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Discussion Starter · #1 · (Edited)
This morning my 1990 16v 900i just died. It worked perfectly, went down a gear entering a roundabout and zap! Engine died. No jerks, no hesitation, no noise, no whisper. Just gone. First realised she was no longer sparking, so assumed it was electrical. The AA guy turned up, established that the ignition system amplifier unit (control unit) was gone, put a new one in and got the electrics to spark again.
However, the engine still refused to start. After fiddling about a little longer the man assessed that no petrol was reaching the engine. But couldn't tell why. So he removed the new control unit from the car and towed us back home saying he couldn't understand what could possibly cause both the control unit and fuel system to go out all at once. Suggested, though without really believing it, that it maybe be the petrol pump or relay. Was more inclined to think that the car's "computer" was actually the culprit.

Has anyone got any suggestion as to the best way to proceed? Many thanks.
 

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Discussion Starter · #2 · (Edited)
Another question: can I replace the Bosch ignition system amplifier unit from a 1990 16v 900i with a Bosch control unit from a 1986 8v 900 or 1985 8v 900i? Thanks.
 

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lando1 said:
Another question: can I replace the Bosch ignition system amplifier unit from a 1990 16v 900i with a Bosch control unit from a 1986 8v 900 or 1885 8v 900i? Thanks.
I dunno, those 1885 cars were put together a little differently :lol:

I think those amplifiers are non-compatible, but I'm not positive.
 

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Discussion Starter · #4 ·
That's right. Guess mechanical things on wheels changed a bit since 1885 (will try correct it above).

Anyway, spark back, petrol coming and just managed to get the old girl started again. Only, after running for a short while, the engine begins to tick erratically and then dies, shaking. What does this mean?
 

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:confused: Layman here but it sounds like the timing to me...
 

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I'd look at a number of things - when you first go to start the car the fuel pump builds pressure - it then shuts down until it receives an ignition signal (safety thing - in the event of an accident that kills the engine you don't want the fuel pump to keep shoving fuel through potentially broken lines) - it's possible that the ignition signal isn't "telling" the fuel pump relay that all is well - since it was a no-spark / no-fuel combination (at the get-go) I'd cast a critical eye on the distributor and associated wiring.

It's also possible that your fuel pump is on it's last legs - have you checked your fuel pressure ?

Then there's the old favorite - chassis/engine grounds - you could have a faulty wire(s) or connection(s) losing contact from time to time -

Hmm .. typical of me I've listed the cheapest to test and rectify for the last ..

Best of luck

Steve
 

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Discussion Starter · #7 ·
Thanks SteveTF.
Re "it's possible that the ignition signal isn't "telling" the fuel pump relay that all is well", could be indeed.

Have been tinkering with the car and this is what is happening.

It started first time this morning, ran perfectly for about five minutes and died.

When I tried starting her again it wouldn't fire. When I tried again 15 minutes later it started fine again but died after about three minutes.

So, all I have established this far is that it starts and ticks away fine after being left alone for a long interval. But then just dies. The longer between startups, the longer it runs before dying.

Does this point to an obvious fault? Flooding? Faulty fuel relay? If so, how can this be sorted on a LH 2.4 bosch injection system? Will check the fuel pressure next, I guess...
 

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lando1 said:
It started first time this morning, ran perfectly for about five minutes and died.

When I tried starting her again it wouldn't fire. When I tried again 15 minutes later it started fine again but died after about three minutes.

So, all I have established this far is that it starts and ticks away fine after being left alone for a long interval. But then just dies. The longer between startups, the longer it runs before dying.
Something's going open-circuit as it gets warm. 16v n/a = EZK ignition = crank position sensor. That'd be the obvious culprit to my mind. Chuck a multimeter across the pins when it's cold, then again immediately after it dies.

If so, how can this be sorted on a LH 2.4 bosch injection system? Will check the fuel pressure next, I guess...
Nah, it's not the injection. It's doing exactly what it's told. It's the ignition.

Bet the tacho needle moves whilst the car's being turned on the starter if it's going to start, but not if it isn't.
 

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Discussion Starter · #9 ·
TooMany2cvs said:
Something's going open-circuit as it gets warm. 16v n/a = EZK ignition = crank position sensor. That'd be the obvious culprit to my mind. Chuck a multimeter across the pins when it's cold, then again immediately after it dies.
Ok. But have to ask what and where is the crank position sensor? And which pins is it that I should check? Sorry, but I really haven't got a clue about this electronic side of the old c900.
 

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lando1 said:
Ok. But have to ask what and where is the crank position sensor?
Hidden behind the crank pulley.

And which pins is it that I should check?
Dunno - but there's quite probably only two on the multiplug. Mine hasn't got one, being a turbo. But a quick search on this site should find all sorts of good stuff out about it.
 

