r33 run rough on full throttle

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zureal
Posts: 4
Joined: Tue Dec 12, 2017 6:40 pm
Car: r33 gtst skyline

r33 run rough on full throttle

Postby zureal » Tue Dec 12, 2017 7:23 pm

hey i got a r33 skyline gtst which is running rough at about 5k rpm and over when i full throttle, if i slowly press down on the throttle i can get to about 6k before it start to run rough again,it drives fine normaly has a little flat spot around 2500-3000 rpm but very minor, it has been tuned about a year and 3 months ago, but was taken of the road 3 months after the tune to repaint the car and put new forward facing inlet manifold on it, it was running good after the tune, i have recently check the timing on it and it is on 15 degrees and replaced and gapped new spark plugs, i have checked for vacuum leaks with some carby cleaner and found no change in revs.
the car has an old haltech ecu e11v2 with 3bar map sensor no afm, haltech wideband 02 sensor, garrett gt3582r turbo so turbo doesnt really spoil until like 3k rpm, has splitfire coil packs.
i bought the car already set up with the ecu and turbo and coils, but with blown pistons which i stripped and replaced with forged pistons and conrods and got everything checked and balanced then retuned, when i replaced the plugs recently they looked pretty fouled up so im leaning towards the coilpacks have shat themselfs, or mabye another electrical fault as the car did get some water into the engine bay as it was getting rubbed down for painting, the car is boosting but not enough to set of the screamer pipe which is set to 15 psi, anyone have any ideas on what my problem could be?
thanks


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centralcoaster33
Posts: 2772
Joined: Tue Apr 05, 2005 10:41 am
Car: 240SX #5-1997
Location: Central Coast, CA

Re: r33 run rough on full throttle

Postby centralcoaster33 » Wed Dec 13, 2017 5:27 pm

Welcome to NICO Club!

I'm not too familiar with your engine, but TPS and O2 come to mind. Does your TPS have one or two plugs and have you checked the voltage (and continuity if there's a second plug) on that sensor?

I was cleaning my engine area once (like a deep cleaning) and got moisture into my TPS and it failed shortly after.

zureal
Posts: 4
Joined: Tue Dec 12, 2017 6:40 pm
Car: r33 gtst skyline

Re: r33 run rough on full throttle

Postby zureal » Thu Dec 14, 2017 12:48 am

it has a rb25det motor in it, the tps has 2 plugs but only 1 with wires going to it, i have checked it through the haltech software and it looks to be working but i could double check the voltage do u no how much voltage should be going through it? and the 02 sensor is a haltech wideband which i put in just before the tune so it pretty much new but is there a way to check it?

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M35Squirrel
Posts: 185
Joined: Wed Jul 16, 2014 8:35 am
Car: 1990 GT-R, 2011 M37
Location: Houston, TX

Re: r33 run rough on full throttle

Postby M35Squirrel » Thu Dec 14, 2017 7:36 am

WOT runs in close loop, so nothing to do with O2. The extra wire on TPS is for automatic.
My first bet will be on fuel, 2nd will be on ignition. If you have Splitfire, check your plugs. My 3rd bet is on the Haltech tune, it's just a bad tune.

amc49
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Joined: Mon Jun 19, 2017 7:24 pm
Car: '11 Versa
'17 Altima

Re: r33 run rough on full throttle

Postby amc49 » Sat Dec 16, 2017 9:16 pm

Uh, generally it's closed loop that uses the O2.

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M35Squirrel
Posts: 185
Joined: Wed Jul 16, 2014 8:35 am
Car: 1990 GT-R, 2011 M37
Location: Houston, TX

Re: r33 run rough on full throttle

Postby M35Squirrel » Mon Dec 18, 2017 7:32 am

Oh dang, yeah I meant open loop. You know what I mean, no O2 feedback at WOT. These are old engines, so good maintenance will pay off.

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centralcoaster33
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Joined: Tue Apr 05, 2005 10:41 am
Car: 240SX #5-1997
Location: Central Coast, CA

Re: r33 run rough on full throttle

Postby centralcoaster33 » Mon Dec 18, 2017 4:11 pm

The extra wires on TPS may be used on some automatics, but it is to detect WOT and closed throttle and is used on some manual transmissions as well (mid 90's and up). Moving it a bit in the wrong direction will make it not detect one end or the other. There was a TSB on setting the TPS using the two wires plug and checking for continuity instead of the voltage range of the three wire plug. Not sure which all Nissans the TSB covered, but it had my 240sx in there at the time.

zureal
Posts: 4
Joined: Tue Dec 12, 2017 6:40 pm
Car: r33 gtst skyline

Re: r33 run rough on full throttle

Postby zureal » Mon Dec 18, 2017 6:09 pm

Ok I replaced coil packs and that got rid or the little flat spot at 2-3k rpm I checked the tps and it had 0.37v closed and 3.9 full open is that a bit low? Also I played around with the cas and rotated slightly anti clockwise and it felt like it had more power and ran a lot better but still played up on full throttle idk if that helps diagnose the problem, I got a new tps, cas and fuel pump and fuel filter coming anyways hopefully it fixes the problem.

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M35Squirrel
Posts: 185
Joined: Wed Jul 16, 2014 8:35 am
Car: 1990 GT-R, 2011 M37
Location: Houston, TX

Re: r33 run rough on full throttle

Postby M35Squirrel » Tue Dec 19, 2017 6:33 am

It's been years since I adjusted a TPS, but recalling from memory your reading seems off. I recall it was around 0.5v mark closed. If you google you should be able to find videos showing how to set TPS, most early Nissan TPS' are about the same, unless you have the later model with 2 plugs.

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centralcoaster33
Posts: 2772
Joined: Tue Apr 05, 2005 10:41 am
Car: 240SX #5-1997
Location: Central Coast, CA

Re: r33 run rough on full throttle

Postby centralcoaster33 » Tue Dec 19, 2017 1:29 pm

This is the procedure I refer to for setting TPS using the two prongs instead of three. http://www.lyberty.com/car/Maxima_A32_d ... 9-053b.pdf
It's easy and worth a try, but I could be mistaken about it's applicability to your car. Otherwise, I think your numbers are close and agree with Squirrel that you should see around 0.5v closed and maybe near 4v at wot. I looked at this FSM starting on page 416: http://www.nicoclub.com/service-manual? ... ine-manual

zureal
Posts: 4
Joined: Tue Dec 12, 2017 6:40 pm
Car: r33 gtst skyline

Re: r33 run rough on full throttle

Postby zureal » Wed Dec 20, 2017 9:24 pm

https://www.youtube.com/watch?v=Y3ssWwNsfQQ
here is a video of what it is doing any ideas? i dont think it is the tune as it ran perfect afterwards, it was of the road for over 9months and during the time it wasnt on the road i got it painted and replaced inlet manifold with a forward facing one, that wouldnt cause issues with the tune would it? i just recently replaced battery, walbro 255l fuel pump, filter, spark plugs and gapped, splitfire coil packs, tps and cas. i have checked for vacuum leaks with carby cleaner but would it be possible to only leak once on full boost, mabye from wastegate or blow off valve, or inlet manifold?
thanks

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M35Squirrel
Posts: 185
Joined: Wed Jul 16, 2014 8:35 am
Car: 1990 GT-R, 2011 M37
Location: Houston, TX

Re: r33 run rough on full throttle

Postby M35Squirrel » Thu Dec 21, 2017 10:15 pm

smoke test is the best way to be sure there is no vacuum leak, and i think it's definitely worth the effort because you had manifold replaced.
you sure didn't leave a rag in the manifold? lol


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