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Help? 1983 8v - sputtering and running like poop!

5K views 50 replies 8 participants last post by  saabsbreakdown 
#1 ·
Well, I picked up a 1983 c900 8V non-turbo just yesterday. The car had been running very rough for the previous owner, yet when I went to pick it up it ran great! He stated that prior to parking the car sometime last december it was running as though on 2-3 cylinders and when he would give it a little throttle it would sputter and not build any revs.

Well, I was a little optimistic because the problem seemed to be intermitent. I replaced some vacuum lines and check some things over and it was still running well - until I stated it up to drive it into the garage...

The car starts OK, and it idles OK, but when you press the accelerator it sputters and will NOT build revs! If you give the accelerator a sharp, quick press it will rev a tiny bit until it sputters. The most I could coax out of the car was 2k RPMs.

The timing is at 14 btdc, the plugs are new, the wires are new (and high quality), and the gas tank is 1/4 full. The problem is that I know NOTHING about CIS. Anyone with some tips or experiences like this please speak up!
 
#3 ·
Well Mr Lawyer ;-) you certainly know more about CIS than I do!

I'll check the fuel filter, but it was one of the few clean bits in the engine bay, so my guess it that it is relatively new (but I guess that doesn't necessarily mean that it isn't clogged).
 
#4 ·
You said that the gas tank is 1/4 full, but I saw where the previous owner said in another post that the gas was circa 2005. Have you ran all of the old gas out and refilled with some fresh 93? I'd also HIGHLY recommend the Redline Fuel System cleaner that you can buy at any AutoZone for ~$7. That stuff works wonders on old, dirty fuel systems.
 
#6 ·
I will pull the pump and have a look in the tank. And as far as the gas in the tank goes...maybe I will take the time to syphon the old stuff out at that point and put some newer gas in there.

I know that the gas itself is not the problem however. The car was running just splendidly on the old gas last night. It probably is not helping the situation out...but it certainly is not the root of the issue at hand.
 
#7 ·
ugh... same shit I have gone through with my '88 8V.... I think it's CIS... I don't know what the problem is. I never got around to really digging into it. The car isn't at my house and is about 20 minutes from my house, so kind of a wasted trip.
 
#12 ·
err...have you been able to get it over 2k rpm...it would spin all day at 3500+ when I was having those problems.

And uh...I feel less bad about giving the car away now...sorry man, I was hoping it was just me.

I swear it was ignition related...everytime I changed something (plugs, wires, dist cap) it would run fine again. Probably just trying to make me superstitious, or maybe it liked the attention.

I decided it was either a loose wire somewhere, or a wonky distributor...but you can see how far I got with it.

When I had the crappy cheapo plug wires on it and it ran like that, you could see it arcing from the plug wires to the metal valve thing in the radiator hose (horrible design IMO). So maybe pull the disrto cap and check for signs of arcing?
 
#13 ·
Dizzy cap looked good when I pulled it yesterday. And by the end of the day it was running fine again.

I did find a deteriorated rubber hose in the gas tank connecting a return feed line to the gas pump...not sure if that would cause anything or not, but I replaced it anyway.

Also, would it have these problems when the gas tank was full? I know I keep straying away from the ignition stuff, but I want to make sure it is not something minor that it having a big effect.

I plan to test the injector flow, as well as look through my spare parts and see if I have ignition components that would fit, and then swap those out.
 
#17 ·
you should only have the igniton safety relay i have no idea what palmer is talking about, or its just something thats always been there and i always ignored :)

after pulling the pump i would unhook everything. Anything with electrical connector to it unhook it except for the warm up regulator (bolted to thermostat). also you can feel free to bypass anything that has vacuum going to it for testing purposes because none if it is required.

Sounds to me like its running too lean. Usually if the warm up regulator is defective it will run too rich. If its too lean, you can snap the throttle plate open with your hand and the engine will cut out immediately, then eventually come back to life and rev up. If you make it super rich it will have immediate response.

Also pull out the injectors (book says to shoot them in a 'suitable container' but i just let them spray all over everything.. its a small ammount of fuel), jump the fuel pump, take off the rubber bellows, and pull up on the metering plate (or the bolt in the middle). you might have to get a magnet on the bolt to do this.

