Isuzu G-series Twin Cam

Hi all this is my first post here.

Recently I bought a twincam TG sedan and have now put the G180w into my TC sandpiper. The TG was once fuel injected but someone had 'modified' the original injection manifold and bolted on a 32/36 weber carby.

I have since bought a G200 piazza manifold off elky with a computer. The computer has about 20cm of wires then its all been chopped up. I was wondering if anyone could help with the wiring? Such as clear diagrams or even something as simple as the "the black and green wire is the injector wire." As I will basically have to do this from scratch.

Thanks

Andrew

For wiring, I suggest isuzupiazza.com/index and get the 1986 Piazza Workshop Manuals (900 Pages for 4ZC1 Turbo Model) pdf.

However that is for the 4ZC1-t and not the G200W Piazza (which uses an I-TEC system with a locked optical dizzy similar to 4ZE1 Jackaroos & Rodeos).

You need to get the ECU that matches your sensors and dizzy type, and with mapping suitable for the G180W.


But my overall suggestion would be to get a Delco system. That is far superior to the original (almost analog) G180W ECUs and GMH's recalcitrant Bosch Jetronic-based system as used in the Aussie Piazza.
The ITEC G200W system might be ok if you have the Isuzu optical dizzy and if its the fuel & ignition maps suit the G180W, but the I'd still suggest the Delco.


Poida recently wrote about obtaining a suitable Delco (from a 1.8L Nissan N13?) but I think that was on HoldenGemini.net. It has a more versatile (longer) harness and IMO better connectors.
The Delco can be remapped though maybe the 1.8L mapping is fine for the G180W. (We use such Delcos for the G200W.)

When obtaining the Delco, get the harness and all sensors for that ECU, and for manual or automatic transmission as required.
The only OEM item NOT required is the distributor itself, though its ignitor (at the base of the N13 or Camira etc dizzy) is required. Instead, an RG dizzy is used - ie, a RWD T-series Gemini dizzy (G161Z etc) with the upper shaft and reluctor breaker plate with sensor from an early model FWD RB Gemini. It's ignitor is not required - instead the sensor wires are extended to the Delco HEI (ignitor) which can be mounted on the body. The other HEI wires go to the Delco and the ignition coil. (I recommend the RB blue Nippon Denso ignition coil unless you use a modern E-core coil. The RG dizzy with internal RB ignitor and RG IgCoil is one of the best systems around, IMO it's only beaten by a CDI, and maybe by using an E-core IgCoil.)
The RG dizzy suits all G-series engines - as is for G-Z engines, and with a shaft cut for others (G-U OHV, G-S Jap SOHC, and G-W DOHCs), plus some 0.15mm shim or other padding to mount for the 12.4mmID G-W dizzy drive gear onto the 12.0OD shaft.

Not only is the Delco a better performer, but it and its sensors are readily available and common. I think our local Pick-A-Parts charge $35 for ECUs (they were half price recently). You can have the entire EFI system (less injectors) for a mere $200-$300. Remapping costs a bit more, but Poida can explain all that, else refer to sites like DelcoHacking.


As to trying to mix ECUs with other sensors... IMO forget it!

I have most of an EFI setup from a G180W Gemini engine. I have the loom, the computer, the throttle body with the TPS and a few other sensors that were part of the original EFI system if you are keen. The AFM was stuffed and not repairable.

Personally I'd do what IZU069 has suggested and convert to a Delco system, in fact that is what I have done. I am using a system I bought ages back from USA but there is a local system available from the crew at DelcoHacking. Well worth looking into. None of the parts I have (as above) are any use for the Delco system and you will need to change the injectors for a set that suits the Delco. There is a mass of info available to help you through such conversions.

so the piazza computer is a different map to the 180w? I was under the impression the 180 used a fuel only system not a ignition and fuel computer. (I can be wrong)

I would love to go to a delco or a microtech system. but I don't have any more money to throw at this car.

thanks for the replies.

Poida - I thought the Isuzu (low impedance - of course!) injectors were Delco compatible - provided the ballasts/resistors are added.
As I understood it, the Delco could power both low-Z & hi-Z, the only proviso being the current limiting for the low-Z (ie, add the resistors). (If any ECU can to low-Z, then it can also do hi-Z; ie, hi-Z take a lower current.)

Or is it pressure & capacity related? As I recall, Isuzu usually rate their injectors at 2.5 Bar (eg, ~220cc or whatever) but they'd handle 3 Bar.
If however the Delco uses a much different capacity, then I understand the ECU not being able to handle the (smaller?) Isuzu injectors. But even then, I thought the Delco had a scaling parameter, though I might be confusing the Mitsubishi system (eg, RalliArt).

vinesy - I'd assume the Piazza is a different map to the G180W. Though the ignition timing is handled by the distributors (with the Piazza having a knock-sensor retard and limited to an advance of ~5 degrees for the turbo), I'd guess the turbo fuel map to be quite different.
Nevertheless, AFAIK you'd need all the sensors from the Piazza.

but can't confirm its different?

if I was to use the dizzy and ignition set up already on the car could I make the g200w stuff work?

