ZX3tuning

nono.
right now the car idles between 14-15 on AFR.
which for most cars is damn near perfect. with CIS i would assume that it is hard to perfectly meter the fuel at idle, more so with a ported fuel head that i have from Imagine.
under boost, light boost i see 12-13 on the AFR and at full boost it dips down into the 10s. i have not driven the car in a while so i haven't been able to confirm the problem with a Co-Driver. but from what i have noticed, when the car cuts out it seems like it is going rich excessively. Maybe it's dumping so much fuel the fuel pressure drops and the ECU cuts ignition?
the RPMs do not drop off like a rock which, again in most car, would lead me to believe this is not the case but i usually am not staring at the gauges when this problem happens...

where would i get such CIS test gauges?
What would be the tools i would need?
Links if possible would be killer!

I was also thinking that i could be overboosting aswell which is causing the cutout, but again, i have no way of testing this without knowing where to start looking and what i need to test it with...

If someone could give me a run down of things to test, where to test and what to look for i have no doubts i could figure it out..... it's just a matter of knowing where to start!

Thanks for the help.

nathanUK '81 930 G50

Bosch CIS test gauges

Overboost switch

It does sound more like the WUR than the overboost switch.

Could it be the plugs, wires, cap & rotor getting old ?

JBL930

Your car doesn't have an ECU, you need to get your car on a dyno and see what's happening in a controlled environment with someone who knows these systems, if you keep having a fiddle with stuff and then blasting up the road your going to end up rebuilding your engine very soon

ZX3tuning

silly question, WUR?

plugs, cap rotor and wires are all new.

JBL930

Short for "Warm up regulator", the things are a pain in the ****, if you do a search on this forum for a thread called "warm up regulator" there is some good info, it educated me anyway

nathanUK '81 930 G50

Did the fault occur after fitting these ? Is it possible they are at fault ?

NSXTC

I wouldn't touch the CO screw. It affects mixture throughout your range and from your description, it looks really good. Idle at 14-15 and cruise at 13.5. At 6000 RPM, what's your AFR? With the CIS system, it will go down to 11 AFR as soon as boost hits, but will lean out at WOT and at 6000 RPM hopefully you'll see 12.

If you're still seeing 11s, then you may need an adjustable WUR which allows you to tune the boost control pressure. Basically, you need to increase the boost control pressure so put more 'resistance' against the air meter plate.

Brian Leask is really knowledgeable about tunning CIS wrt to the WUR and can rebuilt your WUR to make it fully adjustable. Contact him at bleask@***.net for more insight.

HTH,
David

JoeMag

for CIS pressure tester -- Jc whitney -- something like $70.