924Board.org

tuf-924 · Joined: 05 Nov 2009 Posts: 119 Location: wollongong

Ok story starts when there was heavy rain, car started jerking and woulnt go past 30km/h, thought it was fuel problem tried adjusting the fuel pressure on the air mass meter, ended up breaking the screw, replaced the air meter car started first kick.
2 days after car wouldn't start while warm, next morning started it drove fine for about 10 minutes then started jerking at low revs, got worse and worse as I was driving up the hill to my house car jerked like anything then stopped, checked fuel still had a quarter of a tank, just replaced rotor button since spark was not strong, now I got a decent spark but not starting even when cold.
Anyone help? Please
_________________
Vass...

924-76 · Joined: 05 Jun 2006 Posts: 1489 Location: Ontario, Canada

I would change the front and rear fuel filters, yours might be blocks.
_________________
1976 924 N/A ROW SOLD
1980 931S
1981 931 Part car RIP

tuf-924 · Joined: 05 Nov 2009 Posts: 119 Location: wollongong

Iv been told that but Iv got fuel pumping in I pulled the injectors out and checked and they are spraying really well
_________________
Vass...

leadfoot · Posted: Thu Jun 16, 2011 10:33 pm Post subject:

to start with the screw on the air flow meter is for Co2 mixture and really only effects idle, fuel system pressure is set via the shims on the side of the mass meter and is a little more difficult to do.
Cold starting is one of the more delicate processes as it requires a few things to be in order,
no vacuum leaks
a working cold start valve
a working air bypass valve
and a properly set cold system pressure (aka tuned WUR)
you also need to make sure the timing is set correctly.

most causes of poor tune are an incorrectly set ign distributor,
work through these items thoroughly and carefully and check your spark plugs as these will give you a good indication of whether the car was running rich, lean, or another issue. clean, gap and replace.

there are checks for all the above items listed in the haynes manual and are in the FAQ IIRC,
post back any problems you have with the testing proceedures and we'll do the best to point you in the right direction.
cheers
Stu
_________________
1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...

MRPETE · Joined: 07 Nov 2010 Posts: 67 Location: CALGARY AB CANADA

Had the same problem ran like a bugger until I needed GAS!Fuel filter would let gas through until I needed it.Under demand it gave me grief.Took it off
blew it out YUK but it got me home... HUMMM I don't think I don't think I've
changed it yet OOpps

Pete
_________________
'77 924
"81 924
Lots o' Corvairs

tuf-924 · Joined: 05 Nov 2009 Posts: 119 Location: wollongong

I replaced my spark plugs, leads, rotor button, distributer cap and ignition coil.
It's got a very good spark now.

I just tried starting it before it kicked over but not for long, sound like it was miss firing. As soon as I took my foot off the accelerator it stopped.

I'm thinking I need to adjust the air mass meter screw while someone cranks the car what do you guys think?
_________________
Vass...

leadfoot · Posted: Wed Jun 22, 2011 8:29 pm Post subject:

never adjust the meter screw with the car running....
sounds like you have a timing issue more than anything

double check your leads are in the right order first and the leads are going to the right cylinders. 1 3 4 2 going clockwise.
attach a timing light and set the timing to factory specs for your model,
you also need a meter that can read the tacho signal off the coil and give you the rpm,
Stu
_________________
1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...

stevekat · Joined: 19 Jan 2008 Posts: 719 Location: Los Angeles, CA

What did you do to make sure the injectors are spraying really well? Did you jumper the connections for the fuel pump relay?

You might try jumpering the correct fuel pump relay pins and seeing if she shall start. This checks the fuel pump relay and also eliminates the chance the tach signal is not getting to the fuel pump relay (the tach pulse needs to get to the relay while you are cranking the engine in order for the fuel pump to continue to operate.)

You might see some residual pressure in the system while checking the injectors, but this may bleed off as the car starts to run, in the case of the pump not running due to not having a tach signal.
_________________
"Never get out of the boat. Absolutely goddamn right. Unless you are goin' all the way."

Gone to new home: '81 924T, US version, CGT Intercooler, UTCIS-PT, Euro DITC, Greddy Trust MBC, Forged Fuchs Flat Dish 6's, Factory Recaro's.

ptheskil · Joined: 03 Aug 2004 Posts: 128 Location: Essex, UK

Buy/borrow a CIS fuel pressure tester and check the control and system pressures. With that information you can start to diagnose the problem. Without it you are shooting in the dark and wasting your time. If you adjust the mixture screw in the fuel distributor you are most likely adjusting it away from the proper setting to mask a problem elsewhere. Do the job properly once or fiddle with the CIS for the rest of your life.
_________________
1981 931 series2 Euro spec

tuf-924 · Joined: 05 Nov 2009 Posts: 119 Location: wollongong

Ye I have just been playing with the master screw which is bad I know, shot I didn't think of the pressure tester I got one at work.

And I have no idea where the timing belt is I had one.

One more thing I had it starting again for alot longer but died again I kept trying and trying checked for a spark I used the cam cover for an earth point and out of no where my starter motor stopped now it's not cranking
_________________
Vass...

ptheskil · Joined: 03 Aug 2004 Posts: 128 Location: Essex, UK

leadfoot · Posted: Fri Jun 24, 2011 8:48 am Post subject:

you probably flooded it or are caking up the spark plugs now...
do yourself a favour and go buy a timing light, $49.95 from autobarn, cheaper than supacheap auto...
then pull all your spark plugs and clean / check the gap
9/10 times it's the timing, then fueling...
as suggested change your fuel filters
Stu
_________________
1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...