Jump to content
SAU Community

Help! Another Massive Flat Spot

senilykSkylines

By senilykSkylines,
in Engines & Forced Induction

 Share

Recommended Posts

senilykSkylines Collaborator

senilykSkylines

Posted
Posted (edited)

After researching I tried to fix this flat spot at about 3-4500rpm or so. I have tried setting the plugs at .8mm and it improved slightly. I have just bought yellow jacket coils and installed them thinking the old ones must have had it. If anything, it is now running worse! Good torque at up to 3000rpm and then it just goes flat and pulls a bit more at the end.

What on earth could it be?

Mods are:

Mail/road tuned Z32 ecu

Walbro GSS342 fuel pump

3" turbo back exhaust

GFB Boost T

K&N panel filter

Yellow Jacket coils

Running 11psi

cheers,

Dan

Edited by senilykSkylines
Link to comment
https://www.sau.com.au/forums/topic/354399-help-another-massive-flat-spot/
Share on other sites
senilykSkylines Collaborator

senilykSkylines

Posted
  • Author
Posted

I would get a real tune done as apose to one of those mail order bride ecus! You may be able to make the car run better but not every motor is the same to run the same settings!

I did have a mail order but then the tuner did a road test to check that is wasn't pinging and that all was running fine. I've only notice the missing a little while after the tune was done.

MrStabby Grand Master

MrStabby

Posted
Posted

I did have a mail order but then the tuner did a road test to check that is wasn't pinging and that all was running fine. I've only notice the missing a little while after the tune was done.

So - The tuner reckons it was running fine during the road test (that is, no pinging OR flat spots OR missing) and you agree there was no flat spot or missing.

Since then its developed a flat spot and a miss - did those things happen at the same time? What has changed since the tune? How many kms has it been?

senilykSkylines Collaborator

senilykSkylines

Posted
  • Author
Posted

So - The tuner reckons it was running fine during the road test (that is, no pinging OR flat spots OR missing) and you agree there was no flat spot or missing.

Since then its developed a flat spot and a miss - did those things happen at the same time? What has changed since the tune? How many kms has it been?

It's done maybe 5-10,000 km after the tune. It seemed to run fine around the time of the tune an it has been gradually getting worse.

I thought a miss was a flat spot? As in a stall in power, failure to ignite... possibly?

The spark plug gap and the coils have changed since the tune but I did those because I noticed it after the tune (not immediately) I hope it is not the tune but I was thinking possibly the airflow meter maybe? or wouldn't it be?

MrStabby Grand Master

MrStabby

Posted
Posted

It's done maybe 5-10,000 km after the tune. It seemed to run fine around the time of the tune an it has been gradually getting worse.

I thought a miss was a flat spot? As in a stall in power, failure to ignite... possibly?

Nah - miss is where the fuel doesnt ignite at all, so it is rough running, running on 5 cylinders. Flat spot is just low power, but smooth.

honan Collaborator

honan

Posted
Posted (edited)

I had a similair issue with a z32 ecu on mine..ended up going with a r32 ecu and seperate vct controller, the drama was the z32 ecu for some reason just stopped controlling the vct properly.!

Edited by honan
senilykSkylines Collaborator

senilykSkylines

Posted
  • Author
Posted

  • user_add.png
  • email_open.png

  • Posts: 115
  • Joined: 08-March 10
  • Gender:Male
  • Location:Whangarei, New Zealand
  • Car(s):R33 GTS25t 1997
  • Real Name:Daniel

97 would be series 2, which means no igniter pack.

Ya, one of the last R33's made, when I had the new computer tuned we even had to change around a few pins that would not usually need to be changed.

What I don't understand is why would having new yellow jacket coils make it worse? They are new and suppose to be better.

I really hope i am not leaning out or my engine would be frying itself. I would have thought running it rich rather than lean would be what makes it go slower? Fuel pump is only several months old, unless there is a leak in the line after i installed, but then it wouldn't be pulling hard in the top end I would have thought.

I've emailed the tuner...

  • 1 month later...
senilykSkylines Collaborator

senilykSkylines

Posted
  • Author
Posted

Dynoed it and turned out to be (in theory) the intercooler getting too hot which triggers the knock sensor almost always at 4000rpm. FMIC is on the next to do list.

SargeRX8 Grand Master

SargeRX8

Posted
Posted

How does heat trigger the knock sensor? It's on the other side of the block, it's not affected by heat and has nothing to do with the cooler. Unless the heat is causing the engine to ping which would be strange because you said your tuner said it want pinging.

put the stock ecu in before to cause any damage. I had a pfc which had a tune for stock car and little more boost, sure the highest ping was 38 but it ran like arse. Put my stock in there yesterday and yanked out the z32 afm and it runs alot better, alot more power. If the tune is not on your car it's not for your car.

senilykSkylines Collaborator

senilykSkylines

Posted
  • Author
Posted

How does heat trigger the knock sensor? It's on the other side of the block, it's not affected by heat and has nothing to do with the cooler. Unless the heat is causing the engine to ping which would be strange because you said your tuner said it want pinging.

put the stock ecu in before to cause any damage. I had a pfc which had a tune for stock car and little more boost, sure the highest ping was 38 but it ran like arse. Put my stock in there yesterday and yanked out the z32 afm and it runs alot better, alot more power. If the tune is not on your car it's not for your car.

<i> Unless the heat is causing the engine to ping</i>

This is correct. Tuner sensed a "little pinging" on the dyno but the knock sensor was pulling it back sometimes when it sensed knocking. So it is not knocking badly at the moment, only a little when it is hot which the ecu picks up and takes care of. Goin to get a FMIC and try 98 octane instead of 95. cheers.

Mayuri Krab Grand Master

Mayuri Krab

Posted
Posted

<i> Unless the heat is causing the engine to ping</i>

This is correct. Tuner sensed a "little pinging" on the dyno but the knock sensor was pulling it back sometimes when it sensed knocking. So it is not knocking badly at the moment, only a little when it is hot which the ecu picks up and takes care of. Goin to get a FMIC and try 98 octane instead of 95. cheers.

Your running RON 95 fuel on a GTS-T, and it has being modified for extra power? :(

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

    • 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 
    • Duncan
      After market rear camber arm adjustment

      By Duncan · Posted

      You just need a wheel alignment after, so just set them to the same as current and drive to the shop. As there are 2 upper links it may also be worth adding adjustable upper front links at the same time; these reduce bump steer when you move the camber (note that setting those correctly takes a lot longer as you have to recheck the camber at each length of the toe arm, through a range of movement, so you could just ignore that unless the handling becomes unpredictable)
    • V35Newbie
      After market rear camber arm adjustment

      By V35Newbie · Posted

      I got adjustable after market rear camber arm to replace the stock one's because got sick of having to buy new rear tyres every few months. Can anyone please let me know what the best adjustment length would be. I don't have the old ones anymore to get measurements. I'm guessing the stock measurement minus a few mm would do it. Please any help on replacing them would be fantastic I've watched the YouTube clips but no-one talks about how long to set the camber arm to.
    • GTSBoy
      Unpeeling the Orange

      By GTSBoy · Posted

      Heh. I copied the link to the video direct, instead of the thread I mentioned. But the video is the main value content anyway. Otherwise, yes, in Europe, surely you'd be expected to buy local. Being whichever flavour of Michelin, Continental or Pirelli suits your usage model.
×
×
  • Create New...