SaabCentral Forums banner
1 - 20 of 21 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
Hi,

I have a Saab 900 turbo 1985 and a pregnant partner due to give birth today. Got the car back having had the air conditioner fixed and now find that the engine will start and run for about a second then cuts out.

After 5 attempts it worked and ran fine. This has happened about 2 or 3 times on one occasion it wouldn’t start at all but then started first time after being left for an hour. I’ve just tried it and presently it’s not starting. Apparently the air conditioning had a leak don’t know if that could be related. Any advice would be greatly appreciated as my partner is due to have a baby any time soon and this is pretty inconvenient

Live in Australia, it is hot here at the moment over 30 degrees C. Could this have anything to do with it?

Thanks
 

·
Registered
Joined
·
280 Posts
did you check the hose to the throttle body? or any of the hoses from the turbo to the TB? mine had the same symptoms once and it turned out to be a torn hose to the throttle body.
 

·
Registered
Joined
·
1,320 Posts
If it would just die after 1s or so, I would think the fuel pump relay is not being told the engine is spinning.

To test the air mass meter, just disconnect it and start the car. If it works you may have issues.

That said, I wonder what the shop has touched when they pu tthe AC to work.
 

·
Registered
Joined
·
230 Posts
Sounds to me like

Its an issue with the fuel pump not getting the signal it needs to run properly.

I'd say:

1) A bad LH ECU
2) bad LH main power relay
3) bad fuel pump relay.

PS - Starting, then dying immediately, on a 16v LH car, is generally the classic and obvious symptom of a bad ECU. If you can get an ECU from another car of the same year, might want to swap it in to see if that fixes it. The ECU is under the passenger side carpet just forward of the door, it plugs in and is held in by 3 or 4 torx head screws. On your 85, the torx screws may actually be phillips head screws, unsure.

Good luck! Keep us posted!
 

·
Registered
Joined
·
230 Posts
I totally forgot to mention

This could also be a symptom of (and the FIRST THING) I would check would be a massive vacuum leak like the prior post says. Ie, one of the big throttle body hoses to the AIC or turbo/intercooler -- if one of those is disconnected or has a huge air leak, you'll get a symptom like this.
 

·
Moderator
Joined
·
4,637 Posts
Check also for vacuum hoses off. If you do identify the fuel pump relay as being at fault, you could do an emergency jump of the relay to get to the birthing room. Pull the relay and jump pin 30 to the one on the opposite side. Only do it when you want to start the car as it will make the fuel pump run continuously.


Remember, of course, that you will have only about 2 days in which to do the next 4 year's tinkering before mother and baby get back home!... :cheesy:
 

·
Registered
Joined
·
716 Posts
8v or 16v? Why keep it secret - it is difficult for folk to give advice without knowing this basic information.
 

·
Registered
Joined
·
7,034 Posts
Could be the Hall or the Pickup in the dizzy, I had that problem. But this sounds slightly different then the symptoms I had when that happened. Mine would do the run every 3 or 4 hours then quit, but it would run for 15 or 20 minutes when it did run until the heat killed it. Also in the primary ignition circuit is the ignition amplifier in the wing/fender by the charcoal canister. A fault in any of these three things could give symptoms like this.
I still vote for fuel pump.
 

·
Registered
Joined
·
4,078 Posts
RickyS said:
8v or 16v? Why keep it secret - it is difficult for folk to give advice without knowing this basic information.
85 Turbo would be a 16V, would it not (with the infamous wiring harness unique to that year)? At least here in the states -
 

·
Registered
Joined
·
7,034 Posts
hmm, yes Steve and equally infamous and dodgy distributor also unique to that year...
 

·
Registered
Joined
·
3 Posts
Discussion Starter · #15 ·
Thanks for all your suggestions, great to hear from so many Saab enthusiasts!

