86 Alfa Spider Veloce Ignition Computer (Behind Driver and Passenger Seats) - Alfa Romeo Bulletin Board & Forums
 5Likes
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 39 (permalink) Old 05-10-2017, 06:10 PM Thread Starter
Registered User
 
Join Date: May 2017
Posts: 45
86 Alfa Spider Veloce Ignition Computer (Behind Driver and Passenger Seats)

Hello Alfa Community!

I just has an ignition computer replaced 1yr. ago (I don't drive the car very much. Maybe 6-7 times within that yr after replacing). After I start the car for the first time of the day, drive for a while, park it (wait 15-20 min) and car wouldn't crank. I know the fuel computer works. So I took it to my mechanic they ran diagnostic and found something to the extent of the ignition computer. The car still drives but sometimes it will choose when it wants to crank or not. My mechanic says it goes into it's limp mode. He did say that you can still drive the car but when it acts as if it doesn't want to crank, put the plug out of the ignition computer (wait 10 sec) and plug it back in and car will start right up. Anyway, my mechanic seems to think it's a computer compatibility issue. I would think that if he's right, then why did it take this long to figure out if it was compatible or not. It was working for a while with the new computer in.

Last edited by dancerodie; 05-10-2017 at 06:12 PM.
dancerodie is offline  
Sponsored Links
Advertisement
 
post #2 of 39 (permalink) Old 05-10-2017, 07:24 PM
BB Janitor
Platinum SubscriberAdministratorSuper Moderator
 
ghnl's Avatar
 
Join Date: Oct 2005
Location: Mebane, NC
Posts: 16,266
Garage
Welcome to the BB. I am not aware that either computer (there are two - the one behind the seat is the fuel injection computer, the ignition computer is behind the right side panel) has any sort of 'limp home mode'. They do have a basic fuel/ignition map that they will use if the inputs are not valid - perhaps that is what he means? And, switching off the ignition should have the same effect as unplugging the wire harness connector.

Let's clarify some terms. When you say 'it won't crank' do you mean the starter motor turns the crankshaft but the engine won't start? Or do you mean you turn the key to the start position and nothing happens - the starter does not operate & the crankshaft does not turn?
rogerspeed and miami592 like this.

- - Eric
don't read this
~ 1984 Spider Veloce ~
- -~ 1981 GTV-6 ~
Mebane, North Carolina


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
ghnl is online now  
post #3 of 39 (permalink) Old 05-11-2017, 12:08 PM Thread Starter
Registered User
 
Join Date: May 2017
Posts: 45
Engine won't start. Car makes noise. I understand your position about the two computers. Looks as though I had them backwards. I'm not even sure what he means by "limp mode" guess it was something he came up with( I don't know). Maybe just car not working.
dancerodie is offline  
Sponsored Links
Advertisement
 
post #4 of 39 (permalink) Old 05-11-2017, 12:12 PM Thread Starter
Registered User
 
Join Date: May 2017
Posts: 45
So I guess that would mean (when I said pull the plug out of the ignition computer) I mean "Pull the plug out the the fuel computer" since I had them backwards.
dancerodie is offline  
post #5 of 39 (permalink) Old 05-11-2017, 12:21 PM
Senior Member
Gold Subscriber
 
sloboy89's Avatar
 
Join Date: Feb 2011
Location: Dallas, Texas
Posts: 1,686
Garage
Quote:
Originally Posted by dancerodie View Post
Engine won't start. Car makes noise. I understand your position about the two computers. Looks as though I had them backwards. I'm not even sure what he means by "limp mode" guess it was something he came up with( I don't know). Maybe just car not working.
Modern cars sometimes have a "limp mode," so it is a thing. But I don't believe that the Bosch L-Jet system in your Spider has anything like that. (And I don't believe that there is any computer diagnostic system that can be run on the L-Jet computers). I'm concerned that your mechanic may be a bit over his head in dealing with the problem. There are many individual tests for the various sensors that are the inputs to the L-Jet system. Normally, the problem is not either of the computers, but rather, one or more of the sensors (or fuel pump, or relays, or something else). My suggestion would be to get the car back from the mechanic and step through the L-Jet diagnostics page here to see if you can diagnose the problem yourself.

Rich

'85 Spider Veloce
'17 Giulia Ti Sport
sloboy89 is offline  
post #6 of 39 (permalink) Old 05-11-2017, 12:30 PM
BB Janitor
Platinum SubscriberAdministratorSuper Moderator
 
ghnl's Avatar
 
Join Date: Oct 2005
Location: Mebane, NC
Posts: 16,266
Garage
OK, removing & replacing the plug from the computer isn't doing anything. Well, it gives you something to do that makes you think you've done something...

Again, trying to be very clear, when you turn the key to 'start' does the engine make the normal R-R-R-R sound or does it sound abnormal? A known problem area is the ignition switch itself. When they get old the internal contacts are not able to reliably pass the electrons needed to activate the starter motor. At first it is an occasional problem (say 1 out of 10 starts) then before long it becomes 1 out of 3 starts. There are two ways to fix this. One is to replace the ignition switch. They are not cheap and the replacements may not be of the best quality. The other way is to add a relay such that the ignition switch only has to pass a tiny amount of electricity to trigger the relay. This canmake a dodgy ignition switch work fine for many years.

