Cranking but no spark Kohler EFI CH26 78511

OP
P

Problemmagnet

LawnSite Member
Without realizing or checking actual pin functions, it is obvious the two most problematic issues through this whole thread were spotted in my red arrow pic. Speed sensor and oil sensor. Talk about chasing tails around the yard....

Really the smarter the ECU, the easier this gets but I recall working on my best friend's prize 1969 Camaro show car with crate EFI engine. Guy helping with the body work was good with that work but other work, not so much. From the first key turn car had a code for an OPEN injector circuit. Open meaning not connected. It went through 3 ASE mechanics before I got into it.

I am not trying to toot my horn here but man, you gotta let the brain think! OL means open, means if you probe the injector and the coil reads fine, you got other issues! I determined the body guy jammed the plug on that #7 injector and totally killed the pins on the injector. I was able to recover the pins and that car is still hitting shows 8yrs later with no other faults.

A "code" does not always means a device is bad, it means there is an issue in that circuit. Revolve in your thoughts and usually ideas come to mind in how to find the issue. SEND IT!
Thanks for your help. I haven't gotten any codes in a while. But sometimes they would come and go. Its just odd the mower would start shortly before I unplugged and plugged in the oil sensor and then after it will not start. The oil sensor plug and harness appears fine. So I will be trying to unplug those three or 4 pins this afternoon on the ECU harness. Just not sure how to get them out I assume I need a long thin flat head to push a locking pin after removing the pin locking tab? According to the flow chart it's definitely speed sensor related because the MIL does not turn off when cranking and now that's its a new properly gapped speed sensor the only thing it could be is this harness or ECU unless the speed sensor came loose again but I doubt it.
 

fastline

LawnSite Member
I don't know what your harness block uses for pins or how they stay in but don't assume they have locks other than the main lock on the back that you identified. Just make sure all of them don't come out and you are stuck trying to repin everything. In most cases things can be fixed without pulling the pins but yours looks bad from here. Getting it right will be worth the effort.
 
OP
P

Problemmagnet

LawnSite Member
Yeah that's the problem I can't figure it out either and no they don't just come out with the One locking tab that's easy to take out they are really locked in there and I can't see what is locking them in there. I poked and prodded in to see if I could unlock it but no luck so far.
 

fastline

LawnSite Member
You might get lucky and find numbers on the plastic block and determine the matching pins that way so you can visually see one. Usually there is a single tang on one side. It takes extremely small tools to depress them without damage. I have an entire 'set' of keys which includes flats, round barrels, and squares. Usually you can look at the contact side (opposite the wire side and see the little tang. Once you get it figured out, you will be frustrated how easy it was.

Do NOT force them! Generally I insert a tool and push/pull the pin a bit until it releases. There should be no force required unless severely damaged or melted. I had one that melted the plastic and the plastic melted into the contact! That is as bad as it gets!

If you have some thin sheet steel around, you can cut a sliver. Using something flat is what you want, not round like even a micro screwdriver. Flat is key.
 
OP
P

Problemmagnet

LawnSite Member
You might get lucky and find numbers on the plastic block and determine the matching pins that way so you can visually see one. Usually there is a single tang on one side. It takes extremely small tools to depress them without damage. I have an entire 'set' of keys which includes flats, round barrels, and squares. Usually you can look at the contact side (opposite the wire side and see the little tang. Once you get it figured out, you will be frustrated how easy it was.

Do NOT force them! Generally I insert a tool and push/pull the pin a bit until it releases. There should be no force required unless severely damaged or melted. I had one that melted the plastic and the plastic melted into the contact! That is as bad as it gets!

If you have some thin sheet steel around, you can cut a sliver. Using something flat is what you want, not round like even a micro screwdriver. Flat is key.
I did manage to get him out and yes I do need a smaller flat head screwdriver I used to have one but I can't seem to find it but I managed to get it off and honestly they are not great but I feel as if they're making connection they're not corroded and they seem to be making connection I would feel better if I could replace the pain all together but I have no idea what it's called all it has is AMP on it. Apparently they make a ton of connectors. Wonder if there would be a good replacement connector that would work better than these. After messing with it for a bit I did manage to get it started for just a second but then turn right back off and could not get it started again. Still not throwing any codes anymore as well. Any help as to finding exactly what type of connector this is would be greatly appreciated I could probably just replace all of the bad ones or maybe all of them and then it would be for sure in better condition because bending them after taking them out does not work very well and they look pretty bad when I put them back in it still
20210716_172407.jpg
20210716_170843.jpg
.
20210716_170837.jpg
 

fastline

LawnSite Member
You will have to make the call on where you go from here. AMP is a very common line of electrics. You could probably call them and show them that pic and they can send replacements. that is an option. Usually I work on Jap stuff that is not obtainable. that should be!

But I still might work on what you have to make a good temporary contact, verify she runs perfect, then get some new pins and put it to bed.

As I mentioned, you need firm clamping pressure in a termination like this to displace the grease. Otherwise the grease ends up between the contacts and insulates. Don't worry about grease right now. Go in clean, get good contact pressure you can feel, and give it a go.
 
OP
P

Problemmagnet

LawnSite Member
You will have to make the call on where you go from here. AMP is a very common line of electrics. You could probably call them and show them that pic and they can send replacements. that is an option. Usually I work on Jap stuff that is not obtainable. that should be!

But I still might work on what you have to make a good temporary contact, verify she runs perfect, then get some new pins and put it to bed.

As I mentioned, you need firm clamping pressure in a termination like this to displace the grease. Otherwise the grease ends up between the contacts and insulates. Don't worry about grease right now. Go in clean, get good contact pressure you can feel, and give it a go.
That's the problem partially right now. I don't think it's making persurized contact because some pins are messed up so bad even after attempting to fix them. I'd really like to figure this out for sure. One way is I could just remove all the pins and manually connect them. I feel the harness isn't seating as deep as some of the pins need. Maybe they have traveled backwards overtime causing some insufficient connections? I will be taking it to the local mechanic tomorrow most likely and see what he can see on a scan tool and that may point to the specific pins in need of repair.
 

fastline

LawnSite Member
No, do NOT pull all the pins and try to jam them in the socket. Something will arc and it will be over.

Unfold the connector so you can bend the tabs far enough to get pressure again. they fold around themselves. They are stamped from flat stock and formed. Just unfold. CAREFULLY!
 
OP
P

Problemmagnet

LawnSite Member
No, do NOT pull all the pins and try to jam them in the socket. Something will arc and it will be over.

Unfold the connector so you can bend the tabs far enough to get pressure again. they fold around themselves. They are stamped from flat stock and formed. Just unfold. CAREFULLY!
Noted. What do you mean by unfold? There's a certain way that need to be folded. I may take a good one off and try to match it. I will also message amp and see if they can pinpoint the connector type.
 
OP
P

Problemmagnet

LawnSite Member
Update.

So I have taken it to the mechanic and it will be at least 4 weeks until they can look at it unfortunately. However, do you all think the metal ecu body should be in contact with the chassis or body? There are rubber bushings basically preventing it from having direct content except the bolts are partially fatter and not threaded, potentially providing some contact with the frame. The wire diagram I am using mentions the ecu to be grounded to the chassis, but if that is the case why would there be the rubber bushings other than to reduce vibration? Being the pessimist I am, I'm preparing for the Mechanic to be just as lost as I am.
Screenshot_20210725-132407_Adobe Acrobat.jpg
 

Top Forums



Top