Alfa Romeo Forums banner

501 - 520 of 572 Posts

·
Registered
Joined
·
1,319 Posts
The O2 sensor has that configuration. Single spade to the green wire, the Bosch connector is for the heater element, power and ground.
 

·
Registered
Joined
·
554 Posts
Discussion Starter #503
@John533i, you are the man!

I found all the connections you mentioned and illustrated. Everything is in the right place now. I was beginning to wonder if the PO had hosed me somehow, but it was all self-inflicted.

Thanks!
 

·
Registered
Joined
·
554 Posts
Discussion Starter #504 (Edited)
Success!



The Good:
-No fuel leaks
-No oil leaks
-No coolant leaks (I had to tighten the lower radiator hose a bit more when I started filling it).
-Good oil pressure (one tick mark above 57psi at idle)
-No alarming noises or vibrations of any sort emanating from the engine

The Bad:
-It's still on jackstands, it's now dark, and I have to stop for the night.

I cranked it a few times with the spark plugs removed, then reinstalled the plugs. It fired up on the second try!

It wouldn't stay running more than a few seconds, but if I feathered the throttle, I could keep it going. Although I initially had visions of a serious bout of L-Jetronic troubleshooting, I eventually determined it to be a problem with the electrical connection to the aux air valve. I cleaned out the connector, and problem solved!

It now starts and idles fine. I also took the opportunity to run the trans through the gears. Everything seems to work fine there as well. I didn't want to run the car too much until I can get it on the ground, and drive it a bit to seat the piston rings.

I'll continue to check for leaks while I get the center console reinstalled.

I'll keep everyone posted, as I start to wrap up this project.
 

·
Premium Member
71 Berlina 74 GTV 17 Giulia Q4
Joined
·
6,515 Posts
Far Out!! It's official, you are in!
 

·
Registered
Joined
·
554 Posts
Discussion Starter #509
I have an interesting situation to share:

About mid-day yesterday, I thought I'd go out and start the Alfa again. After all, the fact that my newly-reinstalled engine even ran at all could have been a dream, or a hallucination induced by a steady diet of Oreo cookies and Diet Mountain Dew.

Crap! Similar problem as the day before: starts, runs fine briefly, but won't idle without feathering the accelerator pedal. I had changed nothing since Sunday evening, when it was starting and idling fine. The fact that it starts indicates to me that the Cold Start Injector (CSI) was working, and since it continues to run (although with manual assistance), made it seem that the four main injectors were functioning. It was as if the 'choke' function of the fuel injection system was not functioning correctly, but what had changed since last evening?

Between my wife's '76 Super Beetle convertible, and my Alfa, I feel that I have a pretty good understanding of how Bosch L-Jetronic systems work. I felt like the Grinch staring down at Whoville when the singing starts. I puzzled and puzzed; how can this be?

And then it hit me.

The Alfa has been sitting in the driveway with the hood off. We've had hot, sunny days...and the temperature was already over 90°F outside. I took my IR thermometer, and measured the temperature of various parts of the engine. The AAV read 127°F; the area around the Coolant Temperature Sensor (CTS) and Thermo Time Switch (TTS) read 123°F and 125°F respectively.

I theorized that the thermal action of the sun shining directly on these engine components, had heated them to the point where they were sending signals to the ECU, indicating a warmed-up engine. Of course the engine core itself was not that hot, and would require 'cold start' functions in order to idle correctly.

I made a test of my theory last night. After working late, I got home about 10:30pm, outside air temp was still about 84°F (I didn't think to take a temp reading of the engine with the IR thermometer). The engine started right up, and although not idling as smooth as normal, sustained the idle. This morning, after having set overnight, it started and idled perfectly.

It would appear that vigorous solar soaking of particular FI components led to less than optimal operation. (I should mention that I verified proper AAV operation during Sunday's troubleshooting alternately using a hair-dryer and deep freeze.)

It is certainly possible that there is an actual heat-related failure in one of the components. I am going to once again defer to Occam's Razor, and go with 'too much sunshine' as the cause. I covered the engine today while I'm at work, so I'll test my theory again this afternoon.

I'm hoping that my experience will save someone else some butt-pain later on.
 

·
But Mad North-Northwest
Joined
·
10,739 Posts
It's quite probable your idle air bypass is set too low, and with the warmed-up AAV closed there just isn't enough bypass air to keep it idling smoothly. Get the car fully warmed up and then adjust the nut on the idle adjustment hose (17mm nut with a 19mm lock nut) to set the idle to 950-1000 RPM.

- Don't trust the dash tach: I would strongly suggest using a digital tachometer
- If you unscrew the nut and can't get the idle up to 950 RPM you need a new idle bypass o-ring

Also a good idea to check that your throttle position switch (TPS) is adjusted properly for idle, and check that it's working with a digital voltmeter.

Some more details here: L-jetronic Fuel Injection Technical Troubleshooting Article
 

·
Administrator
Joined
·
12,904 Posts
Please stop idling this "new" engine. A rebuilt engine should be banged up to ~2000 rpm while everything is checked and then buttoned up and loaded to bed the rings.

Time to get her off the jack stands and doing laps :)
Pete
 

·
Registered
Joined
·
554 Posts
Discussion Starter #512
TPS was checked, including VVT functions. Idle speed set at 970. I thought of that too, when I had my initial idle problems on first start.
 

·
Registered
Joined
·
554 Posts
Discussion Starter #513 (Edited)
Please stop idling this "new" engine. A rebuilt engine should be banged up to ~2000 rpm while everything is checked and then buttoned up and loaded to bed the rings.

