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Discussion Starter #1
I have an 85 spider L-Jetronic, i cant get it to start. I have no power on the fuel pump and on the injectors. Is there a relay that control those?
I know there is fuse for the pump, but its in good shape. Can anyone give me some tips?? There are 2 relays by the CPU (one tall one short) are those related???
 

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Look here: Spider L-jet diagnosis

Note that the info about fuel pump control in that page needs to be edited. The 'drive relay' (near the FI computer) gets a signal from the coil to send power to the fuel pump. This relay is unusual in that the signal it is expecting must vary - as the ignition system energizes & discharges the coil the signal to the drive relay oscillates. If no ignition firing = no signal to drive relay = no power to fuel pump.

The drive relay (and thus the fuel pump) will energize briefly when you first switch the key to 'on'. The drive relay reads this initial energy flow as one "oscilation". But then the drive relay switches off (and thus the fuel pumps remain off) until you begin cranking the engine and the ignition system begins functioning.

Note that the ECU (computer) needs a certain minimum voltage to wake up and begin sending the igniton signals. This threshold is about 10.3V If available voltage drops below that threshold during cranking, no ignition, & no power to fuel pumps.

Also, the bullet style fuses in our Spiders can look OK but still not actually work. Replace it anyway.
 

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Discussion Starter #3
Thank you for the info, but do you know which relay (if any) is controlling the injectors signal. In other words, it seems that I have not current at the plug for the injectors. I need to go back and verify the voltage at the CPU (10.3V), so that I can exclude it as a variable, behind that I dont see why the car will not start.

I try the starter fluid, and the car ran fine for a while...with direct current to the fuel pump.Wich made me think that there is not current at the pump and for sure at the injectors (after Voltage measurament). What you suggest I do? I am a little confuse and/or lost.



Look here: Spider L-jet diagnosis

Note that the info about fuel pump control in that page needs to be edited. The 'drive relay' (near the FI computer) gets a signal from the coil to send power to the fuel pump. This relay is unusual in that the signal it is expecting must vary - as the ignition system energizes & discharges the coil the signal to the drive relay oscillates. If no ignition firing = no signal to drive relay = no power to fuel pump.

The drive relay (and thus the fuel pump) will energize briefly when you first switch the key to 'on'. The drive relay reads this initial energy flow as one "oscilation". But then the drive relay switches off (and thus the fuel pumps remain off) until you begin cranking the engine and the ignition system begins functioning.

Note that the ECU (computer) needs a certain minimum voltage to wake up and begin sending the igniton signals. This threshold is about 10.3V If available voltage drops below that threshold during cranking, no ignition, & no power to fuel pumps.

Also, the bullet style fuses in our Spiders can look OK but still not actually work. Replace it anyway.
 

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The large relay back by the ECU is what sends the trigger signal to the small relay, which in turn gives the + voltage to the injectors while the ECU proper cycles them on and off via ground signal interruption.
 

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Discussion Starter #5
OK, Guys, I try everything but I still cant get this spyder to start. I need the your expertise. I checked the voltage and is ok. I get 11.3V, for the ECU, I replaced the fuse for the fuel pump.... but still cant get it to start.
One more guess, please correct me if I am wrong, the cold start sending unit will not let the car start, if it is damaged. I purchased this care after it was overheated....and I mean lots of heat to the point that Head was warped.
DO you think the CTS or the TTS could be at fault here and not allowing my car to start. I really dont know what else to do???

Please help,
Thank you
 

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Back to basics....
1. Have you removed 31 plug and checked for spark?
2. Have you checked for fuel delivery at the fuel rail or at least through the pump (and filter)?
3. What about your inertia switch? Make sure you have connectivity through the switch (bypass the switch during your troubleshooting). I had a problem with my interia switch on an 82 that came out of nowhere....car just wouldn't start one day. Bypassed the switch and it fired right up.
 

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Discussion Starter #8
I got Spark on # 1 and I have fuel in the rail...I will try the bypass switch ( that may be a good idea).
How can i check if the injector are firing.... Can I get a measurament on the INjector harness....(either Ohms or Voltage)??
 

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Discussion Starter #9
Is there a way to test the harness that supplies current to the Injector?. I am starting to think that the problem lies in the Injector current. Thank you all for your inputs, but I have this problem for a 3 weeks, and I cant solve it.
 

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If you have fuel to the rail, the inertia switch is good.

Try pulling the Cold start injector (easiest to get at) and start the car (cold engine) to see if you get fuel out of the CSI. Suggest you put the CSI in a container of some sort so you don't spray fuel around your engine compartment.
 

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Discussion Starter #11
DGhii,

I have done so already and the CSI is praying fine. The problme lies in the Fuel pump not running. But when I bring direct current at the pump i can here the pump run fine. So I think I dont get current to the pump.
 

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Get a Bosch test NOID wafer from auto store and test injector Bosch connecter for flashing light when starting engine. Flywheel Sensor in bellhousing maybe a problem.

If fuel pump not working you probably need a new drive relay.
 

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... I purchased this care after it was overheated....and I mean lots of heat to the point that Head was warped. ...
Since the car had a traumatic incident, what have you done/checked to assess the condition of the engine?

Let's start with the very basic ... Did you pull the spark plugs? How do they look? Any coolant in the cylinder or oil ... Have you done a compression test? ... etc. ... In short, are you sure the engine can start and run after the incident?

You said the problem seems to be the fuel pump not running. Hardwire the fuel pump to run all the time and can you start the car? (The '86 that I'm working on is hardwired by PO, fuel pump goes on with the ignition key turns to ON :eek:!)

BTW, 11.3V is not very healthy if that is the battery supply to the ECU!

Bob
 
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