510 L20B EFI conversion - the project is finished!

[HRH]

Talked to my Datsun guru and he's never messed with the AFM other than fine adjusting the idle via the little screw under the round button cover on the AFM. Tested a known good ecu borrowed from him last night, exactly the same.

 

Figured out it's a fuel issue, namely getting too much. So I yanked off the vacuum cap and made a massive air leak and what do you know, she smoothed out and started idling. Low, but way better response. Therefore I've come to the conclusion it's either the FPR or the brand new injectors which were of a different style nose, but otherwise the same. Going to get the crimp collars off the OE injectors and put those in. If that's all the problem was I'm going to be seriously pissed. And then I'm going to call up the injector people and ask them wtf.

 

It's not guaranteed yet, they might be fine. However, I do know Joe has only used original Nissan injectors in all his conversions. Anyone else use aftermarket injectors like I did? (Granted I used the cheap aftermarket we carried, simply because the good ones were 50 a piece or more.

[datzenmike]

Take the box apart and lean out the MAF by turning the wheel rather than a leak in the hose. That leak will only affect idle and low speed. This set up is quite rudimentary and does not have O2 feedback so larger injectors will just dump more fuel so the ECU needs to be fooled into thinking less air is entering so it leans out.

[Sealik]

Take the box apart and lean out the MAF by turning the wheel rather than a leak in the hose. That leak will only affect idle and low speed. This set up is quite rudimentary and does not have O2 feedback so larger injectors will just dump more fuel so the ECU needs to be fooled into thinking less air is entering so it leans out.

 

 

Yes.....1 0r 2 positions CW

[HRH]

But that's my point, if Joe's truck has the exact same non-O2 system and he hasn't messed with the AFM, yet his truck runs perfect, then I shouldn't need to mess with it either. I'm not using bigger injectors, or at least they're not SUPPOSED to be bigger. They're supposed to be stock replacements. But considering sometimes the aftermarket is not as great as it could be, I'm going to try the OE Nissan injectors first before I change anything else. The system works great on Joe's truck and it's only a L24B versus my L20B. There's not that huge a difference in fuel requirements, and he has a lumpy cam just like I do.

[Sealik]

But that's my point, if Joe's truck has the exact same non-O2 system and he hasn't messed with the AFM, yet his truck runs perfect, then I shouldn't need to mess with it either. I'm not using bigger injectors, or at least they're not SUPPOSED to be bigger. They're supposed to be stock replacements. But considering sometimes the aftermarket is not as great as it could be, I'm going to try the OE Nissan injectors first before I change anything else. The system works great on Joe's truck and it's only a L24B versus my L20B. There's not that huge a difference in fuel requirements, and he has a lumpy cam just like I do.

 

 

I see....then you must confirm injector flow rate

[datzenmike]

Try your AFM on his truck, try the ECU, swap the fuel rail....... one should fix it. Fuel pressure reg???

[HRH]

New fuel pressure regulator works quite well, no more fuel pressure guage fluctuation, so obviously the old one was fuckered. Also started running better until the pressure dropped below 30 and began hovering at 25, then backfire lean pops and no running, which is good. So apparently my pump is giving up the ghost. Cleaned the screen this morning, put back in, takes a LONG time to reach 40 psi without the engine running. Once it does it starts and takes a few seconds between running well before the pressure just starts to bleed off and goes to 20-25 psi.

 

So, debating whether I want to get another junkyard pump or just pony up the dough for a new one. Thinking a new one may be less hassle.

[HRH]

So fortunately for me, Carter (NAPA Fuel Pumps) makes a copy of the Bosch pump that's fairly close. It's a P70304 NAPA number. Bit of a pain to find, but comes up as an option under '83 280zx. And even better we had one in stock! I'll be putting that in tomorrow morning, and hopefully that's the last of the issues with the EFI. Then I can just make my throttle cable bracket and air filter and be done finally.

 

Sealick, did a standard 32/36 weber rectangle filter fit on the AFM? Did you have to cut out or weld up the hole for the carburetor body? I'm going to use the same thing in the 2.5" filter version. Was debating having them ship me two top plates instead of one for the body of whatever carb, then just cut out what I needed.

