510 L20B EFI conversion - the project is finished!

[Sealik]

Found the problem, I was emptying the crankcase through the pcv valve. Unhooked that, no more problem. I'm about two steps away from yanking this motor out and building an entirely different one.

 

 

Take 2 steps back... :) ...and do explain.

[HRH]

I'm at my wits end. Going to go get another harness and ECU and try that first. If it still runs shitty, I'm building the KA I was planning for the truck, and sticking that motor in there. And my neck hurts, which is really pissing me off. Aside from that, beginning to wish I would have just left the carbs on and built another motor in the first place.

 

Good god, my oil is so fucking thin now from all the fuel wash. I'm going to need to change it as soon as I get the motor running well.

[HRH]

Hey Len, when you get back, could you post up the test procedure for the air flow meter? I'm pretty sure it's working, but one thing I haven't fully tested.

[Unclejesse88]

Man, the only thin I can think of right now is, are the plug wires on correct? Maybe have two of them swapped? Seeing as how you have tried two sets of injectors, and the base engine is the same, ignition or injector wiring/ecu is the only thing left. (unless it is actually running poor on all cylinders not just the two)

 

These old jetronic systems are pretty basic, so I would imagine no change with the tp unplugged is normal, and unplugging the afm at idle having little effect would be normal as well. It does tell me that there are no fuel pump contacts in the afm though.

[Sealik]

Usually it comes down to something pretty simple and or overlooked.....

Ground the EFI harness straight to the batt.

You can also do somewhat of a visual test on the airbox.......pull the inspection cover off and see where the wiper arm is relative to RPM.

Should be a steady sweep on acceleration

Maybe there is some damage to the board....? Something obvious?

I know a guy....that knows a guy...... ;) ....see if he can chime in on this.

[HRH]

Yeah, I verified the correct injector plugs on each injector, they only fit one way. It never has been perfectly smooth at highway running, but still smoother than the miss I'm experiencing now. The plugs wires are 1,3,4,2 just like they're supposed to be. That one's a no brainer with an L motor or most 4 cylinders anyway.

 

My roommate thinks it's in the harness. I'm inclined to think that's right. My other worry is that because the SUs ran rich, it masked the problem or something. I doubt it though. But the funny part is the stupid thing will accelerate just fine, just won't hold steady idle and even after warm, still too rich.

 

I have a horrible crick in my neck so I'm going to wait to do pull and save harness yanking until tomorrow in the am. Hopefully I'll be able to move my neck better by then.

[HRH]

I haven't pried off the cover. Maybe I got two dead AFMs? I really doubt it. One was the one with the wiring from Datzenmike, the other I yanked off a Stanza. It does seem odd that manually pushing in the flapper while the engine is running doesn't really change much. But it did that with both the ones I tried.

[Sealik]

I haven't pried off the cover. Maybe I got two dead AFMs? I really doubt it. One was the one with the wiring from Datzenmike, the other I yanked off a Stanza. It does seem odd that manually pushing in the flapper while the engine is running doesn't really change much. But it did that with both the ones I tried.

 

 

Ya...I doubt that you got 2 dead AFMs.....But stranger things can always happen

Hmmmmmmm....maybe I'll go try pushing my flapper........ :D

[motavated]

A while back I was reading that sometimes the early computers had bad welding done to them. And they have to re-solders again or something... Just saying... Skib knows about this...

[Sealik]

Just flashed my truck up.

At idle....the flap is open about an inch.

When I start pushing it in....(1/4 inch) the idle increases slightly

After that....it kills the engine.

[HRH]

Yeah, but I already tested another known to be good ECU, did the same thing.

[Sealik]

Yeah, but I already tested another known to be good ECU, did the same thing.

 

 

I doubt its the ECM or harness.

I've got 3 bucks (Can) says its not......any takers? :lol:

[Sealik]

Just flashed my truck up.

At idle....the flap is open about an inch.

When I start pushing it in....(1/4 inch) the idle increases slightly

After that....it kills the engine.

 

 

Something is amuk.....if your engine does not die after opening the flap all the way.

So.....too much air already....?

Should check IM vacuum...?

[LenRobertson]

Here is book procedure for Air Flow Meter Tests:

 

Ohmmeter leads to pins 33 + 34 -. Should read 100 to 400 ohms.

 

34 + 35 - . Should read 200 to 500 ohms.

 

32 + 34 - . Should read "Except 0 and infinite ohms" There is a component check section in the book that says "While sliding flap, measure resistance between terminals 32 and 34. If resistance is at any value other than 0 and infinite ohm, air flow meter is normal." Beside this text is a drawing of the AFM unplugged from the harness, so they are measuring at 32 & 34 directly on the AFM.

 

All three of these tests are called AFM resistance tests. The final test is called "Insulation resistance":

+ lead to pins 32,33,34,35 in turn, with - lead to "Body ground" Should read infinite resistance.

