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Car Forum / Saab Cars / August 2006Last Chance for My '85 900
I've owned a 1985 900 (8V, non-turbo) for five years. For awhile I've had trouble with it searching (changing RPMs) at idle. I also had a leaky cold-start valve which was flooding the motor and preventing it from starting. I disconnected the wiring and that helped, but it still seemed to be leaking oil so I removed the fuel line from it. I don't know if the problem I have now is related and, if so, how. It runs rough and lacks power. It idles at about 500 RPM. When driving it has a jittery feeling like I up-shifted at too low a speed (even though I didn't). It is slow coming up to speed and I have a tough time getting over 45 MPH. What's odd is that, when the car hasn't been run and I first start it, it runs wonderfully for about 45 seconds or 2 miles before the problems start. It idles at ~750 MPH and runs well but not for long. Another thing is, with the car out of gear and the motor red-lined,it puts just a little bit of black smoke out of the tailpipe. But, about every 5 seconds, it burps a bigger cloud of black smoke. Here's what I've done: * Checked injectors (ionization is acceptable on all four) * Replaced plug wires with OEM (they were showing a bit of blue spark at ngiht) * Replaced plugs with OEM * Replaced distributor cap & rotor with OEM * Replaced fuel filter (routine maintenance) * Replaced injector seals (after checking ionization) * Replaced oxygen sensor (routine maintenance) I checked compression and it is a low on #3. Readings are: #1 -- 130 #2 -- 120 #3 -- 90 #4 -- 135 I can understand there might be a bit of sumble because of this but I don't think all the problems I'm having are related. Especially since it runs fine for a little on first being fired up. I'm ready to sell but I don't want to unless I absolutely can't get this figured out and fixed. -- Christian > I've owned a 1985 900 (8V, non-turbo) for five years. For awhile I've > had trouble with it searching (changing RPMs) at idle. I also had a [quoted text clipped - 31 lines] > #3 -- 90 > #4 -- 135 Hi How have you tested? Removed all plugs, take out fuel fuse crank engine? If yes, please try once more ... and add a little engine oil through each plug hole (Don't know though what happens if you have a catalyst and oil goes down the exhaust pipe). The added oil should show you if you have worn out rings/cylinders. If compression goes up then they are worn ... Hope I am wrong! Do you loose coolant? If yes, compare also the plug on No. 3 with the others. Heads of that era, (definitely on an 1982/83 car ... crack on cylinder No.3. The crack is not repairable. This would explain why the engine does not work once it has warmed up ... > I can understand there might be a bit of sumble because of this but I > don't think all the problems I'm having are related. Especially since [quoted text clipped - 4 lines] > > -- Christian If it helps at all. Regards Charles  SignaturePlease remove _removeme_ to reply. >How have you tested? > [quoted text clipped - 6 lines] >The added oil should show you if you have worn out rings/cylinders. If >compression goes up then they are worn ... The compression does come up slightly on three. I didn't test the other ones since they weren't critically low. >Hope I am wrong! Do you loose coolant? If yes, compare also the plug >on No. 3 with the others. Heads of that era, (definitely on an 1982/83 >car ... crack on cylinder No.3. The crack is not repairable. This >would explain why the engine does not work once it has warmed up ... I lose only a tiny bit of coolant. There's no white "smoke" coming out of the exhaust and no sign of water in the oil. >If it helps at all. Thanks, Charles. -- Christian >> How have you tested? >> [quoted text clipped - 9 lines] > The compression does come up slightly on three. I didn't test the > other ones since they weren't critically low. OK looking for cheap solutions. Take the rocker (head) cover off and check valve clearances. If it is the same head as I am thinking of ... there are metal shims which are used to adjust the gap (they can be ground down to the correct size etc)... If the gap is too small the valves would stay open too long, hence low compression. Alternative is to have the head off and look at the condition of the valve seats. When I had a cracked had ... I think the compression I got was less than the 90 you got but it is a long time ago to remember ... basically the car run on three cylinders. Look for other problems if you can ;-) >> Hope I am wrong! Do you loose coolant? If yes, compare also the plug >> on No. 3 with the others. Heads of that era, (definitely on an 1982/83 [quoted text clipped - 9 lines] > > -- Christian SignaturePlease remove _removeme_ to reply. Sounds like you need a warm up valve and an auxiliary air valve. Check the wiring to them and remove the aux air valve, place in freezer and see if it opens up. >Sounds like you need a warm up valve and an auxiliary air valve. Check >the wiring to them and remove the aux air valve, place in freezer and >see if it opens up. I haven't had a warm-up valve for quite some time (wires were disconnected) but I didn't have problems until I disconnected the fuel from i tdue to leaking. What does the