gslender

iTrader: (1)

Hi,

Have a well running and tuned MX5 (Miata) running batch, wasted spark pretty much stock everything (except for VTPS).

Long overdue upgrade to build and insert a new inj harness and use the Sequential Module that DIYAutotune sell (for the DIYPNP).

Harness was tested and is fine - plugs into the DB15 and wired into the Inj1, Inj2 on mainboard, and Inj3, Inj4 from the Seq Module. I get 12V from a known reliable switched source.

When I switch over to Full Sequential (tune changed to "Sequential/Semi-sequential" with "Additional drivers" everything goes wrong

The car starts, idles rough for about 20 seconds and progressively gets richer and richer... AFR drops to below 7 and white smoke bellows from the exhaust. It almost sounds like it is running on 1 cylinder less than it should, and no amount of tuning the VE lower helps... it just gets really bad.

I assume it is over-fuelling, and yet all the PW look the same as before and I can't really see anything that indicates what might be wrong...

One of the injector circuits leaking to ground perhaps?

I switch back to batch (plug in the stock harness), and it takes a fair while for the over-fuelling to go away (must be fuel everywhere in the intake etc) but eventually she returns to normal and all is good again.

I've completely checked and replaced the entire harness to be 100% sure nothing is wrong - I'm now suspecting the wiring within the DIYPNP - as I've obviously got some gnd leak that is pulling an injector open - does that sound right?

Any suggestions on where to begin to check?

G

ampz

One good way to narrow down which channel is to look at your spark plugs...

Other than that maybe post a couple of hi res pics of your board maybe a keen eye can spot the difference?

gslender

iTrader: (1)

Strange. I pulled the ECU out of the car, tested it on the bench with the Output Tests and LEDs/resistors and it tested fine. I then tested with spare set of injectors in the car (Output Tests again) - it tested fine. I then put the harness back on the installed injectors. It ran fine no issues??

What the?

Ben

iTrader: (33)

Loose wire or bad solder joint.

gslender

iTrader: (1)

Hi, still having problems with the DIYPNP Seq module.

Note that on batch (Untimed Injection) with Inj 1 and Inj 2 wired it works fine. No problems.

I've isolated the issue to this...

Cold the engine runs fine... works well and nothing seems wrong until about 30mins warm-up (idle or driving).

When the problem presents, cylinder #2 seems to be overfueling (I'm assuming a GND leak somewhere) as the spark plug is saturated with fuel, the AFR goes south (down below 7), and eventually the exhaust bellows white/grey smoke typical of too much unburnt fuel being dumped down the exhaust.

Cylinder #2 corresponds with Inj4 in my 1342 firing order, so that explains why I don't have issues with batch (not related to the Inj 1 or 2).

Question I have is... if this is overfueling, that means a GND leak right? In which case it can't be a dry solder joint - that just wouldn't do it yeah? I must have solder near a track or bad wire touching somewhere that when warm/hot it expands and allows the GND leak to let the injector leak open etc.

Also, I have swapped another DIY Autotune Seq Module, so the other other place is the Microsquirt daughter board or DIYPNP mainboard.

Today I spent a few hours replacing the mainboard wiring (inj 1,2,3,4 to mainboard DB15 socket to be sure I had them good). No improvement.

Just not sure where to go, but have these options...

1) there is the DB15 female plug itself (where the engine harness wires from injectors and O2 sensor connect in etc)?

2) the Microsquirt daughter card?

3) the DIYPNP mainboard?

Thoughts?

Braineack

iTrader: (62)

Are you going directly from the module to the db15?

gslender

iTrader: (1)

Nope. From the module to the nearby Inj 3/4, and then from the 3/4 Inj down where the Inj 1/2 outs are.... Could that be it?

G

Braineack

iTrader: (62)

maybe? why not try from the module directly to the db15...since it's a much short bit to travel anyways.

i see no reason to put it to the #4 hole near the proto, then take it form the #4 hole by the opposite end of the board, to bring it back up to the db15.

would be a good way to rule out a bad trace/solder joint on the board between all that.

gslender

iTrader: (1)

Yep - gonna do that plus another DB15 pig tail to be 100% sure I've not got a gnd leak in that area... the DB15 socket is fairly packed together and prime place for a stray wire strand to be poking into its neighbour!

Thanks Scott.
G

gslender

iTrader: (1)

Arrrg... not progressing at all...

