Jump to content
SAU Community

Recommended Posts

Hi all,

Having problem with my R34 GTT:

Engine goes very rough at low boost levels, for instance at idle speed and when revving without any gear engaged to about 2-3000rpm it “coughs” and seems to have very rough hiccups all the time, if you know what I mean…? At high boost levels it runs like a dream though, no problems at all to rev to the limiter and there’s plenty of power without delay or hesitation.

So, wtf!? What do you reckon?

Stuff on the car: pod filter, fmic and 3” cat-back.

Also, thinking about leaving Sweden to move to Australia with my girlfriend. Do you recommend it?

Link to comment
https://www.sau.com.au/forums/topic/333454-engine-works-well-at-high-boost/
Share on other sites

Also, thinking about leaving Sweden to move to Australia with my girlfriend. Do you recommend it?

Yes!! :laugh:

Has your car been tuned or is it stock ecu?

Does it happen while cruising/decel or on acceleration?

hehe, ok! That's all I need to hear, you just made me decide to move there :(

Will need to start looking for jobs first. Thinking about Holden, where's the development site situated?

The car runs with stock ECU. It's all stock except HKS pod, FMIC, HKS cat-back and HKS ssqv.

It happens while cruising, anytime the boost is gentle and even. Decel or acceleration works just fine.

:laugh:

hehe, ok! That's all I need to hear, you just made me decide to move there ;)

Will need to start looking for jobs first. Thinking about Holden, where's the development site situated?

The car runs with stock ECU. It's all stock except HKS pod, FMIC, HKS cat-back and HKS ssqv.

It happens while cruising, anytime the boost is gentle and even. Decel or acceleration works just fine.

:laugh:

I've changed a life. My job here is done :(

So when cruising you would be driving on vacuum not boost yes? On boost you would be accelerating. Does it hunt at idle, like rev up and down? And is it more pronounced when the car is warm or is it exactly the same when it's cold? Sort of sounds like it could be a problem my mates R32 had, was effectively a vacuum leak. The air regulator was stuck open, so when the car was cold it ran fine but when it warmed up the air regulator was still open and the car was getting too much air. Ran fine when you were accelerating, but trying to cruise it would just stutter and jump, etc.

Could also be a problem caused by that atmo bov you have.

YES COME TO AUS! Bring MORE swedish girls with you too! (my GF is Estonian, so if we got more or them/Swedes in this country, we'd be happy men)

Could be the stock ECU is gumby, or the AFM is fail....sounds kinda like it might be running excessively rich, but once the airflow climbs up with more boost, it compensates and evens out...

Might be that you're running too cold plugs. What plugs are you running?

list of mods?

Actually don't know. Havn't checked since I bought the car, the plugs were brand new then. Will check tonight or this weekend. Temp grade 6 is standard, right? With my mods which I've already listed above, should I go for 6 or 7?

I've changed a life. My job here is done :P

So when cruising you would be driving on vacuum not boost yes? On boost you would be accelerating. Does it hunt at idle, like rev up and down? And is it more pronounced when the car is warm or is it exactly the same when it's cold? Sort of sounds like it could be a problem my mates R32 had, was effectively a vacuum leak. The air regulator was stuck open, so when the car was cold it ran fine but when it warmed up the air regulator was still open and the car was getting too much air. Ran fine when you were accelerating, but trying to cruise it would just stutter and jump, etc.

Could also be a problem caused by that atmo bov you have.

Yeah, you're right, vacuum not boost, sorry. I find both the technical issues and the language quite hard you see...

The rpm stays quite even at idle, but not as even as it should be I guess. It "huffs and puffs" quite much at idle, and it's no difference between hot or cold engine. Sounds as your friends R32 had the same probs as mine. Will check the air regulator. One question though; where's the air regulator and how do I check it? :ermm:

In what way might the bov be the thief in this drama?

Could be the stock ECU is gumby, or the AFM is fail....sounds kinda like it might be running excessively rich, but once the airflow climbs up with more boost, it compensates and evens out...

What I've heard before the stock ECU would cope with the mods I've done already (pod filter, fmic, cat-back, ssqv)? Do you have other experiences? If it is what you say, then a new ECU is the only solution I guess..?

How do I check the AFM? Already pulled out the AFM cable when engine at idle and it started to run really bad, almost died. That means the AFM works, at least a little bit? Can I clean the AFM somehow?

Thanks for your feedback! Will have to bring a lot of swedish girls to compensate! :D

Air regulator is located near the plenum, follow the vacuum line that is Tee'd into the hose coming from the AAC valve.

Bov could be the culprit as it is atmospheric, it releases the air into the atmosphere after the AFM, causing the ecu to over inject and run rich. But bov's usually cause problems on decel, so it doesn't sound like this is the cause of your problem...

And is it more pronounced when the car is warm or is it exactly the same when it's cold?

Hey again,

just realized that the problem is much worse when engine's warm! Does that make it easier to say what's might be wrong?

Thanks

Ok, thanks mate! Will have to check that out then. Just to clearify: Air Regulator is the same thing as AAC valve, right? Or am I reading the service manual wrong?

This Air Regulator, does it have a part number and how much does it cost approximately?

THANKS!

Problem fixed!! :thumbsup:

Vacuum hose cracks (one was completely spilt all the way along the hose!), useless plugs (original modified to 0,5mm!) and crack angle sensor set to 27 degrees!! :D

Air regulator, AFM and ignition coils works just fine.