Provided you have all the bits off the Piazza (ie, sensors, TPS, etc) and it's a reluctor dizzy, it should run. The G200W dizzy reluctor should be capable of driving the ECU. (I can't recall if the RG breaker plate is the same dimension as the G-W. If so, it might be swappable if the lobes are compatible.)

It might not run very well however since the maps are probably different.

the car is a carby atm. not sure what dizzy type it has. I was going to use a msd ignition.

I have the complete piazza manifold and the sensors. afm tps everything.

but the wiring.

IZU069... a mention of injector choice from another source:
http://www.delcohacking.net/forums/view ... dbd1#p9810

I got the impression it would be better to source a set of high impedance injectors that fit rather than patching the low impedance ones. The lack of peak and hold capacity is also something to be aware of. You know how much I hate bandaiding when there is a better way. If the Delco is designed to run high impedance injectors, just run high impedance injectors!



G180W (blue top Gemini) and the G200W (red top Piazza) run VERY different systems. From things I have researched the G200W Piazza engine is a fuel and ignition system running a HEI distributor. The G180W Gemini had the absolute basic level fuel injection by todays standards, even 5 years later standards... There is loads of improvement possibility by upgrading to something like the Delco.

The Delco system doesn't run an AFM. It calculates air flow rate by using a number of sensors. The value of this is when one of the components used to calculate fails it's easily found and cheap to replace. The ECU can still run the engine with one of the sensors has failed as it 'knows' the signal is corrupt and calculates (though not as accurately) to compensate. Try finding a replacement G200W air flow meter!

One of my reasons for choosing Delco is the ready availability of and low cost to replace parts.


The last thing I'll mention is capacity to retune.. How do you set up a G200W EFI system in a G180W engine and retune it for the smaller capacity engine? I don't know of a way to retune the Isuzu system.

That link shows what sort of mentality exists on that forum. Parallel impedances indeed! No wonder wiring up an alternator is too difficult for some. Geez!


But lo-Z injectors is not a bandaid solution!
The Delco handles lo-Z injectors and it was designed that way. Otherwise they would have used lower current injector drivers.
The resistor (or ballast) pack is not a bandaid or workaround, it is merely a normal requirement of lo-Z injectors (except where current limiting or special drivers is/are used). VIZ - Piazza and other Isuzu EFIs.

AFAIR, lo-Z is the superior injector, though my reasons are long forgotten. (And it wasn't simply the stupid requirement for voltage monitoring for hi-Z injectors - but I'd use an SMPS constant voltage source instead anyway...)
And Isuzu only used lo-Z injectors which is a testament to their superiority - both Isuzu and hi-Z (LOL). Not that I am familiar with their newer V6 EFIs etc.


The Delco being able to run lo-Z injectors was from a Delco source I read - probably the wiring diagrams for the 808 etc. Maybe it is only applicable to some, though I am reasonable certain it was from Camira etc info.


But I agree totally with your comments re the G180W ECU - its uses two PCBs and has lots of discrete Op-Amps etc; it's virtually analog (and it may well be analog, or effectively so).
And the Piazza 4ZC1-t isn't much better - it's a licensed Bosch Jetronic or whatever but made by JECS (who also made the G180W ECU).
And how to retune either of them.... kuneno!

Certainly the clever option is the Delco.
And I suspect that after obtaining the required JECS sensors and doing the wiring, the Delco will prove cheaper. The fuel economy alone should pay for the Delco - even if the JECS can be remapped.

okay sorta have me convinced just to go the extra bit and get the delco system.

what parts do I need and from what car? do I need to modify the piazza manifold to make the new sensors?

and is a wiring diagram easy enough to find?

also what throttle body to I require to use?

I can get the ecu, wiring loom and sensors for $50 out of a n13 pulsar. is this the model I should get?

See How to strip a Delco setup out of a Pulsar/Astra.

More FYI stuff at G180W injection / ECU issues (4th reply), and...
HoldenGemini's Changing Engines (4th reply).


You'd want the blue-top G180W inlet manifolds, or from the Piazza G200W. They are both the "up & over the top" types.


And something I missed earlier and probably worth clarifying...

Poida wrote:From things I have researched the G200W Piazza engine is a fuel and ignition system running a HEI distributor....