If you encounter any resistance from the plate when the pump is on this indicates a sticky piston in the fuel distributor. Be careful and take it slow.. as you pull up, then go down and back up, the resistance should be the same. If you pull up and force the piston up and then its easy to move again, your fuel will get stuck at a WOT situation with no air. Just be sensitive to whats going on in the system. I'll attach a diagram in a minute
 
#18 ·
Well, I picked up a 1983 c900 8V non-turbo just yesterday. The car had been running very rough for the previous owner, yet when I went to pick it up it ran great! He stated that prior to parking the car sometime last december it was running as though on 2-3 cylinders and when he would give it a little throttle it would sputter and not build any revs.

Well, I was a little optimistic because the problem seemed to be intermitent. I replaced some vacuum lines and check some things over and it was still running well - until I stated it up to drive it into the garage...

The car starts OK, and it idles OK, but when you press the accelerator it sputters and will NOT build revs! If you give the accelerator a sharp, quick press it will rev a tiny bit until it sputters. The most I could coax out of the car was 2k RPMs.
Ok all of my C900's are 8V's with CIS (and none with APC). First thing is to make sure you've got good fuel in the tank - 8V's should run on 97+ fuel (any of the 98 octane fuels providing they have no significant ethanol content are ok). Run a good injector (or generic fuel system) cleaner through the fuel system next time you fill the tank.

It might seem obvious, but check all of the ignition leads to make sure they join to the plugs and the distributor cap properly, and associated wiring to the rest of the ignition parts. If you have thoroughly checked all the vacuum lines (especially the ports on the intake manifold - the rubber bits shrink and get hard/brittle with age), check all the electrical connections to the warm-up reg, etc. though they'll all be having no effect after the engine is warmed up.

If you think the fuel filter is ok, leave it alone, but see if you can find out from the last owner if/when it was changed. What is the coolant and the engine oil like? Do they look contaminated (which might indicate problems in the cylinder head)?

An easy way to check the basic CIS system function is to remove the fuel-pump relay, and using a fused switch connected between pins 30 and 87 of the fuel pump relay socket, remove each pair of injectors (or both pairs if you have a big enough pan/dish) by undoing the big bolt between each pair, place them carefully in a pan taking care with the plastic fuel lines, and when they're in a pan, remove the air snorkel to get access to the airflow sensor plate and lift it gently with pliers while you have the fuel pump manual switch turned on.

You should get an even spray pattern of fuel from each of the injectors. While they're out, look at the rubber injector seals as they will also dry out, shrink a bit and tend to break down over time.

If you get an uneven spray pattern the injector affected might be blocked, or the fuel distributor might not be working properly (though it's usually going to be a blocked injector if that occurs). That's why you should first of all try a good injector cleaner additive and do more tests later on.

Be really careful when you do the injector spray test - don't do it with the engine warm or hot to reduce the risk of fire, and make sure you do it with the car outdoors or in a very well ventilated building.

You can do pressure tests on CIS (the Bentley book is very good with the descriptions) but you need a special test kit which connects into the line running between the warm-up regulator and the fuel distributor to measure the various pressures.

There's no reason why you can't take the fuel pump out of the tank to check that the rubber part of the fuel pickup hasn't turned to goop, but undoing the clamp holding the pump assembly in the tank needs very careful use of a long straight screwdriver or a special screwdriver tool with a movable head.

Another thing you can do is start the engine and just try fiddling with the throttle valve to see what it does to the engine. That way you can stand next to the engine and check out it's behaviour.

BTW, when you have the snorkel off the air box, have a look inside the throttle valve and make sure it's clean. If you can, get the car to a good mechanic who knows about CIS (preferably a Saab person) if you're not able to figure out what the problem is.

Good luck!

Craig.
 
#20 · (Edited)
Well, I've had the pump out of the tank - it is the newer style pump (looks much like the pump from my last 1988 900T 16V) and it had one small section of rotted hose, so I replaced it.

And I had also checked the ignition leads. All seemed good there - new cap, new rotor, new wires....what could be wrong?

Wel...I found one seemingly MAJOR problem (although it should be an easy fix).

Since everyone at saabcentral.com was harping on my about this being an ignition related problem I started checking wires and connections again.

What I ended up finding was when the car is running the distributor cap shakes and vibrates like a woman's play toy! The damn rotor shaft inside the distributor must be bent!!! This would explain why I would smell gas, and when revving the motor it seemed to almost "blow out" the spark. I can't imagine that the car would be firing evenly with a distributor rotor that is spinning out of round.

I'll see if I can pick up another 8v distributor and see if that helps this situation.

