What you showed as the knock sensor in the video was actually the water temp sensor. The Knock sensor is on the side of the block, to the left of the oil filter.
You are 100% correct. I was in a rush to get this edited and published, so when I discovered I'd neglected to get a shot of the knock sensor I slipped in what I had on hand. Good on you for noticing and clarifying.
I had the exact same problem, was only boosting about 0,6 bar with red box. But then I changed the spark plugs and set the correct ignition timing, now it boosts 1 bar!
Lee, Saab central has a sticky for first time turbo owners, I know you are not, but its a great read. I know there are a lot of comments about change this or THIS has to be it. I have the same issue with my 85 SPG. I cant get full boost with APC but ive been going over vacuum, o2 sensor, AMM, temp sensor. before I do the turbo adjustments as everything else needs to be tip top. When I pull the hose off I get crazy full boost too. Anyway, here are the steps. 1. Change the oil to full synthetic quality oil and filter, regardless of what the PO says. 2. You change the coolant and flush the system, regardless of what the PO says. 3. You replace all ignition components, that being the rotor, cap, leads and plugs (NGK BCP7EVX for 16v turbo, BP7ES for 8v turbo), regardless of what the PO says. 4. You investigate or/and replace all vacuum-hoses, regardless of what the PO says. 5. You test/replace the bypass-valve, regardless of what the PO says. 6. You unplug the connector on top of the APC-solenoid (located above the radiator, with three large vacuum-hoses going out of it, and a connector on top), to check the base-boost. Drive the car warm, find an inclining road, go into third and floor it. Note the boost on the CALIBRATED boost-gauge, and adjust to 6 psi or 0.45 bar. Shorten the actuator rod for higher boost, lengthen it for lower boost.
I've seen this and followed many of the steps. Thanks for the post nonetheless. There are other SAAB guys out there who might benefit from this sage advice.
Unfortunately I am not too familiar with the 900 although I always wanted one. A dream car to own really!!! if it's the red apc you are having all the better. It should boost in the 20 psi. I will be very interested to see your next vid when you manage to sort the boost.
Still not hitting base boost so definitely not an APC problem. APC can't drop turbo output below base boost. On my car I didn't get base boost until the waste gate rod was pulled pretty tight. Maybe try adjusting it a bit further and see what happens. Need to get that rod shorter. I think every turn is something like .5 psi. Glad to see someone putting some work into an old 900!
Have a 94 classic 900 turbo convertible. Having a boost problem and removed the hose to the waste gale solenoid Check my new video out and 0-60 times are quick! Engine seems to run great. Have to figure out what is causing the boost problem with apc hooked up
and what you show as the knock, is not the knock, the knock is a bit lower by the intake runners, it has a bolt in the center of sensor, i dont know how much you know, but GREICO will fix the problem
I think it is definitely the apc controller. The later ng 900 do have occasionally boost valves giving up. I went through 2 of them. Your test shows without it the car runs fine. I don't know if a fuse for the apc exists on the classic 900. On the ng900 it does you can check that first
I'd guess at a weak wastegate spring most likely due to the very low base boost but before concluding that you have to cap the ends of the inlet pipes at the turbo air outlet and at the throttle body then pressurise (10psi or so) the intercooler and pipes to check for boost leaks. Ideally with a proper workshop smoke tester but I did find a boost leak at home on the wife's 93ng by welding up two bits of scrap exhaust tube capped off, one with a tyre valve pulled through a hole drilled in the cap. Worked a treat finding an almost invisible split in the intercooler end tank. Boost leaks = overspeeding turbo.
I had no idea this particular turbo might have a waste gate spring. My understanding (always subject to correction) is It's the job of the adjusting rod attached to the actuator to hold the waste gate closed. It takes a fair amount of pressure to open the waste gate manually by moving the rod, so I see no signs the diaphragm in the actuator is too worn to withstand the exhaust pressure.
Turbo is fine, because hitting full boost and fuelcut with wastegate hose disconnected. I think, but you didn't test it, that with hose from compressor to wastegate you hit the baseboost you had earlier. with the hose directly connected instead via the apc solenoid it's the most accurate reading. For now, because you still having too low baseboost it has to do with the wastegate. Get the controlarm more tight or get a new wastegate actuator. If baseboost is 0,5bar, then you should get the full boost from the APC. if then still not enough boost, then there is something wrong with the APC system.
