510 L20B EFI conversion - the project is finished!

[Unclejesse88]

I can't think of any reason to disable the pump during cranking, as that is when you need to pressurize the fuel rail. HRH's system uses an air flow meter, and usually there are fuel pump contacts inside the air flow meter. Meaning, not enough air flow to move the flapper enough to close the contacts, and the pump won't turn on. I'm not sure about nissan, but toyota uses a circuit opening relay for the fuel pump. The relay has two coil circuits, a capacitor in parallel with one coil, and the high power contacts. One coil is energized by the stater circuit, to prime the system during cranking. The other coil has key on power, and the coil ground is provided by the air flow meter when the door opens far enough, meaning this circuit runs the pump when the engine is running. The capacitor in series is used to damp the pump circuit, just in case the flapper door "bounces" closed enough to open the pump circuit. If this happens, the capacitor will discharge into the circuit to keep the relay on.

 

If this were a more modern ecu, then the fuel pump relay would be grounded by the ecu. Those ecu's generally run the pump for a few seconds key on engine off to pressurize the rail, then wait for a few hundred rpm to turn the pump on again.

[HRH]

Okay, time for some more pictures! Got the fuel rail back, after I pressure test it I think I'll probably throw some paint at it. Went to the wrecking yard with Joe he showed me where the Subi pumps are located. Similar to the 280zx pump but outlets are inline and it's mounted to a really nice rubber mounted chunk of metal, so I'll probably use this one instead. I couldn't find one earlier, was looking in the wrong spot, hence grabbing the 280zx pump.

 

The inlet on this one is also 3/8, but Joe said he made a fitting adapter and never had any issues with not providing enough fuel. So I'll be going that route since it's going to be a heck of a lot easier than welding a different bung onto the tank.

 

Also have the pictures of the 2 3/8 hole saw cut through the firewall. Makes the ECU harness almost look factory! It will be mounted right below the hood pop, good thing I never put any speakers there.

 

[Unclejesse88]

Does the 200sx use a cold start injector? I can't tell if that is one just behind the throttle body. If it does, how do you plan on running fuel to it?

[HRH]

It does, not using it. Joe doesn't use one on the roadster or the truck, said he's never had an issue even in cold weather. I did put it in there mainly to block the hole, and that way if I experience an issue I can run a line to it easy enough.

[yellowdatsun]

What was the reason you used the weird TPS? When I did this setup years ago I just used a standard Nissan TPS that matched the later 83-84 200SX TB.

 

A 60mm TB is probably overkill. It might seem like it's "quicker", but it's only because it opens more area sooner. Which may, or may not, be a good thing for driveabilty.

 

You don't need the factory idle control, you can adjust the idle via the setscrew on the TB just fine, assuming the TB you're using has one. The early ones did.

 

On mine I just sectioned the stock Z fuel rail, and reconnected the two halves with efi rated hose. Worked fine, and looked factory, but was still kinda ugly.

 

I used a 280ZX fuel pump on mine.

[Farmer Joe]

so you get this thing runnin yet?

 

that would be hella badass... lol :lol:

[HRH]

No, not yet, I did drill holes for mounting the fuel pump and mounting plate tho. Might finish that up tonight, plumb that in, then need to run power to it. Slow going, spent the last weekends screwing around with the D21 spring bushings, which are done now. Need to update that thread too.

[HRH]

Okay, a little update: Been working sporadically on the 510. Have the pump mounted, almost have my adapters but my Datsun guru turned them the wrong dimension on the lathe the other day, so don't quite have the fuel line hooked up. However, I did mount my new 14 gang fusebox (from NAPA), it's not too bad, but doesn't have a plastic cover or anything. It will still work, I'll probably throw some electrical tape on the connectors or make a plastic cover or something that will completely isolate it from water and/or wet feet as it's mounted in the passenger firewall inside the car. It's pretty high up though, probably won't have any issues.

 

Got some relays and connector plugs at the wrecking yard yesterday, and a good cable half moon for the throttle. I finished rewiring in the new fusebox this morning, still need to run another relay for the fuel pump, and probably one for the ECU, and wire those in, then electrical will be taken care of, aside from rewiring the TPS. The good thing is the new fusebox is all blade fuses, I got rid of the other aux. fusebox which was mounted next to the original fusebox. It was from a 620. Trying to get rid of the glass fuses. Still haven't found the desire to rewire the original fusebox though. That's a project of mass proportions. I'll do that when I find another 510 and have the time and space to completely strip it down.

[HRH]

Ha ha! I love it when you figure something out that someone else couldn't! Back onto the wiring, have the pump connected up, the new fittings worked well being the correct size. Mounted some relay tangs, and was starting to get ready to run connections for the EFI main relay and the fuel pump relay.

 

Since the last time I looked at the ECU was about two months ago, I figured I had better brush up on the wiring diagram and make sure I knew what was going on. This is the ECU/harness I got from Datzenmike, from a junkyard 200sx. I FIGURED OUT WHY IT WENT TO THE JUNKYARD IN THE FIRST PLACE!!! :) Okay, maybe not that exciting to you, but exciting to me. Then again, I'm easily excitable.

