Author Topic: 1994 Nissan Sentra SE-R going VEMS, then turbo.  (Read 194889 times)

Offline BenFenner

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Re: 1994 Nissan Sentra SE-R going VEMS, then turbo.
« Reply #60 on: October 03, 2007, 05:42:08 pm »
So what should I be paying attention to when looking for a change? We think the ignition will behave differently?
1994 Black SE-R (VEMS, going turbo)
1994 Black SE-R (with sunroof)

Offline rob@vems.co.uk

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Re: 1994 Nissan Sentra SE-R going VEMS, then turbo.
« Reply #61 on: October 03, 2007, 07:14:49 pm »
What I'm expecting is the spark to be consistent rather than having to mess around with firmware.

Then introduce each one of the P259 connections in turn to see if you can find one that causes the system to fail.
If that doesnt work, try combinations.

Offline BenFenner

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Re: 1994 Nissan Sentra SE-R going VEMS, then turbo.
« Reply #62 on: October 04, 2007, 01:53:07 am »
Went out tonight, no spark. Unplugged all P259 channels, no spark. Reflashed firmwares like it was my job, no spark. Nothing I did got spark back. I recall yesterday switching the ignition output to EC36-pin 33 with no luck, but then EC36-pin10 recovered spark. I tried that again. No dice.

Manually grounding the P259 stuff would turn things on (fuel pump, radiator fans, etc.)

The only other thing of note: I checked my grounds for resistance. The best ground I have at the front of the car is an 8 gauge wire that goes to my battery in the trunk. This wire powers an audio amplifier under my dash. The resistance from the battery terminal to this ground is 15 Ohms. The resistance between the VEMS grounding pins and the battery terminal is 30 Ohms or so. Not sure if this helps any.

Currently dead in the water with no spark.
1994 Black SE-R (VEMS, going turbo)
1994 Black SE-R (with sunroof)

Offline rob@vems.co.uk

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Re: 1994 Nissan Sentra SE-R going VEMS, then turbo.
« Reply #63 on: October 04, 2007, 08:08:17 am »
When you crank the engine does the RPM read on MegaTune?
Remember to make sure that you save your configuration inbetween firmware upgrades using the download-config.bat, generate-config.bat and upload-config.bat files, loading and saving MSQs are not the recommended way of doing things.

No RPM and P259 problems are commonly associated with grounding problems, I dont suppose that you could do me a photo of the harness?
And send me over the config.txt and tables.txt and I'll test them on my bench with the same trigger setup that you have.
Rob
« Last Edit: October 04, 2007, 08:34:34 am by rob@vems.co.uk »

Offline BenFenner

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Re: 1994 Nissan Sentra SE-R going VEMS, then turbo.
« Reply #64 on: October 04, 2007, 03:29:06 pm »
When I crank the engine, I still get an rpm reading. It's been very consistent.

Yes, I've been saving and loading the config files to restore settings. But now that you mention it, I haven't been generating the config files I don't think... so maybe I've been using old *.mtt files this whole time. I'll look into that. Even so, I made sure the settings were correct each time before moving on.


I'll get you pictures of the wiring harness adapter, and e-mail you my configuration files. I'll probably send you the one's I've been using, and the one's I thought I should be using. =P
« Last Edit: October 04, 2007, 03:34:15 pm by BenFenner »
1994 Black SE-R (VEMS, going turbo)
1994 Black SE-R (with sunroof)

Offline BenFenner

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Re: 1994 Nissan Sentra SE-R going VEMS, then turbo.
« Reply #65 on: October 04, 2007, 03:48:47 pm »
Here is the wiring harness adapter in all it's glory.
The common grounding point should be easy to spot. It may look ugly, but there's no resistance across it.































1994 Black SE-R (VEMS, going turbo)
1994 Black SE-R (with sunroof)

Offline BenFenner

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Re: 1994 Nissan Sentra SE-R going VEMS, then turbo.
« Reply #66 on: October 04, 2007, 10:34:17 pm »
So, any thoughts on what to do/test next?
It's so humid out, I'm not going to go mess with it unless I have a plan.

I turns out for the most part I was creating the config files prior to uploading them. I just wasn't in charge of that, and so I'd forgotten it needed to be done. My friend said he'd been doing it.
« Last Edit: November 29, 2007, 04:47:53 am by BenFenner »
1994 Black SE-R (VEMS, going turbo)
1994 Black SE-R (with sunroof)

Offline rob@vems.co.uk

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Re: 1994 Nissan Sentra SE-R going VEMS, then turbo.
« Reply #67 on: October 04, 2007, 11:03:09 pm »
Good ground cluster there, thats fairly key.

