G200zEFI

Gemininja · Post by **Gemininja** » Sun Apr 05, 2009 5:11 pm

i have a G200z EFI out of a piazza siting in my TG.

it idols sweet and is all good as long as you dont rev it -D

basicly an overfueling issue... just trying for some ideas (less obvious ones preferd as youl probably be repeating what ive tried) to get her running.

and anyone with an ECU wiring diagram and pin location would be worshipd. its not the itech one with 3 plugs and like 42 pins. it has a single plug and 35 pins.

Cheers

F3ARED · Post by **F3ARED** » Sun Apr 05, 2009 7:39 pm

What fuel pump you using? If its too big itll flow too much @ the pressure dictated by the Piazza pressure reg, hence overfuel.

Buggzy · Post by **Buggzy** » Sun Apr 05, 2009 9:19 pm

check air flow meter? if they arnt connected they generally act like this too...

paddles · Post by **paddles** » Sun Apr 05, 2009 10:07 pm

GeminiCoupe wrote:What fuel pump you using? If its too big itll flow too much @ the pressure dictated by the Piazza pressure reg, hence overfuel.

que pasa? Provided rail pressure is correct and flow is adequate, all will be sweet won't it?

Gemininja · Post by **Gemininja** » Mon Apr 06, 2009 7:30 pm

VL commy fuelpump but i have a sard adjusty regulator.

and yea AFM is the most likley culprit so im trying to track down a replacement to swap and see if it makes a difference. it seems to test ok but is a bit weird... i physically hold it back slightly while reving and it seems to go better. and if (while idleing) i hold it fully closed it doesnt stop the engine wich is also strange...

***ECU info needed***

F3ARED · Post by **F3ARED** » Tue Apr 07, 2009 12:45 am

que pasa? Provided rail pressure is correct and flow is adequate, all will be sweet won't it?

Que pasa mangz. Nope it wont be sweet. I had a VLT pump on my DOHC, when that s*#t itself it ended up with an 044. Because of the flow difference etc, car was ridiculously fuelly across the board, even with the pressure screwed down. Ended up having to redo the fuel maps.

Gemininja · Post by **Gemininja** » Tue Apr 07, 2009 5:13 pm

so even if i dial it rite back it could still have issues?
interesting... how would you recomend proceeding? what could i do?

06EMInick · Post by **06EMInick** » Thu Apr 09, 2009 9:15 am

To proceed, I would recommend taking the car to a tuner. Assuming it's not the standard piazza computer, they can adjust the fuel maps to suit your setup.

If it's the standard computer check ALL other wiring and connections, especially the AFM and TPS.

If the fuel pressure at the rail is identical to what it is standard, then there is no credible reason why this should affect the tune.

I know this is against what GeminiCoupe has said but there is no reason why it should change it. It's just different tools doing the same job achieving the same result (pressure at the rail). I never hear of any of my friends' imports cracking up when they replace the standard pump with a walbro...

F3ARED · Post by **F3ARED** » Thu Apr 09, 2009 11:54 am

Hes running an AFM nick, so it can only be a standard Piazza ECU.

I know this is against what GeminiCoupe has said but there is no reason why it should change it. It's just different tools doing the same job achieving the same result (pressure at the rail). I never hear of any of my friends' imports cracking up when they replace the standard pump with a walbro...

Thats because its in a certain percentage. I doubled my fuel pump flow when i went from the VL to the Bosch, assuming the flow increase @ pressure is linear, it wouldve doubled the flow @ the pressure it was already on. Where as say your going from an R33 to a Walbro, pump may be say 20% bigger then the stocker and the ecu may have enough it to compensate. I know the haltech sure as f*#k doesnt.

Gemininja · Post by **Gemininja** » Fri Apr 10, 2009 8:10 am

im going to check and set the pressure properly. as far as i know the only effect a larger pump may have is creating backpressure from the return lines being too small... an injectors only ever going to inject what it can so i dont see how flow would effect that... then again i dont claim to be an expert.

F3ARED · Post by **F3ARED** » Sat Apr 11, 2009 6:54 pm

In basic terms.

Fuel injectors are opened for an amount of time - ie mili-seconds. The fuel squirted in is whatever fuel is in the fuel rail @ that time.

Lets say for example [figure are just off the top of my head] the injectors squirt 250cc of fuel in when opened for .10 seconds. This is with the standard 200hp pump @ 30psi pressure where its delivering 100hp of fuel flow [figures are like i said, simplified/out/its just for examples sake].

Now, lets say you leave the ecu alone, so the injectors still only open for .10sec, but youve doubled the pressure from 30psi to 45psi, and a result fuel flow from 100hp to 150hp. Because the press/fuel flow has gone up 50%, so does the amount of fuel gone in despite the opening time for the injector being the same.

So lets say 250cc/.10sec/30psi, it now goes [assuming its perfectly linear] 375cc/.10sec/45psi. Following me?

Now, i would assume the VL pump your using is not too-big to cause major issues with the amount of fuel being squirted. Its worth a shot if you try AFM and its still f*#cked, but heres something else to think about.

Some factory ECU's run two power triggers for a relay for the pump, in the event that the car stalls or you have an accident so it doesnt keep circulating fuel. Could be worth a look. That, or the wiring for the injector switching isnt done properly.

Nick-

Germinator · Post by **Germinator** » Sat Apr 11, 2009 7:38 pm

A higher pressure fuel pump shouldn't make any difference as long as the fuel regulator is in place, set for the right pressure and working properly. It governs the cut off pressure limit, the pumps doesn't. The pump will always provide higher pressure than the system needs. A fractional change in pressure increase will add significantly more fuel to the engine. If you fiddled around trying to increase pressure to send more fuel, back it off to where it was supposed to be, in fact, just use the original pressure regulator if you have it.

I'm with Buggzy, assuming the pressure is correct, it's most likely an AFM problem. My G180W twin cam is the same, dumps masses of petrol through it because it has a faulty AFM and gets no AFM reading. It assumes it needs more petrol so it just keeps oversupplying it. Your system should be very similar to the G180W JECS system used with the twin cams.

Just for the record, the VL fuel pump is identical to the JD 1.8 litre MPI and 2.0 litre JE Camira pump. Same pump!

Gemininja · Post by **Gemininja** » Sun Apr 12, 2009 11:19 am

thanks for all the help guys. ill be setting the fuel pressure properly next week and seeing if that helps. then ill just be waiting for a guy to get back over to NZ and lend me an AFM to try. if that doesnt work then well.. yea.. im realy gona need the ECU pin out so i can start at the begining and work through it all, but noone seems to know where i can get it =s

Germinator · Post by **Germinator** » Sun Apr 12, 2009 12:05 pm

Just curious, does the inlet manifold plenum have ECGI on the side of it or does it have I-TEC on it? As far as I can figure, the genuine G200Z EFI engines had very similar EFI system to the G180W as fitted to the ZZ/? Gemini. I'm guessing it's an ECGI setup with normal points distributor and the EFI controls fuel delivery only.

Am I on the right track Gemininja?

Burntrubber · Post by **Burntrubber** » Mon Apr 13, 2009 8:59 am

Its ECGI I sold him the engine I had it running in my TE for a while with a vl pump and after market reg so thats not the issue. He had someone wire it up for him and they had issues with wiring the coil and dizzy in properly I think they may have damaged the ecu personaly.

I still have a couple of spare ecu's and afm's if you want to try them.