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Discussion Starter #1
Well my friend after receiving the 1988 alfa romeo spider veloce back after about 3 weeks called to explain it wouldnt start, I went over and started diagnosing the problem, no spark and no injector pulse was found, I then checked all grounds except for ecu's and checked to make sure battery fully tested and enough voltage during cranking and tested both crank/flywheel sensors all tested good, moving on I all of a sudden gained spark where before I had no spark from coil and no spark of corse at plugs but then all of a sudden I had perfect spark out of no where, tried starting, still no start found I still had no injector pulse. I had a hunch it was a faulty ignition ecu so I started taking panels off to gain entry to check harness connections, all where nice clean and solid, put back together still no inj pulse/no start then all of a sudden it started and had good inj pulse. She then ran for about 10 mins then died and had no inj pulse again and no start, I called my friend/customer and explained it needed to be brought to my shop. He got home that night and the car started and ran perfect with no stall, 2 days later he tried again and drove it with no problems, I explained to him do not drive it as the problem is still there, now the car is here at my shop.

Today went out to start, no start no inj pulse 1 min later had inj pulse, car ran idle for 5 mins and died then, started back up and now has not stalled since. I cannot test inputs to ecu for problems I explained so far until problem is there. I'm still almost sure of a faulty ignition ecu but I need to test inputs to it first. With that said the diagrams do not help when no electrical values are given, ie: just because I probe lets say pin 8 ( no real test just as example) on the connector not attached to ecu and lets say I where to get 7vdc this doesnt mean anything without something to compair it to. The alfa service manual is lacking way to much it almost seems it was designed for not so in depth techs to me at least. Their diagrams are also a huge mess to follow. At this point I have no need/use for wiring diagrams I just need pin outs for complete inputs/outputs to/from ignition ecu with VALUES....... does any one have this? I know paperjam has better diagrams but I still need reference values.

If the car fails to act up long enough for testing the only thing I can do is go on my professional feeling and at min replace the ignition ecu. Not sure about fuel ecu. Which one fires the injectors? I know the ign ecu fires spark but which for the injectors?:confused:

Thanks,
Joe
 

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The link in my signature will take you to a page of information about the L-jet system in our Spiders. It includes the ohm or volt readings you should need. If you add PapaJam's wire diagrams to that info you can do a volt/ohm test at the computer's harness connector to make sure the electrons are getting all the way through the wire harness to the computers. Just make sure not to apply your ohm meter to the computer itself. It is rumored stray electrons thus introduced can be detrimental.

The most common issues with our cars are intake air/vacuum leaks, poor grounds & faulty electrical connections. The ECU's (there are two) are pretty robust. I would not immediately jump to replacing them but rather test all the components/sensors & their electrical connections to the ECU. The fact it'd run sometimes would tend to make me think it has an iffy electrical connection somewhere. Good luck finding intermittant problems... Try wiggling/tugging at the various connections while the engine is running. If it stumbles or dies then look really close at which ever item you fiddled with.
 

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Discussion Starter #3
The link in my signature will take you to a page of information about the L-jet system in our Spiders. It includes the ohm or volt readings you should need. If you add PapaJam's wire diagrams to that info you can do a volt/ohm test at the computer's harness connector to make sure the electrons are getting all the way through the wire harness to the computers. Just make sure not to apply your ohm meter to the computer itself. It is rumored stray electrons thus introduced can be detrimental.

The most common issues with our cars are intake air/vacuum leaks, poor grounds & faulty electrical connections. The ECU's (there are two) are pretty robust. I would not immediately jump to replacing them but rather test all the components/sensors & their electrical connections to the ECU. The fact it'd run sometimes would tend to make me think it has an iffy electrical connection somewhere. Good luck finding intermittant problems... Try wiggling/tugging at the various connections while the engine is running. If it stumbles or dies then look really close at which ever item you fiddled with.
I think I need to back up and explain I have been over just about every inch of this car before, I did a complete mechanical restoration on it and tested every sensor on the car. I have not found any bad/dirty/loose connections even at the ecu's, I am aware of both ecu's on the car. I still need to know which one controls the inj pulse/fuel injectors. That l-jet system page actually has no bearing on testing anything to do with this problem what so ever (no offense) but truly it does not have anything to do with ecu and inputs testing.

