[Rodentmaster]

is the error code the same as originally mentioned 12223?

 

[Murry101]

is the error code the same as originally mentioned 12223?

Yes, with a but. After changing out the intake bushings the light came on for a moment and never came back on during a 30-45 minute drive. The hesitation occurs consistently under hard acceleration at about 3700 rpm. I don’t try to push past the hesitation by keeping the pedal down. The hesitation. Seems to be unrelated, certainly to the CEL.

 

[kgrosso]

Yes, with a but. After changing out the intake bushings the light came on for a moment and never came back on during a 30-45 minute drive. The hesitation occurs consistently under hard acceleration at about 3700 rpm. I don’t try to push past the hesitation by keeping the pedal down. The hesitation. Seems to be unrelated, certainly to the CEL.

Not input, but a request: can anyone direct me to a source for above-mentioned 'input bushings'? Sounds like a good idea for any high-mileage 900. I recall replacing the throttle shafts & bushings on the SU carbs that were on my old Volvo 144 sedan. It was the best thing I ever did on that car! It idled like a rock afterwards.The other good thing I did was to rip out that rotten 35- Amp Bosch generator and replace it with a 65A Delco alternator!

 

[02Pilot]

Not input, but a request: can anyone direct me to a source for above-mentioned 'input bushings'? Sounds like a good idea for any high-mileage 900. I recall replacing the throttle shafts & bushings on the SU carbs that were on my old Volvo 144 sedan. It was the best thing I ever did on that car! It idled like a rock afterwards.The other good thing I did was to rip out that rotten 35- Amp Bosch generator and replace it with a 65A Delco alternator!

This should be what you're looking for: SAAB Intake Manifold Bushing 7515208 - Proparts 61345208 | eEuroparts.com®

 

[kgrosso]

Thanks for that suggestion. What I'm actually trying to locate is a set of two bronze bushings for the throttle shaft and I guess, a new throttle shaft. Any assistance appreciated.

 

[Murry101]

Thanks for that suggestion. What I'm actually trying to locate is a set of two bronze bushings for the throttle shaft and I guess, a new throttle shaft. Any assistance appreciated.

I purchased mine from Eeuroparts. Rubber grommets, not the parts your talking about. Responded too quickly.

 

[jvanabra]

I don't think those parts exist. 15 years ago Dave Kennedy was custom making them because they weren't available then.

 

[Murry101]

Thanks for that suggestion. What I'm actually trying to locate is a set of two bronze bushings for the throttle shaft and I guess, a new throttle shaft. Any assistance appreciated.

Sounds like something any decent machine shop could handle. You could probably purchase a bronze bushing that is close and have it modified. I've done that for other parts.

 

[kgrosso]

Where I live, everything is trendy restaurants and nail salons. If I wanted to re-surface a flywheel, it'd be up to me to go out and buy a couple of pieces of sandpaper and grab a wood block! I was going to show my kid how to pack a wheel bearing, but then I thought, "Naahh;... he'll never do this, why make him get his hands dirty?". I'll have to do some serious detective work, to find a guy, around where I live who'll bore and ream a bushing for this. Seriously, there hasn't been an automotive machinist seen in this neck of the woods for almost thirty years!

 

[Jim Mesthene]

If they're really worn (rare), get another throttle body.
These cars don't have constant-velocity carburetors, so they're not terribly sensitive to tiny vacuum leaks before the metering piston/needle. It matters a little to K-Jet, very little to LH.
Prove it to yourself by putting tiny O-rings on the shaft; they'll last a while.

 

[jvanabra]

Call a shop or a dealer. Those guys get their work done somewhere.

I have never seen a c900 throttle body leak in a measurable way, and I have pressure tested many .

 

[kgrosso]

If they're really worn (rare), get another throttle body.
These cars don't have constant-velocity carburetors, so they're not terribly sensitive to tiny vacuum leaks before the metering piston/needle. It matters a little to K-Jet, very little to LH.
Prove it to yourself by putting tiny O-rings on the shaft; they'll last a while.

Even less to an LH 2.4.2 Yeah, that makes sense. Thank you.

 

[kgrosso]

Call a shop or a dealer. Those guys get their work done somewhere.

