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Thread: New guy here with a SR20 (Obviously) powered Datsun fairlady Roadster

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Posts: 11-19 of 19
2015-09-15 18:30:16
2015-09-15 18:56:23
nice project!
2015-09-15 19:57:41
wow awesome car.
2015-10-01 19:35:36
OK, getting back to the basics here and Ben's questions

"For example, how is your idle? Were you able to get the engine into ignition timing mode to set the ignition timing properly? How is cruising? How is WOT? How are throttle transitions?"

As you all can see I was unsure how to set or change the timing. The link to the timing guide was excellent to say the least, I had no idea about disconnecting the TPS and locking the timing, but I did have some hurdles to jump in order to accomplish this seemingly simple task.

So I grabbed my timing light, then realized that there are no spark plug wires to clamp to, tried the leads to the coil, this produced nothing so in a McGuyver way I made kind of an adapter using an old plug wire from a recent tune up on my Saturn

This allowed me to get the inductive flash to read the timing marks, so I thought.

This engine took most of my engine compartment and getting the light pointed at the timing marks, and to be able to see them was not working. I could see the backside of the pully clearly but the belt was interfering with my line of sight for the timing marks.

So I got under the car and hooked up a remote start switch so I could bump it around and have access to the pulley, then (McGuyver again) I put a small disk on my dremmel and using tape I carefully marked where the timing marks were at the front of the pulley, and created a new set of marks at the back of the pulley
Seen from the underside, (the last one is hidden in the shadow)

Anyway after all of this, warmed up the car, disconnected the TPS, revved to 3K a couple of times and checked the timing. It is currently set to 15 degrees advanced.
Still not idling well, but at least now I know where the timing is set, and how to adjust it.

I did run it around the block a couple of times hoping the computer would learn more, but still not idling well
Last edited by 68fairlady on 2015-10-01 at 19-42-55.
2015-10-01 19:47:41
Most of us with COP have to do the same thing to check timing with the temporary spark plug wire since the coil signal wires won't trigger the light, or trigger it at the wrong time.

You say you're using a stock S14 SR20DET Blacktop ECU and MAF. And the main problem you want to tackle right now is the idle?

Have you downloaded the S14 SR20DET Factory Service Manual? I would grab that and work through the diagnostic procedures for a bad idle. It will probably involve checking the MAF, and blocking or unhooking a bunch of tubes one-by-one to narrow down the issue.

You could also do a smoke test on the intake to look for leaks. I'm assuming you got rid of some emissions equipment. Did you cap and block off all of that properly?
Last edited by BenFenner on 2015-10-01 at 19-48-50.
2015-10-02 17:07:58
Your MAF is too close to the turbo. Turbulent air caused by the compressor blades is throwing off the reading. Well, it's a little more complicated than that, but there's the short answer. You need 15-18" of pipe between the MAF and the turbo. Your BOV should be recirculated somewhere in the middle of that pipe. Crankcase vent can be hooked in pretty much anywhere on that pipe post MAF.
Last edited by bhowle on 2015-10-03 at 04-34-01.
2015-10-09 15:53:13
Bhowle, That was good information, to test this I added a long pipe between the turbo and the MAF and ran the engine to temp. The idle was much more steady and the engine did not die after revving and rapid deceleration.
Not pretty, but did confirm that was the issue

So I had to re-engineer my cold air intake and now have this setup

Making good progress, Thanks for taking interest and helping me get the most out of this conversion.

Now on to some wiring and vacuum questions.... a new thread in the proper sub forum :-)
2015-10-09 17:33:16
Hell yes. Some times you just have to snorkel it.

2015-10-14 01:48:57
Glad I was able to help! I would also recommend recirculating the blow off valve somewhere between the turbo inlet and the MAF if you haven't already done so.
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