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Discussion Starter #1
hi, i hope one of you can help me. i know nothing about early computerized or foreign cars. the car is a 1986 spider and the rear 2 cylinders have no injector pulse. it runs rough and eventually dies down if i don't give it gas, it has spark across all 4 cylinders although it is weak sometimes. i suspect the ecu. any help is welcome.
 

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It could be the ecu but it could be the connector at the ecu. Buy a can of Deoxit and use it and Q-tips to clean them up on both sides of the connector.
 

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I can't remember on the Bosch Spiders, but on the Milano there is a single ground for each two of the six injectors (so three grounds). Can't remember if it was only one or if it is two ground wires on the Spiders.

It is possible it is the ECU but in my experience the Bosch ECUs are quite reliable and I've never had one go bad, it has always been something else, wire, sensor, etc. As Ed mentioned above, you could pull the connector off the ECU and clean them. Did you in fact prove that the rear two don't actually get a pulse (with a noid light or something) or are you guessing?

Kevin
 

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Discussion Starter #6
yes, it was proven with a noid light. i read on a page that was linked from this forum, the ecu's are fairly delicate and can be damaged only by testing resistance on circuits with a multimeter, is it really not safe to test resistance or is that just hear-say?
 

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Discussion Starter #7
new update. there is a long relay in the back of the cabin, under the area the top folds, into next to the FI computer. unplugging it makes all the injectors pulse. this has not been confirmed with a noid light however there is a change in idle behavior when each of the previously dead cylinders' spark-plug wire is removed. does anyone know why/what that relay does?
 

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There two relays next to the FI computer. The drive relay is used to power on the fuel pumps and the main relay controls the injectors. I suspect you are looking at the main relay. If, indeed, only two of four injectors are firing then I suspect either a faulty main relay or an electrical connection from the main relay.

I suggest you contact BB member Papajam (send a Private Message) and ask for copies of his color coded wire diagrams. Include your email address and he send you some pdf files that will help chasing where Alfa electrons are supposed to go.
 

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Discussion Starter #10
New update. i took a similar relay that had 2 extra pins from a old Chrysler and tried to start it with that one but no start. and now it wont start with any relay. no spark at all and no injector pulse. could wrong relay have fried the computer
 
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