At this moment the car is no longer starting which is good for testing, no injector pulse at the moment, this is the confirmed problem with the car. The car is no longer loosing spark only inj pulse is now lost when problem developes.

Thanks,
Joe
 

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Discussion Starter #4
Ok, now since the car is having the fault I could begin testing the system with the flow chart where as before I could not, all tests are yes and test correct to specs at bottom of chart through findings leads to "replace ignition ecu" since car is giving the problem now I was able to diagnose the problem where not before, however I need to know does the ignition ecu or fuel ecu control the fuel injectors system/ fuel injector pulse?
 

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The fuel ECU, Bosch 0 280 000 221, controls the pulse width.

Question; with KOEO, is there battery voltage at one of the injector wires?
 

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Discussion Starter #6
The fuel ECU, Bosch 0 280 000 221, controls the pulse width.

Question; with KOEO, is there battery voltage at one of the injector wires?
Yes, battery voltage at both terminals.......

Does the ignition ecu pass to the fuel ecu? What I am wondering since the one no spark issue is that if the ignition ecu would be bad/faulty if it could effect how the fuel ecu reacts as well......
 

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I I still need to know which one controls the inj pulse/fuel injectors.
Perhaps it is a big assumption on my part but I believe the FI ECU controls the fuel injection portion and the ignition ECU controls the ignition portion.

lousy sketch from Alfa Shop Manual:


That l-jet system page actually has no bearing on testing anything to do with this problem what so ever (no offense) but truly it does not have anything to do with ecu and inputs testing.
You'll have to try a lot harder to offend me!

Agreed - the L-jet page is designed more for the DIY home mechanic. 99% of the problems with our cars can be sorted out by running through all the tests outlined. Note that L-jet is a system and thus all the bits have to work right for it to work at all. That is why I suggest going through everything and not focusing too much on any one aspect.

At this moment the car is no longer starting which is good for testing, no injector pulse at the moment, this is the confirmed problem with the car. The car is no longer loosing spark only inj pulse is now lost when problem developes.
The main relay (located next to the FI computer is also involved in controlling the fuel injectors. I think that one is a 'standard' Bosch relay so it should be easy to replace. Just make sure it is the same - some have terminals 87 & 87A, some have two terminals 87. And I don't recall offhand which one is the 'right' one...

And of course as our cars get older I suspect we will be seeing more faulty computers. Usually they are not intermittently faulty however. But if all inputs are verified as good then the only thing left is a faulty computer. Unfortunately I do not know of any real-world way to test the computer. All we can do is make sure everything else is 100%.
 

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Discussion Starter #8
Perhaps it is a big assumption on my part but I believe the FI ECU controls the fuel injection portion and the ignition ECU controls the ignition portion.

lousy sketch from Alfa Shop Manual:




You'll have to try a lot harder to offend me!

Agreed - the L-jet page is designed more for the DIY home mechanic. 99% of the problems with our cars can be sorted out by running through all the tests outlined. Note that L-jet is a system and thus all the bits have to work right for it to work at all. That is why I suggest going through everything and not focusing too much on any one aspect.



The main relay (located next to the FI computer is also involved in controlling the fuel injectors. I think that one is a 'standard' Bosch relay so it should be easy to replace. Just make sure it is the same - some have terminals 87 & 87A, some have two terminals 87. And I don't recall offhand which one is the 'right' one...

And of course as our cars get older I suspect we will be seeing more faulty computers. Usually they are not intermittently faulty however. But if all inputs are verified as good then the only thing left is a faulty computer. Unfortunately I do not know of any real-world way to test the computer. All we can do is make sure everything else is 100%.
Unsure on fuel ecu testing, I'll have to look over the manual again to see if I missed that. However back to the problem I doubt a problem with the relay but I will check that the reason I say this is that relay should have no bearing on spark unless 2 sep problems going on.

before when it ran perfect the problem it had was that sometimes the first cold start of the day would be a hard start where lets say you would have to crank for 1 min off and on before it would start, then possibly start then stall but then would have no problems and would run perfect, this only happened every now and then not all the time and I tested everything I could at the time and could not locate any problems since problem would resolve so fast, I have a feeling that problem was related to this one.
 

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Discussion Starter #9 (Edited)
Eric there are two relays there, I know one is for the fuel pump(s) now I can assume the other is for the injectors? So there is only one relay for both fuel pumps then.

