My friend is being a huge idiot when it comes to his fuel pump...

[Lej]

So we put a rb20det into a s13 the other night, and we still have the stock KA fuel pump. I told him he needs to upgrade to either a walbro, or a 300zx pump later on.. but for keeping the engine at idle, the KA pump would be fine.

The engine starts, and dies after 3 seconds no matter what. I told him the ecu is either not detecting the cas and stops grounding the injectors, or either something else.. BUT NOT THE FUEL PUMP. The fuel pump is fine and you can feel gas going through the return line. But NOO he thinks just because it's a 6cyc instead of 4, it can't even idle without going and getting a Walbro...

so my question is, will a rb20det idle off a ka fuel pump for more than 3 seconds.. I told him that the fuel pump doesn't come into play until he gets into some higher rpms.. NOT idling.

[Kaifd3s]

Most likely, it should provide enough fuel just to idle the RB.

[brndck]

well have either of you tested to make sure you have fuel pressure AT THE RAIL?

[Lej]

we don't have a gauge with the right couplings to fit after the fuel filter. But we're speaking theoretically

[brndck]

put a voltmeter on the fuel pump, when the engine dies, to you still have voltage at the pump? if no, get a power probe or a powered test light and manually feed voltage to the pump to keep it active, and see if this keeps the engine from dying.

[racepar1]

That fuel pump will work fine on an RB20 PERIOD. A stock RB20 does not require a fuel pump upgrade to run, just like an SR. Once you start UPGRADING the RB20 a fuel pump upgrade should be a high priority, again JUST LIKE AN SR.

You need to properly diagnose the issue. Throwing random parts at the car on a whim will not be a productive way to go. Test for fuel pressure, test for injector pulse, test for spark, and figure out what's going wrong.

[wbierogram]

get a power probe or a powered test light and manually feed voltage to the pump to keep it active, and see if this keeps the engine from dying.

[Fries]

Stock S14 fuel pump is fueling my 1uz just fine... I doubt its the fuel pump man. Or it is, cause it's jacked.

[Loufig]

Stock pump will be enough

[AZRB20]

I've ran my RB20 with OEM pump just fine.

[Croustibat]

Your friend is an idiot for putting that engine in an S13 instead of a bin. The only reason to use that engine is so you can say "i have an L6T in my car"... which may make you proud when starting the car, but sad as soon as you actually drive it.

[soundboy]

^ how does that affect the vehicle?


It's a problem he's having.

[jacobs13]

sounds like you got your fuel lines backwards

[blkvrtswp]

Originally Posted by jacobs13

sounds like you got your fuel lines backwards

Yes, indeed. Exactly what happens on an SR with reversed fuel lines - starts for a few seconds and dies over and over.

[MilkMan1218]

https://vimeo.com/101977021

So I'm the "idiot" in question here, so you guys tell me. This is currently what it's doing. I've gotten it to at least start back on its own, but still cuts out. I've already switched the tubes and it would refuse to start.

[Lej]

So that video above shows the car being in limp mode.. the car won't start at all if we unplug the MAF, and we took the CAS off and spun it and it makes the coils spark. So both the CAS/MAF appear to be working... What else would throw it into limp mode? We are checking for codes later tonight... I'm guessing just plug a test light up to pin 32 (Orange/Black)? and count the flashes?

[s13mikesr20]

id let your friend figure it out stop holding his hand.... but what are friends for...

limb mode...

incorect maf
02 sensor is going out
incorect wiring for 02 or maf
tps sensor fault
list goes on...

[Lej]

Keep that list going, it can't be much more... Some other guy on the NICO forums said O2 sensor doesn't matter.. But who's right?

Also TPS is good, reads a fluid voltage up and down as throttle is pushed in and let off on pin 56

[racepar1]

Originally Posted by Lej

Keep that list going, it can't be much more... Some other guy on the NICO forums said O2 sensor doesn't matter.. But who's right?

The O2 won't cause an issue that major. The WORST it could do is cause the engine to run a bit lean or rich. The O2 is just used by the computer for fuel trim corrections. There are limits programmed into the computer for how much it is allowed to lean or enrich the system. The O2 can't be causing this issue.

You need to diagnose the issue. You have done very little diagnostics up to this point. You and everyone else are simply speculating, which will do nothing but waste time and money. The fuel lines are simple. The line off the filter goes the the fuel rail, the return line comes off the fuel pressure regulator. On the chasis, the line that's bent 90* is the fuel return line. The line that sits lower and has about a 30-45* bend is the pressure line. Have you even taken a fuel pressure reading yet? You know Vatozone loans tools right?

I would suggest you look into the MAF wiring from what I saw in the video. Also, you CAN pull codes from the ECU. It should be the type with the screw on the side of the ecu that flashes red and green lights in the ECU to show the codes. I would do some research on pulling and identifying the codes on an RB20.

