Alfa Romeo Forums banner
1 - 20 of 83 Posts

·
Registered
Joined
·
315 Posts
Discussion Starter · #1 ·
My 1982 spider stopped running at a traffic light. I have not been able to get it started since.
I just had a flywheel sensor replaced prior to this latest event but both sensors test ok even at the ECU harness. Also both sensors are still properly mounted in their housings. (I am moving this discussion from a post on flywheel sensor wiring test to here)

While cranking I do not seem to getting spark. Tested this using a spark plug in one of the spark plug wires with the plug grounded to the block.

Started testing voltages and cleaning hot connections and grounds.
Battery is new this spring and just had it tested at the store using a load tester. Test shows it is OK

Car had been sitting for about 5 years. This summer I drained the tank of stabilized fuel and put fresh gas in and with the new battery it started right up and ran well until I had to take it in for an inspection once the ten day temporary tag expired.

Battery voltage not under load typically starts at about 12.8 volts after charging and drops to about 12.5 or so after a number of cranking attempts while I take voltage measurements.

Voltage at the battery while cranking is 11.7 to 11.4

Voltage at the power distribution block on drivers side of the engine bay is about .4 volts less when using the frame as ground. This should be a good measurement of the voltage at the starter itself. This .4 volt drop seems to agree with calculations of a 290 amp load on 6 feet of 1 gauge wire.
One thing that is rather odd is that I get another .3 volt drop if I measure the voltage from the distribution block using the engine as ground. The braided ground has been removed cleaned and the contact points cleaned and the strap was reinstalled.

Voltage at the ignition ECU wiring harness is 10.0 on 4 and 5 while cranking and 10.3 at 1 and 19.

Just completed checking and cleaning connections on hot side of fusebox with no issues found except for some bad wiring that must have been done when the ac was installed (three butt splices in a 6 inch span and the wrong spade connector) At least I think it is AC wiring (red with white stripe on fuse 2). Fixed that but it should not have any impact.

Still need to check ignition switch wiring but that I replaced that switch a number of years ago. And it sure hasn't been used much since the car has been off the road for much of the time since it was replaced.

Overall all of the wiring and connections looked pretty good. I am not finding corrosion or grime.


Am I on the right track? I have not started on coil and cap and rotor since I don't think I am getting enough voltage to the ignition ECU to wake it up. My shop manual troubleshooting section however states that the voltage at 4 and 5 during starting should be between 6 and 12 volts.

Before it was taken off the road
All of the air hoses have been replaced
all fuel lines and filter replaced
new plugs
all vacuum hoses replaced
all vapor recovery hoses replaced

Other checks completed
CTS tests ok at 2.14k ohms at about 70 degrees
TTS also tested ok with zero reading at ambient temperature
 

·
Registered
Joined
·
315 Posts
Discussion Starter · #3 ·
Coil measures .7 ohms across primary and 3.99 k ohms across secondary. This is just what my shop manual specs out. IAP tech bulletin calls for .75 -.81 ohms and 10 to 11 k ohms.

I'll have to get to inspecting cap and rotor tomorrow.

Checked my records and wires were last replaced in 87 so I think it is time to get a new set
 

·
Registered
Joined
·
9,974 Posts
you mentioned a lot of voltage tests before, but not whether you have battery voltage at coil (IGN on)?

If voltage 'yes', do you also have a pulse at the coil when cranking (put a simple 12v test light between -/+ coil terminals (LT) and crank the starter)?

If you do, then I'd check the dizzy cap, make sure the little carbon spring brush is in place and contacting the rotor, also that the coil HT lead is firmly located, both at dizzy and at coil.
 

·
Registered
Joined
·
315 Posts
Discussion Starter · #5 ·
Still no start.

Checked cap and rotor and replaced both since there was some pitting and marking on cap.

Restested the spark but at the coil instead of the spark plugs and still no spark.

