Alfa Romeo Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
Hi all,
New to this very nice site. Have a 24v engine from 164 I have installed in a LB Stratos kit and am having issues starting her up . Suspecting that the ECU needs a signal from the immobilizer ( which I am not using) to start. See that ECU pin 81 goes to the immobilizer controller . Have tried grounding it to no avail . Does anyone know if putting 12 volts to that will help or hurt??
 

·
Registered
Joined
·
2,750 Posts
It was a long time back, but I did mess with a 24V 164 that had 'issues'. I recall that the immobiliser (assuming it is the OEM Alfa CODE system) communicates with the ECU using a serial protocol rather than just a simple volts or ground type setup. I also recall that the two units are coded together - you can't mix & match parts without getting the pair synced up.

Lacking the CODE unit, unless you can get the ECU reprogrammed, I don't think you are likely to get any joy with it. Is Gus from Alfatune still on here? He could certainly advise if not actually sort it for you.

You may be looking at sourcing a complete ECU/CODE/keys set, or perhaps going aftermarket ECU to get you going.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #4
Thanks for the info Chris. I can check with them .
I do know of another kit that is using the 24v engine and ECU and had no problems , so it can work . He has a different part number of ECU , I might look into that as well . The funny thing is I even have a pulse from the ECU to the ignition amplifiers and a running fuel pump !
 

·
Registered
Joined
·
2,750 Posts
I guess it depends on whether the donor had the CODE immobiliser or not. The 155 V6 from the same era had the same ECU, but came without CODE until 1996. I was fault finding on my own 155 many years back and swapped in a non-CODE ECU. It ran fine.

It’s probably just not firing the injectors.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #6
Well here is what is strange. It is firing the injectorsvas we smell fuel from the exhaust pipes when we crank it over. Plus, I can detect a rhythmic pulse from the ECU at the inputs to the ( new ) ignition amplifiers that trigger the coils!!
12 volts to the coils and grounds verified too ! Now what ??
 

·
Registered
Joined
·
2,750 Posts
Mmmm, now that is weird....

OK, start with the basics - assume nothing.

Did you strip this engine & ECU from the donor or did you buy it from someone else as a package?

What sort of fuel pump are you using?

What fuel pressure are you seeing?

Have you checked for actual sparks?
 

·
Registered
Joined
·
8 Posts
Discussion Starter #8
I bought the engine ( a new one), ecu, fuel pump etc all from an Alfa specialist in Detroit I have know and worked with for years . The ecu and harness came from a running car. The pump is a new Bosch pump, I have not checked fuel pressure but we smell fuel from the exhaust as we crank the engine over . We did remove a plug & coil and checked for spark during cranking and have none . I have run through tests many tests in the Alfa manual and have found no issues wrong . Even tried another ecu, same result .
 

·
Registered
Joined
·
2,750 Posts
Worth checking fuel pressure.

I was once asked to help start a V6 (a 12V a mate owned). He’d fitted a low pressure pump. It stank of fuel but wouldn’t run. Not surprised given it only had 2psi of fuel pressure.

What has the supplier got to say about it?
 

·
Registered
Joined
·
8 Posts
Discussion Starter #10
He has been very helpful, supplied me with a second ecu to try. All the coils ,relays, ignition amplifiers, fi/spark harness is new . I will check fuel pressure to be sure , assumed it was good with a new pump, but things happen !!
 

·
Registered
Joined
·
8 Posts
Discussion Starter #11
Well, fuel pressure about 40psi when cranking, check valve holds it at about 35 afterwards.
checked it twice . Tried to get engine codes out but doesn’t seem to record at cranking speed. Tried both ECU’s, same result . !?!?
 

·
Registered
Joined
·
2,750 Posts
Fuel pressure good then.

Next has to be absolute basics.

Check for a spark - remove a coil pack and rig it up so the wiring is restored and the plug base is grounded. Crank it and look for a fat healthy spark.

Check for an injector pulse - a NOID if you can get one, or failing that, rig up a bulb or LED across an injector. Crank and look for a pulse.

If it has fuel and sparks, it has to run...unless there is something fundamentally wrong with the mechanical basics - cam timing being most likely, but check compression too.
 

·
Registered
Joined
·
2,750 Posts
Given it was a North America car, I'd guess the donor had the check engine light and push switch on the column shroud? If so, you could replicate that for easy code reading. I fitted one to my 12V V6 when I had one on the OEM ECU in the Stratos to start with.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #14
I found the lead for the check engine light and hooked it up, however at cranking speed i am not sure if the ecu will detect codes . I tried to retrieve them and the light did not blink as I was expecting .
 

·
Registered
Joined
·
2,750 Posts
If the CEL setup is working right, you should at least get the 4 4 4 4 flash sequence to indicate no stored faults.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #16
Well, the engine now starts !!! A friend of a friend had an experienced engine guy I heard of . He stopped by and went through his non start sequence and found what I had thought I checked and missed, a bad relay !! Kind of embarrassing as I’m sure I checked it , but maybe I was looking for bigger problems , a mistake easily made . The other good news is the immobilizer fears I had are unfounded . I have tried two ECU’s now that my coils have power and they both work fine .
Thanks for all your help and ideas , they are appreciated for sure .
 

·
Registered
Joined
·
2,750 Posts
Good news.

Don't fret over missing stuff. I spent over 2 years off & on looking for a lambda fault on my old 155 V6. Finally found it - it was the very first part I had inspected, tested and declared OK. A fuse. When testing I had mistaken the intermittently buzz of the continuity test as poor contact with the fuse blades. It wasn't, it was the fuse link being broken internally and the two parts moving about as I tested.

Result on the immobiliser too - they can be a pain.
 
1 - 17 of 17 Posts
Top