Not going good

[valitank]

HI all,

just got a good carby from a fellow member but the car still has a problem keeping up. eg if you put her down it will surge (like its running out of petrol) but if you back off a little then put her down again its fine. It can easily redline in the driveway its just if you put her flat she wants to die : btw it will do 100 if you go easy on her but if you go hard shell hardly got 60 Please help me with this one guys! because weve got to 500k's on friday to pick up another sigma

P.S it was embassing the other day because we were beating a commo and then she started playing up then the commo won cuz it wasnt running its best .

[valitank]

btw its an astron 2000 out of a ge se thanks

[camB]

it will surge (like its running out of petrol)

?? So it's surging, then cutting out? Sounds like mixture. When you pump the pedal it dumps raw fuel into the carby (you should be able to see this with the engine off and the butterfly open). If it's dumping this into an already rich mixture it just won't go bang.

Anyone else?

[shuggy]

sounds like the secondary jet in blocked. but you say its a new carby?
if its not carb problem i would be checking compression in your head for broken valves. take your exhaust manifold off n turn the crank with a ratchet. you should feel the compression n each valve shoud hiss as if air is slowly leaking out. if you feel or hear the air come out of one of the valves (makin sure that tha valve isnt open) then you have a bad valve seat.
but this doesnt really explain why it only works at flat foot to ground..
forget that my guess is timing haha.

[81GL]

Bit more information might help mate.

By the sounds of it, your saying that when ever you put the car under a fair amount of load the engine just gives up? coughs and splutters? just dies? back firing? what sounds does it make.
& when this happens you can let up on the throttle, gently put it back on and it will run fine?
If you are gentle with it you can slowly build up speed again?

and the problem is exactly the same as with the original carby? have you replaced all the fuel lines? fuel filter?

Have you done anything else to the car recently?

[valitank]

Thanks for the reply guys,

Yes its a new carby and it still has the exact problem the secondary isnt blocked because when you redline it it opens up and squirts.

I have changed the furl lines + filter one at a time and the pump seems good as that bottle where the 3 lines goes is almost full.

81GL is dead on about what happens

It sounds like its running out of petrol and then it gets a bit of pertol then it will throw the car forward then a second or two later the revs drop to lets say if it was doing 100 at 3000-4000 rpm it'd drop to 1500 rpm.

If you go easy it will slowly build up speed but if you put her right down it will get to about 4500 then start playing up then because of that it wont change gear (auto) so you have to back off then slowly build it up then it will be fine.

The only diffrence the new carby has made is that its alot easier to start.

It will rev easy if in park all the way to 6500 rpm (dont wanna push her any more than that)

[13bsigma]

the carby is from me. it worked fine on my GE and was a very clean unit, low km unit.

it mustn't be the carby, as he is getting the same issue as before he got it off me. 2 carbys with the exact problem, one which was a good unit?? i doubt it highly. . Could it be fuel pump maby? or distributor playing up? when ever i got these issues with my car, i'd just rip parts off my spare pats car and swap heaps of stuff till problem gone haha

i have a dizzy and a fuel pump if you need them bud. can express post today again

[81GL]

Nar with you there mate, if the carby has been changed and the fault is exactly the same, you would assume elsewhere.

interesting fault though... your not picking that other sigma up from Mildura are you?

You wouldn't be able to post a couple engine bay pictures up would you?

Few more Questions too:
-When did this problem arise?
-Did it 'suddenly' happen, or progressively get worse?
-Does she ever miss or carry on?

On a side note, i wouldn't go revving the old girl that hard in nuetral (~park). Remember that she is getting on in age, don't want to put the head gasket out or crack a head now do we

Also, when its doing the lack of power thing, will it maintain the RPM at the 1500 mark by its self, or is that the cars momentum keeping the engine ticking over?

Nick.

[75wagon]

Some of these things have already been covered, but I'll give you a checklist to check anyway so nothing gets missed...
Sounds like the float level to me, or just fuel supply.
If you accelerate, the motor asks for a lot of fuel (which might not be there)
If you rev it up on your driveway there might be enough fuel in the bowl for it to do that.

So I would be looking at where the fuel comes from. Check these things in this order...
- Start with the fuel pump, check it is putting out decent pressure.
- If that is fine move to the carb, check the float level (do you have a workshop manual?),
- If that is fine take the needle and seat out and check the brass screen/ filter for blockages.
- If all these are fine check your fuel filter and lines.

Important questions:
- Was it all running fine before you changed the carb?
- Why did you change it?
- Do you have any foreign parts (or custom) to make it fit?

That makes the most sense to me, that's where I would be starting

?? So it's surging, then cutting out? Sounds like mixture. When you pump the pedal it dumps raw fuel into the carby (you should be able to see this with the engine off and the butterfly open). If it's dumping this into an already rich mixture it just won't go bang.

Mixture screws only effect the idle circuit in the carb. It has no relevance to any part of the rev range over that. That is what all the other jets do. Have a look at an exploded diagram of a carby. The Solex carbs on my wagon have mutiple jets per curcuit. The primaries have 2, the secondaries have 3. The idle circuit has a screw that adjust the air fuel mixture.
That is how it all works. Here's my carbs in exploded pics.
Note.
primary jets No.s 12 (main jet 1), and 16 (pilot jet 1)
secondary jets 13 (main jet 2), 17 (pilot jet 2), and 19 (enrichment jet)




Hope some of this helps?

