Assembled board not working very well

Ask questions about DIY board assembly issues, fault finding and testing. (Covers all Megasquirt versions and board.)

Moderators: jsmcortina, muythaibxr

Post Reply
nathaninwa
Super MS/Extra'er
Posts: 2637
Joined: Tue Sep 14, 2004 4:17 pm
Location: Aberdeen, Wa

Assembled board not working very well

Post by nathaninwa »

Problem, v3 board runs, but lacks power, possibly lean

What is it, diy kit based pcb3, with pwm iac, boost control added, setup a year ago for a Dsm cas install with cam input added and running wasted spark with stock Dsm coils via the led's and batch fuel

At time of assembly, two boards were put togther identical, one to control a 22re and the other to control a vw aircooled motor

Both were to run ms2 chips

History, the 22re got running first, after some minor hiccups the truck was on the success block with a minor engine stumble ( later to be identified as the Dsm flipped cas wheel which is now a 24/1 hi res wheel with no more problems)

For testing we swapped out megasquirt and loaded the same msq, on the VW Ecu the truck runs but very week, and showed a dead lean afr, adding a bunch of reqfuel help but didn't solve the issue. Then items were swapped, 22r Ecu with vw chip, vw Ecu with 22r chip, nothing solved the lack of power running condition

The vw board was looked over and I soldered up a few cold joints and tried again with no luck.

At this point the vw Ecu sat till the ignition stumble was found, and in that time i assembled an ms3 and borrowed it's processor for stumble testing, only after getting tuned with ms3 did the new hi res wheel get installed. So I have a great running ms3 v3 on a 22re and today we decided to try the vw pcb again

Before install tho, I looked through the schematics and found the O2 input section, checked the resistors and capacitor solder joints, probed from the 40pin header to the db37, all tests were 100% with the other 2 pcb's I have here, so I feel nothing is wrong electrically

So installed the ms3 processor onto vw pcb and it still runs with lack of power

Something I noticed that might help here. A few weeks ago I had the autometer wideband controller crap out on me, so I'm borrowing another autometer from another car I have till I can get another one. The new wideband is an analog style and for about 20 seconds after key on, it will bounce from 9afr to 10afr during warmup then come online

With this wideband something is goofing ( or so I think). If I key on and start while in warmup with ms3, 22r pcb, it never comes out of warmup, if I key on and wait for the heating cycle the truck starts and wideband, Ecu are just fine. On the previous wideband, I could start or wait and was no problem

What I noticed today is with ms3 chip and vw Ecu, the wideband would not even warmup, it sat at 9 afr. If I switched back to the 22r pcb the wideband would warm up and work as normal, I pulled the ms3 chip from the 22r pcb and it would not warmup, acting just like the vw pcb


Sorry so long winded, just wanted to get out all that I know to this point. Any ideas?
Volvo 940, 2jzge, MS3Pro, daily
240Z, 2JZ, MS3Pro boost control
arran
Master MS/Extra'er
Posts: 617
Joined: Mon Oct 29, 2012 2:34 am
Location: Brisbane Australia
Contact:

Re: Assembled board not working very well

Post by arran »

What does the composite log look like? Have you trimmed the level and hysteresis trim pots? Are they oriented the same way on both the vw and 22r ECUs?

You haven't taken the inverted versus the non inverted signal from the trigger circuit?
RX7 Series 2 13B Turbo. Megasquirt 3 with 3X Expander and V3 CPU. Firmware 1.4.1
Knock module, twin EGT, real time clock, WBO2, full sequential fuel and spark
http://web.aanet.com.au/arran
nathaninwa
Super MS/Extra'er
Posts: 2637
Joined: Tue Sep 14, 2004 4:17 pm
Location: Aberdeen, Wa

Re: Assembled board not working very well

Post by nathaninwa »

I can take a log of both pcb's with the same ms3 chip. I'll do that in a bit

Iirc at the time of install th Dsm instructions did not have us use the vr circuit, so yes they are installed but not adjusted at all
Volvo 940, 2jzge, MS3Pro, daily
240Z, 2JZ, MS3Pro boost control
nathaninwa
Super MS/Extra'er
Posts: 2637
Joined: Tue Sep 14, 2004 4:17 pm
Location: Aberdeen, Wa

Re: Assembled board not working very well

Post by nathaninwa »

Update, comp love looked identical, but did find one of the 3 prong transistors near the led not soldered, it was under some proto wiring so the first couple visual inspections it got missed. Now it runs well just with a high idle

I need to get in there and verify timing with this combo and look at the pwm idle circuit
Volvo 940, 2jzge, MS3Pro, daily
240Z, 2JZ, MS3Pro boost control
nathaninwa
Super MS/Extra'er
Posts: 2637
Joined: Tue Sep 14, 2004 4:17 pm
Location: Aberdeen, Wa

Solved Re: Assembled board not working very well

Post by nathaninwa »

Turned out to be the led mod for logic level control and a reversed wire on the pwm idle mod. All works great and running good now
Volvo 940, 2jzge, MS3Pro, daily
240Z, 2JZ, MS3Pro boost control
Post Reply