1994 Nissan Sentra SE-R going VEMS, then turbo.

[BenFenner]

The config file I sent to you the first time, or any other time may or may not have had the fuel pump output disabled. I was enabling and disabling it quite often trying to get the P259 channels to work. The fact that it was disabled shouldn't mean anything, as I'm surely enabling it on my end when I'm messing around (remember I'm still just trying to get spark to work again).

1.1.18 is a COP only firmware you say? Well terrific. So that's why I only get 1/4 the spark, and have to "trick" it into giving me the correct amount. Okay. I can live with that. Still doesn't help me get spark back I guess.

I see what you're saying about the IGBT channel. Is that the next step?
Keep in mind I've tried channels 00 (EC36-pin35), 01 (EC36-pin33), and 07 (EC36-pin10) thinking the same thing you are. Once when I had no spark, moving to channel 01 didn't help, but then moving to channel 07 produced spark immediately. I then went back to channel 00 and had spark still. So, I can try as many outputs again as you'd like, but I'm doubting it's a bad IGBT. Still worth a try I guess.

So what should I try now? Do you want me to upgrade to 1.1.27 and give the configs you sent earlier another go?

[rob@vems.co.uk]

I really don't think that the intermittent nature of the spark is related to firmware or configuration, and electronics either works or it doesn't... If there was a dry joint somewhere then you'd get the intermittent failure, but a dry joint wouldnt be effected by the configuration.

I know this sounds stupid, and its not in anyway trying to detract from whats happening, but I hade all manner of issues with those AMP plugs securing properly, the soldering can cause the pins to become loose, and the not line up particuarly well.  In the end I zip tied the plugs together through the screw holes that are on the socket I sent you.  That bolt needs to be massively tight too.

[BenFenner]

Yah, when soldering I had a couple pins start to melt the plastic, and come out of line. I made sure they lined up correctly each time I finished, and when I was done, it looked like it'd never been touched.
I felt the connection could be suspect as well, which is why when I had no spark, I'd take the pin out of the EC plug and ground it to the chassis to make sure the connection was made. I'll tighten the screw more, as it is a little loose, but I've been around electronics enough to make sure every little thing like that is taken care of.

Is there any other firmware (older or newer) that will understand my trigger set-up, which also might take to my configuration more kindly?

Have I even given your last conifg files a correct run-through?

By the way, the new server seems to be much faster for me. =]

[rob@vems.co.uk]

What about running a wire from the coil '-' direct to the EC36 pin?  Just to take all the other wires out of the equation.

I'm fast running out of ideas

Its the intermittent nature of this thats really killing the fault finding.

Incidentally the reason that no 6v dwell added is set to zero, is so that no extra dwell is added at high revs.

Rob

[BenFenner]

What about running a wire from the coil '-' direct to the EC36 pin?  Just to take all the other wires out of the equation.

Yah, that's a good point. I'll try that too.

I know what you mean about the intermittent thing causing major problems with diagnosis. I deal with problems at work all the time (computer technician) and I know what this must be like to diagnose.

We'll get it.

I'll try the few things left on my plate soon and get back to you.

[BenFenner]

Good news. I went out tonight and tightened the ECU plug connector to where it should have been all along. We then got spark, and for the entire night we had spark, no questions about it, no matter what config we loaded. I hate to admit it, but I feel it was my fault with the connector, and we can probably assume it won't happen anymore. Which makes it even more odd that you reproduced the results on your test bench. =/

The P259 channels are still not working, and we couldn't get them to work all night. I manually grounded the fuel pump relay, and we had the car starting and sort of idling consistently all night. We got ambitious and tried to get the idle working without success.

I've got a few questions that I'd like answers to.

When setting the base timing, it seemed that when I put a higher value in for "TDC after trigger (deg)" the ignition timing during cranking would retard. A lower value seemed to advance the timing. This was counter intuitive for me. This is the way it should be working though? And when I change this value by 15 degrees, I should expect a 15 degree change in timing? (Because I was getting 10 instead of 15).

Crank timing aside; when the car was idling, I was expecting 15 degrees BTDC as that was what was in my spark table, put I kept getting 5 degrees BTDC, and it didn't seem to matter what I put in the spark table. What's the deal?

I assume since I have ignition working now, we can figure these other things out, but I'm curious as to whether or not there's an older (more stable) firmware I can use that you might recommend instead as I'm not really confident in what I'm using. But then again, I'm not very experienced with VEMS yet.

Tachometer, fuel pump relay and coolant fan relay P259 outputs are not working. I guess that's our next step. That and this annoying timing crap.

[rob@vems.co.uk]

Well thats good news to start with, what I was seeing with your config and tables was: erratic spark (which I assumed was happening when the rotor was not lined up.)  The P259 was disabled (as mentioned before) which initially looked like the whole thing was buggered.

1.1.18 is a good release and we've had a full season's racing with the Time Attack S13 using it, so I wouldnt expect to see any advantage changing it.

I think one of the problems that we're going to have with the distributor providing the timing and the spark distribution is that theres more than likely going to be a mis-fit between the rotor arm and the trigger pattern directly below it, the way to get around that quickly would be to go to 4 coils, or to take a long hard look at where the triggers are in relation to the rotor arm (with that spare coil onto cylinder 1 and the fuel pump off you could - with care) strobe the cranking distributor to see the relative positioning.