Time to get her off the jack stands and doing laps :)
Pete
Yes, sir! If it's not leaking already, it's probably not going to (at least for now). I should be able to hoon it Wed or Thurs evening.
 

·
Registered
Joined
·
554 Posts
Discussion Starter #514
I had some unexpected free time this evening, so I continued with the Alfa. The engine components read 88°F on the IR thermometer, having been protected from direct sunlight today. It started and idled without any issues.

Then I took it out and hooned it. At varying RPMs and engine loads, the engine performed great. I got it up to operating temperature, at least as indicated by the temp gauge, but I didn't have a chance to check the engine idle RPM at that temp as @Gubi had suggested. I'll drive it again tomorrow night, and double-check the idle speed.

I had forgotten how much fun this car is to drive. It's hard to believe this poor thing has been living on jack-stands for the last eight months. I'll check the driveway in the morning to see if any leaks have appeared.
 

·
Registered
Joined
·
554 Posts
Discussion Starter #515 (Edited)
On Monday, I plan on taking the Alfa to get its state safety inspection; the license plates expired last month, while it was still up on jack-stands. To that end, I have a few things to do, in order to get the car completely back together:

Now that I'm satisfied that the trans and clutch are working well, I can go ahead and reinstall the center console. I also have some bad spots in the clear coat on the hood. (I had originally thought the pest-control guy had got some over-spray on it, while it was up on jack-stands...but now I'm not so sure.) I'm going to prep and clear coat the hood this weekend. I don't want it to look like a beater when it goes in for inspection.

Once the Alfa is completely street-legal again, I'll switch my youngest daughter's driver training from the wife's '76 Super Beetle convertible to the Alfa. The oldest daughter took her driver's test in the Alfa; it's a great little car for learning to drive.

In the few times I've driven it since its resurrection, I have a couple of initial observations:

- I cannot say enough good things about the silicone hose kit from Hi Performance Store. I replaced the vacuum lines, including the ones to the infamous charcoal canister behind the right-front wheel well. When I pull the oil dipstick, the change in engine idle RPM is quite pronounced, compared to the previous slight change. Engine idle RPM responds more readily to adjustment than before. I am quite confident that the engine is 'air-tight' now; certainly much better than before. It will be interesting to see if there's any difference in performance or economy.

- The transmission work...repairing the 2nd gear synchro and making the 1st gear synchro mod...has significantly improved the driving experience. I initially found myself continuing to 'baby' the trans while shifting into 2nd gear, and had to remind myself that I don't have to do that anymore. It's a hard habit to break, and you don't even notice you're doing it. This will be a vast improvement on drive-ability for the wife and daughters. I have to give a big thanks to @factotum for cajoling me into doing the trans work, as well as being my mentor and guide for that project.

So far, still no fluid leaks of any kind. Oil still looks good on the dipstick, and the coolant is still clean; no sign of any cross-contamination there. For a brief, shining moment...I have a leak-free Alfa Spider! I've never had that before.

I am organizing my thoughts, to post a summary of this project at its conclusion.

NOTE:
I eventually purchased an optical tachometer, and set the idle speed to 970 RPM. Removing the oil dipstick results in a drop of 300 RPM, so it indicates the engine is still very 'air-tight'.
 
  • Like
Reactions: PSk

·
Premium Member
Joined
·
4,784 Posts
Don't forget to set the fuel mixture.
 

·
Registered
Joined
·
8,428 Posts
Are you referring to the idle bypass screw on the AFM, or adjusting the AFM's spring tension?
I wouldn't touch that, tbh, unless you have a specific afm based problem!
(...also not sure what Jim means by adjust fuel mixture...)
 

·
But Mad North-Northwest
Joined
·
10,739 Posts
Are you referring to the idle bypass screw on the AFM, or adjusting the AFM's spring tension?
Don't mess with the spring tension, and in the absence of any running problems or emissions test failure I would suggest against messing with the idle bypass screw.

You can check the idle mixture using a digital voltmeter on the O2 sensor as a mixture gauge and if it's properly being controlled then you're fine.
 

·
Premium Member
Joined
·
4,784 Posts
You use the screw under the aluminum plug on the airflow meter to adjust your fuel mixture. Screwing it up and down makes the mixture richer or leaner. This was suppose to be checked at every tune up.

Use either a CO2 analyzer or an AFR meter. I use to use an old Sun 75 machine until it died for the third time years ago. I now use the Innovate LM-1. Its been replaced with the LM-2. For the AFR I just put the sensor up the tail pipe since I don't have a cat. If you have the cat you can install the AFR sensor in place of the O2 sensor. You can find a conversion chart to convert AFR numbers to CO2 percentage.

Unplug the O2 sensor. Insert or install the AFR sensor and read the number. Alfa wanted the CO set to .70 percent which would drop to around .20 percent when the O2 sensor is plug back in. This is why back in the day when they were driven as daily drivers they burned an exhaust valve between 50,000 and 80,000 miles.

Nowadays I set the mixture around 1.0 percent if it has a cat or 1.5 percent if it doesn't have one.

Do not take the black cover off and mess with it. To remove the aluminum plug take an 1/8 inch drill bit and drill 2 holes side by side with a little space between them and use a pair of needle nose pliers and pull up to remove the plug.

The double nutted fitting on the intake is used to set the idle to 900 give or take a 100. Sometimes adjusting the fuel mixture changes it. This usually happens on one thats had a valve job, engine rebuild or hasn't been adjusted in many years.

This can all be found in the factory manual.
 
501 - 520 of 572 Posts
Top