This one is the modified APC box. The Red ones were offered in the Dealerships as part of the Performance package which also included a 2.8bar fuel pressure regulator, upping power to 185bhp. The Red box was also standard on the 900 Carlsson in Europe.
not true, hi boost is done using the RED apc ecu, there is no one burning chips for the classic 900 ,jack stall was, but no one can find him and his chips sucked..................................
I need to know now!!!!!! I've a 1999 93 aero! I feel lucky I bought her! Knew nothing of saab b4! Now I just love them! Mine did the same as yours! I put a variable valve on, now that works! But every time I change gear the revs take time (1second) to reduce! I've cleaned the Mas, replaced the throttle body, she is fully serviced and money no object maintenance! But Noone can seem to fix the problem! Anyone any ideas? I've asked a saab ' specialist' but they only work on 2000 + Vauxhall GM saabs! Not the real deal! Someone please help!
So.. with the apc solenoid wiring disconected, it has no boost. With the apc physically disconnected, it has full boost. That would mean the apc valve is leaking internally, shouldn't it?
Hi Lee, just reviewing this vid because I need to check boost on both SPG and vert. SPG seems to have similar problem as yours, and vert has Boost OOC (Out Of Control, lol). Did you solve your problem?
It's better, but still not full-strength. I shortened the waste gate actuator rod as much as possible. That puts the boost needle almost to the red, but I believe it should go just a bit higher. I plan to put the gauge back on it and hit the road for a new measurement soon.
@@LeeKelso Did you ever solve the boost problem entirely? I'm working through base boost (or less, like your car) on two 900s right now. I did notice in the video that the electrical connectors on your APC solenoid are naked and no longer insulated (crumbling on mine too). I read a Saabnet thread (www.saabnet.com/tsn/bb/900/index.html?bID=453579) where the lack of insulation was a significant part of the problem for the original poster. He said it went from 5 PSI to 8 when he added new insulated connectors. Fortunately, new insulated female ends are still made: www.esaabparts.com/saab/parts/7874498. The theory is that the solenoid is magnetic, so it's sensitive to electrical interference. I've also read elsewhere to make sure the starter-to-cap cable is routed as far from the solenoid as possible. That's easier said than done, I know.
@@cmbaker91 Thanks for the tip on the insulator. I've added a new connector and will enhance the insulation. The car is back on the road after a total engine rebuild that includes enlarged bores and forged pistons. The boost gauge now touches the red, but I'm still tuning and getting things dialed-in. I'll check boost and post an update soon.
@@LeeKelso sounds great! Also, what gauge did you use for testing? i'm trying to find a simple and cheap - but also detailed - gauge for testing only. Most gauges i see online to buy are electronic, expensive and made for mounting inside - not what i want.
The apc valve on my 9000 didn't work either,tried everything from a new valve to rewiring. Never found the problem. I decided to delete the apc valve altogether and run the turbo on Base boost pressure, which I can now regulate by means of a pressure regulator between the turbo and the wastegate.
When the triacs in the ECU go bad the solenoid doesn't work the way it should. I tried to replace them but as I did not have a small enough soldering iron I screwed up part of the circuitry of the ECU. Only thing left to do then was to buy a good working used ECU and do an adaption run. After that all was well again.
Your wastegate actuator basic spring load (in wastegate) is to week. Spring weekness is Often the case with the later 900 wastegates. You cant get them anymore ( aftermarket still are) Put a extra pull-spring outside the wastegate to get some basic pleasure of around 0.35 -0,4 bar or try to adjust the wastegate rod, Or modify a earlier wastegate (up on 1990 are stronger) to your td04. If you want to be sure you can put your wastegate hose directly to the pressure site of the turbo (like a LPT version). If you still have low basic pressure then you are sure. The spring generated the pre-lowed you need to get to 0.4 bar. I am 100% sure this is your problem
Yet another mention of a waste gate spring. Hmmm, I better dig deeper into this and see if this particular model has one. I've seen them on other turbos, but not on either of my 900's.