I have never seen a c900 throttle body leak in a measurable way, and I have pressure tested many .

Dealerships don't do "machine" or "resurface", here in Sodom & Gomorra. They roll with "Sell 'em new"! Thank you.

 

[jvanabra]

That makes zero sense. Nobody puts a new head on a car with every head gasket change, burned valve, or plugged up EGR passage, not even BMW or Mercedes, nevermind independent shops. Someone within driving distance is doing that work.

 

[Murry101]

Update on my CEL and hesitation issue. The CEL turned on briefly a couple of times after I replaced the intake manifold bushings. Since then I replaced the PCV valve and the CEL has not returned. Don't know if that was also an issue, but it seemed to help.

As for the hesitation, it seems to be a bit better, but has not gone away - I did not expect it to. A couple of weeks ago I dumped a bottle of Chevron fuel injector cleaner in the gas tank. I figured it couldn't hurt. As I mentioned before the hesitation is most noticeable in second or third gear under load (hard acceleration when boost is at its highest) and happens most often in the 3k to 4k rpm range. I have new NGK BCP7ES spark plugs on order and will install them when they arrive. Feels like I'm grasping at straws. I going to take it to Saab works and have Jared take it for a spin to help diagnose a transmission issue, maybe he will have some insight regarding the hesitation.

 

[jvanabra]

This is a long shot, but I had an '87 SPG that had a very pronounced hesitation under boost that turned out to be the vacuum module on the distributor misbehaving. I can't say precisely what the issue was - I assume the actual mechanical plate binding or something - but replacing the module fixed the issue. You could plug or clamp the vacuum line and go for a drive or maybe use a pressure pump and a timing light to see if yours works right.

 

[Murry101]

This is a long shot, but I had an '87 SPG that had a very pronounced hesitation under boost that turned out to be the vacuum module on the distributor misbehaving. I can't say precisely what the issue was - I assume the actual mechanical plate binding or something - but replacing the module fixed the issue. You could plug or clamp the vacuum line and go for a drive or maybe use a pressure pump and a timing light to see if yours works right.

I plugged the line to the vacuum module on the distributor (intake side) and road tested. Unfortunately the hesitation still occurred. It's an engine so the problem has to be air, fuel or spark related. The fact that it happens with consistency and under specific conditions should help with the diagnosis (I think). If it only happens at high boost, unplugging the APC valve limit the boost to baseline, ~5psi. If the engine does not hesitate under lower boost, could that eliminate spark as an issue? Don't know if I mentionet yet but the engine pulls smoothly all the way to 5k rpm minus the slight dip in power at 3700 rpm.

 

[jvanabra]

Not really, because spark plugs have a hard time when cylinder pressures are high. By limiting cylinder pressures you've made their job easier.

But, the fact that it clears up makes me think it's not spark anyway. A flat spot at a specific point makes me think timing or mixture.

 

[Murry101]

Not really, because spark plugs have a hard time when cylinder pressures are high. By limiting cylinder pressures you've made their job easier.

But, the fact that it clears up makes me think it's not spark anyway. A flat spot at a specific point makes me think timing or mixture.

Makes sense. As I recall the "resistance" of air is about 10K ohms per inch. I thought it decreased as pressure was reduced, but it's been a couple decades since I took physics.

When I wrote my last post I was speculating as to what might happen if I disconnected the APC valve. I did go for a quick test ride since then. After I let the engine warm up I started in second gear at about 2000 rpm and pushed the pedal down (not quite WOT) and accelerated to 4000 rpm. The hesitation was dramatically reduced, but I still felt a dip. It was almost imperceptible.

I think you mentioned checking the timing at idle. I've done that in the past (16° BTDC). If this were off could it cause slight hesitation at a specific rpm under boost? I don't see how, but as I said I 'm grasping at straws here.

IAnother observation worth mentioning, the engine hesitates a bit off idle if I quickly actuate the throttle when the car is in neutral (or at least it did before I replaced the vacuum lines and intake bushings.

 

[jvanabra]

Given the ignition system is in good repair, that sounds like a MAF problem to me, which could also explain the flat spot. Since the c900T has no way of sensing load, it relies on the MAF for pretty much everything.