Jump to content
SAU Community

Engine Occasionally "hiccups"?

angusis2fast4u

By angusis2fast4u,
in Engines & Forced Induction

 Share

Recommended Posts

angusis2fast4u Enthusiast

angusis2fast4u

Posted
Posted (edited)

So i've read around but not getting a straight answer, I'm believing it's CAS but coming here for a second opinion

So occasionally the engine will "hiccup". ill be driving down the road (usually I only notice it during freeway driving) and then the engine will like die for a short period of time, (it feels like when you lift your foot off the pedal for a split second)

I think I read somewhere it was CAS but can't since find that page to read up on it.

any help / confirmation / ways to troubleshoot it? Compression is good: 142, 150, 145, 145, 150, 150. New o2 and cleaned AFM.

is running a Power FC

RB20DET 1992 SKyline r32

Thanks for the help guys!

Edited by angusis2fast4u
Link to comment
https://www.sau.com.au/forums/topic/449952-engine-occasionally-hiccups/
Share on other sites
angusis2fast4u Enthusiast

angusis2fast4u

Posted
  • Author
Posted

I have splitfires, walbro 255 pump, brand new spark plugs (I forget if this issue was around before I changed them... Could that be it??) So i would hope it's not the coils or pump... Also the issue generally doesn't happen under power like usually just when im cruising along...

How did you check your CAS??

One of my old r32 did that
Checked cas, fuel pump, coilpacks etc
Ended up being dirty AFM

kaneryan Rising Star

kaneryan

Posted
Posted

i had an issue like this, but it only happened about like 5000 rpm. then it started to get worse and worse like 4000rpm then above 3000rpm. to the point i could hardly drive my car. ended up being my haltech has a safety cut when it leans out to much it will cut the engine every time its to lean,
ended up being a split hose pipe from my fuel pump to the top of my tank, so the full was getting sucked up the fuel pump then not even leaving the tank squirting out the hose then back down into the tank and then back into the pump again. only letting a little bit of fuel through at a time so was causing it to hickup so to speak, maybe check that, if it gets worse and worse maybe check this. also replace your fuel filter......... cost about $10 and is easy to do! and will rule it out, peace of mind

Ben C34 Grand Master

Ben C34

Posted
Posted (edited)

How does a dirty throttle bofy cause a hiccup?

And a car doesn't need tuning due to new coils. ...

Sounds like the power fc miss.

Just in case you missed GTSBOY ' S post

Edited by Ben C34
  • Like 1
Ben C34 Grand Master

Ben C34

Posted
Posted

i am aware of that, hence the "other mods" words in there..... clearly trying to sus out and get the most information to diagnose this issue.... you annoy me.

Ok cool. Seems odd you would mention it then.

Sorry that pointing out facts annoys you. I suppose I could just let it slide and let people think they need a retune due to replacing their coils, but hey, I'm not that kind of guy.

chiksluvit Experienced

chiksluvit

Posted
Posted

I have splitfires, walbro 255 pump, brand new spark plugs (I forget if this issue was around before I changed them... Could that be it??) So i would hope it's not the coils or pump... Also the issue generally doesn't happen under power like usually just when im cruising along...

How did you check your CAS??

Mechanic did back in the days

It was my first car 10+ years ago

Ben C34 Grand Master

Ben C34

Posted
Posted

Typically to check a cas you play swap tropics with a known working one.

Perhaps there's a way to check it with an oscilloscope, but as the issues tend to be intermittent it would be difficult and unlikely picked up like that.

angusis2fast4u Enthusiast

angusis2fast4u

Posted
  • Author
Posted

Typically to check a cas you play swap tropics with a known working one.

Perhaps there's a way to check it with an oscilloscope, but as the issues tend to be intermittent it would be difficult and unlikely picked up like that.

Yeah it like rarely happens like probably not even once a week, It probably only happens like once every 2 weeks

Ill look up the PowerFC miss.

Sparks were done like 600km ago

ill check out that throttle body as well

Thanks for the help ill report back when i've got an update!

Piggaz Grand Master

Piggaz

Posted
Posted

The power fc "miss" generally happens coming away from a set of lights, for example. Low rpm, generally low load. Well, mine did anyway.

There is a decent discussion on here somewhere about it.

Sarumatix Veteran

Sarumatix

Posted
Posted

I had this problem and it was a bastard to track down in the end for me it was the AFM pins getting a dry solder joint.

There is a guide on re-soldering in the DIY section. To diagnose I used CONSULT connected to a laptop datalogging all values. As soon as it happened I pulled over and spotted which value started it, AFM voltage dropping to 0.

