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

[rob@vems.co.uk]

So when the fuel pump is on the tacho goes mad?  I've had a problem where the fuel pump primes, sets up some sort of a ground loop which holds the ECU on, but nothing like that.
Thing is, that if the ECU thinks its reading a crank trigger it will turn the pump on and fire the ignition.  If thats the case you'll have to check for noise on the trigger wires.
The sheild is only grounded at one end isnt it? (Yeah I know its a n00b question, but its tricky to even know where to start with noise)
Engine block is well grounded?
Can you get a timing light on a coil and see if you cant force the trigger - I'll be interested to see if the coils are sparking.
Rob

[BenFenner]

I'm not sure about the shield ground. How ever it comes factory. I'll have to check.

The engine block is well grounded.

How would I force the trigger when I have the timing light on a coil?

[rob@vems.co.uk]

We've managed to get timing working pretty well (minor fluctuations, but we're attributing that to timing chain slop). We had to unbolt the distributor and turn it to an extreme angle (much more than normally available).

That is the CAS I have, just stripped it down - and guess what?  The screw wouldnt shift and gnarled up pretty nastily!

I've found some nice COPs in my collection and will basically end up doing the same as you've done there, got these nice little Toyota ones with built-in igniters 

Can you give me your CAS wiring info?  Cheers

Rob

[BenFenner]

This is the best you get from me right now:



I'll get the multimeter out and test the leads later (tomorrow) and tell you what is what. As far as the other plug goes that is not in the picture: it is coil related and not used either. Enjoy the pink!

[danmartin]

the two lines with the quick disconnects are the cas signal wires. On the far right is the ground and the second from the left is 12V.

[danmartin]

Also, Ben I will try to grab some coax from the power electronics lab and we can strip it down and use the shielding and ground it off and see if it helps. I really want to make a new harness, but then again im c - r - a - z -y!

[BenFenner]

Dan, your avatar needs to be bigger.

Also, thanks for the info. I remember the wiring order now. Hilarious how you know it better.

Uhh... We'll see about that shielding... I had break-up today like woah. I thought my spark plugs were getting much worse until I remembered we went back to the short dwell time. I really need new plugs.

[rob@vems.co.uk]

Excellent, thanks for that!  I was going to be able to find the CAS signals by probing the ECU connector, but you only get once chance to get the power + & - round the wrong way!

I'm still tempted to use that coil you know, just to see how its charge times relate to the COPs.

There is almost no tuning information about the DEs in the UK because they're not as common as the DETs and if you want power you use the turbo.

But...  If I run a turbo in MSA competitions I'm a man stuck in a category with Mitsubishi Evos, Subarus and specialist track cars, so I will loose massively.  If I can get this engine to kick out some power I'm in the Modified Production Saloon car category with NA 1400 to 2000cc engines, which means I still loose but by less of a margin

As I understand it I should be able to fit GTiR throttle bodies to this head, and as it has the solid valve lash adjusters potentially rev the thing way past 8K, the guy who did the solid adjuster kit for my S14 SR20DET revs his engine to 9500 daily...

[BenFenner]

The GTi-R head has the solid valve lash adjusters in it's head, so you'd need one of those. Not sure if the ITBs mate up to any other head, other than the GTi-R.

The best place for that sort of question is at:

http://www.sr20forum.com/

You can get any question you've ever dreamed of answered there. Also, there's an NA section where you'll find out just how much HP you can make NA. I believe there are some very serious numbers being put down. Also the guys with the variable valve timing SR motors (SR20VE) will give you something to dream about. =]

[danmartin]

Dan, your avatar needs to be bigger.

thats what she said 

[bcool]

She said no such thing.

...and where did you get a red display at???

[BenFenner]

Red LCDs were new when I was ordering a couple months back. I picked one up for Dan, as it matches his gauges better than the blue one.

[BenFenner]

A minor update on the break-up I've been having. I tried new spark plugs with no luck. It turned out I still had one bare wire floating around that I finally found. I've wrapped all the wires now, and it's looking a lot better. As for the car, it runs great now. I've still got some work to do with idle, and cold start but those are looking much better as well. The new starter will go in soon, and that should help even more. I finally got the old ECU out, and put VEMS in it's place. It's nice to not have VEMS and tons of wires in the foot well anymore. =]

Things are looking really great. The only nagging issue I'm having now is with the LCD.

Rob, what happens when the LCDs fail as you say they tend to do? What behavior have people described?

[rob@vems.co.uk]

They start to show black blocks rather than characters, or they start dumping text on the screen.

Everything else seems to function fine though.

[BenFenner]

Yah, mine is dumping characters (usually numbers) in spots where they shouldn't be. It seems to happen most when the engine dips below 700 rpms for a second.

Anyway... It seems as though it's the VEMS component, and not the LCD itself that is messing up. I feel like it could be solved if all of the LCD blocks would update once in a while, or refresh instead of just the currently changing data. This would keep my screen clean, as it takes a bit of time to mess up, and when it does, all it would take is a refresh of that block to clear it up. Would this be something the developers would be interested in considering?


Also, does it get worse? Or is this as bad as it should get?