When the 900 got the mitsubishi turbo's the problem with those week springs happends. You can try to adjust the wastegate rod a bit. Basic pressure is the key word here and that comes from your wastegate spring. goo.gl/images/574MJu I work with saab since 1986. Its my full time job since that time. At the moment i run Saabpartners.com and have a staff of 9 in the workshop. Great brand and busy times. Saab is still alive here in Holland. Keep up the good work. Cheers
Well, what do you think is holding down the boost pressure? Engine is set to 16 degrees BTC as recommended. I've checked for vacuum leaks and replaced a bad rubber charge tube coupling. There is an exhaust leak at the manifold, but I don't know how much of a factor that would be. Suggestions?
Also the control gate in the cast manifold has sticking points as it becomes worn on its hinges. These hinges have no lubrication due to the temperatures involved and often will hiss as exhaust gas leaks through. If you disconnect the actuator control arm and manually operate the gate you will be able to feel excessive play and rough movement.
The APC solenoid is a form of magnet. I noticed that the connectors on yours aren’t in a connector. They aren’t isolated. The magnet of the solenoid interferes with the connection. Get some connectors that are sealed in rubber, that way you isolate them and the solonoid will work! It took me months to figure this out on my 87.
I hadn't thought of that. The solenoid clicks with application of the brakes and when you do the "blow test" it tests out fine. Since the solenoid keeps the wastegate closed until the engine pings, if it were not working I'd think the boost would be higher not lower. Make sense?
Well he doesn't even have base boost yet, so not apc valve related. Those old ones never fail. You can squirt Carb Cleaner through the ports of the APC valve until it runs clear, to remove any gunk.
@@LeeKelso Absolutely, but I haven't started my latest project which will be a 900 conversion to a turbo. When that gets rolling, it will be a good segment.
I don't think that's going to be a direct fit as you'll probably need to create some way to tell it the position of the crankshaft. There's lots of expertise available in the Facebook Classic 900 group. One of those guys will probably have a solid answer for you.
It certainly could overheat and warp the rotors, so keep the test brief. It takes less than a minute to get things to settle down and give you a solid reading.
Not before tearing the engine part for a total rebuild after a head gasket failure. After that process I found that adjusting the waste gate rod to keep the system closed and holding pressure helped. I'm now boosting just across the red line on the gauge. Here's something interesting: The CE has a special "red box" APC controller that supposedly boosts power by something like 10HP. I found a tweaked APC controller from Swedish Dynamics boosts it even more into the red than the "red box".
@@LeeKelso Yes you have the Red Box APC which was set from the factory at 0.85 Bar boost. (12.5 psi). But you will only get that on high octane fuel, such as Shell V-Power. Base Boost with the APC unplugged should be 0.45 bar ( 6psi). Base boost must be set correctly, before plugging the APC valve back. As always with the B202, its critical the ignition timing is set correctly. 16 degrees BTDC at 900 rpm with the Distributor Vac hose removed. They need setting about once every 2 years as the chain stretches, then the ignition timing drifts out.
you know we charge for finding the problem, so this one is free, un bolt the exhaust the down pipe, dont loose all the way, but a leak is what you want ,try it if boost is better remove the cat, you dont need it anyway if its under 1995...................................... it's the cat i think
Same exact problem and symptoms with my 1988 900 Turbo convertible. Trying to figure it out! Will let you know what I find
Well done, Lee!
Keep it up-would love to see more of Saab 900 vids!!
Thanks! Share the link with any SAAB fans you know and help spread support for our cars.
Love the passion you have for the classic Saab 900! I have 2 on the road, and one starting
the restoration process!
Right on! Would you be willing to join me on a livestream to share details of your SAABs? Any problems you're having get resolved?
What you showed as the knock sensor in the video was actually the water temp sensor. The Knock sensor is on the side of the block, to the left of the oil filter.
You are 100% correct. I was in a rush to get this edited and published, so when I discovered I'd neglected to get a shot of the knock sensor I slipped in what I had on hand. Good on you for noticing and clarifying.
I had the exact same problem, was only boosting about 0,6 bar with red box. But then I changed the spark plugs and set the correct ignition timing, now it boosts 1 bar!
Lee, Saab central has a sticky for first time turbo owners, I know you are not, but its a great read. I know there are a lot of comments about change this or THIS has to be it. I have the same issue with my 85 SPG. I cant get full boost with APC but ive been going over vacuum, o2 sensor, AMM, temp sensor. before I do the turbo adjustments as everything else needs to be tip top. When I pull the hose off I get crazy full boost too. Anyway, here are the steps.
