Very Slight Partial Throttle Miss, 2000-3000rpm

[paulr33]

yeah afm surging is a known issue when the afm is close to such a large compressor inlet

put a bend in the pipe work between the afm and the compressor inlet, that should sort it out

or make long and a bend

[Guilt-Toy]

hey guys

I been re-tuning my car in the lasst couple of weeks.. long story why it needed a re-tune but i started to do it with the Hand Controller as i dont own the PFC adapter myself.

Anyway i found this issue appeared on my car!! I ended up finding out (after a long time muckin around) that my TPS was set incorrectly. It took me 3 goes to get it right.

How i did it was losened off the 2 phillips head screws and then moved the tps untill i heard it click. then held it there and tested the throttle - the idea is to have the throttle move as little as possible before the tps clicks.

The way i got it was made it click and then moved it very slightly as well before doing the screws back up and that fixed the problem for me.

Although my engine was leaning off bad when it was missing like that.

Hope this helps

[Rezlo]

Finaly got round to going over more,

Fitted my tomei pump and ensured the correct 300kph at idle with no vac

Lengthened the intake by almost half a meter and put in 2 90deg bends, no change, also tried with no filter, and a spare maf.

Cleaned out the CAS that was nasty, still no change

set TPS all over the place, no change, though i didnt notice the click? S1's click as well?

Threw new plugs in with .85mm gap, yep, no change....

Pulled the fuel rail off the head, no leaks, no dribbles, all the testing all the bottles were evenly filled,

Compression tested it, 155psi +/- 3 psi for all.

I then sat long and hard and thought, I only realy noticed the slight miss after i fitted the gizzmo launch controler, I think it might be making problems, going to un-solder the wires and use 6 pin electrical connectors so i can remove and re-install it easy...

Edited October 1, 2007 by Rezlo

[Rezlo]

I have now gone over everything electrical, nothing has changed, i have fcked with every setting in the pfc, no change, full re-set on the pfc, no change.

its amazing how my 1975 Datsun 1200 runs better.

[h2k]

I have 2 suspicions, either my coils might be the source of the problem, or it is because of the large size of the q45 throttle body. Very little throttle percentage lets in large amounts of air into the plenum and Im suspecting the pfc doesnt let go of the "idle" mode.

[Rezlo]

It could be this that agrivates it, but I think it could be my splitfires failing, I only noticed it start doing the miss about 2 weeks after fitting a gizmo launch controler, which I have now removed and it still runs with a slight miss.

I am going to try stock coil packs out of another S1 I have tonight and see if there is any change.

[Rezlo]

Besides testing ohm's between + and - on the coils, what other testing specs are there on the ignitor and coil packs? want to get to the bottom of this problem, did a search but all i found was people wrapping them up.

[sl33py]

I had a very similar problem on my all-but stock R33. I would be driving at very low throttle through say a car park and the rev would drop JUST below the minimum needed not to stall. This would happen at lights too while trying to sedately take off. Very annoying. My mechanic only found it by bashing my TPS with a hammer (he was getting desperate lol) while the car was idling - the voltages went berko and all over the place. He said they looked fine while just measuring them normally, but a bit of stress or a bump or whatever and it was game over. Might be that. Get violent