I've checked the hoses they all seem OK, I've noticed if I put my finger on the fuel pump relay you get one click when you turn on ignition and another click as you turn it to start. When fault arises I notice a click on the relay a split second before the engine cuts out. Some one suggested air mass meter is what gives signal to relay to say engines spinning presently thinking that could be the problem. Don’t really know what an air mass meter is or how to test it though :D



Appreciate all your help and any other suggestions. Thanks
 

·
Registered
Joined
·
716 Posts
SteveTheFolkie said:
85 Turbo would be a 16V, would it not (with the infamous wiring harness unique to that year)? At least here in the states -
Sorry. I was just having a bit of a dig. Its difficult to remember all the variations in models and when they changed from year to year. Seems sensible to me to put this information with the vehicle details under the user name.
 

·
Registered
Joined
·
3 Posts
Discussion Starter · #17 ·
Getting somewhere at last have bridged across the relay with a wire so the fuel is permently on and the car runs fine. Have tested the relay with a vault meter from what I can see there are cables that bring the relay in. 1 I think comes from the ignition when you start the car but as soon as you turn the key back from starting it you lose the 12 vaults and it cuts out.

Presume I am loosing the signal from the air flow meter. Have looked in the Haynes manual but can’t seem to locate where this is in the car. Am I right in thinking I could just short out this switch when I find it to confirm the fault is the air flow switch?

Sorry. I was just having a bit of a dig. It’s difficult to remember all the variations in models and when they changed from year to year. Seems sensible to me to put this information with the vehicle details under the user name.
Sorry am new to using forums didn’t know this, will edit it now.

Many thanks for your help. Haven’t had the baby yet, two days overdue but at least I know I can get her to the hospital now :lol:
 

·
Registered
Joined
·
1,320 Posts
If it is a 16V turbo, it is probably LH 2.2. That means in the distributor is a Hall sensor that tells the ignition and the fuel system the engine is spinning and how fast (AFAIK it does not know when it passes TDC; it only knows when it passes a cylinder but not which one). If this was a LH 2.2 Volvo 740, I would suggest to check if the Hall sensor is working. The Volvo way to test it is to disconnect the 3-pin connector at the distributor (pictures based on my 88 convertible),

turn the ignition on, but not crank the engine, then short one of the outer pins (I keep forgetting which one) against the block. If you hear the pump and the injectors, your know the Hall sensor is boink. If not, well, there could be something else.

Now, if you have a spare distributor,

you could just connect it to the harness, turn ignition on, and then spin the distributor shaft while listening to the pump and injectors (and spark plugs!).
 

·
Registered
Joined
·
230 Posts
Dont think this is hall sensor related

Doesn't feel to me like hall sensor-related ... since if the hall sensor isn't working, the car won't start. At all. (ie from what I can tell, yours is consistenly starting then dying immediately, right?)
 

·
Registered
Joined
·
1,309 Posts
nashvegas said:
Doesn't feel to me like hall sensor-related ... since if the hall sensor isn't working, the car won't start. At all. (ie from what I can tell, yours is consistenly starting then dying immediately, right?)

Agreed, the car will not run at all without a hall signal even for 1 second. There is no spark what-so-ever if the hall sensor is at fault.

The Air mass meter is the aluminum "barrel" thing with a black plastic top on your '85 16V. It's attached directly to the top of your airbox. the connector is on the side. The car will run with it unplugged in a "limp mode". Un-plugging it can sometimes rule out the AMM when looking for a problem.

I think you may be on the right track with the relay. If I remember correctly, it may be a relatively standard-type relay, compare the small diagram on the side to other relays you have. You may be able to find a match to test it with (like a fog light relay, etc)

On my 1986, I had a similar problem. The relay was fine, but the large square electrical connector just down stream was corroded. This can be a common problem. The connector is a gray square type under the hood in the small recess where the passenger side door hinge is. Ensure it's a good connection there.

Good luck,
-Rob
 
1 - 20 of 21 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top