[SaabFox91]

Hi. I'm back with another rousing round of everyone's favourite game, "What's Wrong With The Saab Now?™"

1984. CIS 8V Single Jingle turbo. Just had a rebuilt APC and boost regulator placed in the car. Some new vac lines as well, and a new reverse lockout gear.

She's peppier, but. But.

She's still only hitting mid yellow. The needle is trying to go further over, but something isn't letting the car do so. She can finally do triple digits, as on an old highway I got her to 102. That's in Bald Eagles per NASCAR units. Before hand she struggled to hit 90, so improvement!

So, to all my 8V CIS buddies. Have you had this issue? What did you do to resolve it, besides buy a T16.

 

[jvanabra]

Boost is separate from fuel is separate from spark, so first thing is to figure out what system has the issue. What's the maintenance history on the car? Filters, injectors, pumps, cat, etc.?

 

[Matt Dupuis]

Spark timing. Spark quality. Fuel quality. Fuel quantity. Fuel injector spray quality. Fuel distribution. Vacuum leaks. Boost leaks. Knock sensor could be bad. (Knock sensors also register piston slap on older engines.) Wastegate actuator could be out of adjustment. Generically awful exhaust. Etc. These are general queries to any turbocharged engine that's lacking performance.

 

[SaabFox91]

Ok, new problem. (Seems like a common phrase with Saab ownership...hmm).

1. Changed my plugs and wires. Now my car bucks when I accelerate. Maybe missgapped the plugs? All wires seem nice and tight on the dizzy and plugs

 

[jvanabra]

Maybe.… only you would know!

Did you use the correct plugs and appropriate wires? Did you disturb or damage the distributor cap? Did you correctly torque the spark plugs down? Are the threads in the head clean & clear?

 

[SaabFox91]

Yes, yes, no, yes, and yes. I'm gonna Hazzard the fuel filter is next on my list. The bucking isn't terrible, but you can kinda feel it on WOT.

Also cyl 3 and 4 were out of spec. Got them back to spec gap, and yeah, running a bit better. Time to get a fuel filter!

 

[Jim Mesthene]

Changing the fuel filter wont fix a thing; 100% guaranty.
Try putting the old parts back on.

 

[SaabFox91]

Would if I could, but the old plugs were burnt and when I gently tugged on a spark plug wire boot, the whole core came out. Now the car is cutting out here and there with an almost (¼) full tank under acceleration, and I'm hearing a very loud, consorning noise from the back, like a loud screeching noise.

 

[jvanabra]

Only you can tell us where the screeching noise is coming from, but try reducing the gap on the plugs slightly to see if the problem goes away.

Also, "bucking" is a pretty severe symptom... possible it's just missing?

 

[Jim Mesthene]

Worse on left turns? If it goes away with a full tank, replace the fuel feed pump.