1. Change the oil to full synthetic quality oil and filter, regardless of what the PO says.
2. You change the coolant and flush the system, regardless of what the PO says.
3. You replace all ignition components, that being the rotor, cap, leads and plugs (NGK BCP7EVX for 16v turbo, BP7ES for 8v turbo), regardless of what the PO says.
4. You investigate or/and replace all vacuum-hoses, regardless of what the PO says.
5. You test/replace the bypass-valve, regardless of what the PO says.
6. You unplug the connector on top of the APC-solenoid (located above the radiator, with three large vacuum-hoses going out of it, and a connector on top), to check the base-boost. Drive the car warm, find an inclining road, go into third and floor it. Note the boost on the CALIBRATED boost-gauge, and adjust to 6 psi or 0.45 bar. Shorten the actuator rod for higher boost, lengthen it for lower boost.
I've seen this and followed many of the steps. Thanks for the post nonetheless. There are other SAAB guys out there who might benefit from this sage advice.
For my SPG, faulty knock sensor wiring was the culprit for low boost.
I put in a new knock sensor a few months ago, so I don't think that's my problem. I'll keep after it so keep watching.
the apc has 3 small axis 1 f freak,2psi,3 knock, can be adjusted with small screw driver, do this in very very small turns, problem solved
Man .. this vlog is right on time. subscribed and liked...
I’m due for an update. With a rebuilt engine it’s time to measure output again
Unfortunately I am not too familiar with the 900 although I always wanted one. A dream car to own really!!! if it's the red apc you are having all the better. It should boost in the 20 psi. I will be very interested to see your next vid when you manage to sort the boost.
Still not hitting base boost so definitely not an APC problem. APC can't drop turbo output below base boost. On my car I didn't get base boost until the waste gate rod was pulled pretty tight. Maybe try adjusting it a bit further and see what happens. Need to get that rod shorter. I think every turn is something like .5 psi. Glad to see someone putting some work into an old 900!
PS, start looking for a spare transmission. :)
Yep, know what you mean. I have one with type 5 gearing in a donor car on standby.
Have a 94 classic 900 turbo convertible. Having a boost problem and removed the hose to the waste gale solenoid Check my new video out and 0-60 times are quick! Engine seems to run great. Have to figure out what is causing the boost problem with apc hooked up
and what you show as the knock, is not the knock, the knock is a bit lower by the intake runners, it has a bolt in the center of sensor, i dont know how much you know, but GREICO will fix the problem
I think it is definitely the apc controller. The later ng 900 do have occasionally boost valves giving up. I went through 2 of them. Your test shows without it the car runs fine. I don't know if a fuse for the apc exists on the classic 900. On the ng900 it does you can check that first
No its not. Its the waste gate that's the problem. APC is fine. See my comments above.
This videos are epic I love them 😂
Thanks! I hope you'll share them with other SAAB fans and help keep our cars on the road.
Well explained. Learned a lot - and now i will get my hands dirty ;-)
I'd guess at a weak wastegate spring most likely due to the very low base boost but before concluding that you have to cap the ends of the inlet pipes at the turbo air outlet and at the throttle body then pressurise (10psi or so) the intercooler and pipes to check for boost leaks. Ideally with a proper workshop smoke tester but I did find a boost leak at home on the wife's 93ng by welding up two bits of scrap exhaust tube capped off, one with a tyre valve pulled through a hole drilled in the cap. Worked a treat finding an almost invisible split in the intercooler end tank. Boost leaks = overspeeding turbo.
I had no idea this particular turbo might have a waste gate spring. My understanding (always subject to correction) is It's the job of the adjusting rod attached to the actuator to hold the waste gate closed. It takes a fair amount of pressure to open the waste gate manually by moving the rod, so I see no signs the diaphragm in the actuator is too worn to withstand the exhaust pressure.
Turbo is fine, because hitting full boost and fuelcut with wastegate hose disconnected. I think, but you didn't test it, that with hose from compressor to wastegate you hit the baseboost you had earlier. with the hose directly connected instead via the apc solenoid it's the most accurate reading.
For now, because you still having too low baseboost it has to do with the wastegate. Get the controlarm more tight or get a new wastegate actuator.