I have >12 v power at positive terminal of coil with key on

Test light constant on and bright with engine cranking between positive coil terminal and engine ground - as it should be.

Test light also constant and bright with engine cranking between coils negative terminal to engine ground. Unfortunately meaning that I am not getting ground signal from ECU to that point. Light should flicker.

I think that means that one of these issues remain:

1. Not getting enough voltage to ECU to wake it up. What is really needed measured at ECU harness?

2. Not getting all the required input signals. Both flywheel sensors test ok. Are any of the other inputs necessary to get spark?

3. Shorted wire from ECU to Coil Will need to do a continuity check on that wire

4. Bad ground at ECU. I think this is just the grounds going to the valve cover which I have checked.

5. Faulty ECU. I don't think there is any way to test that other than eliminating all other possible causes.
 

·
Trained (ex)Professional, , 1953-2018 RIP
Joined
·
16,232 Posts
A shorted tach/tach wire could also result in a no-spark. Try disconnecting the smaller of the two white wires on coil negative and see if the symptom changes.
 

·
Registered
Joined
·
863 Posts
Pretty sure the all white wire goes to the Fuel Injection ECU.... the thin one not the thick all white wire in its own sheath, so if you disconnect that you will not have a signal at pin 1 of the Jetronic Box. However is noteworthy to disconnect the tach lead as papajam suggested. That would be the white wire with the black tracer. It could very well be a failed
Ignition box. In my experience when the 82-89 L-Jet cars have an intermittent ignition I replace the distributor and coil with an RML performance ignition, its the easiest cheapest (long run) fix with an accelerating performance gain.
Ric
 

·
Registered
Joined
·
315 Posts
Discussion Starter · #8 ·
Ric, Jim is right that the small white wire goes to the tach. Jim/Papajam creates some great color coded wiring diagrams that have been absolutely essential in helping me troubleshoot. However to be doubly sure I checked that the small white wires routing goes into the wire harness that goes to the fuseblock area and in addition my shop manual wiring diagram has that as a 1 MM white wire. The big white wire and the white wire with the black tracer go into protective sheaths and go to the drivers side firewall.

Tried starting the car with that lead off the coil with no start

I checked for a short in this tach wire and it shows it is open not shorted to ground

Beginning to think my next best approach is to put in a starting relay
 

·
Registered
Joined
·
315 Posts
Discussion Starter · #9 ·
Found the following on Centerline Alfa's tech section on Bosch Electronic Fuel Injection.

Voltage. One of the design parameters of the L-Jetronic system is that there must be 10 volts on the #10 pin connector at the ECU for the car to start. If there is less than 10 volts, the ECU shuts off. This requires a very good battery because the electrical load during starter cranking can cause the voltage to drop below 10 volts at the #10 pin. Check your battery condition and battery/ground connections first. Once you’ve determined that the battery and battery cabling are in good shape, try the following. From the #10 pin at the ECU connector, trace back into the harness (green/black wire) as far as possible. You will need a couple inches of wire. Cut the wire and tape it off going into the harness. Now, locate the main power relay next to the ECU. It has a large gauge red main power wire going into it. Take the wire from the #10 pin on the ECU and attach it to connector #87 on the main power relay. This provides more voltage to the starting circuit.

My tests at pin 10 has had the voltage either slightly less than 10 volts or only about 10.3 volts. This fix they propose sure seems like a rather simple approach that uses the existing main relay. Has anyone done it this way?
 

·
Registered
Joined
·
315 Posts
Discussion Starter · #10 ·
Decided to go with a separate dedicated relay just for the starter solenoid. I already have headlight relays from Daniel Stern Lighting so ordered some parts from him. Also gives me the ability to swap parts in a pinch. I will give an update when I get this installed
 

·
Registered
Joined
·
315 Posts
Discussion Starter · #11 ·
Caution!
One of the tests I did on the coil should not have been done.

