[Snyper]

I just bought a Saab 900 from a friend who didn't maintain it well. Right now the problem is that it won't start. A buddy and me got it working right after I bought it, but I didn't notice the gas gauge was broken and ran it dry. Then I flooded the engine (after running all of the junk crap from the bottom of the tank through it as I was running it dry). So compound problem: junk in the tubes/engine and flooding.
I'm pretty sure I got the junk out by removing the plugs and turning it over for 20-30 secs. Did this a few times, both with the pump relay in and out, so the junk should be out of the engine and out of the lines. Last things I put in the tank were ~ 2gals premium and 2 bottles of dry gas. I've had it come close to holding a start a few times now, but like this guy (http://www.saabcentral.com/forums/showthread.php?t=25606&highlight=flood+engine) it just didn't want to stay lit.
Currently the plugs are out and sitting on my desk, and the battery was getting a trickle charge.
Next on my list of stuff to do:
Try to start it normally (I predict it will flood, as this is what has happened each time. It turns over, gets compression, and starts to spark, then tries to get up to idle and dies - this has happened around 5 or 6 times now.)
My buddy suggested disconnecting the "5th injector." apparently this was disconnected when we got the car, I remember a plug being disconnected but I don't remember which one it was. I know I should get a haynes book, but right now the funds aren't there (everything's going towards getting the car running) - are there diagrams or illustrations available online?
From the post linked above, after that I'll be trying:
The ignition module (is it properly connected)
Firing order (looks right to me - I already checked - but to make sure, what tool do I use? [i.e. looking at the cables it all looks correct, and I don't think they've been switched since it started correctly last time.])
Cold Start injector/valve (no clue how to check this)

Lastly, a clue to all of this perhaps: the girl I bought it from said anytime you pushed on the throttle too much it flooded. Any ideas what might be causing this?
Thanks for any help.

 

[cdaly]

First thing to do is to change the fuel filter. It's under the car, just forward of the tank.
Is this an 8-valve or 16-valve? I'm not aware of a fifth injector on the 16-valve engine. AFAIK there's an 'NTC' sensor on the head just below the inlet manifold. See this post for location http://www.saabcentral.com/forums/showpost.php?p=448386&postcount=9

 

[Snyper]

Is this an 8-valve or 16-valve? I'm not aware of a fifth injector on the 16-valve engine. AFAIK there's an 'NTC' sensor on the head just below the inlet manifold. See this post for location http://www.saabcentral.com/forums/showpost.php?p=448386&postcount=9

Fairly sure it's 8 valve, just got up from the parking lot - disconnected the electrical connector I was talking about and it started right up with a healthy roar, but then died shortly thereafter. i've left the plugs out for about a day or a bit more now, and the battery is also charged.

cdaly, I looked at the link, and sure enough it is the NTC sensor. I found a few places to check the resistance on it and will post the resistance I get, but the sites I found w/ recommended resistances have all resistance with cold and warm engines. I can't get it to run, so should it be the "cold engine" resistance?

Snype

 

[cdaly]

Yep. Cold resistance should be higher than warm resistance.

 

[Snyper]

so yeah, I got a resistance of zero Ohms. I think the NTC sensor is busticated. I'm gonna throw a 2200 Ohm resistor in the connector and see if it starts again - oh and also,

I got it to start! it won't hold idle, it dies after a while, the fuel pump keeps going. The guy at Advance Auto Parts said to listen for it, and sure enough, the pump keeps running even after the priming period.

So I think if I have the circuit right in my mind, the NTC sensor would control the fuel pump and tell it how much to add, but maybe not. Am I correct in this?

If so, putting this resistor in will let me make it to Hess and fill up, then back to the proper parking lot the thing should be in, and work on it more there.

Does anybody know if the Fuel pump running problem could be solved by replacing the NTC sensor?

Ah one last thing, will the fact that my "cold resistance" is the same as my "warm resistance" be a problem? I'm not going to drive it for more than 1 mile, so unless the fan or some cooling system or oil is affected by this NTC, then I don't think it will be a problem for these few drives til I can replace the NTC.

 

[eggsngrits]

Here's the electrical diagrams for the 1987 900. May be for the 16 valve, so check your car. Valve cover on a 16-valve says '16-valve' and is almost the width of the engine.

http://saabpics.org:3000/gallery/album176

 

[cdaly]

The fuel injection is significantly different between 8 and 16 valve. The 8V uses a mechanical system and individual pipes running to the injectors, the 16V uses an electrical system with a common rail fuel supply and electrical connectors on the injectors.

In the 16V, the fuel pressure is regulated by the fuel pressure regulator {FPR} located at one end of the injector rail. The amount of fuel injected is controlled by the time for which an injector is open. The NTC sensor tells the ECU how warm the engine is and the ECU adjusts the amount of fuel being injected. If the resistance is zero {the NTC is shorted}, the ECU should assume a hot engine and only send enough fuel for that. It might not run properly {or at all} until warm. Adding the 2k resistor should put it into cold-enrichment mode which should allow you to start and warm up. Plugging the sensor back in at that point should put it back in warm running mode...

The fuel pump should only run in response to the engine turning. The NTC sensor shouldn't affect it.

 

[drcoopster]

I'm the buddy mentioned in Snyper's first message.

The car is an 8v (with the mechanical fuel injection) and the fuel pump runs any time the ignition is on. I guess the question right now is is this the correct behavior? Also, Steve (Snyper), have you tried starting it with the CSI unplugged?

