Watson

Wow, that paint looks good! Good job, man!

Real quick, the car runs well while the engine is cold/warming up but leans out a lot at running temperatures despite an extreme fuel increase in the VE table. Also, there is an intermittent fuel cut that I can't quite figure out. I have also tried adjusting the VE table with and without O2 correction and I still have a lean mixture. Please see the video for more information.

Thank you! Its running. Its moving. Got a basic tune done to at least take Watson around the block. Huge thanks to my buddy Zach for helping out with the build. It took just over a month to make this all happen and now its all about tuning to get it to run great. Stay tuned to witness the true power of Watson the Datsun!!!!

Its alive!!!!!!

Problem solved. A phototransistor just couldn't cut the mustard. An IR receiver and IR LED combo worked perfectly. Interesting...

Software to view the tune is free by the way. Either MegaTune or the unregistered version of TunerStudio can be used to at least view a tune FWIW. Of course you would need to limit the voltage going to your resistor based on your application, which I have done, but I feel the issue lies with the phototransistor. I noticed that Crane Cams uses a sort of diode as opposed to just a phototransistor so now I wonder what the difference is between their diode and my phototransistor. They also don't have a resistor inline with the signal-generating diode so clearly there are multiple factors different between my setup and theirs. Tomorrow I will find out if that does in fact make a difference. If this post ever comes up in a Google search in the future (I hate unfinished forum threads) please locate my build thread. Google "Watson the Datsun" and I'm sure you will find it somewhere on the internet. Here or elsewhere.

There have been many late nights of tuning and trying different setups only to still not have it start. I've ordered a replacement XR700 optical sensor as I suspect my frankenstein sensor may not be up to the task of automotive use. It should be here tomorrow. Fingers crossed.

Hmmm, interesting. I don't have a tach other than the megasquirt's display. I'm beginning to question the quality of my optical trigger. You see, I constructed it with just an LED, a resistor (can't remember the value), and a phototransistor. In theory it should work but I wonder if it is up to the task of rapid changes in light value (or lumens if that's how it's measured. Ultimately its just a resistor though). I think I will go ahead and order a new optical trigger. Any other suggestions? How does the tune look for at least getting running?

Every once in a while I can get the car to idle but only at 200 rpm, and if I give it any gas or let off, it dies. The ideal TPS ADC seems to be 38 for it to even somewhat idle. Any more or any less and it dies. I've tried so many different settings it hurts. I'll attach my current tune. Specs: N42 Block/Head Stock L28ET turbo and injectors S13 240SX TPS Innovate MTX-L wideband O2 sensor MS1V3 running MSnS-E on code version 029y3 MS controlling Crane Cams Fireball LX91 coil firing NGK BPR7ES plugs gapped ~ 32 Crane Cams optical sensor and trigger wheel although I ended up tearing it apart and making my own working optical sensor. At least the RPM readings are steady and accurate. I think that's the pertinent stuff. With my current static spark settings I'm reading 10 degrees BTDC according to my timing light while cranking. I'm definitely getting fuel as I can really smell it and I've fouled out some plugs. It cranks and kicks like it wants to start but it just wont get going. Any help would be greatly appreciated. Watson.zip

So close! So very close! I figured out a solution for the optical sensor and I've now got fuel and spark. I got even closer than this video but I need to hash out my enrichment table and uhhh get a new starter. Shit.

I have been busting my brain-balls trying to get this ignition thing sorted out. Many solutions have been tried and I ended up frying a CDI module and I think I broke the optical trigger. So I built a new one. After testing many different setups with mixed results, it was time to call it a night. I'm exhausted. Until tomorrow...

So close! Everything works, I just don't have spark. I'll have that hashed out soon!

Don't forgot the oil pump. You'll need to remove that to gain access to a bolt on the timing cover. Be extra careful (liberal use of PB Blaster) not the break the waterpump and timing cover bolts off into the block. Ask me why I know this...

Today was quite interesting. I fabricated an exhaust system with scrap pipe and started wiring the the harness. I then just hit a brick wall in regards to exhaustion and just decided to call it a day, have a beer and enjoy the rest of the afternoon. Watson has a real rat rod look now! Or just a ghetto look...

The engine is in! I had a dream last night that the engine would just mesh up the next morning without a hitch and sure enough, it did. Weird. Got a lot of bits installed. Good news: The lights are working and the fuel pump is working as well as the FPR which is reading at a solid 3 BAR. I stared working on the panel for switches, fuses, and relays. Will tomorrow be the day it starts? I hope so; there's a drift event next weekend. A video update will happen tomorrow.

The day started with people just stopping by to chat and decided the engine bay needed cleaning. I didn't ask for it nor did I care, so on with the cleaning they went. While they did that, I worked on removing more unneeded equipment. No more dashboard. Lets do this. So close, yet so far. The engine needs to move another half an inch and mesh up with the transmission to make this task complete, but I'm tired. Until tomorrow.

I finished the engine; time for a beer.

Great job on the exhaust! Are you still using the stock downpipe?

It's finally starting to look like an engine.

Today was not my day to work on Watson. I took apart the front of the engine to address the broken stud. I accidentally drilled the hole into the block too large and there is no room for me to expand the hole in the timing cover without risking cracking it, so I just had to put it back together. I then broke one of the studs while installing the exhaust manifold. I at least had extras. I was having issues getting the bolts to go in for the intake manifold so I just called it a night. I'll pick up again tomorrow.

Tell me about it... After everything is broken in and tuned, 300 whp.

About $4000. $1000 for the car and $3000 in parts. There are miscellaneous nickle and dime costs though as with any build.

I finished the ECU and got it buttoned up.

I got the differential welded today. It was quite a task considering the half shaft bolts didn't want to come out, so I ended up welding it with it in the car.