auxiliary air valve do? -- Christian You need to buy a book on Bosch fuel injector system. I own an 85 900S. It has over 250000 miles and still runs perfect. I do all tune ups myself. It is very important that there be no vacuum leaks anywhere in the system. For instance if I fail to replace the oil filler cap correctly it will allow excess air into the system and make the engine run rough. Go over all the hoses carefully and make certain that they all seal, especially the large hose from the cam box to the intake plenum. You must plug any holes in intake air system if they are not connected to some other device. The aux air is normally open and allow excess air into the intake to make the engine idle fast until it warms up. The temp sensor electrical resistance decreases with increasing coolant temperature and makes the aux air close down, thereby slowing the idle. You need to get the warm up valve working also. >You need to buy a book on Bosch fuel injector system. I own an 85 >900S. It has over 250000 miles and still runs perfect. This is what I hear of Saabs. So, I hate to let mine go at only 167K. > I do all tune >ups myself. It is very important that there be no vacuum leaks [quoted text clipped - 4 lines] >intake plenum. You must plug any holes in intake air system if they >are not connected to some other device. I've gone over the vacuum lines several times. I found no leaks. There was a section that looked like it was close to cracking so I went ahead and replaced it. >The aux air is normally open and allow excess air into the intake to >make the engine idle fast until it warms up. The temp sensor >electrical resistance decreases with increasing coolant temperature and >makes the aux air close down, thereby slowing the idle. If this were the problem, wouldn't it run poorly until warmed up? Mine runs well for the first 45 seconds (or so) and then goes quickly downhill. >You need to get the warm up valve working also. I've had the elecrical portion of this disconnected for months and the car ran like a champ. I live in NM, USA, so winters are very mild. It doesn't make sense to me, but is there any way that removing its fuel line might have caused a problem? -- Christian >Sounds like you need a warm up valve and an auxiliary air valve. Check >the wiring to them and remove the aux air valve, place in freezer and >see if it opens up. It's easy to check the operation of these components - use the methods described in the Bentley manual. In my 1985 900i there is a break in the +12 v wire coming from the fuse/relay panel going to the warm-up reg and auxilliary air valve resulting in the at-start idle speed being really low (around 500 rpm), but as soon as the engine starts to warm up the idle speed comes up to the standard 850 to 900 rpm. One of my future repairs is to fix that broken wire. Apparently the 1985 cars are particularly prone to failed wiring which is something to do with the manufacturing of the wiring harnesses by a contract supplier to Saab. I'm not sure if it's a quality-control thing or simply using sub-standard wire. Regards, Craig. SignatureCraig's Saab C900 Page at | Craig's Classic Saab Workshop - Sydney .au http://lios.apana.org.au/~c900 | http://www.classicsaab.net and other URL's Email: c900@lios.apana.org.au | For Saab 99/C900/9000 Enthusiasts World-Wide! Alternate: saabonaut@gmail.com | Web-forums, galleries, library, links, etc. >It's easy to check the operation of these components - use the methods >described in the Bentley manual. In my 1985 900i there is a break in the +12 [quoted text clipped - 4 lines] > >One of my future repairs is to fix that broken wire. How important is the cold-start injector? Does it have to be hooked up (wires & fuel line) for the car to run well? I live in a warm climate and don't have trouble w/ winter starts? >Apparently the 1985 cars are particularly prone to failed wiring which is >something to do with the manufacturing of the wiring harnesses by a contract >supplier to Saab. I'm not sure if it's a quality-control thing or simply >using sub-standard wire. The wires in the '85 are terrible. The insulation seems to be made out of a substance about as durable as gelatin. -- Christian >>It's easy to check the operation of these components - use the methods >>described in the Bentley manual. In my 1985 900i there is a break in the +12 [quoted text clipped - 4 lines] >> >>One of my future repairs is to fix that broken wire. >How important is the cold-start injector? Does it have to be hooked up >(wires & fuel line) for the car to run well? I live in a warm climate >and don't have trouble w/ winter starts? Well you don't have to use it - all it does is inject pulses of fuel vapour to make starting easier and after about 10 seconds it shuts off when the thermo-time switch's bi-metallic strips heats up. So if the cold-start injector isn't working it just makes the engine harder to start when it's not already warmed up. My white 900S has the thermo-time switch disconnected as it's got some sort of a wierd semi-short which holds the starter auxilliary relay engaged after letting go of the ignition key. I only had one spare brand-new thermo-time switch and that's already been used up on the turbo car I'm restoring so I need to get another one. 8-) >>Apparently the 1985 cars are particularly prone to failed wiring which is >>something to do with the manufacturing of the wiring harnesses by a contract >>supplier to Saab. I'm not sure if it's a quality-control thing or simply >>using sub-standard wire. >The wires in the '85 are terrible. The insulation seems to be made out >of a substance about as durable as gelatin. Yeah well I've only got one significant wiring faults in my 85 900i and that's with the +12 volt line to the warm-up reg and auxilliary air valve. So that engine runs really slow after starting but is fine after warming up. The wires to the AC high-temp cutout switch are also really bad - almost bare copper at the ends that join to the the female spade lugs which plug onto the thermo-switch itself. 