All G200Ws were EFI - and red tops.
The earlier G200W from the 117 Coupe is fuel-only. It has a mechanical advance distributor with early (crappy) reluctor & ignitor and had the "to the right and forward" intake and plenum.
The later G200W from the Piazza was all electronic. It has a dual-row locked optical dizzy (same dizzy pickup module as the 1989 4ZE1 Jackaroo) and its ITEC CPU does all the ignition and fuel mapping.

The original G180Ws (light-green tops) were all mechanical and carbies (twin Mikuni, Hitachi etc - ie, Weber copies).
Twincam Geminis had the later blue-top EFI G180W. There is an early and later blue-top but I am unsure of the differences, though guru reckoned the later was "better" than the Piazza G200W.
There are variations - like a "black-top" kit that was issued for the Gemini EFI G180Ws (black-tops are otherwise the G161W), and the dark-green top - a fast (high compression) twin-carb GW from the 117, though I am now unsure if that's a G180W or G161W. All G161W had carbies and points dizzy.

I have seen those links before.

which tps is used with the vn throttle body? the Commodore one or the pulsar one?

I have a blue.top 180 and the piazza manifold is a over the rocker cover manifold.

Hmmm - I'd assume the one with the ECU, ie, N13.
But it might not matter.

Poida - HELP!

The TPS from the Commodore TB is the one to run, I think each TB has different locating notches to suit in the TPS. Same with the IAC valve, the Astra one is slightly different (the angle the wiring plug fits in). As far as I can figure, the components are the same electrically, just physical variations so they suit the angle of the dangle.


So, use the G180W blue top (Gemini) inlet manifold and plenum, get a 10mm thick aluminium plate welded to the mount face, drill it to suit and attach the VN-VR throttle body.

thanks guys.

and the normal Isuzu injectors are used still?

I won't have the money to buy the tuning stuff straight away. but if it can run that'd be a awesome start.

sorry for going over and over stuff already posted. I just am sick of getting told one thing and buying stuff like ny brake kit then finding out later its illegal. (waste of 1k)

poida I onky have the g200 I Tec manifold.

I got the wiring loom from a 1.8 n13. I will probably need some help with wiring. I couldn't get my hands on the computer though. would it be possible to use a different model computer and just tune it to suit? also would you have a 'base' map poida for the 180w?

so far I'm happy with the delco conversion.

also do I use the 180w injectors or the 200w injectors or the n13 injectors?
I didn't get any pulsar ones as the wrecking yard had none.

turns out the car I got the twincam from has a n13 dizzy module in it and an o2 sensor. so my list is basically complete.

Never mind, i have since found a g200w bin file, this should be a good basis I'm hoping.

Turns out I have a 808 computer at home, but its a VN auto memcal.

It's sounding pretty good - just get a manual memcal.

And it sounds like you are using the RG dizzy feeding the remote N13 ignitor.
[ The RG for Delco being the non-sparky ignitorless version else with the ignitor bypassed feeding the Delco HEI (N13 ignitor), else RG ignitor output thru a capacitor to trigger the Delco HEI. ]


The injector situation has been interesting. The easiest is probably to use N13/Camira etc injectors though that requires a fuel-rail change to the newer o-ring instead of fuel-hose types.

I had always intended to use lo-Z injectors for their IMO better performance, but as I recently learned, as of late last decade, the more common hi-Z is now the way to go.
Hi-Zs now meet or exceed lo-Z injector performance and capabilities.
The Camira & N13 etc hi-Z injectors predate that evolution, but they are still adequate, and of course match their 808 ECU.


As to the o-ring fuel rail migration, that IMO was always desirable - not only for reliability and simpler maintenance, but also a modern selection of injectors.

Besides, although now of trivial importance, there is some conjecture whether the stock 808 can run the older Isuzu lo-impedance injectors, and the 808 (GMH version) apparently does not do the Peak & Hold that lo-Z injectors should use (though apparently few OEM ECUs actually implement P&H anyhow).

We (IZU069 & myself) have been discussing options for the right injectors.

I have found that the low impedance original injectors will run but they don't run well straight 'out of the box' using the current DelcoHacking tune data for the G200W. I think it would be logical to swap to the same injectors the Delco is expecting to see AND Antus has used in his G200W tune. It makes more sense to all stay consistent so any thing we work on can be shared. If everyone has a different setup it's hard to accurately compare notes and in the end each of us has to battle from scratch.

We cannot be sure how long they low impedance injectors will keep running run for without causing issues with the ECU. The truth is, the 808 was made to drive high impedance injectors so we think it would be advisable to swap injectors.

Most of G???W injectors seem to be hose tails with a different means of attaching the injector to the manifold. I'm in the process of making a new fuel rail that will allow mounting the Bosch o-ring type injectors using the original mount threaded holes from the hose tail injector mounts. Once I prototype the first one, I'll make more fuel rails the same.

