Saabscene Saab Forum - Saab Technical Information Resource banner
1 - 12 of 12 Posts

·
Registered
Joined
·
2,886 Posts
Discussion Starter · #1 ·
Well after the success of the idle valve clean on my 2.0ltp MY96 I decided to do the same on the K reg.

Only one slight problem is that it doesn't have one.

I've done a quick search for symptoms on the board but not found a definite answer.

Car starts fine, idles fine when cold, actually seems to idle fine when warm but occasionally mis fires.

Anything obvious to check apart from the DI cart (Which isn't showing the usual symptoms)

Steve
 

·
Registered
Joined
·
548 Posts
I have been chasing an occasional rough idle for many years on my Aero. Check the following: condition and connections on all vacum lines, s/plug condition and gap to .9 or 1.0mm, clean AMM, check grommet on PCV valve on cam cover, make certain BPV valve is working, check torque of intake manifold bolts, run injector cleaner thru fuel tank, change fuel filter if original.

When 4 yrs old Saab paid to change the DI and head gasket on mine as well trying to chase the problem. I have had a few months w/o rough idle, but it always comes back.

Good luck, let us know what happens.
 

·
Registered
Joined
·
2,886 Posts
Discussion Starter · #4 ·
Quite a list of things to do then... anyone know how to clean the AMM - my copy of haynes seems to gloss over a lot of things like that.

Maybe I should be lazy and take it to the new Saab specialist in Cheltenham who came round and fliered all the saabs in the area the other night.

Steve
 

·
Registered
Joined
·
548 Posts
Sorry I don't have any pictures, perhaps someone else will be along that does, but cleaning the AMM is just a matter of disconnecting all the connections, clamps and hoses and removing the pipe from the air filter to the turbo and using spray carb cleaner CAREFULLY cleaning the AMM and generally any oily mess you find.
 

·
Registered
Joined
·
2,886 Posts
Discussion Starter · #6 ·
OK heres an update.

Plugs checked fine - tips are gapped correctly and are all a nice brown colour. AMM all cleaned - no oily crud in the pipe ways. Air filter all nice and clean. Throttle body clean (no sticky residue or anything). DI cart all looks fine (can't beleive its the original but there is nothing in the paperwork that I have that shows it has been replaced).

Started the engine and went to wobble all the pipes..wobbled the injector connectors, one of then was a bit loose and the engine stumbled when I wobbled it... so have disconnected and reconnected them all.

Time for a test drive I think

Steve
 

·
Registered
Joined
·
2,886 Posts
Discussion Starter · #7 ·
Update

Well the car now has a lot more
than it did before. The odd idle is still there... it will sit there idling nicely and suddenly there will be what feels like a mis-fire on one cylinder. The mis-fire is not constant...sometimes you can sit there for a couple of minutes waiting for it to happen. Oddly enough I have felt a similar stumble when cruising at a standard speed.

Steve
 

·
Registered
Joined
·
393 Posts
Originally posted by StephenA:
[qb]Oddly enough I have felt a similar stumble when cruising at a standard speed.
[/qb][/b]
Steve, when my DI packed up (at 130+ k miles, so I was lucky) the only warning symptoms were a slight stumble at cruising speed, exactly as you say. It would do it once or maybe twice on a 100 mile run, and it did it for maybe 6 months before packing up completely. I say completely, but in reality it packed up by 25% and one coil stopped working, so I was running on only 3 cylinders.
So maybe your DI cassette is on the way out. Is there anyone you can borrow a known good DI cassette from to check?
 

·
Registered
Joined
·
2,886 Posts
Discussion Starter · #9 ·
Yess I can swap it with a known good one.

I actually have a 75% good one at my brothers and they do look like they come apart.. has anyone tried rebuilding 1 from two partially dead ones or is it not really worth it?
 

·
Registered
Joined
·
1,925 Posts
The cover comes off, but that's it. Inside is completely sealed, you can't see anything unfortunately.

By the way my car has this occasional "misfire" as well, but it's a new DI, and does it with other new DI's. But still worth checking.
 

·
Registered
Joined
·
2,886 Posts
Discussion Starter · #12 ·
Problem Solved!

I ran a dose of Injector cleaner through on one tank of fuel.

Then filled up with Optimax and another dose of Injector Cleaner.

Then drove from Cheltenham to Canterbury doing a good speed along the motorways (averaged 60mph from Cheltenham to Guildford).

Car now idles as sweet as a nut, there is plenty of
and a nice noise when you push the turbo upto the edge of red .

Only managed 28.9 mpg but thats the autobox and its inistance of staying in third until just over 40mph.

Steve
 
1 - 12 of 12 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top