code 12, only runs if timing is very advanced (15 degrees or more)

[lagged]

well i just got everything about squared away and started it up. while trying to set the timing, the car will only idle if the timing is advanced more than 15 degrees. if i try to set the timing to 10 degrees the car will die out.

im getting a code 12.

all the spark plug wires are in the correct order, the CPS is installed the right way.

is there something simple i am missing?

 

[MDCmotorsports]

Lagged:
Ive gotten code 12 before when one of my grounds was not correct off the bottom of the intake mani.

Pull the efi fuse, reset and try it again.

 

[lagged]

Lagged:
Ive gotten code 12 before when one of my grounds was not correct off the bottom of the intake mani.

Pull the efi fuse, reset and try it again.

all the grounds are good. i didnt think reseting it would help but, might as well give it a shot!

 

[lagged]

reset ECU, code went away, car still wont run unless the timing is very advanced. keep in mind that when it does run, i have to pretty much have the CPS a tooth off to advance it this much and it idles very poorely.

 

[lagged]

bumpppp. im sure it has to be something simple that i am overlooking.

 

[jetjock]

lagged, verify you're getting both G signals from the CPS to the ECU.

 

[lagged]

lagged, verify you're getting both G signals from the CPS to the ECU.

i would assume so since the code 12 went away after resetting the ECU? ill figure out how to check for sure and post back.

 

[jetjock]

Probably OK but I say that based on if one G is lost the ECU can calculate the missing one based on the other but the engine will run like crap. That and the code 12 is suspisious. Does the tach seem to be working OK? Can you keep it running at 10 with the throttle off idle?

 

[lagged]

Probably OK but I say that based on if one G is lost the ECU can calculate the missing one based on the other but the engine will run like crap. That and the code 12 is suspisious. Does the tach seem to be working OK? Can you keep it running at 10 with the throttle off idle?

yes i can keep it running with the throttle while the timing is still advanced, im alone right now so its difficult to keep it running and then adjust the timing.

when i do manipulate the throttle to keep it running, it is running like crap. that code 12 is making me think the CPS might have gone bad? but its such a simple thing i couldnt imagine it flaking out for no reason. also the code went away after i reset the ECU and hasnt come back.

the tach seems to be working fine.

 

[lagged]

It is simple but stuff happens. They get filled with oil, the wiring gets messed up, air gaps can change, or maybe the connectors on the CPS or ECI need to be cycled. The signals are AC and tiny compared to the rest of the EFI system so they have to be solid. What do you mean by "got everything about squared away"? Did you have the engine apart?

oh yes, sorry. i had to pull the motor due to another BHG (metal head gasket blew this time...).

the motor was rebuilt so i only had the guy deck the block and put it all back together. theres no knocking and the oil pressure is good when i get it to stay running. so i dont think there is a problem there.

ive checked and double checked everything. i took the cover off the CPS and it is clean as a whistle in there.

a while ago i had an engine fire which damaged the wire harness. i repaired that my self. the CPS was wired up correctly (car ran fine after i made the repair) and i checked my wiring again and everything seems to be good.

i think maybe i should try to find another CPS to test it out with. i had a second one too and i sold it last winter.

 

[lagged]

Huh. Well, assuming valve timing is correct and the CPS was installed right be sure the IDL contact on the TPS is closed. The ECU needs that to happen before you can set base timing. Course if it were open you'd be getting a code 51 so I'm not sure how helpful that advice really is. Are you sure the ISCV is working? Shut the car off and listen for it to step back then unplug it. If it's working the engine should have a high idle on the next start. You can't set timing like that but it'll at least keep the engine running and prove a few things.

Fwiw I doubt your CPS is bad but without putting a scope on it there's really no way to tell. You can ohm the pickups but that'll only prove they're not shorted or open. Still, in my experience an actual internal failure of the CPS is rare.

the TPS is working correctly. come to think of it, i dont think i heard the ISCV clicking. ill check that out!

i agree with you about the CPS. experience has shown you they rarely fail, and in my opinion it is a very simple device with few reasons to fail.

 

[lagged]

the wiring for the ICV is shot. thanks for the point in the right direction JJ!

with the ICV unplugged it idled high and i was able to set the timing close enough to keep it running. thanks again.

 

[johnathan1]

wow, it was the ISCV... why didn't it throw a code...?

 

[jetjock]

Good deal but I'm confused. If the ISCV wiring was bad it wouldn't have stepped back and the idle wouldn't have been high on the next start. Plus unplugging it shouldn't have made a difference. Ah well. Just be sure to check timing again after you get it all fixed because it really should be timed at 650 rpm with the ISC system working. That's one of the functions of the IDL contact on the TPS, in addition to stopping ESA.

Johnathan: The ISC system isn't monitored by the ECU in a diagnostic sense. There are no codes associated with it nor is there any failure mode that I can think of right off hand involving the ISC system that would set another code. It wouldn't have set his code 12 for example so that remains a mystery.

 

[lagged]

Good deal but I'm confused. If the ISCV wiring was bad it wouldn't have stepped back and the idle wouldn't have been high on the next start. Plus unplugging it shouldn't have made a difference. Ah well. Just be sure to check timing again after you get it all fixed because it really should be timed at 650 rpm with the ISC system working. That's one of the functions of the IDL contact on the TPS, in addition to stopping ESA.

Johnathan: The ISC system isn't monitored by the ECU in a diagnostic sense. There are no codes associated with it nor is there any failure mode that I can think of right off hand involving the ISC system that would set another code. It wouldn't have set his code 12 for example so that remains a mystery.

im afraid that ill probably be having some electrical gremlins in the next coming months. the wiring is probably not too great throughout the harness. ill probably have to find time to rewire the whole thing in one shot.

yes, after i wire in the new plug for the ISC i will let the car warm up and set the timing the right way.

thanks for the help.

 

[supra90turbo]

Buy a new harness while you still can is my only advice, Lagged!

 

[lagged]

Buy a new harness while you still can is my only advice, Lagged!

a new one would be nice, but over time ive already replaced several connecters here and there, rewired the knock sensors and made major repairs to it when some sections got melted in a small engine fire.

it wont be too hard to rewire the whole thing. i do work like that frequently, the only problem is finding the time to do it.

 

[lagged]

alright, rewired the ICV, still same problem. if i have the timing around 10 degrees the motor stumbles and dies. i can keep it running with the throttle. if i start it with the ICV unplugged it will idle but very high.

there are no codes. i have tried resetting the ECU, letting the car stall out to see if that would throw a code.

thought maybe the AFM might have been going bad but not thrown a code (dont know if thats possible..) so i tried starting it with the AFM unplugged, still same symptoms.

maybe the ECU just has to relearn everything? i do have a lexus AFM and 550 cc's but i would think it would idle a little bit better than this.

theres a small oil leak so ill have to fix that before i do anything else.

anyone have any other ideas?

ill have to check all my IC pipes, i am sure i put everything on good and tight but at this point i woudlnt be surprised to see the lower ic pipe hanging off..

 

[lagged]

fixed it! got it running today!

the problem? something stupid as i had suspected..i had the timing belt on the exhaust cam one tooth off.

DOH!

i was so sure that i had put the belt on correctly, ive done it many times before and never have made a mistake. oh well!

i feel as though a hugeee weight has been lifted off my shoulders. as long as i dont break down (crosses fingers) ill have a car for school and what not.

thanks for everyones help!

 

[jetjock]

20 lashes