As in keeping with my original concept of everything I modify using easily obtainable parts from existing cars, I'm using Bosch 0-280-150-725 injectors readily found on LD Astra/N13 Pulsar, JE Camira, YE Calibra, 305 & 505 Peugeot, 760 & 780 Volvo, numerous Opel and numerous Vauxhall engines. The Delco ECU will work with these as it's a factory part match. You will also need to use the fuel pressure regulator off the Astra or Camira.

So, for the sake of consistency, for either the G180w or G200w I'm suggesting run the reluctor ignition switching with a fixed shaft (no mechanical or vacuum advance), the ignition module used in the LD Astra/N13 Pulsar and JE Camira, the Bosch 0-280-150-725 injectors and the same fuel regulator off one of the LD Astra/N13 Pulsar and JE Camira. I have used the VN-VR throttle body but you could also use the JE Camira one. Use the correct TPS and IAC as would normally go with the throttle body you choose. Use the G200W base tune as found on DelcoHacking web site.

I hate awaking old threads, but there is a G161W EFI. However whether you call factory standard or not is conjecture, not that it effects anyone because only one remains.

GMH imported 3 G161W 117s for evaluation back in the 1970s. I have a pic of one I parked on Hoddle St Melbourne in the late 1970s (1978?). It may be the one my mate now has...

All 3 G161Ws were converted to EFI.
They probably used the original G180W PF60 or 117 ECU.
They used the same injectors as some old Audi or similar (BMW?).
Not sure about the dizzy but I expect the old crap type - ie, G200W & G180W non-optical multipole reluctor.

I might find out this weekend as the one remaining 117 is visiting me and will later be at a public show on Sunday (Como Park?).

I think I thought this 117 had a G180W EFI since I recall a fault with its (EFI) fuel pump wiring and since there were no G161W EFIs... Of course maybe I forgot it was a G161W?
And now I realise another possible confusion - maybe its rocker/cam cover is one of the dark greens that used to fly... So maybe they were G161W as I think I thought and not G180W that I later thought they had to be. Or maybe that was the other way around?
Not that I care. I have my proposed G200Ws (even if some may be on G180S blocks) & sparts...


As to previous stuff in this thread, for once I can't find any obvious d'ohs that haven't already been corrected.
It seems most now have cottoned on to using RG dizzies for ALL G-series engines (except for buyer(s) of this $995 sucker LOL, or buyers of non-Peteronix systems (double-LOL)) except where Piazza G200W or 4ZE1 Jackaroo optics are used for locked sequential or phased bank systems. (None I deal with use other sequential dizzies or CASs.)
My only change was considering a modified VY or similar delco/delphi for sequential ignition & injection though I recently spied a neat 200MHz "automotive" CPU, and recently Link G4 Atoms etc.


Sorry I digressed. (Who? Me!)

The point was these 117s may account for EFI G161Ws being a "factory" release even though these 117s were not an Isuzu release nor were they ever released to the public. (And no Bellett was ever EFI even if they now run G200W 200HP/400Nm n/a EFIs.)


But now, let's get back to some hibernation. (eh bits 'n pieces?)

Corrections to the above.

The 117 G161W EFI uses a JFUX4 dizzy and Bosch D-jetronic EFI. After figuring that out for myself I found that info is available in webland. (Not that webland is accurate - I still can't believe the errors on "Isuzu Engine" sites (wiki?).)

Still not sure if this was an Isuzu EFI prototype or GMH prototype but its plenum was obviously 117 and not some other fabrication - not that I compared it side by side with a 117 G200W plenum.

Apparently the dark greens are G180W and were fitted to 117s (with "SS" carbies). (They were the only DOHC I'd consider using other than blue G180Ws & G200Ws. Oh, and the G180W blacks of course!!! Mind you, that was before I learned of the simple "add-on" 400Nm G200W tune.)


I also fitted a GZ dizzy to a G200W LUV/KB20 which had SS carbs and typical aftermarket air filters - those elongated dome foam types (geez my memory is bad!)
Whilst the original dizzy was difficult to get out because of the filter base plate, it totally fouled the GZ. But the front filter was remounted at a downward angle which required no drilling etc and the SU-style carby aux air holes still got air.

At the All Jap Day (6Dec15, Como Park) I saw a lovely chromed etc Gem coupe. Let's just say it had a Scorcher dizzy (maybe the 1 of 5 already sold of the previously posted linked $995 offerings?) which was feeding a chromed can type ignition coil.

And in case I've canned (pun intended) Bosch GT40 igCoils, note that I mean the can types. I forget that GT40s are also available as E-types or C-types.
And for fook's sake, externally resistored/ballasted igCoils wasn't just about extra cranking spark (eg, 8V coils). Not that that should be relevant anymore with E- & C-types. Nor are ballast with any decent electronic ignition. (Do Pertonix still require retention of external ballasts? )