There, that took 5 seconds...
http://www.nissansilvia.com/forums/i...showtopic=5082

This one shows the skyline specific codes, but you won't be able to use the procedure to retrieve the codes because I'm POSITIVE your consult port is not wired up. AGAIN, took 5 seconds...
http://www.skylinesaustralia.com/for...how-read-them/

And AGAIN, 5 fucking seconds...
http://fctuning.com/FCTUNING/NEWS/En...20DET_ECU.html

Just search "rb20det ecu codes" and stop being a toolbag.

[Lej]

Excellent info on the fuel lines.. Thank you. And thanks for reminding me they loan tools. Forgot all about that.. We will get a gauge and check that tonight.. Although it can't be fuel pressure throwing it into limp mode. It's obvious it's got a pure cut on the injectors right at 0:37 in the video.. Also it won't start at all without the MAF, and the cas spinning does fire the coils. TPS reads a good voltage, so yeah, just speculating up some ideas at this point as we are both at work and not near the car. What else could it be? Maybe the MAF wiring is wrong, yet still "works" to start the car?.. hmm

[racepar1]

Originally Posted by Lej

Excellent info on the fuel lines.. Thank you. And thanks for reminding me they loan tools. Forgot all about that.. We will get a gauge and check that tonight.. Although it can't be fuel pressure throwing it into limp mode. It's obvious it's got a pure cut on the injectors right at 0:37 in the video.. Also it won't start at all without the MAF, and the cas spinning does fire the coils. TPS reads a good voltage, so yeah, just speculating up some ideas at this point as we are both at work and not near the car. What else could it be? Maybe the MAF wiring is wrong, yet still "works" to start the car?.. hmm

If it's in "limp mode" there WILL be codes stored. Pull the codes and get yourself a clue as to what's going on.

[l adam l]

My rb20 swap came with the wrong maf...it came with a rb25 maf i think it had a pink sticker...and then i had to get myself one with the green sticker...also had to hold the gas to get it started and for it to stay running till it warmed up...bad iacv.

[SR20?]

Just curious what kind of engine management you are using? You sure the tune is correct for your setup? Everything is definitely plugged in/connected? Sounds like MAF issue to me

[Croustibat]

No DET sensor can send it in limp mode too. But first thing to do is read ECU codes.

[Lej]

Ok so first time we checked we got a code 55 (ALL GOOD), then we unplugged the TPS, tested again, and got a:

12 Air Flow Meter/Mass Air Flow Sensor.
34 Knock Sensor.

... Which is odd because all we did was unplug the TPS.... So we plugged the TPS back in, reset the ECU by pulling the negative side of the battery terminal, then we continued to get 12, and 34 again. SOO seems like the MAf is the main issue at the moment.... as for the knock sensor, we're not really sure where it plugs into.. there's only one wire, but the plug has 2.

[racepar1]

Originally Posted by Lej

Ok so first time we checked we got a code 55 (ALL GOOD), then we unplugged the TPS, tested again, and got a:

12 Air Flow Meter/Mass Air Flow Sensor.
34 Knock Sensor.

... Which is odd because all we did was unplug the TPS.... So we plugged the TPS back in, reset the ECU by pulling the negative side of the battery terminal, then we continued to get 12, and 34 again. SOO seems like the MAf is the main issue at the moment.... as for the knock sensor, we're not really sure where it plugs into.. there's only one wire, but the plug has 2.

The knock sensor only has one wire. The second wire on the harness would be a shield wire that wraps around the signal wire. The knock sensor is simple, replace it and the sub harness. Knock sensors on old Nissan's are common to go bad. Most of the time you will see the sensor itself has a large crack in the housing. The knock sensor is located on the block under the intake mani.

Indeed the MAF code is the one you should go after for the issues you're having. The knock sensor code would simply lead the computer to run less aggressive timing and fuel maps to prevent any pre-ignition. I would start by looking into the wiring harness. You have to extend the MAF wiring for a LHD car and it's very possibly wired wrong. Also, try grounding the ground wire for the MAF directly to a known good ground.

[Lej]

Yep we actualy figured out the car has the same effect with or without the maf plugged in. So I did some testing on the maf and it reads .02v with the ignition on, and like .03v when it runs for a few seconds then shuts off. So We took a compressor to it and got it up to like .04v, but that was max.. So the maf is definetly bad.. We tried the KA with the same test and it was up to 3.4v with regular airflow.. But obviously wouldn't work for rb. It wouldn't crank with the ka maf. (which is weird I thought..) The maf was wired right, 12v constant, ecu ground, chassis ground, and signal wire (0-5v)

[Dima1127]

Just out of curiosity how old is the gasoline in the tank?


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