[Saab c900] Start, Fires, Dies

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sweller - 28 Jan 2006 19:05 GMT

Ho hum.

After a productive afternoon replacing the defective heater valve I had
my 1985 8 valve injected 900 idling away quite happily to get up to
temperature so I could check for coolant leaks.

The car idles a bit too fast so I took the opportunity to just back off
the throttle stop a touch. It started to hunt then died. No worries
thought I, just speed it a little...

It now starts on all four cylinders, runs for a second or two then dies.

Throttle position has no effect. It was low on fuel but now has over two
gallons, the pump in the tank can be heard to run for a few seconds and
then stops, fuel reaches the filter and is under pressure.

The car ran perfectly this morning.

Ideas? I'm a bit stumped and it's in the way where it is at the moment.

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Simon

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mrcheerful . - 30 Jan 2006 09:17 GMT

> Ho hum.
>
[quoted text clipped - 15 lines]
>
> Ideas? I'm a bit stumped and it's in the way where it is at the moment.

try hotwiring the pump

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James Sweet - 30 Jan 2006 16:51 GMT

mrcheerful . wrote:

>>Ho hum.
>>
[quoted text clipped - 15 lines]
>>
>>Ideas? I'm a bit stumped and it's in the way where it is at the moment.

Is this CIS injection? If so, it might be a plugged control pressure
regulator, unplug the starting injector and see if the car still starts
at all. I've been cleaning up a very similar mess on a '79 Volvo, the
car sat and the inside of the fuel filter rusted apart and puked a whole
mess into the injection system.

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Paul Halliday - 30 Jan 2006 18:01 GMT

> mrcheerful . wrote:
>>
[quoted text clipped - 17 lines]
>>>
>>> Ideas? I'm a bit stumped and it's in the way where it is at the moment.

> Is this CIS injection? If so, it might be a plugged control pressure
> regulator, unplug the starting injector and see if the car still starts
> at all. I've been cleaning up a very similar mess on a '79 Volvo, the
> car sat and the inside of the fuel filter rusted apart and puked a whole
> mess into the injection system.

As a 1985 8V, it will be CIS.

Unbolt the injectors from the manifold and arrange them into transparent
collector (like jam jars), pop the bellows off the fuel mixture unit and
pull the plate up. Do the injectors spray well?

Do you have a massive air leak somewhere? Try firing up with the throttle
open and then back down to part throttle. Let off the throttle and see if it
dies. That would indicate a huge air leak.

Did you check the oil when doing your recent work? Make sure the dipstick is
correctly inserted and pushed down tight.

Paul

1989 900 Turbo S
http://saab.go.dyndns.org/

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sweller - 31 Jan 2006 08:55 GMT

> Unbolt the injectors from the manifold and arrange them into transparent
> collector (like jam jars), pop the bellows off the fuel mixture unit and
> pull the plate up. Do the injectors spray well?

Thanks for all the responses but frustratingly it turned out to be the
pump.

The mechanic at Mann & Woodland (Hove, E. Sussex) told me how to check
the injectors which weren't getting fuel. It was then a process of
working backwards down the system which led to the pump.

Which ran but didn't pump fuel.

The filter appeared to be under pressure on initial checks and coupled
with the sound of the running pump when I bridged the relay led me to
believe all was well in that department. I discovered with a replacement
pump just how under pressure the fuel delivered was...

£30 for a s/h pump and a bit of head scratching. Respect to Mann &
Woodland for their advice and putting me on to another Saab specialist,
Hawkleys (Southwick, Sussex), when they didn't have a used pump.

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Simon

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Paul Halliday - 31 Jan 2006 18:20 GMT

>> Unbolt the injectors from the manifold and arrange them into transparent
>> collector (like jam jars), pop the bellows off the fuel mixture unit and
>> pull the plate up. Do the injectors spray well?
>
> Thanks for all the responses but frustratingly it turned out to be the
> pump.

Well, it's good news you've found the problem.
<snip>

> £30 for a s/h pump and a bit of head scratching. Respect to Mann &
> Woodland for their advice and putting me on to another Saab specialist,
> Hawkleys (Southwick, Sussex), when they didn't have a used pump.

Sounds like two garages worth using again, there.

Result!
Paul

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Craig's Saab C900 Site - 31 Jan 2006 22:46 GMT

>Thanks for all the responses but frustratingly it turned out to be the
>pump.

>The mechanic at Mann & Woodland (Hove, E. Sussex) told me how to check
>the injectors which weren't getting fuel. It was then a process of
>working backwards down the system which led to the pump.

>Which ran but didn't pump fuel.

>The filter appeared to be under pressure on initial checks and coupled
>with the sound of the running pump when I bridged the relay led me to
>believe all was well in that department. I discovered with a replacement
>pump just how under pressure the fuel delivered was...

That's good news! I'm yet to try the simple idea of swapping the fuel pump
currently in my 8V turbo car with the one that I'm assuming to be good still
mounted in the tank of the donor car. Once I receive a package of AMP
connector parts from Eagleday.com I will repair the hall-effect wiring
harness and see if I can get the engine to run. So far I've done fuel
pressure tests which seemed to give correct results, and I've changed the
fuel filter as well.

Last time I had the engine running it stalled when I tried to give it some
more throttle and hasn't started again since. 8-)

Craig.

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