Newbie (don't flame) [Archive] - SaabCentral Forums

: Newbie (don't flame)


slowtsi
19th March 2006, 10:32 PM
Hi, I don't own a saab but I do have a quick question. I'm sorry for not searching I'm sure this has been answered 1000 times. My friend recently bought a 1995 9000cs turbo and we have been messing around with it all day. It would only boost 10 pounds then cut out really hard. We thought it was plugs so we did plugs and it still did it. So we went at the blow off valve because it seemed to be opening early. We put a blow off valve from a 1g dsm on it. Still cuts at 10 lbs. Any answer why and how to get around this? Thanks, and these cars seem to be pretty fun to tinker around with :cheesy:

johncc
20th March 2006, 05:40 AM
This is a pretty easy going forum so you shouldn't need your flame-retardent suit! :)

It sounds like you are hitting the fuel cutoff, which is a feature built into the ECU to protect the engine.

The only thing which can make this go wrong is the MAP (pressure) sensor. This is how the ECU reads the boost pressure, but it is also a crucial part of calculating the fuelling so you can't just fudge it to get around the cutout (just in case you were thinking that.. ;) )

Are you sure that your boost gauge is correct? And is the car an LPT (light pressure turbo) model? The safest way to tell this is whether it has a boost gauge on the dash. If it doesn't it's an LPT. I am pretty sure the LPT has a lower fuel cutoff pressure.. I'm sure someone here will provide us with the figure shortly.

On my car (a full pressure model) the cutoff is about 18-20psi so if yours is a full pressure model there's something wrong. How does it run otherwise? Does it seem to run rich or lean or about right?

By the way, on these cars you must use the specified NGK plugs, and only NGK plugs, even if you're told something else is equivalent. Because of the way the Direct Ignition uses the plugs to sense engine data, it won't work with any other type. Luckily the NGK's are pretty cheap too..

Stefano
20th March 2006, 08:37 AM
I think that 10psi is fuel cut-off for LPTs.

Only good way to get rid of it is a ECU remap or an ECU from a FPT, you really don't want to mess with the MAP sensor.

slowtsi
20th March 2006, 06:46 PM
Thanks for the information. I'm used to working on eclipses and talons, anything can really be hacked on them. It doesn't have a stock boost gauge in it. All I can really say is you cannot go wot in it without hitting this cut off, it's really bad. My understanding is that they have 560cc injectors? I could be wrong. So I was assuming it was a computer thing. I dunno, I mean it's just a beater, paid $500 for it it has 158,000 miles on it. But it would be fun to get it running strong. Thanks again guys

93Saab9000turbo
20th March 2006, 08:01 PM
Sorry...doesnt have much to do with ur post but what johncc said about the NGK's.

John, what do you think about iridiums? I just put them in and they seem to be doing fine. Pulls a bit harder to but thats probably because of the fuel filter i did. I heard the iridiums like to melt.....but whatever....I should have asked the form what the best plug to use was but I couldnt find anything in the search...its a 1993 saab 9000cse turbo....the fuel filter wasnt as bad as i thought it was gonna be btw...

boxman
21st March 2006, 05:26 AM
i would say you have a boost pressure control solinoid fault slowtsi, you will find it fixed to the radiator fan housing, its black with three hoses on it and a three pin connector, they can stick so it stops the boost pressure reaching the waist gate actuator, thats assuming your mates car has one, saab did away with it on the later lpt cars, if this is the case you should check the waist gate actuator hasnt been adjusted up to far