[I'm BLUE]

HRH I love this thread man :cool:

[Sealik]

So fortunately for me, Carter (NAPA Fuel Pumps) makes a copy of the Bosch pump that's fairly close. It's a P70304 NAPA number. Bit of a pain to find, but comes up as an option under '83 280zx. And even better we had one in stock! I'll be putting that in tomorrow morning, and hopefully that's the last of the issues with the EFI. Then I can just make my throttle cable bracket and air filter and be done finally.

 

Sealick, did a standard 32/36 weber rectangle filter fit on the AFM? Did you have to cut out or weld up the hole for the carburetor body? I'm going to use the same thing in the 2.5" filter version. Was debating having them ship me two top plates instead of one for the body of whatever carb, then just cut out what I needed.

 

 

Yes.....that Weber filter will fit.

 

 

 

Just auged the base out a bit, drilled a couple holes.....then 'slathered'. ;)

Ill post some pics.

 

I ordered an equivalent 200sx pump a while back....was a 83 ish 280zx....from the States.

Who would of thunk.......... :D

[HRH]

HRH I love this thread man :cool:

 

 

I'm glad, this has been a pain in the ass. My roommate Buddy asked me tonight if it was cheaper than just buying a new manifold and carb(s). Originally I had thought so. On paper it worked out cheaper. In actuality, it seems it's easily as expensive, if not more so. Time aside, because if we counted time I would have already lost my ass!

 

But I keep telling myself once it's finished, I'll be happier with the end product. I should have more power, better mileage, and no retweaking after finally getting it set. Trying to balance dual SUs at -5 degrees in the middle of winter at Deer Park Airport during rallycross will no longer be on my list of things to do!

 

Even though it's a pain in the ass, it will be worth it in the end. I think if I do another fuel injection project I'm just going to put in a motor that already has everything attached to it. Probably an SR20 or KA if I go that route. I'm hoping the L20B will still keep my interest with the new management.

[MicroMachinery]

Funny. When you read that DQ article, it makes it sound like a snap. Thanks for going through and documenting the hell that some of us may or may not be willing to see through to the end.

[HRH]

I think it also used to be a lot more of a snap at the time when people were doing these conversions. Hell, even finding a 200sx in a junkyard is royal pain because they're 30 years old! At the time people started doing these conversions, you could still find a wrecked 200sx or mid-80s Subaru that was barely 5 years old with limited mileage. Thus all the parts, harness, fuel pumps were basically new. Now we're picking over rigs that may have sat in a field for 10 years before going to the pick n pull. It's like when my Datsun guru counters me with it's easy, or they aren't too expensive, and I ask him, yeah, when's the last time you bought one of those? Was it the 80s or 90s? :) And then he thinks and says, well yeah it has been a while. When things have been in use for a long time, it's easy to remember how cheap they were to do earlier even though everything else costs more due to inflation, the times, and availability.

[Sealik]

So fortunately for me, Carter (NAPA Fuel Pumps) makes a copy of the Bosch pump that's fairly close. It's a P70304 NAPA number. Bit of a pain to find, but comes up as an option under '83 280zx. And even better we had one in stock! I'll be putting that in tomorrow morning, and hopefully that's the last of the issues with the EFI. Then I can just make my throttle cable bracket and air filter and be done finally.

 

Sealick, did a standard 32/36 weber rectangle filter fit on the AFM? Did you have to cut out or weld up the hole for the carburetor body? I'm going to use the same thing in the 2.5" filter version. Was debating having them ship me two top plates instead of one for the body of whatever carb, then just cut out what I needed.

 

 

You can see where I cut out the base of the lower (filter) plate.

Slathered with urethane and a couple of small screws to attach it.......good to go.

 

 

 

[HRH]

My air filter housing is actually going to go on the end of the AFM, where that aluminum piece bolts with the four bolts and square 0-ring. I'm just wondering if the cut out for the 32/36 is going to be bigger than the square inlet and four mounting holes. That's why I was thinking about two top plates so I can cut out one. Although I have a few alum pieces and they would ramp the air better, maybe I'll see if I can't cut one down a little smaller. Really just out of room with the way the intake goes.

