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New Rb30 Running Like Crap.

Gts4RB30

By Gts4RB30,
in R Series (R30, R31, R32, R33, R34)

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Gts4RB30 Collaborator

Gts4RB30

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Have just put new rb30 into r32 with rb25de head and rb20 cams. Since I've tried running it it idled like a dogs breakfast and stalls and in doing so the apexi avcr is saying injectors are at 90% duty cycle at idle. Car will running and revs out and when warm is ok but the idle starts to hunt from 1000 to 1500 also the idle at 800 is like its miss firing but its not. I have new temp sensor new coil packs new plugs new coil harness and the list goes on. The one plenum is a side intake and the aic valve sits underneath. Can anyone helps please. This making me pull my hair out.

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Shoota_77 Veteran

Shoota_77

Posted
Posted

Could be a miilion things.

Has that ENTIRE setup come out of another running car or is it a freshly built engine with all the newly acquired parts used to put it all together?

What computer are you running? Has is been tuned at all to run on the current setup?

Is there a vacuum leak? Old fuel?

There's a whole lotta variables that you're going to have to go through one at a time in a logical order.

Good luck!!

Gts4RB30 Collaborator

Gts4RB30

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Thanks mate. Yes all is new and its waiting to be tuned has bigtime in it. Found out it was typical aac valve issue but now its missfiring on cylinder 6. Has spark has fuel. Has new coil packs plugs coil loom and freshly clean injectors can't seem to isolate the issue. Ignores has good resistance and signal. Any help on that?

Shoota_77 Veteran

Shoota_77

Posted
Posted

There was a guy just last week that found he had low battery voltage and that was enough to drop a couple of cylinders so try that first.

Have you swapped coils/injectors/spark plugs from cylinder 6 to see if the problem moves? If not do each item one at a time.

Gts4RB30 Collaborator

Gts4RB30

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^^^ damn dude. ok so check low voltage. well today i pulled the coils out and swapped them with 3 others plus a spare nissan set i had in the shed with a spark tester and it has spark on every single tested coil pack i also pulled the injectors and checked that they have flow and swapped them around and ALL injectors have flow. also recalibrated fuel pressure regulator as it was getting 100psi pressure....................................??? anyway didnt fix the issue my ecu has a nistune daughter board it it to so what voltage should i be looking for from a skyline alternator?? 14.4v?? also now engine wont stay idling just dies pissing me off big time this has cost me 30k to build this thing.

Shoota_77 Veteran

Shoota_77

Posted
Posted

Get a stock computer and try that (one that matches the head/wiring you're running).

It sounds like you might be on to something when you say it only plays us when bolted down. Possibly coil pack harness? Try one of those too if you can get your hands on one.

Gts4RB30 Collaborator

Gts4RB30

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cas works well tested it, sctraching my head bout ecu been lots of rain here lately just did code check on ecu came up 55. has z32 afm wondering if that maybe an issue with old wiring i know alot of people fall on that too and doesnt come alot as being wrong will try sitting coil pack on head with a lead running from coil pack to plug tomorrow. timings right. it has rb25de head on forged rb30 awd bottom end in a r32 gts4 stock cams fully recoed head and new 100lb valve springs arp head studs and rb26 head gasket. so i'm ruleling out compression issue. stupid thing has piston slap above 1500 rpm in 1st cylinder though thats another story i know what i have to do to resolve that. theres not much that isnt new on it. maybe needs more earthing out from block???

StevenCJR31 Veteran

StevenCJR31

Posted
Posted

any number of reasons (including the above) for cylinders to randomly drop. . . when mine did it -turned out the stock ecu was as crook as a chook

forgot to add. .electrician told me some of the pins on the wiring loom(going into the ecu) was a bit dirty , when you moved the ecu with the engine running it would sometimes drop a cylinder or just stall, maybe if you sniff around there you might find your problem

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