Help with engine miss ( long)

[RTED]

Hi everybody.

New to forum and the Skyline as of this weekend gone.

Having come from a carbied big block ford with little technology this is all new, please help?

As best i can tell i have a standard ceramic turbo and most other ancilleries are standard except for a k&N air filter and a 3 inch exhaust from dump pipe and large aftermarket intercooler and 2 stage boost control.

My problem is this.......

On standard boost the car seems to go ok with little drama. As soon as the boost control is turned up on either the low variable or the high variable it develops a nasty surge in the mid range and cleans itself out in the 5500 to 7000 rpm range.

Have changed plugs to genuine nissan spec platinum plugs ( i work in a Nissan dealership) to rule out that with no change!!!!!!

Have only had the car for 3 days and have only driven for 150 klms so far but would like it run cleanly before giving it some serious stick

Had the workshop look over breifley but hard to get stuff done being staff, BUT, It appears that the TPS is a dual plug which would indicate it may be for an auto????? Can anyone advise as to what i should be looking for in and around the engine bay

Thanks in advance....

Also, can anyone tell me whether it is series 1 or 2. It is a late 1995 GTST manual R33 2 door

[grigor]

Might need a bit more info than that. I'm guessing way too much boost. Have you got a gauge?

Does it have the power transistor pack at the rear of the plug cover or not?

Series 2 has that circuitry incorporated in the coil packs so not visible.

[Slide]

when you replaced the spark plugs what was the gap?

try smaller gap most people seem to say around the .6mm to .750mm for best results

that may be a help to you if you are runing bigger boost

[RTED]

Might need a bit more info than that. I'm guessing way too much boost. Have you got a gauge?  

Does it have the power transistor pack at the rear of the plug cover or not?  

Series 2 has that circuitry incorporated in the coil packs so not visible.

Yes it has the factory guage plus an aftermarket one. The aftermarket reads in bar and gets to about 0.7>0.8. the original guage wont read full boost but i really don't want hold my foot into it yet incase it is leaning out.

In the coil packs there appears to be nothing after no6 coil pack. only the harness that runs into the main harness which has a white wire looped on itself not going anywhere?

Thanks

[RTED]

when you replaced the spark plugs what was the gap?

try smaller gap most people seem to say around the .6mm to .750mm for best results  

that may be a help to you if you are runing bigger boost

Put in at factory settings at 1.1. Theses are 224011p116 nissan part number, which come from ngk anyway. The ngk number on the same box is NGKpfr6g-11 platinum tip. What i took out was bkr6e11 which were set @ .75 mm . The plugs look fairly new and clean with only a few with some slight brownish discolouration on the porcelin.

We moved the TPS last night to the lean side and it did exagerate the condition. What sort of readings should come from TPS?

Thanks

[Slide]

about the series look at the build plate also quick checks are if your dash surround is a rough surface its series 2 if its smooth series 1 there are heaps of little other checks like abs for series 2

as for your questionon the throttle position sensor

this may help

On the TPS is two sets of wires, one is the idle contacts, the other is the variable resistor, The plug that plugs directly on to the TPS with 2 wires is the idle contacts, the other set with the wiring connector about 5cm's or so away from the TPS and with 3 wires is the variable resistor, can't remember wiring colors, in the lot of 3 wires you have to get the correct one, with the ignition on and everything connected get a multimeter and connect one lead to earth on the battery, the other lead you need to backprobe one of those 3 wires, you need to get a reading of around 0.5 volts, if not, loosen the TPS screws and rotate it to get exactly 0.5 volts with the throttle fully closed.

Now, with that set the idle contacts are probably crap.

You now need to connect the multimeter to the other set of two wires, unplug the connector on the TPS and put both leads onto the two terminals on the TPS, they should be closed, rotate the throttle slowly till the multimeter shows no contact, this should be JUST off idle, if not, well, the only way to fix it is to remove the TPS and dismantle it and bend the contacts inside to get it right as you can't rotate the TPS to fix it as you will muck up the other setting, It takes a while to get it right

One thing to add, the plug that plugs directly on to the TPS may have three wires, have to check it out but, manuals may have two wires, auto's may have three wires, the two top pins are the idle contacts.

also regap new plugs to .6mm otherwise on boost it will run like poo at 1.1mm which the NGKpfr6g-11 are set at thus the -11 at the end of model number

hope i help

[Slide]

this thread might also shed som light on your problem as it has mine

[Zahos]

this is common on RB25DET

coils usually have small hairline cracks, so spark arks on head and is weaker,

ont high boost, ECU runs rich, and retards timing to protect engine. At this point the cracks in your coil become noticable as your car starts to hesitate. The problem is most apparent at 4500 -> 6000 rpm

cheapest solution is:

araldite, silicone or whatever the cracks on the coils AND get a SAFC to lean out your mixtures.

gapping down your spark plugs may make it less noticable, but won't fix it.

best solution:

new spitfire coils + new stand alone ECU

also the more expensive solution

I have gone for the cheapest solution, and my car runs incredibly smooth. The problem does not exist anymore

Read through this thread, as it details where to cover the cracks on your coils.

Invest in a SAFC to adjust your Air/Fuel ratios - you will NOT regret it.

[RTED]

this is common on RB25DET

 

 coils usually have small hairline cracks, so spark arks on head and is weaker,

ont high boost, ECU runs rich, and retards timing to protect engine. At this point the cracks in your coil become noticable as your car starts to hesitate. The problem is most apparent at 4500 -> 6000 rpm

 

 cheapest solution is:

 araldite, silicone or whatever the cracks on the coils AND get a SAFC to lean out your mixtures.

 gapping down your spark plugs may make it less noticable, but won't fix it.

 

 best solution:

 new spitfire coils + new stand alone ECU

 also the more expensive solution

 

 I have gone for the cheapest solution, and my car runs incredibly smooth. The problem does not exist anymore

 

 Read through this thread, as it details where to cover the cracks on your coils.

 

Invest in a SAFC to adjust your Air/Fuel ratios - you will NOT regret it.

Will the unichip do the job for fuel curve. I am speaking to a unichip guy tommorrow to find out what are it's features.

I strapped up the coil pacs today with nitto tape and reggapped plugs to 0.71 and it runs a s@#$load better. will be able to take for a bit of a drive sat or sun

[Slide]

get a powerfc man you wont regret the extra couple of hundred bucks plus with hand controller you can hot tune

[The Dan]

Try checking knock sensors, not sure if the 33 has them also but it should do. They will effect you in this exact rev range.

TPS, KNOCK SENSORS and AFM are all integrated into the fuel map and Timing map so any of them could be faulty. That or what the others are saying about the coil packs.