[Sealik]

I see.

Was thinking the same thing initially....

Now the AFM can be rotated 180 if need be.....filter straight 'out' the end.

[HRH]

DAMN IT DAMN IT DAMN IT

 

ROUND 666: So I figured out why the car wouldn't start this morning. Since I moved the fuel tank line to the pickup above the original 1/4" pickup, I lost a little bit of tank capacity. And even though I had the car 1/4 tank full while dicking with it, it's rich enough that it apparently had gone through most of it. So after the other pump swap and losing fuel, I finally disconnected the fuel line at the rail to bleed the air, and realized I was sucking dry almost. Pump is fine, but anyway, put another gallon or two in and then wow, plenty of fuel.

 

So that figured out, and the new fuel pump swapped in, started her up and now the same as before. Rich as almighty fuck and missing at midrange, but an organized miss, like the injectors are pulsing at the wrong speed. Whomping the throttle revs it right up, doesn't die, but still rich.

 

Fuel pressure guage shows roughly correct. At idle it holds steadyish, and full throttle it holds steadyish, at mid range where we get the whum whum whum noise of the "miss" it operates erratically in a 30 degree or more fluctuation.

 

The new fuel pressure regulator is in place, and now seems as though it might not have needed it.

 

I went so far as to cut the boots on the injector plugs to verify wire color. They are indeed going to the correct injectors.

 

Things I've checked:

 

AFM - Tested another junkyard one, problem the same.

TPS - Tested another junkyard one, problem the same.

ECU - Tested a known good one, problem the same.

FPR - Installed new '80 200sx one, run to manifold vacuum.

Fuel pump - Installed new one.

Wire harness ground - double grounded, not the issue unless broken somewhere in the harness.

PCV - hooked up on top of manifold.

Air regulator - not using.

Temp sensor - attached new plug to end, verified correct wiring.

Tach wire to ECU - currently jumped with alligator clip, any chance that could screw something up not being properly attached? (Not spade terminal or clamped with the coil nut)

Yellow wire that usually goes to the starter is hooked to 12v, not to the starter.

 

The only other thing I just though of is does the ECU need a fuel pump signal? Is the fuel pump somehow connected? I don't think it is, doesn't look like it is in Joe's truck. I'm going over the wiring diagram right now.

 

Here's something I just found: The tach lead that should go to the ignition coil negative shows a resistor inbetween the coil and the ecu. I am not running a ballast resistor on the 510, I wonder if that's somehow affecting the tach signal?

[MicroMachinery]

[Sealik]

DAMN IT DAMN IT DAMN IT

 

ROUND 666: So I figured out why the car wouldn't start this morning. Since I moved the fuel tank line to the pickup above the original 1/4" pickup, I lost a little bit of tank capacity. And even though I had the car 1/4 tank full while dicking with it, it's rich enough that it apparently had gone through most of it. So after the other pump swap and losing fuel, I finally disconnected the fuel line at the rail to bleed the air, and realized I was sucking dry almost. Pump is fine, but anyway, put another gallon or two in and then wow, plenty of fuel.

 

So that figured out, and the new fuel pump swapped in, started her up and now the same as before. Rich as almighty fuck and missing at midrange, but an organized miss, like the injectors are pulsing at the wrong speed. Whomping the throttle revs it right up, doesn't die, but still rich.

 

Fuel pressure guage shows roughly correct. At idle it holds steadyish, and full throttle it holds steadyish, at mid range where we get the whum whum whum noise of the "miss" it operates erratically in a 30 degree or more fluctuation.

 

The new fuel pressure regulator is in place, and now seems as though it might not have needed it.

 

I went so far as to cut the boots on the injector plugs to verify wire color. They are indeed going to the correct injectors.

 

Things I've checked:

 

AFM - Tested another junkyard one, problem the same.

TPS - Tested another junkyard one, problem the same.

ECU - Tested a known good one, problem the same.

FPR - Installed new '80 200sx one, run to manifold vacuum.

Fuel pump - Installed new one.

Wire harness ground - double grounded, not the issue unless broken somewhere in the harness.

PCV - hooked up on top of manifold.

Air regulator - not using.

