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Na2t: Injectors And Ecu Swapped, Now Wont Start

Mitchd03

By Mitchd03,
in Engines & Forced Induction

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Mitchd03 Rookie

Mitchd03

Posted
Posted (edited)

Hey guys, don't post on here much (if at all), but i hope u can still help. I searched, i didn't find.

Didnt know if this should go in forced induction or n/a forum, since its got aspects of both... There should be an electrical/ecu subforum.

Basically, my friend has gone and purchased pretty much everything he needs to turbocharge his n/a S1 R33 (1993) off these forums (bar dump pipe, which he is getting tomorrow). We swapped the injectors and ecu over and now his car wont start. Everything is connected the way it was before and it doesn't sound like the fuel pump is priming, so that would be my first guess.

All the turbo parts (bar intercooler piping, which isn't attached) are off the same car, which was running at the time the parts were removed but I'm not sure if the car was an S1 or an S2.

So, basically, is there any reason why a S1 RB25DE R33 running just the ecu and injectors from a RB25DET R33 wont start, remembering it may possibly be s2 ecu? Is there any wiring/control differences in the fuel pump/ecu circuits, or could the ecu just be a dud?

Only mods to his car are pod filter, exhaust, steering wheel, rims and springs, so none of these should be making the difference.

EDIT: He got the turbo bits off "R34GTFOUR" so if you could reply stating if S1 or S2, I was the one who said I would be putting it together :P

Edited by Mitchd03
666DAN Grand Master

666DAN

Posted
Posted

The pump should still work, the only difference is a relay for upping the voltage to it under load, that doesn't come into effect at idle.

Where is the AFM hooked up? You need a closed system so the air goes through it and gives a reference voltage for the ECU.

Also has he got the turbo fuel pump fitted? He'll run into dramas with it leaning out if it's not already in.

666DAN Grand Master

666DAN

Posted
Posted

Yep grab a GTSt pump and fuel regulator (or did you get the complete injectors and rail?) if you can...but saying that, your car isn't starting for another reason....as it will still idle on a GTS pump just fine

Kyro Apprentice

Kyro

Posted
Posted

Well all we did last night was remove fuel rail and insert the new GTST injectors and then plug in the GTST Ecu, is it possible we need to reset the settings by unconnecting the battery? Could it also be something to do with a fuse?

Kyro Apprentice

Kyro

Posted
Posted (edited)

Ok, it starts and idles now, but it blows light grey smoke, and misfires. Smells like there's no catalytic converter.

Could this be wrong fuel pressure for the turbo ecu? If so, what is the correct fuel pressure, as we are using an N/A fuel press reg.

Remember, its an RB25DE with T injectors and ecu.

EDIT: Just took it for a drive and its definitely running way too rich, the cat light came on when taking it to higher (4-5k) revs, huge exhaust pops when shifting gears, hunting for idle etc. but the misfiring got better (wasn't cured) at higher rpm (around 3)

Stuck injector? Wrong fuel pressure? Fuel pump? (remember, NO BOOST, its still an n/a, no more air than before, therefore no more fuel needed, so pump should be capable for now)

Edited by Kyro
axe s Experienced

axe s

Posted
Posted

why are you installing injectors before the turbo.... the ecu is tuned to run the injectors with the forced induction, all the problems you have are the sign of over fueling, if you's keep running it u'll burn out the cat (thats why the light is coming on, it's getting to hot), install all the components needed Turbo, intercooler, pump, FPR...

Mitchd03 Rookie

Mitchd03

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Posted
why are you installing injectors before the turbo.... the ecu is tuned to run the injectors with the forced induction, all the problems you have are the sign of over fueling, if you's keep running it u'll burn out the cat (thats why the light is coming on, it's getting to hot), install all the components needed Turbo, intercooler, pump, FPR...

The ecu adds fuel as the AFM reads more air, if the ecu just smashed more fuel in all the time, the car would be rich (like this) when not under boost, then stoich when boost hit

You can have a turbocharged car with ecu and injectors designed to run boost, remove the turbo and it will run fine.

I know this is true, i've done it twice. One time to my ford Telstar TX5 turbo. It uses an air flow meter, just like nissan use. The only difference is the tx5 has one massive injector instead of smaller ones on each cylinder (like a carbie). The turbo blew an oil seal, i pulled turbo out, reconnected the afm and it runs fine, its just really slow and loud.

The second time to my z31 300zx. It was a VG30E, naturally aspirated. I had turbo injectors and a turbo ecu lying around, waiting to get a turbo. I had to pull the intake manifold off, so i changed injectors and ecu at the same time. The car runs exactly the same as it did before (misfiring, a little rich, hunts at idle, backfiring on overrun, it's always done this, its an '84 model car). Old injectors were ~180cc, new ones are 269cc (they sound tiny i know, but higher fuel pressure than RB25DE) and the ecu is calibrated to those injectors. We did exactly what i did to the zed, yet i got a completely different result, and my assumption was the fuel pressure regulator, as with the RB swap we kept the n/a fuel pressure reg, but on my VG30E I swapped the regulator with the turbo one (as i got a complete rail).

And now that an N/A ecu is running bigger Turbo injectors, when the turbo ecu couldn't run them... it doesn't make sense. If you put big injectors in the car goes really rich, anyone who has tuned a car should know this. You then have to shorten the injector times to get it to run stoich again, which is what the turbo ecu does.

Bah!

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