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Analyze This Short Video For Me Please!

DRFT 14

By DRFT 14,
in Engines & Forced Induction

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DRFT 14 Collaborator

DRFT 14

Posted
Posted

http://www.zippyvideos.com/2429972605285026/new_misfire/

Car Details: S14 Silvia

NEO RB25DET

Custom top mount manifold / 38mm WG

T3/T4 Masterpower Turbo .63ar

Walbro Fuel Pump

Wasted Spark Ignition, using VL Commodore coil pack

LinkPlus ECU

DSC01302.jpg

The car has been running as per the video ever since the first time the engine came to life in my S14. In the video, the car was running on 1bar. It runs ok and revs to redline without a hitch about 80% of the time with my other 8psi WG spring. I hoped the problem was a tuning issue, but the car was turned away at the dyno because of the problem. The tuner said it was not a tuning issue. I have gapped the sparkplugs to .8mm and that didn’t help anything.

I have been trying to fix this problem for over 6 months now. I was very proactive in trying to sort it out at the beginning of my conversion. I gave up on it ages ago and am running my car on 8psi all day everyday. As you can imagine, getting the car dyno tuned is a waste of time on 8psi, so I have been forced to drive it at an un-tuned 8psi for over half a year. My $10,000 investment has gone to waste to say the least.

This is my last ditch attempt to try and get some answers before the car is put up for sale at a ridiculously low price. Id love to keep the car if ran to its full potential, but right now it’s just a POS sitting in my garage.

So, from the video, can you guys come to any conclusions? Does it look like a fuel problem? Ignition problem? Perhaps it’s the wasted spark ignition setup? I’m changing the ignition setup back to coil packs this month to see if it fixes the problem.

Any ideas would be great.

Abo Bob Grand Master

Abo Bob

Posted
Posted

Sounds like a fuel problem to me. I would be looking to see that all your fuel plumbing in the engine bay is the right way round. It would help to have an R34 engine bay side by side to check it.

I hooked mine up backwards once. It went but not well.

Failing something like that, change the pump to check that or at least check it's wiring.

mad082 Grand Master

mad082

Posted
Posted

i'm going to suggest a few things.

firstly put a standard plenum on it. the way it is number 1 will be running really rich, and number 6 really lean.

take the coil pack cover off. even though you have a wasted spark setup you could still benefit be getting rid of some heat.

what plugs are you running? you have said that they have been gapped to 0.8mm but what type? and it might be an idea to gap them smaller, to say 0.65mm or 0.7mm.

MR331307 Experienced

MR331307

Posted
Posted (edited)

DO you mean Vn Coils

Anyways sounds like either Spark Problem Missfiring or Fuel can only be one or the other

Have you got a Fuel pressure guage Whats it doing

what is the dwell timing setup on the ecu and What is the Voltage to the coils

What spark plugs you running and What gap

id check the plugs first run .65 m gap & check fuel pressure

Then if you find thats not the problem check the Voltage to the Coils

Does it happen all the time or sometimes and have you got a printout of your last dyno run

Where you from

The only way to check the Problem Quickly would be on a dyno

Edited by MR331307
Wheezy Mentor

Wheezy

Posted
Posted

From what ive seen using commodore coils is a bad idea, falcon ones seem to be alot more reliable...there are also two type of commodore coils, the supercharged ones are defenantly different.

IRC fuel lines on NEO's are also the other way around to R33's, but then fuel wouldnt be getting into the rail?

hope that helps...

jez

paulr33 Grand Master

paulr33

Posted
Posted

what boost controller? does the problem occur if you remove the boost controller and just run off the actuator or gate spring? can u get any logs from the link ecu? does the link ecu sensor screen / check show anything obvious?

my hks evc3 when it was shorting out and earthing would do that, the solenoid would chatter on and off making the boost surge which made the engine sound like that, as pressure was up and down wonky style

nemini90 Enthusiast

nemini90

Posted
Posted

what computer is it??

if it is haltech or ems then then the problem you might have is running wasted spark on my car when we ran haltech if i wanted to run wasted spark i had to go to ls1 coils

DRFT 14 Collaborator

DRFT 14

Posted
  • Author
Posted

Really appreciate the input guys...

DynoRun.jpg

For those that asked, here is a dyno run. I did this at an open dyno day, so diagnostics was not available. The blue line was a 10psi run. The car missed badly at high revs and the tuner got scared and let off (as you can see the early drop off in the graph). Anything higher than 10psi, and it would not have revved out at all. Can anyone pick anything up from the graph? I dont think it gives much of an indication but I thought id post it up anyway.

As far as spark plugs go, im running NGK Platinum. Ive tried all kinds of gap combinations and that doesnt solve anything. I used the same Walbro fuel pump setup I used with my old RB20DET engine and that engine ran fine. Then again, it was a standard RB20 running standard boost, so the fuel pump wasnt worked very hard at all compared to the new engine.

As far as fuel lines being on the wrong way etc as some have suggested, ive been using the car on 8psi for a long time and its been ok. Even took it drag racing. Surely it wouldnt have run properly at all if the fuel lines were not correctly installed?

paulr33, in the video it was running a 1bar wastegate spring with no boost controller. I used a boost tap in the dyno run to dial up 10psi.

DRFT 14 Collaborator

DRFT 14

Posted
  • Author
Posted
what computer is it??

if it is haltech or ems then then the problem you might have is running wasted spark on my car when we ran haltech if i wanted to run wasted spark i had to go to ls1 coils

Interesting. Im using a LinkPlus Ecu. Its a standalone computer, made here in New Zealand. Perhaps there are compatibility issues with the Link and this particular ignition setup. Chances seem abit slim, but i have made a deal on some NEO RB25DE coilpacks and will receive them at the end of the week. I will get them running and fingers crossed the issue will go away. If not, il place my attention towards the fuel setup as others have suggested.

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