Temp sensor - attached new plug to end, verified correct wiring.

Tach wire to ECU - currently jumped with alligator clip, any chance that could screw something up not being properly attached? (Not spade terminal or clamped with the coil nut)

Yellow wire that usually goes to the starter is hooked to 12v, not to the starter.

 

The only other thing I just though of is does the ECU need a fuel pump signal? Is the fuel pump somehow connected? I don't think it is, doesn't look like it is in Joe's truck. I'm going over the wiring diagram right now.

 

Here's something I just found: The tach lead that should go to the ignition coil negative shows a resistor inbetween the coil and the ecu. I am not running a ballast resistor on the 510, I wonder if that's somehow affecting the tach signal?

 

 

Yes.....the numbers of the beast. :blink: :D

I'm running the stock 720 tac resistor.....I'll pull it and see if there is a difference...other than my tac not functioning :P

Does Joes truck have an O2 sensor.....? He is also not running an air reg .....correct?

I just pulled my tac resistor.....truck would not start......interesting

[HRH]

Yeah, seriously. It's a good thing I can't afford a new carb and manifold otherwise it would have been done already.

 

I'm thinking the next step is since it's running, to get it running and start detaching connectors. The AFM connector has a pretty sharp tweak in it from where it was originally located in the 200sx. I'm just wondering if when it was pulled out maybe a wire got pinched and broke, or it was already broke. Figure a 30 year old harness doesn't like to be moved too much, unlike a nice new supple harness.

 

The miss is like it hits a rev limiter, so I'm wondering if it's dumping signal somewhere in the harness and the ECU is going to full rich as almost an early limp mode. That's the other thing, I could get another harness and try that, course don't have one available. Wish I would have grabbed all the 200sx stuff in PNS when it was there, but at the time I already had everything! :D Hindsights a bitch, huh?

 

Think I'll start with disconnecting the AFM while it's running, maybe that will do or not do something, then the other components after that. It runs, it just doesn't run well. Weird.

[HRH]

Yes.....the numbers of the beast. :blink: :D

I'm running the stock 720 tac resistor.....I'll pull it and see if there is a difference...other than my tac not functioning :P

Does Joes truck have an O2 sensor.....? He is also not running an air reg .....correct?

I just pulled my tac resistor.....truck would not start......interesting

 

 

Really? That is interesting. Is your tac resistor just like a ballast resistor, the little ceramic block mounted above the coil? I have one still, maybe I'll put that inline and see what happens.

 

Joe's truck does have an air regulator, but Katherine's roadster and a few others have the same system and are not using an air regulator. Says it's just a bit harder to start in the morning. No O2 sensor either.

[Sealik]

I'm not sure what repair fixed my truck the other day.....but...

Was running like crap......and rich.

The AFM clock was at 1/2 cog CCW.....now at original settings.

I also installed the air reg......

Runs good now.....and not rich at all.

Not sure now 'who' did 'what....or which repair actually remedied my problem.

I'm thinking that without an O2 sensor and air reg.....the engine will run rich until it warms up.....?

Actually.......I have no idea.......... :blink: :lol:

[Sealik]

Really? That is interesting. Is your tac resistor just like a ballast resistor, the little ceramic block mounted above the coil? I have one still, maybe I'll put that inline and see what happens.

 

Joe's truck does have an air regulator, but Katherine's roadster and a few others have the same system and are not using an air regulator. Says it's just a bit harder to start in the morning. No O2 sensor either.

 

 

[HRH]

Talked to Joe, he has never run a resistor on his tach line, even though it says there's one in the book. It looks like yours disconnects, thus breaking the circuit if removed, probably why it didn't work when out I'm thinking.

 

Debating about the injector dropping block not dropping current enough. May fiddle with that. Running but way rich could be explained by poor connections there.

[wildmaninid]

Too much work for EFI Matt........

I just did:

92 dodge shadow TBI throttle body, steel adapter plate to stock manifold

18 psi electric pump

adapted shadow distributor to a datsun distributor (uses hall effect switch for computer reference)

Computer and small part of harness out of shadow.

 

96 bucks at pull n save and car quest and about 13 hours of total fab

 

Runs out good

 

Have fun

Bill