3000GT/Stealth International Message Center - View Single Post - Lean Misfires at 2700-2800 rpm

DoctorDex · 12-18-2006, 05:19 PM

Edited:

I finally got a chance to pull my ECU today and I checked the continuity of as many circuits as I had patience for. I have a 1st Gen ECU with a part number of MD159966. There is another number on the case and I'm not sure if its used for anything, but its E2T35678

I measured the polarity in two directions. Here's what I found:

DMM Diode Test (
_____|_+_to_-_|_-_to_+__ |
D102 | 490 | infinite |*
D103 | 453 | 685 |*
D104 | 531 | - |
D106 | 532 | - |
D107 | 557 | - |
D108 | 567 | - |
D111 | 553 | - |
_________________________
D105 | 438 | - |

Capacitors (@ 2000K Ohms Setting on DMM)
_____________________
C102 (22 uF) = 022 <-- @ 2000k Ohms
C104 (100 uF) = 0 (but @ 2000 Ohms = 266). **
C105 (47 uF) = 0.03 --> 0.02

* Resistance and bidirectional current flow differed between D102 & D103 versus D104, D106, D107, D108, D111 despite appearing to be the same component. I'm curious as to whether or not this is significant. Does anybody have an explanations? The only explanation I can come up with is that its not actually measuring the resistance across the diode, instead its taking a long route through the boards other circuits and it measuring the resitance in parallel to another diode or resistor.

As an experiment, I'm going to change out my caps tomorrow because I'm especially worried by C104 & C105. I think I might also switch out D102, D103.

Thanks.

Declan

12-18-2006, 05:19 PM	#106 (permalink)
DoctorDex Forum Member Join Date: Jul 2005 Location: Edmonton, AB Drives: '91 VR4 - RIP Trader Rating: (14)	Re: Lean Misfires at 2700-2800 rpm Edited: I finally got a chance to pull my ECU today and I checked the continuity of as many circuits as I had patience for. I have a 1st Gen ECU with a part number of MD159966. There is another number on the case and I'm not sure if its used for anything, but its E2T35678 I measured the polarity in two directions. Here's what I found: DMM Diode Test ( _____\|_+_to_-_\|_-_to_+__ \| D102 \| 490 \| infinite \|* D103 \| 453 \| 685 \|* D104 \| 531 \| - \| D106 \| 532 \| - \| D107 \| 557 \| - \| D108 \| 567 \| - \| D111 \| 553 \| - \| _________________________ D105 \| 438 \| - \| Capacitors (@ 2000K Ohms Setting on DMM) _____________________ C102 (22 uF) = 022 <-- @ 2000k Ohms C104 (100 uF) = 0 (but @ 2000 Ohms = 266). ** C105 (47 uF) = 0.03 --> 0.02 * Resistance and bidirectional current flow differed between D102 & D103 versus D104, D106, D107, D108, D111 despite appearing to be the same component. I'm curious as to whether or not this is significant. Does anybody have an explanations? The only explanation I can come up with is that its not actually measuring the resistance across the diode, instead its taking a long route through the boards other circuits and it measuring the resitance in parallel to another diode or resistor. As an experiment, I'm going to change out my caps tomorrow because I'm especially worried by C104 & C105. I think I might also switch out D102, D103. Thanks. Declan __________________ '91 VR4 - Modlist: DR650R turbos, Snow stage 2D alky kit, DSM SMICs, blowthrough ported LT1 MAS, Dejon Tool intakes & y-pipe, Blitz DSBC Spec R, HKS SSQV BOV, PTE 580cc injectors, Dual feed fuel system with Aeromotive FPR & filter, Hotwired Supra pump, HKS DLI, MSD Wires, Apex'i S-AFC II, MAFTranslator, Turbobob ECU, Scanmaster III, LC-1 WBO2, ESP downpipe, Vac/EGR delete, Gutted precats and test pipe, Maximal solid mounts, 300m 18 spline output shaft, Centerforce Dual Friction clutch, RPS flywheel, GC coilover conversions with helper springs, Powerslot slotted rotors, Goodridge SS brake lines, Hawk pads (front), Stillen metal matrix pads (rear) Last edited by DoctorDex : 12-19-2006 at 12:28 AM.