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Rb20Det Into Vp Commodore

GTS 221

By GTS 221,
in Engines & Forced Induction

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GTS 221 Rookie

GTS 221

Posted
Posted (edited)

Hi guys

I have a bit of an unusual problem, and I have been reccomended to come here and look for help. So please be nice :)

Ok so after 2.5years I got my project car back from my mechanic far from finished, I am going to be finishing it myself. Now I need to get the car running before I go any further, it is a vp with an RB20DET.

My problem is that when the ignition is turned on the fuel system won't pressurise and hence my problem of the car not starting, the car does have a new fuel pump. On the car it came out of (which I no longer have.. grr) it was running a smalll surge tank and an external fuel pump. I can start the car if I bridge 30 and 87 on the fuel pump relay in the engine bay, the car will run but it will stink badly of fuel. So coming to that conclusion the ignition is not triggering the relay to open. Which is where I am stuck now, I don't know where to go from here as i'm a chef not a mechanic, and because of the nature of this car noone really want's to touch it (too hard basket) so if I can get some direction that would be great. Please keep in mind this engine conversion was done in another vp and was transferred into mine by my mechanic who lost interest in it. So i'm trying to pick up the peices but the car is a mess. I have attached a video if that is of any help of the car running, it won't rev freely.

MVI_0329_zpsf4efb611.mp4 Video by Kaz654 | Photobucket

Thanks in advance.

Some problem solving I have tried. Fuel lines are around the right way, I can feel the relay triggering when ignition turns on.

EDIT: I should mention too that this conversion was already in a vp and it was meant to be a simple matter of transferring it over.. yeah right. So this setup used to run and drive fine before it was pulled apart.

I'm starting to think it may be a sensor playing up and messing with the ECU. Being an rb20 into a vp there is a few spare wires floating around which don't help..

Edited by GTS 221
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https://www.sau.com.au/forums/topic/420982-rb20det-into-vp-commodore/
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ARTZ Grand Master

ARTZ

Posted
Posted

^^^vp weighs about the same as a skyline...just wont handle or look as good...

anyway what smells like fuel..the exhaust fumes or does it smell like its leaking fuel somewhere...is your pump cutting out once system is pressurized??

that video is completely useless by the way..

from what i can tell you have actually bridged 85 and 87 and 30 is the missing wire which is your power...85 is your ignition which would mean your fuel pump is being powered by your ECU.. :unsure:

try plugging the relay up as normal but instead running a power wire direct from your battery (or any direct power source) to your missing plug port which i think is 30 and see what happens..run an inline fuse if you can on this wire..

portaz Mentor

portaz

Posted
Posted

It sounds to me like an ecu/ wiring issue which I guess you will just have to do the hard yards a few spare wires is a little scary though, check the connections on the fuel pump but u really need direct connection to battery anyhow if it were me get a rb20 ecu pin out diagram and see what those wires are with engine conversions this stuff can always pop up unfortunately .scott

GTSBoy Grand Master

GTSBoy

Posted
Posted

^^^vp weighs about the same as a skyline...just wont handle or look as good...

There's 50 kg in it. RB is not lighter than the Moo6, so no expected change there.

What about the non-RB20 friendly moonshot diff ratio?

RB20s into any Commodore, including VL, have always been full-of-fail .

GTScotT Grand Master

GTScotT

Posted
Posted

Lets not pick on the guy re what he chose as a project. It may be his fav car and fav motor rolled into one.. or maybe he just likes the idea. Either way its a pretty cool thing to have in the end.

OP where are you located?

There are some basics you can run through to make sure it SHOULD start.

You will need a fuel pressure gauge in line from the fuel filter to the rail, and will need a noid light to check for spark, injector pulse and pressure. You can turn the CAS by hand to test.

GTS 221 Rookie

GTS 221

Posted
  • Author
Posted

I know you asked us to be nice....but why the hell did you do this? For a big lump of steel like a VP, the original Moo motor is a much better engine than an RB20. You should cut you losses and run away.

Maybe because I love commodores and I wanted to do something different than putting an LS1 in it.

^^^vp weighs about the same as a skyline...just wont handle or look as good...

anyway what smells like fuel..the exhaust fumes or does it smell like its leaking fuel somewhere...is your pump cutting out once system is pressurized??

that video is completely useless by the way..

from what i can tell you have actually bridged 85 and 87 and 30 is the missing wire which is your power...85 is your ignition which would mean your fuel pump is being powered by your ECU.. :unsure:

try plugging the relay up as normal but instead running a power wire direct from your battery (or any direct power source) to your missing plug port which i think is 30 and see what happens..run an inline fuse if you can on this wire..

