You could disable the EGR for diagnosis. If the problem changes, that would be an indication.

 

Remember the ECM is a 35 year old computer/electrical device, over time they suffer the effects of age, heat, vibration etc. and the 165 failing is not very uncommon, I remember reading an old magazine article where they were hopping up a third gen Formula and the ECM was bad. It is where I would be looking if I could not get code 12 to flash 3 times and the fan to kick on to enter diagnostic mode. Summit and Rockauto had reman ECMs last I knew.

 

Thanks RedDragon, appreciate the help as always.

Vader, how do I disable the egr ?

 

How do I confirm rockauto is displaying the correct ecm available for my car ? It is open on my cars specs that is able to be put into rock autos site, a 1988 305 V8.
The only one that's available that I'd be interested in is the gm genuine reman.



Thanks for your help. I'm going to get mine out later to look it over and if there's anything obviously wrong, broken solder joints or evidence of moisture etc..

 

Looks like there all out of stock 1227165 or superseded number

 

Well well well boys and girls. ALWAYS check what our knowledgeable thirdgen.org members tell you to check before throwing parts at your problem. While removing my ecm to inspect it for any damage I dare say I found my problem, as the pics will show..










So now my question is... does it look ok inside around the ecm pins ? Is there a possibility there has been internal damage ? Obviously some kind of shorting out going on when that bare section of wire has touched the metal on the other plug.

How do I go about fixing this ?

 

Awesome job finding that! It will definitely cause problems. I would hold off on getting a new ECM until you straighten that wiring out.

I am no wiring/electrical expert, but I would try to possibly get a new connector or at the very least clean up/trim and re-pin your wires to the existing connector if it’s still serviceable but man it looks pretty rough. The more I look at that connector just replace it, maybe the dealer can get one or eBay?

Also maybe someone else can chime in but that red butt connector does not look factory to me but I can’t remember what my ECM wiring looked like.

 

I doubt it is factory, the wiring was a bit of a mess when I got it with an old alarm system in it, no idea why they'd have cut into the ecm plug wiring but who knows why people do what they do on cars sometimes 😂
It has also been converted to right hand drive but I dont see why they'd have just done that one wire during the conversion.
Needless to say I'm excited to get this sorted and see how many issues it solves 😂

 

Unfortunately I'm in Australia so no dice getting anything through a dealer. Rockauto also stocks nothing. I'll try ebay.
If anyone else can chime in on whether or not this could have caused any internal issues with the ecm would be great, and if any one has any leads on where I can get new plugs would be much appreciated.

 

https://www.ebay.com/itm/12341736111...mis&media=COPY

https://www.ebay.com/itm/12116044303...mis&media=COPY

 

Thanks Tuned, I found those exact listings soon after my last post.
Any tips for re doing these connectors, other than take my time and patience lol ? Oh and lots of photos noting locations of every wire ?

Tuned do you think the ecm would still be ok, even though it's apparent that wire has been shorting out ?

 

What pin is effected A12 ?

 

It seems to be the worst affected but would seem B12 has some damage and also the other plug has similar on what I'm guessing is C1 and D1.
But it appears A12 is the wire with melted off insulation.

 

I’m not sure what the case was, loose or poor connection at ecm or ground on back of passenger cylinder head. I’d replace the ecm just not sure the cause.

 

Until a few years ago, the braided ground strap from the right side head to the firewall was broken in half, like that since I bought the car and had never really noticed until a few years back when i really started to get to know these cars and start fixing things on it. I've since replaced it with a 4ga cable. Possible cause you think ?

 

Would you know where else I can find one ? I've been reading that the superceded number 16198259 are superior to the standard original 1227165 due to internal improvements and still take the stock memcal as normal ?

 

I have one but it’s untested, might place a RockAuto order and wait for it to become in stock. I’m not sure if any improvements were made to the superseded numbers.

 

I have one of those 259 ECMs in my car and it works great. Seems identical to the 165 and all I needed to swap over was the mounting bracket and PROM. I found mine on eBay a few years back, was NOS leftover from a dealership.

 

Hey Brian is that yours i see on ebay ? Say tuned--performance is the seller so guessing it is..

 

Yes that’s mine, it’s been sitting around for awhile , I just can’t guarantee it works without issues.

 

I was going to hold off on a replacement ecm till I took care of the connectors and tested but I thought while I have the time I'll look inside the ecm. So this is as far in as I can zoom clearly, directly behind where the plugs clip in and make contact, you can clearly see where it has melted, would you think that would write off this ecm ?





😭😭😭

 

It's a shame cause the rest looks in such good shape.

 

I wonder if a 1227808 ecm could be obtained closer to you.