 

I had a connector harness that had the blade broken off, and the whole thing was marvelously corroded with green crap all over. I marked it as bad, but didn't probe much further until today when I was figuring out where the ECU main power went. I realized it wasn't the yellow gigantic wire I had though earlier; that one went to the starting system, which I won't need to connect since I'm still going through the 510 wiring for starting. Turns out its the spout right next to it (position 27) with a red wire. That red wire was connected in the same block as the broken off blade going to a blk/wht wire. I knew it should be connected to the funky box with a ceramic insulator. Until now I didn't know what that does. Apparently it's some sort of ballast resistor for the injector system, and the blk/wht piggy backs from the other connecter, sends it into the ceramic insulator and comes out as four white wires which go to the injectors.

 

So if the connector with the broken/corroded spade didn't have a good connection, it wouldn't have sent any juice to the injectors. In which case, the car wouldn't have run and would have been a bitch to find unless someone decided to disconnect that particular connector, which they probably didn't. I imagine they went after relays/fuel pump, etc. That's why the car ended up in the wrecking yard!

 

So now I'm all happy because I know where things go and what they do. Going to eat lunch and go back at it. It's been raining buckets all day, the garage is not leak proof.

 

[datzenmike]

Allright! Yeah that's the dropping resistors and heat sink for the injectors. It was mounted below the air box.

 

[LenRobertson]

Allright! Yeah that's the dropping resistors and heat sink for the injectors. It was mounted below the air box.

 

Am I correct in thinking this part must be used, at least when using Nissan injectors? I recall reading in my '81 200SX shop manual these resistors drop the voltage to the injectors to about 3 volts (not sure about the exact number, but think it is considerably less than 12V). Do most make injectors run at less than 12V, or is this peculiar to Nissan?

 

Len

[HRH]

Yep, it must be used for this system. I have no idea what other systems used. Considering these injectors were relatively cheap to obtain even new, I would imagine other systems use the full 12v for better control and probably higher pressures.

[HRH]

Here's a video I made tonight. Got most everything finished. Called it quits after I wired the fuel pump to the hot side of the switch and couldn't figure out why it wasn't switching. :) Decided I was tired enough, fixed it, and going to vegatate a little, eat a waffle, then go to sleep. Enjoy!

 

[HRH]

I might add I'm soldering all connections and heat shrinking. I hate crimp connectors! Also all fuel line has been switched out to fuel injection fuel line regardless of suction side or pressure side. Don't want to have a failure. I have left the return lines for now as they're the old plastic clear kind and they're on there with a vengence due to age. I'm going to see if they hold since they're fairly easy to get to and replace if need be.

[HRH]

Does anyone know if the number 21 ECU connector (goes to fuel pump) needs to be hooked to the fuel pump signal? The pump is turned on by a relay, so it's already energized, but then it piggybacks off that, goes through the air regulator and into port 21 on the ECU.

 

I'm not using the air regulator, and since the fuel pump on the stock wiring diagram already has power at key on, I'd assume it doesn't need to be connected to the ECU, but not entirely sure. Thinking I'm going to leave it unconnected for now, but if anyone can clarify that before I get to that part...

 

EDIT: Corrected, 21, not 27. 27 is ECU main power.

[Sealik]

Does anyone know if the number 27 ECU connector (goes to fuel pump) needs to be hooked to the fuel pump signal? The pump is turned on by a relay, so it's already energized, but then it piggybacks off that, goes through the air regulator and into port 27 on the ECU.

 

I'm not using the air regulator, and since the fuel pump on the stock wiring diagram already has power at key on, I'd assume it doesn't need to be connected to the ECU, but not entirely sure. Thinking I'm going to leave it unconnected for now, but if anyone can clarify that before I get to that part...

 

The 27 (red) from ECU....to connector....than the LgB (light green/black) goes to the EFI relay

[Sealik]

Question.....

 

Does the unplugged air regulator give the ECU false 'info'....thus compromising the engines performance.....?

ie......to rich and or lean?

I'm thinking after the engine is warm.....the MIA AirReg has no affect on performance.

Correct?

[HRH]

I think you're correct Sealik. I just went and tried to find port 21, surprise surprise it didn't have any outlet! Finally traced it to the Air Reg connector (which I'm calling the cold start injector) and that traces back to the big blk/wht power wire I'm going to relay as main ECU power. I'm pretty sure it doesn't need it, I think it may be a fuel cut thing during cranking, not sure. Either way, I'm leaving it off and preparing to wire it as I originally thought.

[Sealik]

I think you're correct Sealik. I just went and tried to find port 21, surprise surprise it didn't have any outlet! Finally traced it to the Air Reg connector (which I'm calling the cold start injector) and that traces back to the big blk/wht power wire I'm going to relay as main ECU power. I'm pretty sure it doesn't need it, I think it may be a fuel cut thing during cranking, not sure. Either way, I'm leaving it off and preparing to wire it as I originally thought.