It smells like its coming from the exhaust plus it blows some blue smoke, Pump just continually runs. The boys on street commodores gave me a wiring diagram of the relays and im sure I wired it from battery to pump, but ill try that method to be sure.

It sounds to me like an ecu/ wiring issue which I guess you will just have to do the hard yards a few spare wires is a little scary though, check the connections on the fuel pump but u really need direct connection to battery anyhow if it were me get a rb20 ecu pin out diagram and see what those wires are with engine conversions this stuff can always pop up unfortunately .scott

Yeah I know what you mean about being scary.. I'm hoping it's just accessories for the rb20 that arent crucial to running properly, ill put up those questions in due time.

And check your fpr and injector seals maybe they are perished ?

I'll check this out, thanks

There's 50 kg in it. RB is not lighter than the Moo6, so no expected change there.

What about the non-RB20 friendly moonshot diff ratio?

RB20s into any Commodore, including VL, have always been full-of-fail .

My moo6 has got an lsd with 4.11's so no problems here. I beg to differ on full of fail. It's different and if it works properly its something out of the ordinary which is why I did this :)

agreed but a project is a project and diff ratios can be changed .. :)

Thanks bud

Lets not pick on the guy re what he chose as a project. It may be his fav car and fav motor rolled into one.. or maybe he just likes the idea. Either way its a pretty cool thing to have in the end.

OP where are you located?

There are some basics you can run through to make sure it SHOULD start.

You will need a fuel pressure gauge in line from the fuel filter to the rail, and will need a noid light to check for spark, injector pulse and pressure. You can turn the CAS by hand to test.

I'm located in country victoria near the Grampians. I've had a couple say I need a fuel pressure gauge, ill get onto these suggestions, Thanks

Look on justcommodores.com there is a thread called rb25det into vs commodore it has some good info aswell, my suggestion with the wiring is using the rb20 into r31 pinout match them up to the vp. Also in that thread.

Oh ok, I asked my question on there and they never gave me a link to that thread, ill check it out, thanks mate!

GTS 221 Rookie

GTS 221

Posted
  • Author
Posted

Well I had a quick play tonight, and if I run the pump straight off the battery the car does run better, I took a video to show where i'm up to, hopefully it's more useful. So is it a matter of reconfiguring the wires on that relay? Injector seals look fine. What's a good inline fuel pressure gauge to look out for? Also what is the 'CAS'.. Crank something?

So pin 7 needs to be connected to the FP relay, ill check that out next chance I have, which number on the relay does it have to connect to?

I apoligise for the dumb questions, I just want it to be crystal clear in my head, thanks for your patience.

Video - th_MVI_0355_zpsb93cceaf.jpg

As you can see it blows a fair bit of BLUE smoke but it rev's freely which is better than before when I was bridging the relay to get it to run. And when I remove the power wire the car's idle speeds up unitl it stalls out.

ARTZ Grand Master

ARTZ

Posted
Posted

you want power to pin 30..

as long as your pump is working and you have a standard fuel reg you shouldn't need a gauge because fuel pressure is already set by the stock reg..if you want to get one to be sure they are only 20-30$ for a basic one..

CAS = crank angle sensor

GTS 221 Rookie

GTS 221

Posted
  • Author
Posted (edited)

This is what someone gave me on Street Commodores

pin 30 power from battery

pin 85 earth (body of car, bat "-" etc)

pin 86 trigger wire (from ignition for example, basically tells relay to send
power to whatever the relay is for)

pin 87 power to ur pump, fan, whatever the relay is for

Ill get a regulator/pressure gauge next week just so I can see what's going on. Out of curiosity what should the fuel pressure normally be?

Also this was above but ill put it here again just so it's not missed

So pin 7 needs to be connected to the FP relay, ill check that out next chance I have, which number on the relay does it have to connect to?

Edited by GTS 221
GTS 221 Rookie

GTS 221

Posted
  • Author
Posted (edited)

No cigar with putting power to 30.. if I run my little wire to 86 or 87 the car will start.

Without going out there until tomorrow.. does it sound like my relay doesnt have power? I have a multimeter ill check it tomorrow

Edit; Hang on.. if the relay wasnt getting power connecting the wire to 30 should of fixed the problem.. but it doesnt.. so what does that mean..?

Edited by GTS 221

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