If you turn the key to 'start' and the starter motor is activated (R-R-R-R-R) but the engine will not start then there is another issue that needs to be addressed. Go through all the checks outlined in the Spider L-jet Diagnosis page (link in my signature). Things to pay particular attention to are system voltage (the computers need about 10.5V to wake up and send the make spark/squirt fuel signals). It can sound like it is cranking over fine but if system voltage is below that threshold it will not start. Dirty battery connections or a slightly weak battery could affect system voltage. There is a stand-alone Cold Start System (not under computer control). It is supposed to squirt a little extra fuel on cold start and NOT squirt extra fuel on warm start. It can fail either way, both ways, one way but not the other, etc. The fuel injectors require properly regulated fuel pressure. A failing Fuel Pressure Regulator can make it hard to start cold or hard to start hot.

One other thought. There were a couple of slightly different computers used during the run of the Series 3 Spiders ('82 - '89). They will physically interchange but they might not be totally compatible. Post the numbers on both of your computers and we'll see if we can figure out if they are the correct ones for your model year Spider.

- - Eric
don't read this
~ 1984 Spider Veloce ~
- -~ 1981 GTV-6 ~
Mebane, North Carolina


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
ghnl is online now  
post #7 of 39 (permalink) Old 05-11-2017, 12:48 PM Thread Starter
Registered User
 
Join Date: May 2017
Posts: 45
I'll get those numbers for you.
dancerodie is offline  
post #8 of 39 (permalink) Old 05-11-2017, 12:51 PM Thread Starter
Registered User
 
Join Date: May 2017
Posts: 45
In and above all the other information I think my mechanic feels that it's a compatibility issue.
dancerodie is offline  
post #9 of 39 (permalink) Old 05-11-2017, 01:24 PM
Senior Member
Gold Subscriber
 
Norseman50's Avatar
 
Join Date: Apr 2014
Location: Bellevue, WA
Posts: 1,462
Garage
I don't understand what your mechanic means when he suggests it's a computer "compatability" issue. When one of the computers was changed out a year ago, was it not replaced with an identical model computer?

If the car starts up fine and idles nicely when it is cold, but when the engine is warm the starter motor turns but the car doesn't "catch" and idle, it sounds like a relatively simple "warm start" problem.

I agree with sloboy89's comment above, in that your mechanic needs to follow the L-Jetronic Diagnostic Guide that was put together by Greg Gordon and Eric Russell and is located here: https://www.hpsimotorsports.com/l-jetronic--spider-

Tell your mechanic to pay particular attention to Step 3 the cold start and warm up system because a warm start issue may be due to something as simple as a faulty TTS (which would make the CSI spray and flood the engine when warm) or an AAV that was stuck in the open position.

A more comprehensive study of the theory of operation, troubleshooting and service of your car's injection system is presented in Bosch Fuel Injection & Engine Management by Charles O. Probst ISBN 0-8376-0300-5. Your mechanic should have a copy of this book (or something better) or he may not be qualified.

Edward
'88 Quad - "Claudia"
Norseman50 is offline  
post #10 of 39 (permalink) Old 05-11-2017, 01:37 PM Thread Starter
Registered User
 
Join Date: May 2017
Posts: 45
That's the issue. He doesn't think it was identical.
dancerodie is offline  
post #11 of 39 (permalink) Old 05-11-2017, 01:38 PM Thread Starter
Registered User
 
Join Date: May 2017
Posts: 45
As ghni said "There were a couple of slightly different computers used during the run of the Series 3 Spiders ('82 - '89)"
dancerodie is offline  
post #12 of 39 (permalink) Old 05-11-2017, 01:47 PM
Registered User
Gold Subscriber
 
rogerspeed's Avatar
 
Join Date: May 2005
Location: OC CA USA
Posts: 3,585
my experience with the S-3 here in SoCal is that the computers are very durable and almost anything else could be the problem. When you crank is there spark? If there is current at the coil but it is not "flashing" (hence no spark) the problem is one of the flywheel sensors or its connections, the check for them is resistance using a multi-meter. When you turn the key "on" do you here the drive relay "click"? Have you checked that both fuel pumps work (with the key off run a test hot lead to the hot (small) terminal on the main pump, that should cause both pumps to operate. There is an inline fuse next to the FI computer, does that have continuity? Another test is to unplug an injector and then crank with a "noid light" in the pigtail, does it flash? My gut feeling is you have a faulty drive relay, When you start cold it works and continues to work as you drive but gets hot, so when restarting it doesn't work, once cold, works again.

current:
84 Spider Veloce
ex:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

solve problems, learn something new!
rogerspeed is offline  
post #13 of 39 (permalink) Old 05-11-2017, 01:53 PM Thread Starter
Registered User
 
Join Date: May 2017
Posts: 45
This is the problem. I'm not understanding. Ypu sa "FI computer" (which to me means fuel ignition). The car has two computers which one is for fuel and other is for ignition.
dancerodie is offline  
post #14 of 39 (permalink) Old 05-11-2017, 01:55 PM Thread Starter
Registered User
 
Join Date: May 2017
Posts: 45
I think you have a point though.
dancerodie is offline  
post #15 of 39 (permalink) Old 05-11-2017, 02:15 PM
Senior Member
Gold Subscriber
 
sloboy89's Avatar
 
Join Date: Feb 2011
Location: Dallas, Texas
Posts: 1,686
Garage
Quote:
Originally Posted by dancerodie View Post
This is the problem. I'm not understanding. Ypu sa "FI computer" (which to me means fuel ignition). The car has two computers which one is for fuel and other is for ignition.
"FI" means "fuel injection" not fuel ignition.
rogerspeed likes this.

Rich

'85 Spider Veloce
'17 Giulia Ti Sport
sloboy89 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Alfa Romeo Bulletin Board & Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome