommended I unplug the cold start injector and try starting it that way. I put the aav back on and voila! She started and idled. and a NEW problem cropped up. I tried giving it a little gas and the gas peddle goes straight to the floor with no feedback or effect whatsoever. Any ideas on that one?
 
#18 ·
Yeah. Seems to be the case. So does that just confirm that the aav is the problem? I'm still gonna check the injectors to be sure but still seems strange that the aav could cause the car to not start. I've seen people talk about irregular/sporadic idles but not preventing the car from starting.
 
#19 ·
No, I don't think the AAV is your problem, all it does is let in more or less air. You should do some more troubleshooting of your CSI and TTS. The TTS is the one that tells the CSI to fire (or not). From your symptoms it sounds like it is possibly always telling the CSI to fire, which when the engine is warm (or it is warm enough outside) will cause too much fuel to be injected and make the car hard to start or even flood the engine (which is why I suggested trying to start in flood clear mode above).

The other possibility is that your CSI is spraying too much fuel when it is told to fire which will cause similar problems.
 
#20 ·
Ok So I tried starting it with the cold start injector disconnected and it started and immediately died. So I retested the thermo time switch and its reading as it should. Also tried the flood clear start you suggested and it started but only ran as long as my foot was on the pedal. Take my foot off, it dies.
 
#21 ·
So I checked the fuel injectors with the noid light and they are getting pulse. Also checked cold start injector and it seems to be working as it should be. I rechecked the plug for the aav, the thermo time switch, the coolant temp sensor, and the aav. All of those checked out except the aav. It won't open at all even when it's cold. That is the only area I am finding any fault in.
 
#23 ·
With the CSI disconnected you said it starts and immediately dies? So it catches and runs for how long before dying? Does it do that multiple times in a row? Up above you said you had the CSI disconnected and the AAV plugged in and it started and idled, does it no longer do that?

Kevin
 
#24 · (Edited)
So with the csi disconnected and the aav connected, the first time it started and idled. It didn't die until I turned it off. After the first time it wouldn't repeat and starts, dies and then cranks and won't start. Then I reconnected the csi and put the copper tube in place of the aav and idles high. I took out the ecu to check for corrosion and didn't find any. cleaned it with contact cleaner and hooked it back up. Then it started raining so I can't mess with it anymore today. http://www.alfabb.com/bb/forums/images/AlfaBB_2015/smilies/tango_face_sad.png
 
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