 

 

The air reg has a bi-metal spring and heater in it. Soon as the ignition switch is turned on, or if the engine is running, electric current flows through the heater......as the heater warms up, the bi-metal spring closes the air passage (which was by-passing the TB)........basically a choke.

I'm assuming the ECU compensates the engine with a more rich or lean mixture on cold start-up?

Disregard my info if you already were wary....... :)

I figured the ECU would be somewhat confused (as I ;) ) when the AR is MIA...... :D

[Sealik]

Yes.... 21 goes to the air reg......

On another note......I believe I routed 27 to my rear window defog (relay) switch....makes a nice incognito kill switch :D

 

Edit.....I have the 200sx manual....80-83.

[Unclejesse88]

Crimp connectors are fine, as long as you use the right crimps, and the right crimpers. Those cheesy blue red and yellow crimps from the parts house are worthless. Get some quality uninsulated butt crimps, and use a proper ratcheting crimper that has teeth on the die, and you will never have a failure. Soldering can be ok, but if you solder in a high vibration location, you risk failure. Also, make sure you use solder with lead in it, other wise it will fail. The lead keeps the solder from forming tiny spikes all over, that lower the solder quality. I will also advise you to go with heat shrink with the adhesive inside, to make a true waterproof seal. Check out this link, http://p71interceptor.com/motorcraftpigtails/tsb051807splicing.pdf and scroll down to figures 7 and 8. 7 shows the style of die in the crimpers, and figure 8 shows the butt connector. The only comeback I've ever had using this setup is a wire in a flex loom breaking right next to the repair.

[Sealik]

Does the 200sx use a cold start injector? I can't tell if that is one just behind the throttle body. If it does, how do you plan on running fuel to it?

 

 

Cold start injector.....?

 

Do you mean the air regulator, the head temp sensor (81+ models) or the water temp sensor (80 models)?

[HRH]

Why would soldering in a high vibration area risk failure? I mean technically crimping is just fine, it's what they do from the factory since it's cheaper and quicker. I actually crimp them first with the teeth crimper and then solder them also and then put some heat shrink tubing over the joint. Never had any of my wiring fail. I'm not too worried about complete waterproofing. If I waterproof, I just take whatever RTV I have and completely seal the joint.

 

And on a side note, figured out today that the potentiameter style TPS found on the SR20 throttle body will not work as the original version is actually a three position switch, not a potentiameter. So I either adapt the three position switch to work (my Datsun guru has one like that) or use a Z car throttle body. I'm leaning toward the latter as I'm also having clearance issues with the half-moon for the throttle and the Z car throttle axis is about a half inch more forward of the intake runner. I'll have to fart around with it later.

[HRH]

The 200sx doesn't use a cold start injector, but conveniently the plug still fits it, just like it fits the air regulator. Talked to Joe about that as well. The air regulator allows air behind the air flow meter to raise the idle on cold start up. It's basically an unmetered (metered) air leak! Kinda neat. I'm not using it, and Joe mentioned it won't do a high idle when cold so you may have to hold the throttle when it's cold, just like a rig without a functioning choke. Doesn't matter once it's warmed up. No problem for me since it's going to be a race car, and I never had chokes hooked up on the SUs either.

 

I have been referring to the cold start injector, but forgot that I'm using the 280z manifold shortened down which has it, compared to the 200sx which had the air regulator. I don't know if they used the cold start injector in later models or not.

[HRH]

Allrighty then! Been making some good progress on the 510. Have a few more things to complete, but she's really close. I figure another week or two and I'll have her rolling around the block for a test run depending on how much stuff goes on.

 

Spent today hooking up most of the fuel system, made a spacer plate for the throttle body since I was having clearance issues with the throttle half moon. Probably should have made the manifold longer, but didn't think about that when we were making it. All the electrical is finished now with the exception of running the battery and cables behind the passenger seat. Wanted to get it out of the engine bay and transfer more weight to the rear. Plus as Datsun guru Joe pointed out, if you punch that side, it'll take out your battery, whereas you might get away with banging the corner and stalling if the battery doesn't take the hit. Minor inconveniences.

 

Next thing to do is clean up the KA throttle body and install, then figure out where I want to put a PCV valve. Then a throttle cable attachment point needs to happen. I'll have to make a little bracket or something. Check out the fuel pressure regulator off the intake! Made a slick little setup, welded one line shut, which traps the FPR in the holder just perfectly. Need one more adapter to fit the return line to the FPR. That's about it. Pictures below.

 

Oh, BTW, if I had this to do again, I would have just put in a complete KA or something with fuel injection already done. Technically this setup is cheaper, but I probably could have bought a new manifold for a single sidedraft Weber for around 800 bucks. While initially this seem much cheaper, all the little tiny bullshit I've had to make, find, etc. has probably about evened the cost. But oh well. I'll enjoy better fuel economy and driveability, particularly in winter, so it's still a plus.

 

It was asked earlier why I was using an SR20 tb. I'm not anymore, you have to adapt the old three wire switch TPS to work with it. As it turns out the KA throttle body (this from a Stanza) is the same size as the SR20 anyway, so that works just perfectly.