Both relay's are engaging. Havent tested them past that yet.
 

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The 'drive relay' (I think it the physically bigger one) gets a tachymetric signal from the coil and it then controls both the power to the fuel pumps and is also linked to the main relay which is involved with injector control. (sorry, I'm at work and don't have all my resources with me to give you more than my poor recollections of the circuitry)

PapaJam's wire diagrams show all the external connections. A smart guy should then be able to figure out who does what. (hehe - no offense...! :p)
 

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Discussion Starter #11
The 'drive relay' (I think it the physically bigger one) gets a tachymetric signal from the coil and it then controls both the power to the fuel pumps and is also linked to the main relay which is involved with injector control. (sorry, I'm at work and don't have all my resources with me to give you more than my poor recollections of the circuitry)

PapaJam's wire diagrams show all the external connections. A smart guy should then be able to figure out who does what. (hehe - no offense...! :p)
Oh, a funny guy!

What I have is battery voltage to each side of the fuel injector connector my belief is that the one side during cranking should switch to neg as the pulse width/injector neg pulse signal....... correct? And in which it is not doing....
 

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Correct.

Does the ignition ecu pass to the fuel ecu?
No.
The fuel ECU receives it's engine running signal from coil negative terminal.

Power to the injectors during KOEO means that at least one (of two) #87 output terminals on the main relay work (the main relay is the small one). The other #87 terminal powers the fuel ECU via a red and a red/black wire to pins 29 & 10 respectively.
If you take the connector off the ECU to check these voltages, also check the resistance to ground on pin 13 (coolant temp signal).
 

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Discussion Starter #13
Correct.



No.
The fuel ECU receives it's engine running signal from coil negative terminal.

Power to the injectors during KOEO means that at least one (of two) #87 output terminals on the main relay work (the main relay is the small one). The other #87 terminal powers the fuel ECU via a red and a red/black wire to pins 29 & 10 respectively.
If you take the connector off the ECU to check these voltages, also check the resistance to ground on pin 13 (coolant temp signal).
Going to check those now
 

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Discussion Starter #14
Correct.



No.
The fuel ECU receives it's engine running signal from coil negative terminal.

Power to the injectors during KOEO means that at least one (of two) #87 output terminals on the main relay work (the main relay is the small one). The other #87 terminal powers the fuel ECU via a red and a red/black wire to pins 29 & 10 respectively.
If you take the connector off the ECU to check these voltages, also check the resistance to ground on pin 13 (coolant temp signal).
Ok, pins 29 and 10 both have battery voltage with koeo......

Pin 13 has 1.26-1.27kohms to ground...
 

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Okay, readings so far are as they should be.

Is it possible for you to connect a dwell meter to ECU connector pin #1 and get a reading?
 

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Discussion Starter #17
Okay, readings so far are as they should be.

Is it possible for you to connect a dwell meter to ECU connector pin #1 and get a reading?
Man your going old school, luckily I just so happen to own a dwell meter, I have no idea how to use it though, I have a pos and neg connections which I assume go to the battery, then the lead connection I go to pin 1 with it?

What setting? dwell, tach lo or tach high? and I then set to 4cyl I assume.

Also I assume this is pin 1 on the fuel ecu with conector removed from ecu and on the connector side correct?
 

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Discussion Starter #18
I set dwell meter pos to battery pos and neg to battery neg then the lead connection to pin one harness side removed from ecu, now with ignition off I show around 85% dwell angle and 0 with key on, this is set to dwell and 4 cyl
 

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Do you get a dwell reading when cranking the engine?

The purpose here is to verify pulsing signal to ECU from coil negative. The value/reading/dwell number is not important (don't know what it should anyway but a points ignition should be about 60 degrees). What is important is whether or not there IS a signal.
 

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Discussion Starter #20
Do you get a dwell reading when cranking the engine?

The purpose here is to verify pulsing signal to ECU from coil negative. The value/reading/dwell number is not important (don't know what it should anyway but a points ignition should be about 60 degrees). What is important is whether or not there IS a signal.
No dwell, no, as I was explaining before with key off is when you get dwell with key on it kills the dwell to 0 so cranking remains 0, now if you switch the meter to lo tach then yes you get a signal only during cranking, just under 100 rpms..... Same response from tach on cluster while cranking...... Note that rpms on tach is usually a good indication of a working crank sensor.
 
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