 

Final test is air flow meter flap: "Fully open flap by hand to check it opens smoothly without binding. If it doesn't, it is out of order."

 

 

 

A diagram in the manual shows all the "Signals for Control Unit" that feed into the ECU. It shows Air Flow Meter, Ignition Coil Negative Terminal, Throttle Valve Switch, Cylinder Head Temp Sensor, Ignition Switch "Start" Position, Air Temp Sensor, and Exhaust Gas Sensor.I realize your system doesn't use the Exhaust Gas Sensor, but are there any of the others you didn't include in your system, or used component from a different system that may send a different signal from stock? I'm wondering if the ECU is getting a confusing input from some component, or no signal at all that it needs. But a bum wire in the harness would screw things up too.

 

If you get to Pull n Save, see if the yellow 710 wagon is still there. Don't look all over for it, but if you see it, I'd like to know.

 

Len

[Creepy Cruiser]

Hey Matt, I was just curious, have you ever driven or ridden in a KA powered 510?

[HRH]

I have not, but from the torque factor alone I would assume it moves along quite nicely. And even with less hp, I would think it may be slightly faster than my 2.0 due to the torque. If you want to offer up a ride, I certainly wouldn't mind one.

 

I only have the truck setup though, don't have the other manifold, not that I probably couldn't grab one. I think there's a FWD KA out of a 91 Stanza in the wrecking yard that might have enough stuff left.

 

My big annoyance is I've spent all this time and money building for the 20B EFI and for some reason it won't work. And I already modified the head and sold the carbs, so I can't throw those back on really easily.

[Sealik]

Update..........?........... :frantics: .... :)

[LenRobertson]

Hey Matt, I was just curious, have you ever driven or ridden in a KA powered 510?

 

No, no Creepy, stay away from Matt with your KA ideas! LOL! I have a horror that if he abandons the FI project, I'll end up with the pieces. I have absolutely no time, energy, or expertise to mess with something like that. But that isn't to say I wouldn't think I should try. I know Matt is just one bad wire or sensor or something away from having this thing working.

 

Matt - Found the ECU from the '81 O2 version SX. Tag on it reads A11-626 575 on one line. Line below that reads 1323 Z20. I've wondered if you might have a ECU that needs an O2 input, even though it is supposed to be for a non-O2 engine. Probably not, but anything seems possible.

 

Len

[datzenmike]

A11 626 575 is for the '81 automatic 200sx. (non California)

[HRH]

I have two more things to do. One is to test the AFM with the specs you've provided, and two is to replace the ignition coil. It should be fine, but that will be the last of things to replace. After that, I have half an idea to replace the cam with a stock cam and see if it runs better or worse with that.

 

It sucks because a 2.4 would actually be the ideal size given the weight requirement to displacement for rally regs (although at this point my racing is so far off it's not even funny.) However, I need to get the 20B done and working considering I have a lot of money into that motor and if I'm going to sell it to offset finishing the Z24/KA motor, it better run correctly, especially since it would probably be for sale on Ratsun, and 12 pages of running like shit doesn't make for a good sale! :)

 

I'm heading off to the monroe NAPA to get the coil now. I'll try a few things and see what happens.

[datzenmike]

A11 626 575 is for the '81 automatic 200sx. (non California)

 

Matt I just checked and I still have an 80 Auto ECU A11 609 571 (non California) This means that the ECU I sent is for the '81 with 02 sensor input.

[LenRobertson]

Factory manual has 5 pages of engine fuel troubleshooting charts. The one section that seems closest to the problem is "Poor gas mileage, or CO reading too high." Here is the list:

 

Improper ignition timing or ignition system.

Improper air cleaner filter.

Improper fuel pressure.

 

Problem with the following circuits:

Air temp sensor.

Cylinder head temp sensor.

Throttle valve switch, idle contact and full throttle contact.

Air flow meter potentiometer.

Air regulator and fuel pump circuit.

Injector circuits.

Exhaust gas sensor (USA model).

 

Probably nothing there you haven't thought of or tried, but maybe reading the list will give you an idea. I can give you the temp sensor check if you like. The spec for '81 ignition timing is 6 plus/minus 2 degrees BTDC @750 RPM for USA model with manual trans. 8 degrees for Canada models. May be different for non-O2 version, I suppose.

 

Len

[HRH]

Matt I just checked and I still have an 80 Auto ECU A11 609 571 (non California) This means that the ECU I sent is for the '81 with 02 sensor input.

 

 

Well that's weird. The one I got from Joe didn't seem to change anything but he's tried that one in his truck and it works fine. Maybe I'll go swap that out here in a second. Tested the AFM, it is indeed within specs, thanks Len!

[HRH]

Joe's ECU has A11-626-575 on it, also marked for Z20.

[datzenmike]

Single plug heads need more advance. Dual plugs have shorter burn time so advance can be reduced.