Jump to content
SAU Community

Need Help Urgently!

Daboss

By Daboss,
in Engines & Forced Induction

 Share

Recommended Posts

Daboss Experienced

Daboss

Posted
Posted

Hey there need some urgent help with my 25/30. I have just installed some tomei 264 poncams and now my car idles like crap. The whole car shakes and vibrates and just doesn't feel right. I have new lifters, upgraded valve springs and retainers, new valve stem seals and the tomei 264 poncams. I have a tomei exhaust cam gear installed with no advance or retard.Controlling everything is a pfc l jetro and I have 700cc injectors.

The car revs and drives ok but idle is horrible. Timing is spot on and no matter how far advance or retard ignition timing or add and take away fuel the idle does not get any better. Now don't get me wrong it changes the idle and ratios but the best idle I can get is still crappy. Every video i see or person i ask that has installed these cams say they are straight drop in and do not affect idle like what I am describing, but my idle woes only happened after the cam install.

I thought bent valves but got a reading of 150 psi on all cylinders doing a dry compression test. Can anyone give any advice? I am totally stumped and bout ready to go back to the original cams cause this idle just is not right.

Anyone with any experience please give some advice.

Link to comment
https://www.sau.com.au/forums/topic/452519-need-help-urgently/
Share on other sites
  • Replies 66
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Posted Images

Ben C34 Grand Master

Ben C34

Posted
Posted (edited)

What revs are you idling at?

The 260 cams are drop in. I thought the 264 weren't drop in but I could be wrong.

Are you 100 percent sure that they are drop in?

Making it richer at idle typically helps.

Also are you sure they are dialed correctly. I would have thought that the extra duration would drop the cranking psi generated, as it certainly drops manifold vaccum at idle.

I recommend double checking cam timing and drop in status of the cams.

Edited by Ben C34
Daboss Experienced

Daboss

Posted
  • Author
Posted

Purchased from tomei stated they were drop in 264 with 8.5 mm lift, they retain vct, idling at about 1000 rpm,don't know what previous cylinder psi was but got 150 psi dry tested with cams installed. Didn't try any dialing in only have an exhaust cam gear cause intake retains vct, manifold vacuum haas dropped at idle from showing -17 on the boost gauge to showing -8 and idle is horrible. Entire car shakes and sputters.

Ben C34 Grand Master

Ben C34

Posted
Posted (edited)

My 2530 with a neo head and 260 cams idled like stock with slightly higher vacuum.

I know if VCT was activated at idle it idled like crap. Could that be the case with yours?

Edited by Ben C34
Daboss Experienced

Daboss

Posted
  • Author
Posted

My 2530 with a neo head and 260 cams idled like stock with slightly higher vacuum.

I know if VCT was activated at idle it idled like crap. Could that be the case with yours?

No VCT activates correctly.

Dial gauge and timing wheel time.

What do you mean?

Ben C34 Grand Master

Ben C34

Posted
Posted

How do you know vct activates correctly?

How did you remove the vct pulley? I have heard of them being damaged with a rattle gun when not holding the cam. The correct way us to hold the cam with a spanner then remove the gear.

GTSBOY means it time to check how the cams are setup. Which to be accurate is done using a dial indicator and degree wheel.

Daboss Experienced

Daboss

Posted
  • Author
Posted

How do you know vct activates correctly?

How did you remove the vct pulley? I have heard of them being damaged with a rattle gun when not holding the cam. The correct way us to hold the cam with a spanner then remove the gear.

GTSBOY means it time to check how the cams are setup. Which to be accurate is done using a dial indicator and degree wheel.

Cause looking at the pfc sensor check and listening to the car you can hear it click at about 1500 and see the sensor indicator light up on the pfc hand controller. So i would need a timing wheel with the 360 degree marks and the dial indicator to place onto the lifter?

The cams didnt come with a sheet to see what it shou;d be dialed in at though as they were just suppose to be drop ins.

What would I be looking for exactly and can it be done with stock harmonic balancer?

Ben C34 Grand Master

Ben C34

Posted
Posted (edited)

The tomei can specs can be download.

