Saabscene Saab Forum - Saab Technical Information Resource banner
1 - 20 of 42 Posts

·
Registered
Joined
·
1,194 Posts
Discussion Starter · #1 ·
Need some help please, my car was serviced 4 weeks ago running sweet speedparts exhaust/ecu/itg filter
it had a slight leak on the head gasket, nothing terrible so its been in for that, the head was skimmed and the three broken studs replaced, it all back together but its running lumpy on tickover and up to 1.5k rpm, its flys like a rocket at anything above that, so today a new DI unit was tried, no better the plugs were checked and one of the plugs was very sooty, like it had been over fueling, tried a new plug, no difference, all the pipes are on and ok, I tried the old ECU back on and it was still the same, no fault codes are being shown and the check engine light is off the timing has been check help please
 

·
Registered
Joined
·
1,194 Posts
Discussion Starter · #10 ·
Like I said before the cars performance is stunning,but at tick over it sounds and feels a bit like a rally car with a highlift cam on. could this be an injector fault?
 

·
Registered
Joined
·
16,524 Posts
You just beat me to it. I had major engine work done on a diesel a while back and somehow some dirt or swarf got in the fuel line while it was disconnected and got stuck in the injector so it wasn't shutting off properly. Haven't looked at the Saab petrol injector but the Merc diesel ones could be stripped and cleaned.
 

·
Registered
Joined
·
1,925 Posts
Having spoken to Leon, we suspect only the pre common rail diesel injectors can be stripped. new ones similar to petrol, as they are electronically controlled there is less to repair. Old diesel one's ran on spring pressure, new ones electronic, petrol one's are all electronic.
 

·
Registered
Joined
·
16,524 Posts
Originally posted by mpen:
[qb]did you car run like I have discribed, lumpy tickover and until around 1.5k rpm then it clears
Mark [/qb][/b]
Can't really say because it was more than one injector and there was so much smoke down the road that I switched off fairly quickly and checked everything on the fuel system and found bits of swarf jammed in the injector outlets.

However, lumpy running and a black exhaust sound like your engine is running rich. If it's only one cylinder that's rich I would check the injector. You should get an opinion from the board experts about this as a check but I would try swapping a couple of the injectors and see if the problem follows it.
 

·
Registered
Joined
·
14,305 Posts
Checking the injectors is posssible- but requires a bit of mesing around. Basically, you pull the fuel rail and injectors out of the inlet manifold, then set it up with clear containers under each injetor. Pull the connector from the DI to prevent any sparks, and crank the engine. If it is a fouled injector, you should be able to see a difference in the spray pattern/delivery rate.

Silly question maybe...

Al lot less hassle than that- have you tried an injector cleaner?
 

·
Registered
Joined
·
1,194 Posts
Discussion Starter · #18 ·
Mark
I have never tried injector cleaner, I will throw a bottle in, I have been using optimax since I bought the car (about 12 weeks ago)but this fault have only shown as soon as the car was started from the head gasket job
 

·
Registered
Joined
·
8,948 Posts
You've gone througn a tank of fuel since 09:00 this morning!

It does seem odd that it hjas only started since the Head G was done.

They did get both cams aligned / timed properly? I have heard of people having problems (without valves hitting pistons) when one on the cams has been 1 tooth out and causing low running problems.

Andrew
 
1 - 20 of 42 Posts
Top