I've run those configs on my test bench and its looking very strange...

First theres spark, then theres no spark, I'm seeing the coil 0 issue its 1/4 the speed of the RPM - very odd...

Theres some investigation to be done here, hold tight and I'll see what I can find...

Rob

Offline BenFenner

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Re: 1994 Nissan Sentra SE-R going VEMS, then turbo.
« Reply #68 on: October 04, 2007, 11:35:40 pm »
I'm not going mad!

Excellent.

I'm so glad you could reproduce it. Take your time to figure it out.
« Last Edit: October 05, 2007, 12:55:15 am by BenFenner »
1994 Black SE-R (VEMS, going turbo)
1994 Black SE-R (with sunroof)

Offline BenFenner

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Re: 1994 Nissan Sentra SE-R going VEMS, then turbo.
« Reply #69 on: October 05, 2007, 06:33:01 am »
Rob gave me new config files to try.

Still no spark.

Awaiting further help.
1994 Black SE-R (VEMS, going turbo)
1994 Black SE-R (with sunroof)

Offline BenFenner

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Re: 1994 Nissan Sentra SE-R going VEMS, then turbo.
« Reply #70 on: October 06, 2007, 04:39:34 pm »
Rob's now told me with the 1.1.xx firmware, the 6V dwell time must be set to zero. No idea what happens when it doesn't, or why the programmers didn't force zero, but what ever.

Also, Rob's given me a new config file to try. My girlfriend is down for the weekend, so I'll see when I can get to trying it.
1994 Black SE-R (VEMS, going turbo)
1994 Black SE-R (with sunroof)

Offline rob@vems.co.uk

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Re: 1994 Nissan Sentra SE-R going VEMS, then turbo.
« Reply #71 on: October 06, 2007, 05:21:25 pm »
We are also doing a load of work on this, I've been scoping the outputs on my unit on the test bench, with Jorgen's help last night we did some diff's on various configs and are trying to see what exactly caused the problem.
Your original configs (The ones that you sent on Thursday) are going to be studied carefully this weekend by Marcell who is doing a large number of tests across a range of triggers and configurations.

One thing that Jorgen said was that you should perhaps quit the firmware uploads, once the firmware is up its the changes to the configs and tables that change the way the system works, the firmware is static, its stored in flashmemory which cannot be changed apart from a reflash.

I'm not sure about the 6V dwell time to be honest, its something that I'll be looking at to try and understand and document, I know that there have been significant changes in 1.1.xx firmware regarding dwell time and the way that VEMS controls the coil charging based on RPM.

Offline BenFenner

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Re: 1994 Nissan Sentra SE-R going VEMS, then turbo.
« Reply #72 on: October 06, 2007, 05:53:57 pm »
Okay, I'll stop the firmware uploading. I understand it's static, but from my point of view, it seemed to change something when I changed it, however crazy that sounds. Thanks for all the work you've been doing, and will be doing. I appreciate it.
1994 Black SE-R (VEMS, going turbo)
1994 Black SE-R (with sunroof)

Offline BenFenner

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Re: 1994 Nissan Sentra SE-R going VEMS, then turbo.
« Reply #73 on: October 09, 2007, 02:47:04 pm »
I'm recalling this from memory, so don't quote me on this. I tried the config and table files you sent. When I try to create the *.mtt files from them, the table file can not create. It complains about the line beginning in "y[0]" saying it and everything after it is an invalid line I believe. When I removed all "y" entries from the table text file, it created the mtt file with two warnings.

I then uploaded the mtt files, and gave the car a crank. No spark. I didn't have much time, so that's all I did. I just wanted to let you know, as I'm still busy with other things. Maybe it's a quick fix for you. Did that table file really work for you on your end?
1994 Black SE-R (VEMS, going turbo)
1994 Black SE-R (with sunroof)

Offline rob@vems.co.uk

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Re: 1994 Nissan Sentra SE-R going VEMS, then turbo.
« Reply #74 on: October 09, 2007, 07:13:51 pm »
The Y entry is from the newere 1.1.27 code.
And yes it did work, believe me I would not waste your or my time giving you configs that were not tested.
The reason the P259 channel on the pump was not working on the config you sent me had the fuel pump 'disabled' which explains the lack of output.

The next thing to try is to move the IGBT channel to 01 (EC36-pin33) we cannot be sure that a short or something has hurt the IGBT.

And I found out the reason why you had to have h[2] = 00 00 00 00 ... thats because 1.1.18 was a Coil On Plug only firmware, which of course the Nissan 200SX has, its no biggie just have to set all your h[2] entries