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312 Posts
Discussion Starter #1
I am in need of some advice on troubleshooting direction regarding my 1986 Spider (L-Jetronics).

The car is fairly hard starting when cold (starts but wants to stop before catching and moving to idle position); also, the car does not start when warm or hot. It should be noted this car does have an occasional miss; happening twice since I have put the car on the road. We took the car on an hour plus trip where it did completely shutdown after running nearly an hour with power and dependability. During this run, the car suddenly shut down and would not start again; car started after letting the engine temperature return to a cooler level (about 30 minutes) and then started again which allowed me to go a couple of miles before shutdown again. The car would not start after multiple attempts start each time. Did again, a couple more times thus returning home as a "trailer queen" on a flatbed tow truck. The engine was running very well with oil pressure better than mid gauge point (57 psig) and coolant temperature running above mid-point (175 degrees) at 210-220 degrees.

The elements that bother me are the sudden shutdown while on the trip, couple to times hesitation while running, and the hard starting when warm/hot. I feel all these symptoms are connected. How? I do not know. HELP!

Cold starting: starts but acts like it needs fuel during the starting phase; idle is 1500rpm and does drop when warm. It appears the cold start system is working and acting somewhat proper except for the engine seemingly want more fuel for a smooth start.

Warm/hot starting: does not start even after running for five minutes and then trying restarting. Does this pattern over several times and different ranges from initial starting. Sometimes immediately to a couple minutes after running the car for sometime, the car will start but acts like it is going to die until the fuel system/control systems take over; delay is something like 2-5 secs plus, just enough time to not have a smooth interface from start to normal running.

Before anyone goes and starts telling me "this or that" causes, I have approached the car as if I am preparing it for another "100,000 miles", currently has 98,400 miles. Compression ratios dry in-between 125-128 psig; wet in-between 135-138psig.

All items listed below have been checked and rechecked both wiring and sensors/switches. The same problem listed above existed before the following changes and I have used Greg's/GLH/Papajam books, suggestions, etc. from existing and historic threads. I have even gone to Fiat, BMW, and Porsche L-Jetronics.

Items changed, replaced etc.:
Found original coil bad and replaced the entire ignition system with
RML Distsributor, Coil and Mag Sender System. This action eliminated
the bad coil found, the reference sender, speed sender, and vacuum
distributor sensor (obsolete and non-supported part); changed the
coolant temperature sensor belonging to the ignition which is now not
required in the foregoing changes. This change alone eliminated four
problem areas with the L-Jetronic system which costs are greater than
RML System.

Eliminated the ignition computer by the above change in system.

Changed to the manual auxiliary air valve controlled by the choke type
cable. It worked but still had the problem is not wanting to start when
warm except when pressing on the foot throttle. Changed back to
original system realizing the AAV is not supported, available, and
obsolete from Bosch. My AAV did check out but it still could be causing
the starting problem.

New injectors installed.

New Cold Start Injector installed.

Throttle Position Switch/Sensor checked and rechecked

New Thermo-Time Switch

New Coolant Temperature Sensor for fuel/injection computer

Both In-Tank and In-Line fuel pumps along with the In-Tank Sock Filter
and In-Line Filter

Dual Fuel Pump Replaced; may have to look at the other relay affecting
fuel delivery referred to as the Main Relay

The only items that have not been replaced are the Air Flow Meter which includes the Air Inlet Temperature Sensor, idle adjustment paths, and the butterfly valve; and, the Oxygen Sensor (Lambda Sensor).

Remember, every thing has been checked both from the sensor standpoint as well as the wiring and computer standpoints.

This appears to be one of those unusual and rare problems. Normally, these types have a simple solution. These solutions may include areas that I have looked at from the correct standpoint.


304 Posts
Just bought one off Craigslist cheap with these symptoms

With the help of this forum, she running great .

Sounds like you burning through un needed parts.

YOU DON'T MENTION GROUNDS! It is said 90% of the problems are caused by corrosion on the grounds. 20-30 years takes a toll. Are you getting spark?
Intermittently, I was not. Hook up a spare spark plug and check. I cleaned each ground, (search this forum for locations), then checked for spark. The one that fixed it happened to be the negative battery cable.

