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Location: Toronto, ON
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Undoing the Bad with the Good

I purchased this 87 Euro Spec 930 Turbo last year and had to put it away into storage right away. It was a very last minute deal and I had to jump on it therefore I didn't have much time to look it over as comprehensively as I'd like. That's fine though, I'm a tinkering kind of guy and my profession warrants me buying cars that are a bit less then tip top shape. Kind of how I like em, cause I get to put them back together to my liking.

This car is no exception. It ran and drove fine, boosted well before going into storage. Well after a winter of reading these forums and making myself somewhat familiar with the engine, I pulled the car out of storage and started inspecting it. The first thing that caught my eye was a vaccum leak at the T in the BOV (not to mention the ugly hose for the BOV but that will be fixed later).


I plugged it but noticed that the car started running richer and even during cruising it felt more sluggish then with the vacuum hose leaking. My first order is to fix this issue. However, I'm at a loss how this car was tuned because it doesnt have an adjustable WUR so I'm wondering how is fueling adjusted on a stock CIS system? I've been searching but can't seem to find a thread that talks about it.

The engine has an Electromotive XDI ignition system (with a map sensor) so I'm going to check timing on monday on a dyno to see where it sits plus get some AFR readings. Any suggestions as to rough timing settings I should be looking for? I know the system has 0-3000 and 3000+ knobs.


I went ahead and pulled the plugs and did a compression check as well. As you can see compression shows 120-ish across the cylinders so I feel as if the engine is in decent shape.


The plugs don't look so hot though


So my fellow wise Pelicans, what is my method of approach here? First and foremost, I'll fix the vacuum leak but I want to be able to fix the fueling when doing so. Is this even possible without a Leask WUR?

Here's a photo of the car and engine bay just because I know someone will ask.





Last edited by Pstl_Pete; 06-21-2013 at 07:36 AM..
Old 06-21-2013, 06:48 AM
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this is what happens when people dont check fuel pressures and fix air leaks and jump right in and start adjusting the mixture.

the fuel pressure "can" still be tweaked even thought it has not been modified.
but first you want to check the pressure.

it could just be that someone tweaked themixture adjustment, although from what i have found, idle adjustment does not have as big of an effect at cruise.
so here you really need to connect to something that can chech your AFR's.

the plugs.
if it is rich and you let it idle before shutting it down, you are not getting a true rreading of whats going on.
how old are the plugs?

with that said, when it comes to messing the mixture, you want to make sure your air leaks are fixed, fuel pressures are where they should be, and the ignition is the best it can be.
new plugs, cap and rotor and good wires. then make sure your timing is correct and the advance is working like it should. then mess with the mixture.
(i know, you have no dist).
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86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ SOLD
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Old 06-21-2013, 07:18 AM
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Thanks for the info! So I am assuming fuel pressure adjustment is what richens or leans out the mixture? Is there a way to adjust fuel pressure on these engines some where?

Sounds like I need to install a fuel pressure gauge asap, any links or suggestions as to how to install one permanently?

As for plugs, the XDI system is about a year old so everything should be newish and not needing of replacement.

Last edited by Pstl_Pete; 06-21-2013 at 07:37 AM..
Old 06-21-2013, 07:34 AM
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Here's one way to adjust AFRs using stock WURs. 2 cautions:

1. You better know what you are doing with AFRs before making these adjustments (WB02, CIS pressure gauges, etc.)! Also keep in mind a little tap goes a long way!

2. You will probably overshoot your first adjustments so it would be wise to read up on WUR internals before you have to take apart the WUR to make additional adjustments.

Old 06-21-2013, 08:11 AM
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take great caution before you go knocking on that sucker. system pressure and control pressure need to be checked.
changing the warm pressure also changes the cold pressure.

if you REALLY want to start messing with this thing, get one that IS adjustable. it lets you adjust it both ways and gives you more adjustability without taking it apart.
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86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ SOLD
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
90 B2200[__] RUNNING:[] NOT RUNNING:__2000 MER E320 WAGON [] WRECKED:[]RUNNING:
Old 06-21-2013, 08:39 AM
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Again, thanks for all the feedback. Looks like Ill invest into the Leask WUR before moving forward. I don't have the time to be taking apart the stock WUR for every adjustment, my dyno guy will kill me!

I've noticed a few setups that have hard mounted fuel pressure gauges, where is the best spot to put one in?
Old 06-21-2013, 09:11 AM
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Might I suggest you purchase the following Bosch Fuel Injection Management book
Pelican Parts - Product Information: BK-112910B
A must-have for understanding CIS fuel injection. If you're not familiar, understand that when you hear the word "fuel pressure", with these cars (or any CIS system) there are several different pressures: System pressure, which is basically the pressure delivered by the pumps and controlled by a pressure regulator internal in the fuel head (easily removed and shimmed to fine tune the pressure). That system pressure is further modulated by the WUR, to provide what's called control pressures. You have a cold start control pressure, which will be lower than the fully warmed up control pressure. These control pressures are what dictate your mixture at cold, warm, and cruise. So it's a combination of system and control pressures that must be correctly set. Unfortunately, the control pressures aren't adjustable (not conventionally, anyway) unless you have an adjustable WUR.

You'll need to obtain the proper gauge setup for testing both system and control pressures.
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Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 06-21-2013, 11:22 AM
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congrats and welcome - looks like a great score, and them Cup II's look pretty cool on there

like Mark said your main fuel pressure is adj via a 'regulator', essentially a bolt threaded into the lower right side of the fuel dist

buy a shim kit and adj by fussing with different combos of shims / thicknesses

need a gauge set tho

def buy the adj WUR - makes these cars so much more driveable... $$$ well spent IMO

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Paul... CT | '87 930 | '08 M3 6gang vert |
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| '07 S6 | '98 M3 vert | '01 M5 | '96 993 C2 cab | '05 S600 Sport - biturbo V12@Just Not Right 495rwhp / 612rwtq |
| '58 TR3A | '01 S8 | '95 S6 6gang | '88 M5 | '87 190E 2.3-16 |

Last edited by krasuskyp; 06-21-2013 at 11:39 AM..
Old 06-21-2013, 11:37 AM
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