Per my Workshop Manual

"10. Do not connect an inspection lamp or positive battery lead to coil contact 1, as ignition ECU would be damaged beyond repair."

I assume a test light qualifies as an inspection lamp.

I will still install the relay one I get the parts but I may be looking for an Ignition ECU.
 

·
Registered
Joined
·
315 Posts
Discussion Starter · #12 ·
Installed the starter relay. Tested the voltages at the ignition ECU wiring harness during cranking before and after installation. Getting about .3 to .4 higher voltage at pin 10 after installing the relay. Now getting 10.3 to 10.4 and sometimes as high as 10.5 volts. Quite frankly I was hoping this would be even higher. Hooked up the harness and unfortunately it still does not start.

Need to wait for my trusty assistant (wife) to get home to check to see if I am getting a pulse at the coil (using test light)
 

·
Registered
Joined
·
315 Posts
Discussion Starter · #13 ·
No pulse or flicker on the test light.

I think I have exhausted all the tests which means the ECU is suspect.

Has anyone used ECU Doctors?

I didn't see any available on the parts section of the BB unless I missed them.

Need Bosch 0 227 400 003

Thanks
 

·
Registered
Joined
·
9,974 Posts
Steve,
there is a couple of 0 227 400 003 ECUs on ebay at the moment.
search ebay for 361357631019 (280$ buy now) or 262018475182 (125$ auction)
 

·
Administrator
Joined
·
18,177 Posts
Has anyone used ECU Doctors?
Not personally but I have read good reports from those that have. In some cases ECU Doctors tested the computer and pronounced it good and charged only a small fee (vs the bigger fee for actual repairs).
 

·
Registered
Joined
·
863 Posts
Steve,
I have several good ECU's taken from cars that had performance upgrades.... They all worked when removed from the cars.
I can sell for $100.00 including shipping. Of course you buy it you own it. Still not sure that is your problem, but I have seen failed units before.
RML
 

·
Registered
Joined
·
315 Posts
Discussion Starter · #18 ·
Decided to give another concentrated effort on voltage to the ECU. So far I have checked and cleaned all the connections from the battery to the ignition switch. Even removed all the hot wires from the fuse box and cleaned and tightened some of the female spade connectors where I didn't think they were tight enough. Did the same with the brown section (ignition switch on). Only connector that I can't check is G121 which is behind the glove box. I can see it and touch it with my finger tips but the AC equipment is in the way.

Still only getting about 10.5 volts at the ECU

From what I can gather from the wiring diagram the only things being fed power through the ignition switch now are:

trigger on new starter relay
coil
cold start injector and thermal time switch
ignition ECU
fuel ECU
fuel relay trigger

I wouldn't think that any of these are big loads

Will do some more checks tomorrow to see where the voltage drop is occurring.
 

·
Administrator
Joined
·
18,177 Posts
If you have not already/recently done so, clean & secure the following: both battery cable connections at the battery, battery negative cable's connection to the body (in the trunk sort of hidden beside/behind the battery, positive cable's connection at the starter motor (do this with the battery disconnected), ground strap between bell housing & transmission tunnel (under the car), red wire's connection at the starter motor (battery disconnected), red wire's connections in the junction box on the left inner fender, two gangs of black wires to the engine block (one group under a bolt for the AAV, one group under a bolt in the right rear side of the block).

While doing all the above, charge the battery. With everything off a fully charged battery should show 12.6V (voltmeter on the battery - not a dash gauge). Our '84 Spider reads ~ 11.8V during cranking (at the battery).
 

·
Registered
Joined
·
315 Posts
Discussion Starter · #20 ·
Thanks Eric. I have been following your diagnostics paper so I have done all those things you mentioned. Still questioned whether I had other issues so tried to check everything I could in the complete circuit.
I do not get as high of a cranking voltage at the battery so I either have a less robust battery or I have higher draw at the starter or elsewhere.

Will recheck voltages tomorrow.
 
1 - 20 of 83 Posts
Top