If you are running poorly, it's probably an air leak on the Jetronic fuel injection,
I had this too.

Search also for the post on the addition of another relay, for no starter condition.

I am now one happy Alfisti!

312 Posts
Discussion Starter #3
Let us see where we are: Burning through un-needed parts? The parts I am replacing are needed and the old ones have a lot of miles on them. These parts will become backup including the complete ignition system. I found by getting involved with each and every element I found three bad parts on the fuel side; the ignition side had at least two parts which were not working and one was discontinued.

With the changes I have made, one can assume that I have both ignition and fuel which I do.

I have had fifteen alfa's which mostly were weber carved; I know about this board and that is why I am here; grounds are critical and everyone has been cleaned, inspected, and reinstalled as per the troubleshooting book by Greg, Papajam, and GLH.

The problems I have are unusual to me and involving the L-Jetronic injection system. It is one of cutting out while on the road without any notice, starting cold thus wanting to cutoff before establishing idle, hard starting/not starting when warm, when it does start it wants to shutoff before going to idle, idle flux in rpm ever so slightly, and occasional engine momentary cutting out.

The foregoing information is giving total background so one can identify with the foregoing problem. This is where I need help and experience.

MCain, thanks for your inquiry and information.


16,986 Posts
Can you connect a fuel pressure gauge and see what it reads - especially when the engine dies? That would help direct your efforts to either FI or ignition.

I have read of wear on the electronic circuit board's wiper track inside the Air Flow Meter. There is a page out there on the internet showing how to move the wiper arm so that it rides on an unworn part of the track. I don't know that this would explain the exact trouble you're having but something to consider. (or substitute a known-good AFM...)

And of course there is the possibility of a faulty FI computer. Usually they are quite robust but they are all getting old now.

312 Posts
Discussion Starter #5
Thanks, Eric.

I am settling into the area you are suggesting; also, have a backup FI computer if I have to go this route. Going to see if I missed a small air leak in the system somewhere, particularly the air intake.

I have found a place that says they rebuild AFMs. Have you ever heard of them being rebuilt and to what extent. I am also would like to know who rebuilds the FI computers. Do you know anyone who does this? I would appreciate anyone who has had the FI computer and the AFM rebuilt recommending someone, or if you know of anyone.

Eric, I have read the thread you are referring too and do have a copy somewhere. It is a good one for retention since as you say, "Parts are getting older and harder to find".

Does Greg clean/rebuild the cold start injector, the auxiliary air valve, etc.? I want to see if these are worthwhile getting cleaned, checked to see if they are good, or whatever can be done. I still have to install Greg's matched flow injectors I got earlier this year.

Thanks for your input, Eric. Now let us see what is going on since this all part of the opportunity to learn. We never have problems, just "Opportunities to Learn".


312 Posts
Discussion Starter #7
The questions and answers are coming to a point where it is only one question: Why is the car starting with a somewhat weak matching of fuel/air at the start of the engine. What I mean is the engine does start on 2-3 turns of the engine but wants to die initially but gradually building up engine rotation to idle speed. Runs great after the start from cold; does start right after initial starting and several times immediately after and a few minutes after initial starting. I am beginning to think the basic mechanical (?) are not setup right if there is such a case. Need input on this problem.

I did appear to take care of the other problems like leaving us along side the road when it suddenly cutout, running with more power and authority, renewed questionable parts and non supported parts, matching discontinued parts with other similar parts, and other subtle items.

Again, cannot say enough of about the advice, support information, and experience from out members. I have always commented on these items, but I should say Papajam's wiring diagrams gives the common road map for how everything is connected electrically. Without all this information and sources, these cars would not be as much fun and enjoyment.

Now, back to the common simple problem facing me which is the initial starting either cold or warm: engine starting but wanting to "seek" cutoff, but eventually working itself up to idle speed. I will continue to drive, look for leaks, rechecking of parts, any mechanical settings, vacuum/air lines, etc.

Input from everyone is appreciated and hope to continue. Not there yet, but will have the engine starting with authority,

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