# Help Needed! CIS Turbo tuning trouble



## A2VW4life (Aug 29, 2003)

My friend is in need of some help with his CIS turbo project. I know very little when it comes to CIS, and would like to ask some of you CIS guru's for some help. 

Here are the symptoms from a short drive in it last night:

Starts hard cold. (After reading a bit of threads on cis turbo's this seems common.)

Once warm it will hold a rough idle. It will sputter while slowly accelerating. Under any sort of hard acceleration/WOT it acts as if it were hitting a rev limiter around 3500 rpms, while sputtering.

It has a wideband installed. I adjusted the a/f to 13.5~14.5 at idle. At WOT it's spot on at 11.5~12.5.

It holds 15Hg at Idle, it would not show me anymore then 2-3psi. 

Here are the spec's:

84' JH Bottom
86' RD Head
t3/t4 turbo
K-jet
oem 84 injectors
MSD BTM ignition system w/ accel coil

Emissions system, vacuum canister, and ac idle booster control have all been deleted.

I will get some pictures within the next couple days.

Any info will help. Here is a pic of the car for clicks.


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## antichristonwheels (Jun 14, 2001)

boost sensitive WUR?


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## A2VW4life (Aug 29, 2003)

antichristonwheels said:


> boost sensitive WUR?



Yeah, hose is connected to the barbed fitting on the side of the WUR. Has a one way check valve as well.


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## antichristonwheels (Jun 14, 2001)

Is the fuel distributor plunger sticking? They can get kinda smegma'd up after sitting for only a few months. Try dumping some seafoam into the tank a drive it. No reason not to have a smooth idle and accel just because its running boost.

Maybe upgrade to a Volvo 240 CIS


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## John Milner (Jul 20, 2005)

Its alittle hard to try & diagnose your problem without actually experiencing your problem but...

when I first started on my K-Jet turbo setup, I fitted the boost line to the barbed fitting on the WUR, but I found that it didn't drop fuel pressure (richen up) under boost.

So fitted I the boost hose to the "big" un-barbed fitting & retested using a air compressor regulated down to 10psi & found that it worked properly & dropped fuel pressure as it does when its initially cold. Depending on pressure, it would drop down from idle approx 45psi to approx 20psi with 10psi pressure applied.

I used a home made K-Jet fuel pressure tester to test the pressures of both the "system pressure" (main fuel pump pressure) & the "control pressure" (warm up reg pressure)

This is a pic of my WUR. Its an Audi 5000T. The barbed fitting is directly under the vent which I have the boost hose pushed onto without any one-way valves etc. Just a straight hose connected to the intake.

This pic is when I initially set the boost reference for the WUR which didn't work











Then after I worked it out & fitted it to the vent












Autometer Fuel pressure tester I modified for testing purposes of the K-Jet, as this is how you basically tune a K-Jet system Note: the fuel tap to switch between "System" pressure & "Control" pressure












Does the setup still use the "aux air valve" or "cold start valve"?
Is the power supply still connected to the WUR?


My car no longer has either the cold start system or aux. air valve fitted, so cold morning starts can be alittle bit hard. But not too hard. It will fire straight away & you only have to hold the throttle a tiny bit to keep it running & after approx. a minute, it will idle fine, although alittle low (600-700rpm) due to still being cold. Once warmed up it idles at 1000rpm.

Once I worked out the WUR operation, I basically just drove the car & started off with 10psi. Then I played around with advancing the timing bit by bit & then played around with the MSD retard dial starting with pulling 1 degree per 1 psi.

Its all a balancing act I found between static timing, timing retard & boost. But "only" adjust one thing at a time & retest. If it doesn't work, you just revert back to how it was & try something else.

Once you get your timing & timing retard worked out, then you can start to increase boost till your A/F starts to lean out (not meaning dangerously lean! Just like WOT, full boost & it starts to nose over & getting to mid to high 13's). Then start increasing your "system pressure".

If you feel like a long read, have a look through my build thread. It has nearly all the info you will need to build & tune a CIS turbo setup.

I can also give you all my exact specs ie. static timing, timing retard, boost & fuel pressure settings if need be to help you for a basic setup. I found once I went over 14-15psi, I needed more fueling ie extra injectors.


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