New spark plugs, rubber hoses and crack angle back to original 15 degrees - it's all fixed and it runs like a dream! :)

Edited by ksx

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


  • Similar Content

  • Latest Posts

    • From there, it is really just test and assemble. Plug the adapter cables from the unit into the back of the screen, then the other side to the car harness. Don't forget all the other plugs too! Run the cables behind the unit and screw it back into place (4 screws) and you should now have 3 cables to run from the top screen to the android unit. I ran them along the DS of the other AV units in the gap between their backets and the console, and used some corrugated tubing on the sharp edges of the bracket so the wires were safe. Plug the centre console and lower screen in temporarily and turn the car to ACC, the AV should fire up as normal. Hold the back button for 3 sec and Android should appear on the top screen. You need to set the input to Aux for audio (more on that later). I put the unit under the AC duct in the centre console, with the wifi antenna on top of the AC duct near the shifter, the bluetooth antenna on the AC duct under the centre console The GPS unit on top of the DS to AC duct; they all seem to work OK there are are out of the way. Neat cable routing is a pain. For the drive recorder I mounted it near the rear view mirror and run the cable in the headlining, across the a pillar and then down the inside of the a pillar seal to the DS lower dash. From there it goes across and to one USB input for the unit. The second USB input is attached to the ECUtec OBD dongle and the 3rd goes to the USB bulkhead connected I added in the centre console. This is how the centre console looks "tidied" up Note I didn't install the provided speaker, didn't use the 2.5mm IPod in line or the piggyback loom for the Ipod or change any DIP switches; they seem to only be required if you need to use the Ipod input rather than the AUX input. That's it, install done, I'll follow up with a separate post on how the unit works, but in summary it retains all factory functions and inputs (so I still use my phone to the car for calls), reverse still works like factory etc.
    • Place the new daughterboard in the case and mount it using the 3 small black rivets provided, and reconnect the 3 factory ribbon cables to the new board Then, use the 3 piggyback cables from the daughterboard into the factory board on top (there are stand offs in the case to keep them apart. and remember to reconnect the antenna and rear cover fan wires. 1 screw to hold the motherboard in place. Before closing the case, make a hole in the sticker covering a hole in the case and run the cable for the android unit into the plug there. The video forgot this step, so did I, so will you probably. Then redo the 4 screws on back, 2 each top and bottom, 3 each side and put the 2 brackets back on.....all ready to go and not that tricky really.      
    • Onto the android unit. You need to remove the top screen because there is a daughterboard to put inside the case. Each side vent pops out from clips; start at the bottom and carefully remove upwards (use a trim remover tool to avoid breaking anything). Then the lower screen and controls come out, 4 screws, a couple of clips (including 3 flimsy ones at the top) and 3 plugs on the rear. Then the upper screen, 4 screws and a bunch of plugs and she is out. From there, remove the mounting brackets (2 screws each), 4 screws on the rear, 2 screws top and bottom and 3 screws holding in the small plates on each side. When you remove the back cover (tight fit), watch out for the power cable for the fan, I removed it so I could put the back aside. The mainboard is held in by 1 screw in the middle, 1 aerial at the top and 3 ribbon cables. If you've ever done any laptop stuff the ribbon cables are OK to work with, just pop up the retainer and they slide out. If you are not familiar just grab a 12 year old from an iphone factory, they will know how it works The case should now look like this:
    • Switching the console was tricky. First there were 6 screws to remove, and also the little adapter loom and its screws had to come out. Also don't forget to remove the 2 screws holding the central locking receiver. Then there are 4 clips on either side....these were very tight in this case and needed careful persuading with a long flat screw driver....some force required but not enough to break them...this was probably the fiddliest part of the whole job. In my case I needed both the wiring loom and the central locking receiver module to swap across to the new one. That was it for the console, so "assembly is the reverse of disassembly"
    • But first....while I was there, I also swapped across the centre console box for the other style where the AV inputs don't intrude into the (very limited !) space.  Part# was 96926-4GA0A, 284H3-4GA0B, 284H3-4GA0A. (I've already swapped the top 12v socket for a USB bulkhead in this pic, it fit the hole without modification:) Comparison of the 2: Basically to do the console you need to remove the DS and PS side console trim (they slide up and back, held in by clips only) Then remove the back half of the console top trim with the cupholders, pops up, all clips again but be careful at the front as it is pretty flimsy. Then slide the shifter boot down, remove the spring clip, loose it forever somewhere in the car the pull the shift knob off. Remove the tiny plastic piece on DS near "P" and use something thin and long (most screwdrivers won't fit) to push down the interlock and put the shifter down in D for space. There is one screw at the front, then the shifter surround and ashtray lift up. There are 3 or 4 plugs underneath and it is off. Next is the rear cover of the centre console; you need to open the console lid, pop off the trim covering the lid hinge and undo the 2rd screw from the driver's side (the rest all need to come out later so you can do them all now and remove the lid) Then the rear cover unclips (6 clips), start at the top with a trim tool pulling backwards. Once it is off there are 2 screws facing rearwards to remove (need a short phillips for these) and you are done with the rear of the console. There are 4 plugs at the A/V box to unclip Then there are 2 screws at the front of the console, and 2 clips (pull up and back) and the console will come out.
×
×
  • Create New...