Hope this helps

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

    • GTSBoy
      R33 Fuel Pump & Brakes after alarm swap

      By GTSBoy · Posted

      Look, realistically, those are some fairly chunky connectors and wires so it is a reasonably fair bet that that loom was involved in the redirection of the fuel pump and/or ECU/ignition power for the immobiliser. It's also fair to be that the new immobiliser is essentially the same thing as the old one, and so it probably needs the same stuff done to make it do what it has to do. Given that you are talking about a car that no-one else here is familiar with (I mean your exact car) and an alarm that I've never heard of before and so probably not many others are familiar with, and that some wire monkey has been messing with it out of our sight, it seems reasonable that the wire monkey should be fixing this.
    • GTSBoy
      After market rear camber arm adjustment

      By GTSBoy · Posted

      Wheel alignment immediately. Not "when I get around to it". And further to what Duncan said - you cannot just put camber arms on and shorten them. You will introduce bump steer far in excess of what the car had with stock arms. You need adjustable tension arms and they need to be shortened also. The simplest approach is to shorten them the same % as the stock ones. This will not be correct or optimal, but it will be better than any other guess. The correct way to set the lengths of both arms is to use a properly built/set up bump steer gauge and trial and error the adjustments until you hit the camber you need and want and have minimum bump steer in the range of motion that the wheel is expected to travel. And what Duncan said about toe is also very true. And you cannot change the camber arm without also affecting toe. So when you have adjustable arms on the back of a Skyline, the car either needs to go to a talented wheel aligner (not your local tyre shop dropout), or you need to be able to do this stuff yourself at home. Guess which approach I have taken? I have built my own gear for camber, toe and bump steer measurement and I do all this on the flattest bit of concrete I have, with some shims under the tyres on one side to level the car.
    • Jarsky
      R33 Fuel Pump & Brakes after alarm swap

      By Jarsky · Posted

      Thought I would get some advice from others on this situation.    Relevant info: R33 GTS25t Link G4x ECU Walbro 255LPH w/ OEM FP Relay (No relay mod) Scenario: I accidentally messed up my old AVS S5 (rev.1) at the start of the year and the cars been immobilised. Also the siren BBU has completely failed; so I decided to upgrade it.  I got a newer AVS S5 (rev.2?) installed on Friday. The guy removed the old one and its immobilisers. Tried to start it; the car cranks but doesnt start.  The new one was installed and all the alarm functions seem to be working as they should; still wouldn't start Went to bed; got up on Friday morning and decided to have a look into the no start problem. Found the car completely dead.  Charged the battery; plugged it back in and found the brake lights were stuck on.  Unplugging the brake pedal switch the lights turn off. Plug it back in and theyre stuck on again. I tested the switch (continuity test and resistance); all looks good (0-1kohm).  On talking to AVS; found its because of the rubber stopper on the brake pedal; sure enough the middle of it is missing so have ordered a new one. One of those wear items; which was confusing what was going on However when I try unplugging the STOP Light fuses (under the dash and under the hood) the brake light still stays on. Should those fuses not cut the brake light circuit?  I then checked the ECU; FP Speed Error.  Testing the pump again; I can hear the relay clicking every time I switch it to ON. I unplugged the pump and put the multimeter across the plug. No continuity; im seeing 0.6V (ECU signal?) and when it switches the relay I think its like 20mA or 200mA). Not seeing 12.4V / 7-9A. As far as I know; the Fuel Pump was wired through one of the immobiliser relays on the old alarm.  He pulled some thick gauged harness out with the old alarm wiring; which looks to me like it was to bridge connections into the immobilisers? Before it got immobilised it was running just fine.  Im at a loss to why the FP is getting no voltage; I thought maybe the FP was faulty (even though I havent even done 50km on the new pump) but no voltage at the harness plug.  Questions: Could it be he didnt reconnect the fuel pump when testing it after the old alarm removal (before installing the new alarm)?  Is this a case of bridging to the brake lights instead of the fuel pump circuit? It's a bit beyond me as I dont do a lot with electrical; so have tried my best to diagnose what I think seems to make sense.  Seeking advice if theres for sure an issue with the alarm install to get him back here; or if I do infact, need an auto electrician to diagnose it. 
    • Duncan
      After market rear camber arm adjustment

      By Duncan · Posted

      Then, shorten them by 1cm, drop the car back down and have a visual look (or even better, use a spirit level across the wheel to see if you have less camber than before. You still want something like 1.5 for road use. Alternatively, if you have adjustable rear ride height (I assume you do if you have extreme camber wear), raise the suspension back to standard height until you can get it all aligned properly. Finally, keep in mind that wear on the inside of the tyre can be for incorrect toe, not just camber
    • V35Newbie
      After market rear camber arm adjustment

      By V35Newbie · Posted

      I know I have to get a wheel alignment but until then I just need to bring the rear tyres in a bit they're wearing to the belt on the inside and brand new on the outside edge. I did shorten the arms a bit but got it wrong now after a few klms the Slip and VDC lights come on. I'd just like to get it to a point where I can drive for another week or two before getting an alignment. I've had to pay a lot of other stuff recently so doing it myself is my only option 
×
×
  • Create New...