Stock balancer is useless for degreeing in the cams. However the issue is likely the cams being out by a whole tooth so aligning the marks is sufficient. Having said that in my experience the marks dont line up well with a 2530 and are out by almost half a tooth . I checked my cams with a degree wheel and found that. So perhaps you are out the other way than before

If the vct pulley has been damaged and stuck on the car would idle shit.

What happens if you activate the vct at idle? Does the idle change at all, if not then the vct is stuck on.

Edited by Ben C34
Daboss Experienced

Daboss

Posted
  • Author
Posted

The tomei can specs can be download.

Stock balancer is useless for degreeing in the cams. However the issue is likely the cams being out by a whole tooth so aligning the marks is sufficient. Having said that in my experience the marks dont line up well with a 2530 and are out by almost half a tooth . I checked my cams with a degree wheel and found that. So perhaps you are out the other way than before

If the vct pulley has been damaged and stuck on the car would idle shit.

What happens if you activate the vct at idle? Does the idle change at all, if not then the vct is stuck on.

Yea I just took a look and the only numbers I can find for the poncams with hydraulic lifters and vct are intake 120 and exhaust 115, but that is for the 256 with 8.5mm lift the set I have are 264 with 8.5mm lift. Which I see no info for.

As for activating vct at idle I cant it only activates when I rev the car. I can hear the solenoid activate and on the pfc controller the vct indicator lights up hand controller wise the dot darkens.

Dont have a degree wheel. We timed and retimed it and it seems to be spot on. All the marks are lined up from timing gear on crank to cam gears and harmonic balancer all lined up with belt on and in place and rotating by hand a few times.

Do you think i should have a go at the exhaust cam retarding or advancing that seeing as that is the only gear I have that I can adjust anyway? To see if it helps with this horrid idle. Any suggestions on which way to start?

Ben C34 Grand Master

Ben C34

Posted
Posted

I wouldn't touch the cam timing until you can rule out the vct being an issue.

I would activate it manually. Disconnect e plug to protect the PFC and put 12v and earth to it with car running and see what happens. Polarity doesn't matter .

Daboss Experienced

Daboss

Posted
  • Author
Posted

I wouldn't touch the cam timing until you can rule out the vct being an issue.

I would activate it manually. Disconnect e plug to protect the PFC and put 12v and earth to it with car running and see what happens. Polarity doesn't matter .

Will do in the am and let you know results. Thanks for advice.

Advancing the exhaust can would reduce overlap and improve idle if you want to try that.

with the exhaust gear i noticed you spin the crank while having the bolts that secure the gear loosened, this causes gear to move without moving cam itself which by default moves everything except the exhaust cam.

I know that advances or retards it depending on which way you turn. What i want to know is on the gear it shows clockwise as advance and counterclockwise as retard, but if i advance it will move the intake forward while keeping the exhaust tdc. Is that advancing the exhaust cause from what i am picturing it seems to be advancing the intake cause it opening the intake valves slightly earlier than than the exhaust set. Or am I just mixed up and over thinking it a bit to much?

I will activate vct firstly thogh and see if idle changes before I fool with exhaust gear.

Is there any other way to tell if i am out a tooth? Like I said we checked and rechecked and everything lines up fine.

Scott Black Rising Star

Scott Black

Posted
Posted

whatever cam adjustment is loose is the one that is being adjusted, as if the exhuast adjustment is loose and you turn the engine clock wise, the exhaust cam will stay stationary, and the intake cam and crack will spin, and the exhuast cam gear will move slightly, and this will RETARD the the ehxaust cam by making exhuast events happen later in the cycle, it will also increase overlap and cause a shitter idle

Daboss Experienced

Daboss

Posted
  • Author
Posted (edited)

I wouldn't touch the cam timing until you can rule out the vct being an issue.

I would activate it manually. Disconnect e plug to protect the PFC and put 12v and earth to it with car running and see what happens. Polarity doesn't matter .

Ok folks i did this test and the solenoid activates. I can hear it clicking, but the idle remains the same it does not change same crap idle at same rev.

So whats the next step find another vct cam pulley and change it out? What is actually damaged? Can you explain what happened? More than likely the mechanic used an impact gun to get it off without holding the cam down.