To get round the issue with the P259, use one of the FET or IGBT channels to switch the fuel pump and coolant fans, even with COPs you'd still have 4 spare coil channels to drive them:
I259   0   EC36 pin 35   Drive 00
I259   1   EC36 pin 33   Drive 01
I259   2   EC36 pin 34   Drive 02
I259   3   EC36 pin 36   Drive 03
I259   4   EC36 pin 11   Drive 04
I259   5   EC36 pin 12   Drive 05
I259   6   EC36 pin 24   Drive 06
I259   7   EC36 pin 10   Drive 07   7 A   Ignition Driver

[BenFenner]

When setting the base timing, it seemed that when I put a higher value in for "TDC after trigger (deg)" the ignition timing during cranking would retard. A lower value seemed to advance the timing. This was counter intuitive for me. This is the way it should be working though? And when I change this value by 15 degrees, I should expect a 15 degree change in timing? (Because I was getting 10 instead of 15).

[rob@vems.co.uk]

The TDC after trigger defines the size of gap between trigger tooth and TDC.
If the gap is for example 60deg, and you set the value as 65deg then VEMS will think that the TDC is 5deg after TDC so the overall timing will be retarded by 5deg.  If you set it a 55deg then it will be 5 deg advanced.  For an extreme example if you set TDC after trigger to 10 deg the whole timing would be advances by 50degrees.

What value do you have?  You should be aiming for 60 to 65 deg TDC after trigger, I've seen some strange advance behaviour happen when I get to either extremes of the possible settings.

[BenFenner]

Yah, I'm around 0.0 to 6.0 for that value. And this is with the trigger tooth set to 0 as well. If I set it to 1, the timing retards aprox. 60 degrees. And if I set it to 2, the timing marks go out of my view area.

I'm going to flip the CAS disc back to the original install position I had it in. I'm pretty optimistic that I'll be able to set the trigger tooth at 2 or 3 maybe, and have the TDC after trigger value to something around 60.



I realize we can use my other outputs to cover for the fact that the P259 channels are misbehaving, but as this is a new item, and something I spent quite a bit of money on, I'd prefer if it worked correctly. If you know what I mean. =]

[rob@vems.co.uk]

So if you set it to 1 and set the TDC after trigger value to 50 you should have a 10 degree cranking advance (if cranking advance is set to 10)?

[BenFenner]

So if you set it to 1 and set the TDC after trigger value to 50 you should have a 10 degree cranking advance (if cranking advance is set to 10)?

I was wrong, when I change the tooth value from say 0 to 1, the timing changes 30 degrees. When I said 60, I was wrong.

I'm not even going to work my head around what you just asked, because I'm pretty sure Dan and I have it figured out.
We've come to the consensus after working on the car this morning that the distributor system is not up to the task. We flipped the disk, tried every combination of trigger tooth and TDC after trigger value, and manual timing advance. We could always get back to where we were, which just isn't good enough. We couldn't get the TDC after trigger value to be anywhere near 60 and have the timing in spec. After finally understanding how this whole system works, we looked at the position of the rotor, crank trigger hole, and cylinder 1 distributor post and decided we needed to turn the rotor within the distributor. It appeared to have 3 positions possible (mounting in a triangle base) but when we tried to turn it, we found this to be impossible, as the rotor would not seat. We think if someone else is going to do a FWD SR20 engine, and they absolutely insist on using the distributor, they could modify the rotor seat or rotor to allow this change, but I'm finished trying to get this to work. Don't get me wrong; I'm not fed up because of all the hours I've put into it. I would have come to the same conclusion much faster had everything been working correctly.

EDIT Nov. 28, 2007: After a lot of thought, I've realized it might be possible to still use the Nissan distributor without going to COPs. Instead of rotating the distributor rotor to another position somehow, the same results could be produced by transposing the spark plug wires on the distributor cap. I don't want to go through the hassle of trying it, but I'm confident it should work.

Coil on Plug, or some sort of ghetto coil near plug is the answer. I wasn't planning on doing it this soon, but I'll grab some COPs very soon. In the meantime I'll get the wiring ready for it, and I'll be working with Dan on his car.

Any recommendations on what type of COP to use? I heard somewhere (SR20 forums or VEMS forums) that Nissan's COPs weren't really the greatest. I assume they'd work fine, but if there's something else I should get, I'm all ears.

[rob@vems.co.uk]

S14 COPs are pretty good, it seems that the Skyline COPs are not much good.

IIRC dnb off this very forum has these:
http://www.034motorsport.com/product_info.php?cPath=26&products_id=39
running his V8, for a CNP installation.

Or you could go wasted spark.  Its upto you.

Me, I go down the breakers and grab what I think might work, I've had Subaru coil packs, Mitusbishi Lancer EVO 4, VW etc etc.  The only ones I couldnt get working right was the Lexus IS200 coils, but I reckon they'd run a treat with a bit of work

[BenFenner]

If you say the S14 COPs are good, then I'll go with those.

If I were to do coil near plug, I'd just grab 3 more of the Nissan coil that I already have, or grab 4 of those VW beetle ones you mentioned to me a while back.

I could do wasted spark, but I figure if I'm doing anything to the ignition, I might as well get it to the point where I intended it to be anyway.

Now I just need to find some S14 kit.

[rob@vems.co.uk]

My thoughts are based more on spending the least until a solution is found.  I was looking at an '04 Ford 4.6 yesterday the COPs on that looked quite good.  I'm not sure that the RWD SR20 and FWD SR20 have the same distance from rocker to spark plug.