If baseboost is 0,5bar, then you should get the full boost from the APC. if then still not enough boost, then there is something wrong with the APC system.
Oh I forgot also to mention Ecu. Some of them had their ecu modified for higher boost. Some soldering done maybe that too needs to be checked
This one is the modified APC box. The Red ones were offered in the Dealerships as part of the Performance package which also included a 2.8bar fuel pressure regulator, upping power to 185bhp. The Red box was also standard on the 900 Carlsson in Europe.
not true, hi boost is done using the RED apc ecu, there is no one burning chips for the classic 900 ,jack stall was, but no one can find him and his chips sucked..................................
Lee, just found your channel. are still working on Saabs?
I have 3, so that answer is yes. They all need something. What’s in your garage.
Do you have the same symptoms with the knock sensor disconnected?
It’s new, but that doesn’t mean its working correctly. I’ll check
I need to know now!!!!!! I've a 1999 93 aero! I feel lucky I bought her! Knew nothing of saab b4! Now I just love them! Mine did the same as yours! I put a variable valve on, now that works! But every time I change gear the revs take time (1second) to reduce! I've cleaned the Mas, replaced the throttle body, she is fully serviced and money no object maintenance! But Noone can seem to fix the problem! Anyone any ideas? I've asked a saab ' specialist' but they only work on 2000 + Vauxhall GM saabs! Not the real deal! Someone please help!
200SX in the background! I had one of those before the Saabs.
That’s my sons car. He swapped in a hotter turbo engine and it really goes. We haven’t had a run-off but he’d certainly win.
@@LeeKelso Rear wheel drive, it was a blast to drift.
So.. with the apc solenoid wiring disconected, it has no boost. With the apc physically disconnected, it has full boost. That would mean the apc valve is leaking internally, shouldn't it?
Hi Lee, just reviewing this vid because I need to check boost on both SPG and vert. SPG seems to have similar problem as yours, and vert has Boost OOC (Out Of Control, lol). Did you solve your problem?
It's better, but still not full-strength. I shortened the waste gate actuator rod as much as possible. That puts the boost needle almost to the red, but I believe it should go just a bit higher. I plan to put the gauge back on it and hit the road for a new measurement soon.
@@LeeKelso Did you ever solve the boost problem entirely? I'm working through base boost (or less, like your car) on two 900s right now.
I did notice in the video that the electrical connectors on your APC solenoid are naked and no longer insulated (crumbling on mine too). I read a Saabnet thread (www.saabnet.com/tsn/bb/900/index.html?bID=453579) where the lack of insulation was a significant part of the problem for the original poster. He said it went from 5 PSI to 8 when he added new insulated connectors. Fortunately, new insulated female ends are still made: www.esaabparts.com/saab/parts/7874498. The theory is that the solenoid is magnetic, so it's sensitive to electrical interference. I've also read elsewhere to make sure the starter-to-cap cable is routed as far from the solenoid as possible. That's easier said than done, I know.
@@cmbaker91 Thanks for the tip on the insulator. I've added a new connector and will enhance the insulation. The car is back on the road after a total engine rebuild that includes enlarged bores and forged pistons. The boost gauge now touches the red, but I'm still tuning and getting things dialed-in. I'll check boost and post an update soon.
@@LeeKelso sounds great! Also, what gauge did you use for testing? i'm trying to find a simple and cheap - but also detailed - gauge for testing only. Most gauges i see online to buy are electronic, expensive and made for mounting inside - not what i want.
masterclass
The apc valve on my 9000 didn't work either,tried everything from a new valve to rewiring. Never found the problem. I decided to delete the apc valve altogether and run the turbo on Base boost pressure, which I can now regulate by means of a pressure regulator between the turbo and the wastegate.
When the triacs in the ECU go bad the solenoid doesn't work the way it should. I tried to replace them but as I did not have a small enough soldering iron I screwed up part of the circuitry of the ECU. Only thing left to do then was to buy a good working used ECU and do an adaption run. After that all was well again.
yes that is correct good job
Your wastegate actuator basic spring load (in wastegate) is to week. Spring weekness is Often the case with the later 900 wastegates. You cant get them anymore ( aftermarket still are) Put a extra pull-spring outside the wastegate to get some basic pleasure of around 0.35 -0,4 bar or try to adjust the wastegate rod, Or modify a earlier wastegate (up on 1990 are stronger) to your td04. If you want to be sure you can put your wastegate hose directly to the pressure site of the turbo (like a LPT version). If you still have low basic pressure then you are sure. The spring generated the pre-lowed you need to get to 0.4 bar. I am 100% sure this is your problem
Yet another mention of a waste gate spring. Hmmm, I better dig deeper into this and see if this particular model has one. I've seen them on other turbos, but not on either of my 900's.
