Need some help badly

Hello all:

I had posted before about an intermittent problem that I have been having with my 1993 900 Turbo 8-valve... 3 times now it has (a) started very hard, (b) ran rough until I got to my first stop sign and (c) quit when I hit the accelerator after stopping... kind of dies with a "PUH" sound and WILL NOT RESTART for awhile. I am getting spark. Okay, this stuff I've posted before. Here's the bad part:

Last week I had a leak in my the fuel line from the fuel distributor to my #4 cylinder. I pulled a set off of a wreck and as they looked in significantly better condition than mine I replaced all of my fuel lines with the "new" ones. Okay, car runs smoother with fuel getting to cylinder #4, but not great. Saturday morning dawned sunny and relatively warm, so there I was out in my driveway again. I replaced my oxygen sensor as I had been having problems getting the lambda pulse ratio into the range... the adjustment screw seemed to have no effect on my mixture (or reading on my dwell meter at any rate, which hovered in the 20-to-30 degree range). Unfortunately the replacement O2 sensor made no difference whatsoever.

Now the really bad part: I noticed that the car was knocking or "pinking" as you Brits say, and as it was brightly sunny outside on Saturday I happened to notice that there were AIR BUBBLES travelling from my fuel distributor to cylinder #2. Huh, I think, maybe that line has a hole in it or a blockage or something; remember I just replaced all four. So I carefully replaced the #2 fuel line with my original. Same symptoms. Every time the engine knocks corresponds to a bubble hitting the injector.

My longwinded question is this: What could cause air to be introduced into my #2 fuel line. No bubbles in any other lines, and the bubbles are definitely coming out of the fuel distributor. Could a failed or failing fuel distributor account for my inability to bring my fuel mixture into range? Could it account for the car stalling and refusing to start? What can go wrong with the fuel distributor and is it internally repairable?

I really don't want to replace the fuel distributor (>$500) if in fact something else may be causing these symptoms... please help.

Thanks

Dave

Reply to
David Spear
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Either the fuel distributor is faulty, or it's not getting adequate fuel pressure/flow rate. They're pretty reliable beasts, so check the line pressure and flow rate first.

Yes.

Yes.

Dunno - I've never opened one up (or had to replace one for that matter).

I don't see that you have much choice - if pressure and flow are good, then it's faulty.

Good luck,

Reply to
Grunff

Car started up just fine at lunch today, drove it home (400m), idles fine, no air in lines... ???

Mixture on dwell still reads ~30 degrees, too lean.

Will test line pressure, etc.

Wife not happy.

thanks for your help.

dave

Reply to
David Spear

It is being asumed that the bubbles are air.

Is it possible that the are vapourized petrol?

Something like "cavitation. . Could that line beunder a slight negative pressure?

Malcolm

Reply to
Malcolm

Went offline with Grunff about this one...

I spoke to my longtime Saab mechanic in the city where I used to live (I live about 400km outside a major city with a Saab dealership or specialized shop) the other day. Turns out he has seen the problem before and that it can be corrected by replacing the washers between the fuel line fitting and the fuel distributor. I did this and so far (only one day later) have no bubbles. So, I am back where I started. No bubbles, but car still quits periodically. I had a fitting made so that I can measure the fuel flow rate where the return line comes out of the fuel distributor, that is my next chore along with fuel pressure testing. I think I'll have a shop do the pressure test as I really don't want to spend the $$ for the guage, fittings, etc which I will probably never need again.

Even with the new seals my original problem persists... I cannot adjust my sensor plate to bring the O2 reading into spec, it hovers around 20-30 degrees dwell. I am very confident now that I do not have any air leaks. When I disconnect the O2 sensor my reading goes up to 58 degrees... right where it should. Voltage output from sensor is in the range. Anybody ever seen problems with the lambda control unit underneath the back seat? Due to the intermittent nature of my performance problems I do not think it's a vacuum leak or bad sensor or something like that, makes me lean towards an electronic problem of some sort. Most of the descriptions of failed emission relay components do not seem appropriate for what I am seeing... the car starts, runs poorly for a minute or two, then stalls when accelerator is pressed...

As a note, when I first started up the car yesterday with the new seals on the fuel distributor fittings, my dwell reading was 60-70 degrees for about

20 seconds or so... I am guessing this corresponds to the cold-start injector enriching my intake mixture.

I have not checked my injector spray pattern so thinking about it maybe one or more is clogged... I am scared to do the disconnect and remove them as I do not want to damage the plastic fuel lines as per the test outlined in my (bentley) manual.

Reply to
David Spear

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