Alfa Romeo Forums banner
1 - 20 of 27 Posts

· Registered
Joined
·
11 Posts
Discussion Starter · #1 ·
Been using the wiring diagrams from here and they are a great help. My spider CTS circuit differs however. On the diagram, the CTS connects to pin 13 on the ECU. I have no continuity (infinite reading) from either wires at the CTS to ECU pin 13. So I have a break in the wire. Now, I cannot seem to deduce which wire at the CTS corresponds to #13. The other side of the CTS, according to the diagram, goes to the altitude unit jumper and to ECU pin #9. My ECU lacks the #9 pin so I'm in the dark. Wire colors are different. Thanks for any help on this.
 

· Registered
Joined
·
11 Posts
Discussion Starter · #3 ·
Looking at the wire diagram for our '84 Spider, the other wire from the CTS is grounded (at the cam cover per note). I wonder if/why that was changed for your model...?
At my CTS, I have a black wire and a brown(maybe orange) wire. Zero continuity from either to pin 13 on ECU. I just confirmed that the black CTS wire has continuity to ground. If I could figure out which wire is supposed to go from CTS to 13, then I can provide a good connection. I don't want to take chances with these ECU's so I must be sure before any attempt. I am about to assume that the orange (maybe brown) CTS wire should go to ECU pin #13.
 

· Registered
Joined
·
11 Posts
Discussion Starter · #6 ·
yes brown to pin #13 ecu
black to main ground bundle on passenger side of head (maybe to AAV, depends)

did you test from pin #13 to ground like post 5 here (this is a Milano thread but it must be the same)?
!you are testing the ecu connector plug!
how to test cts to ecu circuit?

there are two CTS
FI Coolant temp sensors
Thank you! Yes I have done as suggested in post #5; Yes the FI CTS. Definitely no continuity either from ECU pin 13 to ground or to the FI CTS before or after its connector. Both sides, the ECU connector and the CTS connector were tested before the connector at the wire as well as at the connector contact.

I am going to try to run a test wire from ECU pin 13 to the FI CTS brown wire.. see where that leads me.

I appreciate you guys tremendously - I've been troubleshooting this car for a while now. This absence of pin 13 to CTS continuity is the only thing that I've found wrong. The car runs and drives well, and starts well on cold start. But once shut off, after any amount of time running, it will start and die and not restart. Got a dim noid light on cranking as the service manual states normal; all sensors test OK; fuel pressures OK; air leaks eliminated as per initial troubleshooting. The car is relatively nice but for this one issue. It's a great driver.

Despite the service manual stating that a dim noid light is normal on cranking, I did measure 9.5v at ECU pin #1 while cranking. (That will be my next post after this CTS wire fix proves futile *sigh).
 

· Premium Member
Joined
·
3,441 Posts
Not trying to be a smart *** but are you sure that your meter is working in that mode? Many meters have a fuse for the continuity to protect them. I have seen that before. Just a thought.
 
  • Like
Reactions: ARCDuetto

· Premium Member
Joined
·
2,506 Posts
It’s my understanding, though I have no personal experience, that Ljet cars will not start at all if the CTS is disconnected, (Greg Gordon’s article says will not run when disconnected) which is basically what your wire testing indicates.
So the fact that your car does run is a curious detail.
On your ecu plug, the position you think is 13, is there a brown wire going to it? In post one, you mention pin 9 has no wire but should, what colour wire should it be and what pin is it actually going too?
 

· Registered
Joined
·
11,711 Posts
I don't have a wiring diagram for the '87, but the '88 diagram shows:
on the fuel ECU, pin #9 would have two blue/white wires: one goes to AFM and the other to the Altitude compensation device (Alt. comp. device came about MY84 and later, iirc)
It would be odd if that pin is blank?
(unless you are mixing things up with the Ignition ECU, where pin #9 is indeed blank)

@ARCDuetto : does your MY87 have two CTS
numbered #38 and #40 on this diagram?
Text Line Font Circle Diagram


btw: the Greg Gordon jetronic article only mentions one CTS.
Although I am not so sure the car won't run with the CTS unplugged?.....someone?
 

· Premium Member
Joined
·
3,441 Posts
Now I am confusing myself. I just looked at an 85 and an 86 and they all look exactly like the diagram that Dom showed in his last post. I think I have been looking at Motronics too much lately.
There is a coolant temperature sensor between injectors 2 & 3 for the ignition that connects to terminals 12 and 13 of the ignition ECU via tan and Orange/Black wires. The other CTS for the Fuel ECU between injectors 3 & 4 does ground out at the head and goes to terminal 13 of the fuel ECU via a brown wire.
 

· Premium Member
Joined
·
3,441 Posts
SOrry everyone it's all starting over from scratch now that I've begun testing the correct ECU. Damnit. It's not my fault - I'm dumb hahaha!
Okay, do you have the correct wiring diagram?
 

· Registered
Joined
·
11 Posts
Discussion Starter · #14 ·
Okay, do you have the correct wiring diagram?
I have the one provided by this site, which is pretty good, and states "Alfa 2000 Spider Veloce 1987 Model 11541". But, it doesn't quite match up and I do have some unanswered questions. Primarily, I am using the Bosch L-Jet Fuel Injection Troubleshooting Maintenance and Repair manual (Bosch 1 987 722 160).
 

· Premium Member
Joined
·
3,441 Posts

· Registered
Joined
·
11 Posts
Discussion Starter · #18 ·
Everything in the FI system passes every test. So that was fun. But check this out-

I just found a strange looking hidden wire!! Apparently, someone rigged the cold start injector to continuously spit fuel into the manifold while cranking by grounding out the TTS to CSI wire. The car would start, then die (too much fuel), then crank crank crank crank but no start (waaay to much fuel). Disconnect the hidden, grounded out wire, which someone had soldered in prior and the car fires up. I'm going to test the CSI and TTS after the car cools down and fix whatever, if anything... put the thing back to normal. The CSI test light 1-8 second while cranking below 95 deg F revealed this problem. I have no idea why someone would want to ground out the wire - probably in a attempt to solve a previous issue like an air leak. (I repaired numerous air leaks when I first got the car).
 
1 - 20 of 27 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top