Jump to content
SAU Community

Recommended Posts

Hi,

I have recently fitted a Turboetech Boost controller to my car, and after winding the boost up to 9 PSI, the car now has a bad flatspot on acceleration between 4000 and 6000RPM, after 6000 it Revs past it, and seems to be fine. Between 4-6, its not like its missing, but just generally lacking power, like it can't breathe or something - but will rev past it in all gears.

Initally when I installed it, the car started missing badly, so I gapped the plugs to 0.8MM, and siliconed up the coils. The missing got a lot better, but I thought the flatspot was the same problem. I ordered and fitted spkitfire coils today, but the car still has the flatspot. It seems to mainly be when the car makes full boost - after 6000RPM it tapers off to about 8.5PSI and the fault seems to clear and car accelerates better - can feel the shove after 6000 - not sure if boost tapering is just a coincidence....

I have also tried an ECU reset, and have driven the car while watching readouts in OBD Scantech, nothing really stoodout as being massively wrong. There were no faults logged either. Also had quick check for boost leaks, none visible.

A couple of things I have seen on forums is checking ignition timing, or possible turbo breathing issues. I would have thought at this boost turbo would not be an issue. As for ignition timing - what should it be? Can probably check timing tomorrow arvo.

Anyone have any suggestions, or similar issues that have been resolved? Let me know if any more info is needed..I took a log using OBD Scantech, from about 2500RPM in third all the way to redline, as per zip file below Boost was max 9.2 PSI in this run

Thanks, Russel

.

Full list of mods/history

Car is 1993 series 1 R33 GTST

FMIC

Splitfire Coils

GFB StealthFX BOV

Cat-back 3in Exhaust

New plugs/fuel filter/all fluids

test run, third gear.zip

Link to comment
https://www.sau.com.au/forums/topic/348144-flat-spot-4-6000rpm/
Share on other sites

ECU, if standard may be the problem. TBH a good dyno print out could help, along with a good tuner to help diagnose the problem. May cost dollars but who cares, or wait for more people to comment! Come on mad082, I know your lurking some where!

EDIT: BOV may also be a problem, how was it before BOV?

Edited by Shazza24

Just watched the log file, had only seen live....it appears R&R is spot on, at about 4200RPM it drops timing back to 12 deg, at almost exactly 6000RPM it goes straight to 20deg, and works up to about 25 or so after that. So painful that its doing it at such low boost :(

Thanks for the help.

Edited by Pope

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

    • Consider a 35 too...
    • He's right ~ there is no 'magic' with stuff like this ... it is more likely that in the process of looking for the short, the loom/wire 'incidentally' got moved in the process, thus removing the short ~ now, that maybe a wire (in a loom) rubbing against the edge of some grounded metal, that's worn through the insulation, causing the (now intermittent) short to ground. If one wire in a loom has been damaged in this fashion, it's reasonable to presume that other wires beside it may have also be damaged, and now exposed...you can bet the green crusty copper corrosion will start... ...that'd be a pisser, Murphy's Law steps right in as GTS observes...but worse, something like that is easier to find when shorted...ie; unplug bulb and fuse, and put multimeter in continuity mode so you get constant beep, and carefully poke about hoping to find if some movemet of the harness stop the beeping.... ...it's still all a bit Arnie tho' ..It'll be back... 😃
    • Yeah, but knowledge of one wire's insulation worn through to short on earth implies the possibility of other wires doing the same. I had my power steering die, because the wire that runs to the solenoid valve on the rack runs in the same loom as the power wire for the O2 sensor. And when the O2 sensor/wire did something stupid and burnt part of that loom to death, the only indication was the shit(ter) fuel economy and the heavy steering. It took deep excavation of the looms in the bay to find the problem. Not wear through in that case, but similar shit.
    • Ah, I thought he'd wired it to one of the spare ECU inputs! Too long ago since I read that post, ha ha. I've been arguing with radiators, harmonic balancers, alternators and rust since reading it.
    • Correct. The ECU cannot read oil temp. (Well, I think it probably can in some situations. I did have the thought of potentially repinning the ECU when I was doing oil pressure). I am using this into the MPVI dongle, so that the MPVI dongle can read oil temperature. It is attached to a VDO gauge which is obviously calibrated to whatever curve the sender actually is using. This would be easy if I could setup a table of voltage to temperature like many sensors, but it appears I cannot do this and can only setup the transform rule which appears to be Input (voltage) x Multiplier, and add an offset. This to me means it MUST be linear. So it may be a complete waste of time wiring this into the ECU. The idea was that the MPVI3 has standalone logging. I wanted to use this instead of a laptop with serial cable (for wideband) for long datalogs. Given the wideband also has electric interference, I may never trust this either in a world where the serial wideband and the analog output wideband do not agree. Last time I did a trace I could see the two wideband traces follow each other, but one was a little leaner than the other. I plan on playing with voltage offsets and actually driving the thing to see how close they correlate. If they never correlate... then, well, maybe I'll never use either. Ideally I'd like to have the Analog wideband read ever so slightly leaner than the serial one, because the serial one is 'correct'. Tuning the car to be ever so slightly too-rich would be the aim. Not needing to have a laptop flying around in the footwell connected with cables is... an advantage. About the only one from the forced upgrade to MPVI3.
×
×
  • Create New...