Ok, re did the internal wiring to go straight from Seq Module to DB15. Ensured all wiring was good and replace the DB15 plug and harness ensuring really good connections back to injector harness. Double checked all of it to be good.

No good. Same problem!

Interesting development - out of frustration I swapped back my other Seq Module and the problem changed slightly... the prior Seq Module went bad after engine was warm - ie it would work fine until about 20mins and then go bad. This changed Seq Module goes bad immediately... there is no delay and almost immediately after starting I'm running on 1 less cylinder roughly.

So, the problem is either 1) I somehow have two bad Seq Module (given there is little to solder, can't see how I could stuff up two, but possible) or 2) the Microsquirt/DIYPNP board to bad - and just seems to behave differently, but in fact isn't... just my mind playing tricks.

I think I need to take this conversation to DIYAutotune unless anyone has any good suggestions... dang!!

G

gslender

iTrader: (1)

I'm aware of which seq module Inj is failing. Cylinder 2 spark plug is wet (which is Inj #4).

Untimed works... which when rewired as batch using Inj 1 & Inj 2 runs fine.

So I'm now fairly confident the issue is with both Seq Modules (can't believe though I've received or broken two of them?).

The other possibility is the microsquirt or DIYPNP board itself... I have a spare microsquirt so I could try that, but really is that likely? ... And the DIYPNP board I also have another, so I could make up another from the spare kit, but again would it be likely?

Braineack

iTrader: (62)

the module is so simple, unsure how it could be the issue, or even intermittent like that..unless it's a bad solder joint.

gslender

iTrader: (1)

I agree re the module being simple.

What's stumping me is that the injectors are fired by a pull to GND, so a bad solder joint would cause the injector to fire less (meaning it would run lean, not rich).

So for this problem to be happening, I should be looking for a GND leak right? A solder blob touching a track, a failed component that is leaking to GND or something like that... does that sound right?

G

gslender

iTrader: (1)

Update...

Did an untimed with additional drivers test and got the same result... it runs rough and starts over-fueling etc.

I checked cylinder #2 spark plug (which uses inj 4 output on the module) and it is wet as predicted.

I've now got the DIYPNP on my bench and I'm studying it looking for issues on the module, mainboard and the microsquirt module itself... something must be bad.

I just grabbed another Microsquirt module (spare) and flash boot, and latest 3.2.1 s19.... same problem too.

Ran the entire system on the new harness configured in batch (1 & 3) on Inj 1 output, and (2 & 4) on Inj 2 output - all via the DB19 and it worked fine. Which points to when it has to run off the Seq Module (3/4).

So the problem is one of these:

a) The DIYPNP mainboard - nothing obvious to see but I could build another mainboard and swap it in... lengthy but an option to try.

b) Both Seq Modules have failed - hard to believe, but possible. I will need to wait for DIYAutotune to send another across the pond (takes about 5-7 days) as I'm down under etc.

Any other thoughts?

G

ampz

Post a couple of Hires Pics, four eyes are better than 2?
I've got no experience with the DIYPNP boards, so I'm curious to see if they have the flyback components like the V3 board.

it could the the FET driver which drives the seq module causing it to stay on?

gslender

iTrader: (1)

I've now got the DIYPNP on the bench plugged into a 12V 500ma adapter.

When powered up, the following is seen.

Between 5V (on the mainboard) and J1 on the uS card at PT6 is 4.99V, between 5V and PT6 is 2.67V ??

At J1 on the uS card, between GND (pin3) and and PT6 (pin9) is 0.05V, between GND (pin3) and and PT7 (pin7) is 1.75V ??

With the uS module removed, PT7 (pin7 on J1) to GND has 12V across it, whereas PT6 (pin9 on J1) has 0V.... so something ain't right there !!

Seems to be all related to the DIYPNP board... I'll have to get the boys from DIYAutotune to help.

Will start looking at the board traces and solder joints... but so far nothing obvious.

gslender

iTrader: (1)

I've sorted it with super-support from DIYautotune.

Turned out I had a wire incorrectly placed into the X-connects instead of the many inputs below... and this is what was slightly bringing down PT7 enough to not cause any major fault, but enough to muck up the sequential timing for Inj4 and dumping more fuel than needed (impacting the PW).

Fixed and now running smooth.

Thanks DIYautotune again for such great support.

G