When the 900 got the mitsubishi turbo's the problem with those week springs happends. You can try to adjust the wastegate rod a bit. Basic pressure is the key word here and that comes from your wastegate spring. goo.gl/images/574MJu
I work with saab since 1986. Its my full time job since that time. At the moment i run Saabpartners.com and have a staff of 9 in the workshop. Great brand and busy times. Saab is still alive here in Holland. Keep up the good work. Cheers
Well, what do you think is holding down the boost pressure? Engine is set to 16 degrees BTC as recommended. I've checked for vacuum leaks and replaced a bad rubber charge tube coupling. There is an exhaust leak at the manifold, but I don't know how much of a factor that would be. Suggestions?
I was thinking it could be the turbo boost actuator control arm. Maybe it is heavily corroded inside or the diaphragm is split.
Also the control gate in the cast manifold has sticking points as it becomes worn on its hinges. These hinges have no lubrication due to the temperatures involved and often will hiss as exhaust gas leaks through. If you disconnect the actuator control arm and manually operate the gate you will be able to feel excessive play and rough movement.
Maybe the pressure sensor over the pedals or the APC valve or the Box.
The APC solenoid is a form of magnet. I noticed that the connectors on yours aren’t in a connector. They aren’t isolated. The magnet of the solenoid interferes with the connection.
Get some connectors that are sealed in rubber, that way you isolate them and the solonoid will work! It took me months to figure this out on my 87.
I hadn't thought of that. The solenoid clicks with application of the brakes and when you do the "blow test" it tests out fine. Since the solenoid keeps the wastegate closed until the engine pings, if it were not working I'd think the boost would be higher not lower. Make sense?
Remove the APC solenoid and install a grainger valve.....done
You've got a parts car there, swap out the APC Solenoid.
I thought of that but will do some testing to isolate the problem first.
Well he doesn't even have base boost yet, so not apc valve related. Those old ones never fail. You can squirt Carb Cleaner through the ports of the APC valve until it runs clear, to remove any gunk.
@@LeeKelso Absolutely, but I haven't started my latest project which will be a 900 conversion to a turbo. When that gets rolling, it will be a good segment.
do you know how to install msd 6200 on a saab 900 turbo 16v year 1990
I don't think that's going to be a direct fit as you'll probably need to create some way to tell it the position of the crankshaft. There's lots of expertise available in the Facebook Classic 900 group. One of those guys will probably have a solid answer for you.
@@LeeKelso thanck you
Will pushing the brakes and throttle at the same time damage the brakes?
It certainly could overheat and warp the rotors, so keep the test brief. It takes less than a minute to get things to settle down and give you a solid reading.
people it's not the apc , the apc is somthing that seldom breaks, it not the APC
Did you ever find out the cause?
Not before tearing the engine part for a total rebuild after a head gasket failure. After that process I found that adjusting the waste gate rod to keep the system closed and holding pressure helped. I'm now boosting just across the red line on the gauge. Here's something interesting: The CE has a special "red box" APC controller that supposedly boosts power by something like 10HP. I found a tweaked APC controller from Swedish Dynamics boosts it even more into the red than the "red box".
@@LeeKelso Yes you have the Red Box APC which was set from the factory at 0.85 Bar boost. (12.5 psi). But you will only get that on high octane fuel, such as Shell V-Power. Base Boost with the APC unplugged should be 0.45 bar ( 6psi). Base boost must be set correctly, before plugging the APC valve back. As always with the B202, its critical the ignition timing is set correctly. 16 degrees BTDC at 900 rpm with the Distributor Vac hose removed. They need setting about once every 2 years as the chain stretches, then the ignition timing drifts out.
you know we charge for finding the problem, so this one is free, un bolt the exhaust the down pipe, dont loose all the way, but a leak is what you want ,try it if boost is better remove the cat, you dont need it anyway if its under 1995...................................... it's the cat i think