Dave...

[13bsigma]

he changed thet carb because he had these problems. . and they are still there, thats why i'm leaning towards fuel pump of something. .

it seems like the engine is not getting enough fuel. also revving in driveway is easy, as dave said the fuel bowl might even have enough to do that. add some load, like 3rd gear on ther freeway and you'll be needing a lot more fuel that its not getting. When removing the feul pump, be care full not to break the plastic spacer behind the fuel pump. that is if you remove it haha.

[75wagon]

This may sound primitive and damn dangerous, but I check my petrol pumps by taking the outlet hose off (and the coil lead) and cranking it over a couple of times, if the fuel doesn't make it out side the engine bay you've got a problem...
They should shoot fuel way over a metre...

Dave...

[13bsigma]

i'm known for my dodgyness lol. sounds like a great plan to me hahahaha i showed some mechanic mates of mine JET-51G the other day. and they said they gatta love my style hahaha

if i had money on me, i'd just post down a fuel pump now for you mate before hearing a reply as i know you have a big trip comming up very soon. .

[zabatron]

Try checking that your fuel filter arrow is pointing in correct direction-towards carby.Also check that your accelerator pump diaphragm is not split/broken and that the spring is in one piece and not weak.Another area to check, as stated earlier,would be that the fuel pump is delivering sufficient fuel and at the correct pressure.If fuel pressure is too low it will idle fine and rev fine in neutral/park but will not run properly under load(e.g heavy acceleration/freeway speeds).
Also try checking ignition timing is set correctly (5 degrees Btdc for GE Sigma 2 litre auto)Get a timing light and check that timing advances as engine speed increases,if it doesn't advance as revs rise,problem is in distributor advance mechanism.(also check condition of vaccuum advance canister and vaccuum hose connected to it, as these can dry out and split with age,and also check reluctor air gap in distributor is not too wide(should be .2mm from memory-use non magnetic(brass) feeler guage to check/adjust).
Also,if car has tacho,does it idle smoothly?if idle is erratic(bouncy),it may be a sign that your coil or ignition module is on the way out.
Hope this helps you,but very hard to diagnose problem without car in front of me.If you need further help,please let me know.

[75wagon]

How are you going with this problem?
Has any of the advice you've been given helped you at all, or are you still having the problem?

Dave...

[13bsigma]

yeah. i was wondering that lol. haven't heard from him at all. maby he got annoyed and threw the car out hahahaha.

[valitank]

Hi guys

The reason i havnt been on is because we went to adelaide to pick up a yellow ge gl with 88000 on the clock! runs like a dream just needs new bumpers and guard bottoms.

the gold one on the other hand is still playing up. we changed the fuel pump of there and is throwin petrol now but its still there.

i notice on its last service the reciept says "blocked of vacum advance" .

would this havce anything to do with it guys?

once again guys thank you for helping me out

[13bsigma]

hha could be dizzy lol

it mustn't be the carby, as he is getting the same issue as before he got it off me. 2 carbys with the exact problem, one which was a good unit?? i doubt it highly. . Could it be fuel pump maby? or distributor playing up? when ever i got these issues with my car, i'd just rip parts off my spare pats car and swap heaps of stuff till problem gone haha

what a guess if it was lol. i must admit i stuck with the fuel pump idea, but i suggested dizzy first hahaha.

[75wagon]

To test if you distributor advances,
Test 1. with the motor off, take the cap off and the button out. Take the vacuum hose off from the carby end and suck on it. The advance plate should move easily, if it doesn't then that is your problem.
Test 2. with the motor going, use a timing light, rev the motor you should be seeing total advance go to about 30 degrees.

Note:
If test 1 works and test 2 doesn't, you'll have to find out why your vacuum isn't working.
Test 2 won't work if test 1 doesn't

Hope this helps

hha could be dizzy lol

it mustn't be the carby, as he is getting the same issue as before he got it off me. 2 carbys with the exact problem, one which was a good unit?? i doubt it highly. . Could it be fuel pump maby? or distributor playing up? when ever i got these issues with my car, i'd just rip parts off my spare pats car and swap heaps of stuff till problem gone haha

what a guess if it was lol. i must admit i stuck with the fuel pump idea, but i suggested dizzy first hahaha.

I just thought that was a desperate attempt at trying to say there was nothing wrong with the carby you sold him

Dave...

[13bsigma]

haha, yeah lol. well i was 99% sure the carby was fine lol. but was worried, as i didn't want to have sold him a dodgy part. . lol

[valitank]

FOUND THE PROBLEM YESTERDAY!!!!!!!!!!!!!!!!!!!!!!!

Leaking intake manifold was the cause of the problem.... new gasket and bit of gasket goo and now shes fine YAY!!!!! after all that it was just that.... so as a precaution ive changed all fuel lines and put a new filter on there and now shes good as new!! Thanks guys for all your help, hope this helps someone one day with the same problem as me

[ddt]

Excellent, how did you spot the leak -or was it a guess?