Edited by Daboss
GTRPSI Mentor

GTRPSI

Posted
Posted

Check you cams are correctly timed before going further in case your a tooth off somewhere.

Check your valve clearances while your there.

It could just be something very basic that was missed on assembly causing it.

All you need to cause this if for a cam to be out a tooth or for a valve shim to have popped out of place.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • uchoa
      Yet another RB Neo misfiring thread after reading all the others.

      By uchoa · Posted

      Good tips, will get on those tomorrow. When doing the maintenance I did move a few of those connectors around, and things that are old tend to not like moving around. (Like me).
    • GTSBoy
      Yet another RB Neo misfiring thread after reading all the others.

      By GTSBoy · Posted

      Don't try it. It will be shit. Better chance of damaging the engine than gaining any knowledge about the old one. Maybe, but unlikely, especially if the O2 sensor is working. You can use NissDataScan to look at the stock ECU.   Cleaning the AFM is seldom necessary and seldom helps. The R35 coil & loom conversion should eliminate dud coils or plugs. But as you still have misses - look to the plug where the coil loom connects to the engine loom, and the CAS plug. Need quality connections there. Also look to injector plugs. And the AFM plug while you're at it. Also look to whether your injectors are clean and flowing evenly. Get them out and onto a testbench.
    • uchoa
      Howdy from the states.

      By uchoa · Posted

      Good to know, I feel like I am in for a rollercoaster ride that looks like a sine wave. 
    • GTSBoy
      Howdy from the states.

      By GTSBoy · Posted

      You'll fit right in. Acceptance is the first step.
    • uchoa
      Yet another RB Neo misfiring thread after reading all the others.

      By uchoa · Posted

      Hey folks. I've been lurking and browsing the forum for a while, since I got into my head that I wanted a skyline. Having purchased an overpriced completely stock GTT, (only "mods" it has is HKS pod filter and catback) now that it became legal in the US, it was all glorious and sututu noises here and there. But then I wanted to do things right and went to do basic maintenance. After all the fluids, filters done, I did the spark plugs, that's when the problems started.. First the car started spluttering at around 4.5k RPM. Which I gapped down the new plugs and that solved the sputter there, but the car now always misfires at idle with pops when lifting off and shifting 2nd to 3rd. Similar to the issues in this recent thread. I've been banging my head against the wall, reading the threads here and trying suggestions for a couple months now, so decided to start this one to explain exactly what I tried and what is going on. The symptoms of the issue: Idle and low revs misfiring intermittently. You can hear the exhaust tone change and the shakes on the shifter knob. It happens frequently, but doesn't seem to have a rhythm to it. Pops when backing off throttle. It pops and or burbles almost feels like it spits fire when it pops. (Happens mostly in 3rd gear at around 2k RPM). When under load and after 6k RPM, it also pops when shifting from 2nd to 3rd. There's a ticking noise at around 2k RPM in 2nd gear going downhill, seems unrelated though but I am out of educated and downright dumb guesses. Not noticeable lack of power when putting the car into load. The attempted diagnosis and solutions: Unplugging coils when the car is running This did nothing to change the idling and tone shift for every cylinder. Checking the exhaust headers with thermometer They all are within what I'd say it is margin of error of the laser thermometer New spark plugs Tossed two new sets, copper, iridium and using the old ones, still misfiring, even re gapped to 0.8mm, still same thing. MAF cleaned with the "specific" spray cleaner No changes in the issues what so ever. Brand new loom and r35 coil conversion (was going to add the r35 coils anyway) car runs arguably better, still misfires, but seems like does less frequently. Placebo? Code 21 now being thrown, thanks nissan gods. Removed the CAS to check the shaft for play or anything. CAS seems all fine, nothing that indicates any issue, visually speaking. Things to attempted next: Ordered a new MAF (chinesium from Amazon, to be able to return regardless of result). Fuel with proper gas, maybe it is this California water that they sell as gas that is to blame? Plugin the link ECU and check the info using the built in base map. Go back to BMW and eat my rob bearing breakfast without milky oil mixture.   Do any of you have experienced anything like this or have any suggestion?
×
×
  • Create New...