 

[Zelandeth]

For the 8v, pump should run when the ignition's on, to prime the system, then it should shut down until the engine's started. So if your pump's running all the time, you've got a problem.

Try taking the air intake hose off (at the airbox end) and seeing if the airflow flap's stuck open, as the engine would think it was getting a lot of air, hence would pump a heap of fuel in. THe flap in mine was sticky when I got it and it caused all kinda wierd behaviour, flooding included as I recall.

 

[Snyper]

Thanks Zelandeth, yes the pump continues to run even after the priming cycle. I'll check the air flap when I get back from a trip.
Thanks!
-Snyper

 

[Snyper]

A little better, but still not running continuously

after just looseing a nice detailed post I'll make this short:

I don't know exactly where to find the air intake that Zelandeth posted about. Can someone please help me out with this?

This image can be used to diagram what I did / found.
Under the orange arrow hose I found another hose which was loose. I reconnected it and the whole thing started much better, but still cut out after a 20-30 seconds. The longest it ran was about 1 minute.
While I had the orange arrow hose off (if someone knows the names of these hoses it'd be great), I found another hose diagramed it green and the direction of shown in blue, connected to the orange-arrow hose at the sensor circled in red. I drew how the hose looked in green. This hose isn't connected to anything, I'm wondering if it might be from the air conditioning unit. As you can see there is none any more. (the hose connected to nothing is similar in size and texture to the one outlined in yellow.)

A family friend who used to be a mechanic said the relay might be burned open. Anyone know how to test this, or should I just get a new one.

I'm assuming the fuel pump is still running too long, but I'm not sure since I was working alone today

In the top of that image on the right is a vent. I'm wondering what it was for, if it too was for the AC

I don't think the NTC sensor is bad, I got a resistance reading off of it today, but the multimeter fell off the car before I could see what exactly it was.

The car still floods after running for a bit (~30 secs), suggestions of what to do next?

-Snyper

 

[Snyper]

relay search

The part number for a fuel pump relay is 95 50 948. Is my best bet a junk yard, cause the dealership I called had to spec. order one from the warehouse.

 

[REDTURBO84]

Hi, I would pick up a spare ignition module first and try that.Sounds like it may be failing or test it at a parts store but don't install anything that don't say Bosch.Also check for vaccum leaks between the Air box to intake including the gromets in the intake. If it starts the fuel pump relay is fine.Do a voltage test at the fuel pump and cleen the plugs also. Pat

 

[Snyper]

Hi, I would pick up a spare ignition module first and try that.Sounds like it may be failing or test it at a parts store but don't install anything that don't say Bosch.Also check for vaccum leaks between the Air box to intake including the gromets in the intake. If it starts the fuel pump relay is fine.Do a voltage test at the fuel pump and cleen the plugs also. Pat

It starts, but doesn't stay running, so I'm guessing the ign. mod. is still okay.
How do I pull the sucker out to test at parts store?

Would air leaks cause it to die, or just run not well - doesn't seem like they would cause it to die to me.

Plugs are clean

where's the best place to get to the pump to test voltage?

-Snyper

 

[REDTURBO84]

A ignition module (amplifier )starts the car on 12 volt+ then shuts down to 7-8 volt . Swaping for a known good parts is a easiest test.A common failure is loosing spark on the run cycle.(not start cycle )Bentley shows some pin test.A bad coil also will do this but usually it runs much longer .(till its almost hot)Check the wires are clean and terminals to the wires are not rotted off. Air leaks on a 8 valve will also cause a rich flooding as you discribe .A air leak causes the airflow sensor (they stick sometimes along with the fuel distributor,can be cleaned also) )readings to be out of range. I have left off a small hose before(accidently changing oil)and it floods out like you discribe also.I test the fuel pump voltage at the terminals,(plugs) thats the plugs I meant.It's gotta be something simple!Good Luck,Pat

 

[Snyper]

Pat, see this picture - I think the air intake hose is the one pointed at in orange. At the sensor on that hose (oxygen sensor? - in red) is another hose extending downward (illustrated in green). It's not connected to anything. I'm buying shop manual, but until it gets here, what should that hose be connected to? AC? Cause there used to be one in this car but there isn't anymore.
Thanks, -Snype

 

[Zelandeth]

Finding the air metering flap.

Simple enough. Find the air cleaner housing. The flap's on top of the cleaner housing (and the fuel distrubutor), underneath that big rubber air intake pipe. Undo the big hose clip and pull it off (a lot easier if you take the end on the throttle housing off too - then you can clean the throttle valve when you're at it, as that's always a good idea).

Be aware that the afforementioned pipe is a pain to get back on again! There's a groove on the fuel distributor housing which a ridge on the hose fits on to. Once you get it on you're fine, but it does take a bit of fighting with the first time.

Ignore the ??? that's from another post I used this image for.

Air metering flap's under that really big hose in the middle of the image.

 

[REDTURBO84]

The green hose may be the breather from the valve cover that goes onto the air filter box .The red part is not on my 84 car so I have no idea. All the ac hoses should be on the other side. By the way the clamp on the intake appears to not seal. Pat

 

[Snyper]

I took a close up of that mystery hose today: (it's the one hanging off of the Bosch plug going into the air intake hose)

manual's on its way, hopefully it will be in there, but if not, any ideas?

and Pat, I took that picture before I had put the clamp back on

 

[REDTURBO84]

Hi, The thing you called a oxygen sensor is the "decel solenoid" .Its in my Bentley page 254-14 .The hose goes from it straight down to the airflow sensor.Shure to cause a vacuum leak. Pat