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the connection to the c/c is under the inlet manifold,3 pin, to get at the c/c you have to take off the alternator belts, ant then undo the crank pulley bolt and the you will need a small(cannot remember size) torx head to undo the two screws that hold it in place, and then it's just a reverse to put back.
to undo crank pulley you either have to give the socket and wrench a sharp tap or lock it in gear and heave ho. It can be done from the top(as i did ) or from underneath, there is noyt a lot of room between c/c bolt head and bulhead but if you angle it on it will go, but then once loose undo by hand, else you wont get either off.
Mine played up like yours, it just cooled down and then worked ok till warm(ABOUT 2 MILES) and then start misfiring etc,(so replaced0 but when it went a 2nd time afetr 6 mnths?(2nd hand replacement, both times) it just died and that was it, completely had it, put another in ,fine.
easy job 2nd time as you know exactly what to do and how long etc:cheesy:
 

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Discussion Starter · #13 · (Edited)
Hi 16 Saabs. Thanks for the tips.

When you write <<Mine played up like yours, it just cooled down and then worked ok till warm(ABOUT 2 MILES) and then start misfiring etc>> do you mean that the engine kept going, albeit erratically, or did it cut out altogether?

The thing about my current problem is that she starts easy from cold, the engine sounding good and even for between 2 and 5 minutes, but then simply dies. Quickly and easily. Then it won't fire up again untill the engine has cooled somewhat, but only to die again. I'd really like to know if you (or anyone else) has had the same problem, just to help me understand what am doing and why...

And does anyone know where best to get a replacement part? I just checked eurocarparts (UK) but it doesn't look like they stock it.

Cheers.
 

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I feel your pain... (see my post "intermittant stalling)

When my stalling degraded to the point you descibe and finally quit for good I was able to tell it was the EZK (magic ignition box). Replaced it with one from a junkyard and all has been well for several thousand miles now. If you can get one cheap at a junkyard try it--even if it's not your problem it will be good to have as a spare.

You really need a manual to run through all the ignition checks-- Basicly next time it stalls check for spark-if there's no spark then you know it's an ignition issue and start working backwards from there (by the book). My experience with magic ignition boxes is that since they contain several silicon diodes and resisters it's all too easy (now that its over 20 years old!) for one of those sub-componets to work while cold but as it gets hot it's properties change and no longer functions the way it should--this causes the EZK to do funny things or fail altogether.

Maybe a saaber a bit closer to you than Colorado can swing by with a spare EZK to see if that's your problem--it only takes 5 min. to swap them.

Good Luck!
 

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i would be taking a look at the distributor. again, if you can try a known good one... i suspect your hall effect sensor may be failing.
 

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Discussion Starter · #16 · (Edited)
<<i would be taking a look at the distributor. again, if you can try a known good one... i suspect your hall effect sensor may be failing.>>

I'm not 100% about this but, as she's got the crank position sensor thing, I don't believe my 900 has a sensor on the distributor.

About the EZK control unit, I guess I better try locate one, Banman. An hour search on the net has not proved very successfull thus far though.
 

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lando1 said:
About the EZK control unit, I guess I better try locate one. An hour search on the net has not proved very successfull thus far though.
Get off the 'net and on the phone... Ring ATP. I'll bet that a small part number difference is merely a small difference in ignition map, and perfectly usable. Or they can test & rebuild yours.
 

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Discussion Starter · #18 ·
TooMany2cvs said:
Get off the 'net and on the phone... Ring ATP
Did that, was told they haven't got the EZK ECU I need and they don't know where one may be found... Great.
 

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hi, yes i did mean once it cooled it started perfect and would last about 2 miles, before misfire like hell and just impossible to drive, cool down and of you go again, but i also had had the check engine light flash now and again and it would miss a beat at the same time, but with me not knowing the problem i just thought it was a missfire for some reason till it did stop one day, but the replacement one died once and that was it, no check engine etc just STOPPED.
It's basically once the engine heat gets to it or just on it's own? it cut out.

i think if you could have a stream of cold water running down the back of engine it might work,:nono; but highly impractible:cheesy:
will take max 2 hrs, its' more time consuming in awkwardness, then actual work, as once the alt belts are off it's just a pain.
I had a spare accident write off car when it went again, so i litterally cut a hole in the bulkhead with an angle grinder to get at it as it was easier than having to do it properly, and then had to do a proper job on the car to replace the broke one,
 

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lando1 said:
The thing about my current problem is that she starts easy from cold, the engine sounding good and even for between 2 and 5 minutes, but then simply dies. Quickly and easily. Then it won't fire up again untill the engine has cooled somewhat, but only to die again. I'd really like to know if you (or anyone else) has had the same problem, just to help me understand what am doing and why...
Perhaps my experience is related. My 86T had very similar symptoms until yesterday. The engine would crank, sputter run for a minute or two and then cease running...or not start at all. I replaced the spark plugs, cap, rotor, tested the ECU, relay and fuel pump to no avail. I took STF's advice,... added 4 bottles of dry gas and the girl started right up. Is it cold over there? It is here...


SteveTheFolkie said:
Hmm .. typical of me I've listed the cheapest to test and rectify for the last ...
 
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