Hesitating

[nicr4wks]

Hi Guys,

Looking for some troubleshooting advice, I have a 96 S2 R33 with turbo back exhaust, 12psi (turbotech mbc), Bosch 040, super spark coils and iridium plugs.

For the past couple of months the car has been 'hesitating' under full throttle, you put your foot flat, the car builds revs as normal then all of a sudden it jolts like you've taken your foot off the accelerator and slammed it back down again, revs will continue to build for another ~5 secs then it will do the same thing again. This happens the worst in 3rd, 4th and 5th, occasionally in 2nd, never in first and occasionally it won't happen at all. Typically the earliest I see this problem would be roughly 3000rpm in 3rd, it does not occur in neutral.

Things I've tried:

- Removing intake from turbo right up to throttle body, visually checking joiners for splits and replacing hose clamps.

- Tested BOV operation with a compressor, eliminated (blocked) BOV.

- Tested wastegate with compressor.

- Checked vac lines to boost controller, dissasembled boost controller and checked spring/ball moving freely.

- Checked IAC vac line for visual splits, checked boost guage/fpr vac lines.

- Visually checked SMIC for damage.

- Checked AFM voltage not maxing out via consult.

Anyone have some advice of what I can try next?

Cheers.

Edited November 15, 2010 by nicr4wks

[XxNinjaxX]

its R&R. your boost is too high for standard ecu so it chucks a sad. set your boost to 9psi max and you should be alright. my 33 used to do it at 10psi so im only running 7 now, havent had it happen since

Edited November 15, 2010 by XxNinjaxX

[MrR33666]

and cold weather will make it worse

[nicr4wks]

 Car used to run on 13.5psi without issue, problem has occurred several months after going down to 12psi, also occurs at 10psi.

Doesn't R&R occur when the AFM is maxed out? Which if I'm correct is at 5v, according to Consult I'm only getting ~4.5v max on the AFM, I'll try logging tonight to get a better picture. Also, having hit R&R previously, there was a lot of black smoke and loud backfires from all the extra fuel, this is not happening. It feels more like the throttle body is snapping shut then opening straight back up.

Edited November 15, 2010 by nicr4wks

[Randon_I_Am]

could be the super spark coil packs letting go...

[nicr4wks]

It would seem that it is not R&R due to AFM maxing out, in 3rd the AFM was reading 4.12v when the jolt occurred, in 2nd I was able to read 4.80v without any jolt.

Do not believe it is the coilpacks, the hesitation is very different from failing coil(s)

[myskyride]

tried replacing spark plugs??