[SOLVED!] OBD1 S52 Swap No Start No CEL

[GaryJ]

[Tuning chip on the ecu was fried, replaced with a TRM Chip, run perfect]

1990 325i auto -> Manual obd1 s52 (413 red label w/ ostrich 2.0 chip

Engine was previously in a manual 91 318is

Fuel pump and starter motor run properly, main relay is working fine. c101 ign pin 7 wired to the two factory joined green wires from the s52(x20 pin 21). Tested 12v to pin 7. Getting 12v to the following dme pins: 24,25,26,27,49,54,57,58,59,87. CEL does not turn on in any position. Tested crank and cam position sensor, reading good resistance.

I want to rule out everything before assuming My ecu is fried.

[e30austin]

if this car was equipped with a 6 button computer, make sure the small green bypass connector (a little "looped" connector, if you will, used for fuel pump lock out on a 13 button equipped car), did not come unplugged under the dash. it happened to me once when changing the brake booster. if 13 button equipped, make sure the big black box (mounted on the firewall, inside the car) has both connectors plugged in. it's otherwise known as the "OBC relay" and has been known to fail, i would just bypass it altogether.

does the ICV hum when the key is in the "on" position? did you confirm you installed your DME chip in the correct orientation (notch to notch)? is the DME securely grounded to the chassis? what does your power distribution block, at the firewall, look like?

[GaryJ]

if this car was equipped with a 6 button computer, make sure the small green bypass connector (a little "looped" connector, if you will, used for fuel pump lock out on a 13 button equipped car), did not come unplugged under the dash. it happened to me once when changing the brake booster. if 13 button equipped, make sure the big black box (mounted on the firewall, inside the car) has both connectors plugged in. it's otherwise known as the "OBC relay" and has been known to fail, i would just bypass it altogether.

does the ICV hum when the key is in the "on" position? did you confirm you installed your DME chip in the correct orientation (notch to notch)? is the DME securely grounded to the chassis? what does your power distribution block, at the firewall, look like?

Looped connector present (6 pin obc)

cannot hear icv (I do have 38% hearing loss though)

dme chip seems to be secure and line up properly

Dme is sitting in the glove box. Just be sure, are you saying the body of the dme needs to be grounded? If so, while I'll be happy that I found a solution, I'm gonna be pretty salty that this was the only thing holding me up from getting this car running.

[e30austin]

Looped connector present (6 pin obc)

cannot hear icv (I do have 38% hearing loss though)

dme chip seems to be secure and line up properly

Dme is sitting in the glove box. Just be sure, are you saying the body of the dme needs to be grounded? If so, while I'll be happy that I found a solution, I'm gonna be pretty salty that this was the only thing holding me up from getting this car running.

DME exterior case 100% needs to be grounded to the chassis. that is how the e36 harness grounds terminate.

i see your problem though. your two red cables are not connected to any 12v source. the two lower 6mm lugs are just securing studs for the battery cable mount. the upper most 6mm lug is the fuseable link, for the main DME power wire (fused in the trunk in case of reversed polarities so it doesn't fry the controller). you need to put the smaller of the two wires on the upper most 6mm stud, and the larger of the two wires needs to be bolted to the battery cable itself.

would almost guarantee your car will start after fixing those two items. :)

[GaryJ]

DME exterior case 100% needs to be grounded to the chassis. that is how the e36 harness grounds terminate.

i see your problem though. your two red cables are not connected to any 12v source. the two lower 6mm lugs are just securing studs for the battery cable mount. the upper most 6mm lug is the fuseable link, for the main DME power wire (fused in the trunk in case of reversed polarities so it doesn't fry the controller). you need to put the smaller of the two wires on the upper most 6mm stud, and the larger of the two wires needs to be bolted to the battery cable itself.

would almost guarantee your car will start after fixing those two items. :)

Moved the wires, I was however getting 12v to that bottom bolt. What is the best way to gound the ecu? I dont have a bracket. Would running a wire from a screw on the ecu to the strut tower work?

[e30austin]

Moved the wires, I was however getting 12v to that bottom bolt. What is the best way to gound the ecu? I dont have a bracket. Would running a wire from a screw on the ecu to the strut tower work?

that bolt should not have power of any kind going through it...

you can use the e30 318is DME brackets (which are available new at the dealer for under $50), but as a temporary solution, you can ground it with a small jumper wire with alligator clips (also referred to as a "jumper lead").

[GaryJ]

that bolt should not have power of any kind going through it...

you can use the e30 318is DME brackets (which are available new at the dealer for under $50), but as a temporary solution, you can ground it with a small jumper wire with alligator clips (also referred to as a "jumper lead").

Well I tried with a jumper cable, no dice. It's starting to look a lot like the dme is shot.

[e30austin]

get any red label 413, you can run it for a few minutes on the stock m50 tune and it'll be perfectly fine.

[GaryJ]

get any red label 413, you can run it for a few minutes on the stock m50 tune and it'll be perfectly fine.

Just ordered a new one. Hopfully this works. I appreciate the help.

[GaryJ]

Its running! Turns out it was the ecu. Most likely fried it when I tried getting it to run way back before my ground was installed correctly. Anyone planning or in the process of a swap, be sure to check wiring PRIOR to attempting to start. Patients is a virtue.