8-) But that'll be simple to fix when I get some auto-rated wire of the right gauge, or just 'borrow' some out of the wiring harness in the 83 GLi that's my current 'donor' car. Craig. SignatureCraig's Saab C900 Page at | Craig's Classic Saab Workshop - Sydney .au http://lios.apana.org.au/~c900 | http://www.classicsaab.net and other URL's Email: c900@lios.apana.org.au | For Saab 99/C900/9000 Enthusiasts World-Wide! Alternate: saabonaut@gmail.com | Web-forums, galleries, library, links, etc. >Yeah well I've only got one significant wiring faults in my 85 900i and >that's with the +12 volt line to the warm-up reg and auxilliary air valve. [quoted text clipped - 4 lines] >some auto-rated wire of the right gauge, or just 'borrow' some out of the >wiring harness in the 83 GLi that's my current 'donor' car. I've wondered if some of the problems I'm having are due to a wiring fault. I have one harness where every wire was bare copper. I taped the individual wires as best I could to prevent shorting but that didn't seem to help. Not too sure how I would track something like that down unfortunately. -- Christian >>Yeah well I've only got one significant wiring faults in my 85 900i and >>that's with the +12 volt line to the warm-up reg and auxilliary air valve. [quoted text clipped - 4 lines] >>some auto-rated wire of the right gauge, or just 'borrow' some out of the >>wiring harness in the 83 GLi that's my current 'donor' car. >I've wondered if some of the problems I'm having are due to a wiring >fault. I have one harness where every wire was bare copper. I taped >the individual wires as best I could to prevent shorting but that >didn't seem to help. >Not too sure how I would track something like that down unfortunately. Best way is to use a schematic diagram of the wiring, and where you have suspect wires, work out where each wire connects to something, or joins into a connector, and do continuity checks, etc. That's how I worked out the wiring issue with the 85 900i. It can be very tedious if you're tracing a lot of wires, but in general, all the wiring in the engine bay is going to degrade much faster than elsewhere, but if your car doesn't have an exhaust shield under the floor the wiring running down the centre can also cook (and in one recent case I saw on a forum site, short and start a fire!). Also keep an eye on the rear light cluster wiring as that's a common place for water to get into the electrics. Craig. SignatureCraig's Saab C900 Page at | Craig's Classic Saab Workshop - Sydney .au http://lios.apana.org.au/~c900 | http://www.classicsaab.net and other URL's Email: c900@lios.apana.org.au | For Saab 99/C900/9000 Enthusiasts World-Wide! Alternate: saabonaut@gmail.com | Web-forums, galleries, library, links, etc. >Best way is to use a schematic diagram of the wiring, and where you have >suspect wires, work out where each wire connects to something, or joins into [quoted text clipped - 9 lines] >Also keep an eye on the rear light cluster wiring as that's a common place >for water to get into the electrics. Thanks, Craig. I'll take a look and see what I can track down. -- Christian keep us posted on your saab. as another 1985 saab owner i am hoping for a happy outcome. rod > I've owned a 1985 900 (8V, non-turbo) for five years. For awhile I've > had trouble with it searching (changing RPMs) at idle. I also had a [quoted text clipped - 40 lines] > > -- Christian >keep us posted on your saab. as another 1985 saab owner i am hoping for a >happy outcome. >rod Thanks, Rod. I do not want to let this car go. I'll keep everyone updated. -- Christian Get a copy of: How to Tune and Modify Bosch Fuel Injection by Ben Wilson ISBN 0-87938-570-7 published 1992. Barnes and Noble will order you a copy. Or try Amazon.com Regarding your questions: The carburation on this car is extremely complicated. You need to understand it completely to make the car run well. It might be simpliar for you to take the car to a Saab dealer and make them tune it up. >Regarding your questions: The carburation on this car is extremely >complicated. You need to understand it completely to make the car run >well. It might be simpliar for you to take the car to a Saab dealer >and make them tune it up. Unfortunately, I don't want to invest much more money into this vehicle and dealership garages aen't exactly cheap. The second problem is, the nearest dealerships are in Albuquerque & Santa Fe (180 miles each) so I'd have to haul the car. -- Christian
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