The other thing I noticed is that the car could idle down OK with the cap flopping all over, but when I gave it a rev it seemed to vibrate too much to be making contact with the rotor inside the cap...so that would explain the sporaticness of this problem.

I'll try to find a replacement and report back when I do.
 
#21 ·
Since everyone at saabcentral.com was harping on my about this being an ignition related problem I started checking wires and connections again.

What I ended up finding was when the car is running the distributor cap shakes and vibrates like a woman's play toy! The damn rotor shaft inside the distributor must be bent!!!
Well put!

Did you pull it off?
 
#23 ·
Update

:roll:

I got the car registered and drove to the gas station to fill 'er up with good gas.

So, there 1/2 tank of new, good gas in the car. I took the car out to beat it around a little bit to see how well it ran. It was running great!

I tooled around for about 20-25 minutes and everything was great, I brought the car back home and shut it off in the driveway. I opened up the garage door to drive the car back inside and fired the car back up. It started right away, however by the way it idled it was obvious that all was not good!

The problem is certain not solved! I do, however, have a bit of insight into the issue.

The frequency valve (the little buzzy thing with fuel lines going into it on the frame rail near the fuel distribution block) was not buzzing as it does when the car is running correctly.

I've noticed that when unplugging the frequency valce when the car is running well makes the car run like crap. I messed with it before on the advice of Quinn, however I just plugged it back in and didn't give it a second thought. Now I am beginning to think that it isn't working correctly, since it seems to run the same when unplugged as when the car is "acting up"

Anyone have any insight to what the frequency valve does?
 
#25 ·
I'll give it a try...the odd thing is that the valve no longer seems to be working at all when it's plugged in! :shock:

Someone on SAABcentral said that it may be because the readig from the O2 sensor is sensing that the car is too lean or too rich and the lambda/frequency valve is then cut out of the loop...this seams like a reasonable idea. I guess giving that a try is my next best bet.

Another thing, when I snap the throttle plate open it does like you say, and cuts out, and I can hear air meter plate slamming open and closed...it's probably normal, but who knows....not me :lol:

Also, might a gunked up fuel distributor cause intermittent shit like this? If the mixture adjustment fails I may take the dist out and see if its gunked up.
 
#27 ·
... righty richy!
and that covers my next question.

Lean might make sense now that I think about it. Reason being, when the car is cold it generally runs fine, it has only ran like shit after being sufficiently warmed up...and in that case the cold start valve would be applying extra fuel right? When the cold start valve is taken out of the equasion it would run less right...if I'm thinking correctly (which might not be the case).
 
#30 ·
So, as usual, after running craptasticly yesterday I was able to start the car this morning with NO problems. So I went about pulling plugs on sensors to see if I could replicate the problem - success!!!

I have found that the problem is replicated EXACTLY with the O2 sensor and the lambda/frequency valve unplugged. With each one unplugged individually the car runs a little rough, but with both unplugged the symptoms that I have been getting are duplicated.

So, my question now, it what would cause both of those to, in essence, fail at the same time when the vehicle is warmed up? I know all fuses in the car are just fine, could it be the ECU acting up on occasion (seeing as this is not constant)? Relay somewhere?

???

PS - I've looked through my Hayes manual and they describe the system, but do not elaborate how to troubleshoot it. They also describe a relay for the system, I might suspect this to be a potential faul, however I have not seen the relay...I'll try to sniff it out.
 
#31 ·
So, as usual, after running craptasticly yesterday I was able to start the car this morning with NO problems. So I went about pulling plugs on sensors to see if I could replicate the problem - success!!!

I have found that the problem is replicated EXACTLY with the O2 sensor and the lambda/frequency valve unplugged. With each one unplugged individually the car runs a little rough, but with both unplugged the symptoms that I have been getting are duplicated.

So, my question now, it what would cause both of those to, in essence, fail at the same time when the vehicle is warmed up? I know all fuses in the car are just fine, could it be the ECU acting up on occasion (seeing as this is not constant)? Relay somewhere?
Loose connection at the ECU? Do those two sensors share a wiring harness or connector somewhere?
 
#32 ·
The lambda system is pretty isolated...it involves the O2 sensor, the frequ. valve, the ECU, and throttle swtich.

So I'm happy that I have the system isolated, and i still think the mixture might need tweaking.

I will pick up a new O2 sensor from Chris Luek and maybe borrow a 8v bently manual.
 
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