 

Distance isn't an issue, I buy my parts from the US anyway and send them to my in laws who bundle them up to save me on shipping to Aus. Just an issue finding one that has been tested and is genuine reman.

Is that melted bit inside cause for a new ecm you think ?

 

1227808 appears to be from a 5.0 VN Holden, would that be plug and play ? I wouldn't have thought it was, and the memcal would plug in ?

 

It’s hard to see the extent of the damage in the pictures. I figured a ecm
close would be cheaper . Could of been a bad solder joint that caused the issue on the pcb.

 

pretty sure with memcal swap it’s plug and play just different case and baud rate for datalogging if i remember right.

 

Will that baud rate cause any running issues ?
Also, how many of these would I need ?
I notice there's only two rows of pins for each plug on the ecm, but I can see the metal connectors inside all 4 rows of the plugs, just confused about that.

 

Hang on here guys, I just re-read my thread to double check everything that's happened and what I've done, and I realised that I have in fact tried a friend's ecm in my car, (I totally forgot I tried it) despite having that bad wire and plug, and there was no difference in the cars behaviour. Although I know that wire and plug needs fixing, am I barking up the wrong tree here thinking this is the root of the problem ?
Can I get anyone to confirm all locations of factory grounds ?

 

Grounds are on the rear of passenger side cylinder head.

to release the ecm pins lisle makes a tool or paper clip works. The lock tab can be seen in the small hole of the connector. You may need to replace a few of the locking tab gets mangled trying to remove .

 

Thanks man.
All my grounds seem to be intact. Seen some people say there's one on the driver's side head too but i can't find it.
Do I only need to put new pins in every hole or just on the ends of the wire as my connectors have pins in the holes that don't have wires going into them.

 

I think aldl ground is drivers side head

 

So over the weekend I spoke with someone who suggested the pick up coil could be the culprit. It tested ok going by the suggested test methods, within range even with wiggling the wires.
Since I had a brand new Ac Delco one in my parts bin and knew how to do it I thought why not.
All done and back together, fire it up to adjust the timing and it fires up immediately and doesn't stumble and stall or stumble and catch itself just before stalling like it normally does 🤷🏽‍♂️
Timing was off a touch so I adjusted it 8° like I normally have it and the video is how it is idling now.
I left it running for a bit longer than it took to get to operating temp and nothing happened.
I can now also pull codes without a problem 🤷🏽‍♂️

Have a listen and see what you think 🤷🏽‍♂️

At :25 the video switches to the engine bay and gets louder, beware!!


I still don't trust it. Also that lovely sound is the Bosch 3 injectors not lifter tick 🤣

 

Hi guys, I haven't been able to get the car to replicate any issues outlined here basically cause I'm scared of taking it out and getting stranded again and forking out for another tow home.
I'm waiting on parts to arrive to address the bad wiring on the ecm plug but would like to know if anyone thinks the fuel pump could be a culprit ? I do still have a slight misfire, occasional stumbling with accelerating, occasionally surges when driving... pump was replaced in 2020, less than a few thousand miles on it.

 

This has been a challenging thread to read.

Why would the fuel pump be the culprit? You tested the fuel pressure and it was good!

You have melted wiring/ecm and you worry about the fuel pump!!!!

May I suggest you focus on one problem at the time, do your testing in a systematic manner and make notes?

Test one system at the time and make notes.

I would definitely start by unplugging the battery and fixing the ecm/wire issue first, before you fry something else or burn the car and the garage with it.

Peace

 

How did you go with this.
Have you sorted the burnt wiring issues yet. Definitely check the contact on the wires that were 'spliced' together.
The PCB tracks around the header look to have received a fair amount of heat. There may be a break in one or more of the traces, this may cause intermittent issues.
I am also in Sydney, if you wish you can send me the ECU or the board and I can check it over.
Cheers.

 

All fixed. I replaced damaged wiring and connectors, repaired ecm works perfectly and had my maf repaired by the same people and it starts and runs perfectly.
Where in Sydney are you from ?

 

Good to hear it's all done!
I'm in the Parramatta area. I've done some work on 'upgrading' Holden's '808 ECUs and love tinkering with automotive things in general.
Did you repair the ECU yourself?

 

I've moved to the Gold coast now, would've been cool to have caught up when I was still in Sydney.
Didn't repair the ecm myself, sent it to a place in Melbourne and they did it, they also repaired the maf sensor too. I replaced the wire with the melted insulation and repinned some of them and replaced the connectors myself after no auto electricians wanted to work on my car. I did have at least one auto electrician offer his advice after looking at it that the damage would've been there since before I owned the car given the aged appearance of the exposed wires and since the ground strap on the engine bay was not connected (something I noticed and repaired a few years ago) it would've definitely been the source of the issue since that strap grounds the ecm.