Serviced My Car, Now Feels Sluggish And More Rich.

[__PhaseShiftDown]

I serviced my car last weekend, changed oil, oil filter, tranny oil, transfer oil and spark plugs. I didn't have enough time to do the diff and the fuel filter.

Anyway, car now seems to be running sluggish than before and uses more fuel. The plugs I took out were platinums with heatrange 5 and I believe they were gapped at 11. I replaced them with some copper ones but colder BCPR6E-11s. Car is a 32GTR and running stock boost level. Should I gap the plugs down to 0.8?

Edited August 30, 2008 by __PhaseShiftDown

[paulr33]

check the basics, check timing, reset the ecu, then go see a mechnic if you cant figure it out

[__PhaseShiftDown]

I think I might've found the problem.

All this time I thought the car is running on stock boost level (7psi), but now I suspect its actually running at around 9psi. Maybe?

When the car is sitting idle, the stock GTR boost gauge shows the needle is around the middle in the last block, very slightly more towards -7 (x100hhmg). The HKS evc3 is showing 483 - 493 mmhg.

Is this the normal reading or higher reading?

I have yet to record the reading when the car is hitting full boost. Will try that later.

[__PhaseShiftDown]

ok.. thats not it. Boost is running standard @ 7psi. Boost controller works fine also. hmmmmm.....?

Could it be the hotter plugs I had before made the car more responsive?

Edited August 31, 2008 by __PhaseShiftDown

[Julz89]

if ur previous plugs were hotter ones and u changed them it is probly affectin the performance

[__PhaseShiftDown]

yea.. thats what I figured.. But the new ones I put in should be the correct ones.. arn't they?

So I'm thinking maybe the coil pack is starting to show its age.

[WYTSKY]

I would have thought plugs aswell... if your sus of your coils then take each one out and check for any wear and tear... but if there was a crack or weak point in the plastic I would have thought missfiring at higher rpm would have happend.. not just an overall performance loss...

speaking of which.. wot is the difference? not hitting into boost as hard? not as responsive under the throttle?

[__PhaseShiftDown]

Defitnitly not as responsive as before. When I floor it in 1st gear up to about 4500 RPM, I don't feel as much acceleration.

I changed my oil to Edge 10w60, I was running Edge 5w-30 before for about 3000k. That wouldn't affect the performance that much will it, even though the new oil is slightly thicker. I'm gonna check my plugs tomorrow, I have a feeling I didn't tighten them enough. Also, gonna clean out the coilpacks and reset the ECU might possibily help as well.

[Ionos]

5w-30 to 10w-60 is not slightly thicker, it's a lot thicker. I'd suggest it's probably too thick for your engine.

Why didn't you use 5w-30 again?

[blind_elk]

The heat range of the plug is correct, but what about the reach and electrode shape. Can you compare the new plugs with the old platinums?

[PsYLoR]

Maybe try put the old plugs back in, see if that makes a difference. Do this before you reset ecu etc, so you can at least eliminate the plugs as a problem.

[(OO)SKYLINE(OO)]

^^ Yeah I think it's engine oil too.

I went from Martini engine oil 10W-40 (Very Good) to Valvoline 20W-50, very sluggish.

Switched to Shell Helex 15W-50, bit better.

Then my mechanic said to use Mobil Synthetic S 10W-40 and the car runs a lot more smoother.

[bnr#@]

Sock boost for 32GTR is a bit more then 7psi btw. the springs alone in the wastegate are 9psi (im running just the springs now, no boost controller of any sort, not even the factory) stock boost is a bit over 10psi

[__PhaseShiftDown]

5w-30 to 10w-60 is not slightly thicker, it's a lot thicker. I'd suggest it's probably too thick for your engine.

Why didn't you use 5w-30 again?

I did a lot of research on this forum before I decided to settle on 10w60. It was also the oil suggested on the Castrol website, so I decided to change it. When I was using 5w-30, I find the oil pressure was quiet low, and takes slightly longer to build up the oil pressure. But its a better now with 10w60.

Also, the engine was cold when I tested the car, 5w (old oil) vs 10w (new oil) at cold. A difference of 5, will that really make that much difference?

I'm just gonna do everything at once tomorrow, tighten plugs, change fuel filter, clean afm, reset ecu...etc and see if that helps.

Anyone got vacumn reading on their car at idle? I'm seeing 483 - 493 mmhg, is that good?

[Ionos]

I did a lot of research on this forum before I decided to settle on 10w60. It was also the oil suggested on the Castrol website, so I decided to change it. When I was using 5w-30, I find the oil pressure was quiet low, and takes slightly longer to build up the oil pressure. But its a better now with 10w60.

Also, the engine was cold when I tested the car, 5w (old oil) vs 10w (new oil) at cold. A difference of 5, will that really make that much difference?

I'm just gonna do everything at once tomorrow, tighten plugs, change fuel filter, clean afm, reset ecu...etc and see if that helps.

Anyone got vacumn reading on their car at idle? I'm seeing 483 - 493 mmhg, is that good?

The vacuum reading is normal, there is a vacuum because the throttle is closed.

Not an expert on oils, perhaps someone who is can clarify whether that oil is ok. It is a lot thicker then what most use however.

Agree with the rest of your suggested steps, do those things then take it from there.

[GTR 94]

like posted previously throw your ol plugs inn first and see if this helps, ive never ran thicker oil in my gtr but it is true that you could possiably be feeling more sluggish due to more friction in your engine, hence if you could run an engine with no friction it would preform alot better so glugging it up with a thicker oil to previous is going to make a difference, also not sure if i read correctly but "Also, the engine was cold when I tested the car, 5w (old oil) vs 10w (new oil) at cold." wouldnt recommend thrashing your car at cold engine temps, not a good idea, and if your oil pressure gage was reading low, your gonna need a new oil pressure switch (common r32 gtr problem) id recommend replacing this asap, as this will tell you honestly what oil pressure you are running, no oil pressure + faulty gauge could = BANG!

hope this helps

[MBS206]

I'd first check your throttle position sensor, next up would be change back to the same weight oil as you pulled out.

[DLOOOK]

yeah, numerous people on this forum run 10w60 Castrol on there Rb26's, and yeah this is the viscosity Castrol recommend for GTR's. Perhaps give Castrol tech support a call. But i doubt its the oil, try your old plugs again

[PM-R33]

5W-30 to 10W-60 is quite a difference, 30 viscosity to a 60 viscosity....

Not saying that is the problem but just stating that it is a very different oil.

Don't think the heat range in the plugs would cause this.

[__PhaseShiftDown]

Thanks for the feedback guys.

I resetted the ECU today, tightened my plugs.. change my fuel filter and also found my rear driver side tyre is only at 20psi!!.. so I pumped it up.

seems to drive a little bit better, but more or less the same. I figured its probabaly the oil.