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Discussion Starter · #1 ·
This old chestnut again (know I've been here before for this)...
I've got another Spider with the ole start/run for 3-4 sec./stall problem. Each time I come across this it seems to have a different cause, this one really has me stumped. Let me start by saying I've read the Bosch L-jet link provided on similar threads and checked everything accordingly, oh yes; there is fuel in the tank. Now let me tell you what I've checked (don't laugh): * all air intake hoses- large and small- no air leaks,
* popped the AAV in the freezer and oven and replaced it with a known good one- all okay but still start/stall,
* tested continuity of leads off every sensor back to the pins on the large connector at the ECU to rule out broken wire in the harness- all okay,
* swapped out the injector ECU and spark ECU with ones from a good runner which also came in for service- no change- put them back in the other car and it runs like a champ,
* replaced both relays located at the ECU,
* replaced the Air Flow Meter from the other car- no change,
* tested both coolant temp sensors for varible resistance within spec- all is good but no run,
* replaced the throttle position sensor- no change, reinstalled it using an ohm meter to insure correct positioning
* replaced (just for fun) the altitude compensator, no change,
* replaced both flywheel sensors, no change
* replaced the battery (reaching here) with one with higher CCA
* replaced the vacume advance device at the spark ECU
* checked/cleaned all grounds and connectors (even added an extra braided ground strap from head to firewall knowing how Alfas like grounds)
* checked wiring at coil, all fine and a nice fat spark...

The car is in near perfect tune and sounds great for the few seconds it runs. It has excellent spark and fuel pressure at the rail is spot on. Cold start injector circut is working as is fuel pump until the engine stalls. Just no injector pulse as confirmed by the noid light. Please guys; what am I missing? The last time I delt with this it turned out that someone had installed the wrong fuel pump relay at the ECU, not the case here. Someone must know the answer. This thing is becoming my White Whale! Help!!!
Cheers,
Two Point Oooooo
 

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Discussion Starter · #3 ·
Thanks Jim,
Diffucult, yesh. I did as you recommended and observed that the coil voltage remains steady up to and after the engine stalls and the spark continues to look fine until the engine is at rest. The noid light to the injector, however, never flashes an injector pulse. I have test the noid light via the CSI to validate its function and its fine. I can supply voltage to the injectors and they 'click' away happily and spray fuel - when instructed to do so. No joy here yet. What sensor could tell the ECU to keep the injectors off? or ??? Hope solving this will add to the considerable knowledge of these L-Jet systems as I see a lot of threads on this issue. Thanks
Ken,
'91 164L (daily driver)
'74 GTV
'67 GTV Jr.
 

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Discussion Starter · #6 ·
Thanks guys,
I'm finding that both pins on the injectors are hot. If I use a jumper wire and ground one pin the noid light flashes and the injector pulses, indicating the ground is not being provided by the ECU, no? Pin 2 at the ECU shows about 11volts from the ing switch and pin 1 has full battery power with key on. Also pin 87 on the main relay has full power. Thanks for the heads up on the different ECUs as I had exchanged one in this '88 for one from an '82. I have since replaced it with a green tagged one from an '85. Still no go. Also switched out the ingnition switch with no success but it was a red/brown/green/2 blacks one and the one in the '88 is a red/brown/black one. Only hooded up the main 3-terminal connector on the switch to see, but no go. Hate to send this car to another shop and concede defeat (and watch the owner get blead dry). But I'm out of theories. Any other suggestions? Please...
Cheers,
Ken
'91 164L
'74 GTV
'67 GTV Jr.
'79 Lancia Zagato
2 Citroens, 2 Panhard Dynas, VW bus
divorced (go figure)
 

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Discussion Starter · #9 ·
Well you were spot on about a ground fault. It turned out to be a ground wire from the tachiometric relay to the ECU. Not sure how that became detached or even where it was supposed to ground except through the ECU (my wiring diagram is not clear on this). Splicing into that black wire and grounding the other end to the body at the ECU and the car started right up and is now running fine. Thanks again for the help. I reckon there'd be a lot fewer Alfas on the road and a lot more Italian lawn ornaments around without you guys. Cheers, Ken
 
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