Help reguarding 2TG

[WeekendWarrior]

hey mate check all your sparkies to see if your getting any fowling you mite be getting blowbyon a dead or limp cylinder take your oil filler cap off and put ur hand just above it and if you feel a light thumping of air on your palm, if so it would be a dead cylinder causing this miss in alot of cases it will only miss under load in these circumstances. also has the idle been varying at all has it been overheated recently. if so it could possibly be a slightly warped head which caould be sucking forien air and causing it lean out on one cylinder. just thought id run those by ya mate. oh and yeh do a compression test that is also a good way of eliminating or finding problems

thought it mite help

[Celica_73]

Mate look up about 5 posting the reluts of compression test are there. As for blow by yes i know it has some. Although the engine doesn't use oil between oil changes so can't see the point at this stage to strip it done. As for the Head has been off about 2 years ago when a valve got bent. At that time i replaced the valve and did a 3 angle cut on the head for all the valves. Also replace timing chain as I notice one link was broke and just holding together. I have another head here that I purchased of Rod. Got some Cam ground just have to get them shimed. But can't see the point putting that head on until i rebuild the bottom end.

Just for a recap the Compression results were
Hot Dry results only
1 150
2 165
3 155
4 155

As saying before I know these are low but results are the same as when i first bought the enigne over 3 years ago.

Haven't Check the Dizzy shaft or the auxiliary venturi in the carbies yet I'll have to some reading do see where it is. But I'll be having a look tomorrow thank kingmick and Billzilla for some ideas.

[tricky]

I'd do the fuel filter for peace of mind, and if you are running an electronic fuel pump, get a pressure gauge onto it, and see what condition it's in. If it is the mechanical pump, do you know how old it is? Sounds like a fuel problem now, from the extensive ignition work!

[Steve M]

Here are my three suggestions.

1. When we first started the 18RG we had the same problem. In that case it was air filters.(Won't make my own foam filter again! Duh!)

2. I had a problem with a missfire under accelleration this week with the same engine, the no.2 spark plug lead was loose on the plug and would vibrate under revs and settle back in place while cruising.

3. Have you checked everything to do with your ignition timing, not just the part quality?

Is your vacuum advance connected? If yes, read below, if no, don't.
Due to only happening when you put your foot down, it could be a vacuum thing. If your ignition timing is not quite right, the disengagement of the vacuum advance (when your foot goes down) could be causing cross-sparking between the electrodes in your dizzy cap.
That will result in a missfire.

From the many vacuum leaks that we've had, they generally show up more at idle and while cruising as the ratio of right air v's wrong air is closer.

[71TA22]

My only experience of this problem was a faulty coil resistor. Coil would over heat.

Replaced the coil resistor and no problem after.

[Celica_73]

Update

Ok now i have check leads. Had a set on the 2t in the shed grabed them to test that idea.
not fuel pump as also grbed the one off the 2t or fuel filter as i removed it from the flow.

Vaccum advance is connected and the igntion time is fine did all that while tuning carby. To tune the carbies i followed the step layed out in the Yellow trackor book (the Scans river gave me).

The GT40 coil doesn't use a resistor

Question what the chances of point causing a miss under load?

[kingmick]

Update

Ok now i have check leads. Had a set on the 2t in the shed grabed them to test that idea.
not fuel pump as also grbed the one off the 2t or fuel filter as i removed it from the flow.

Vaccum advance is connected and the igntion time is fine did all that while tuning carby. To tune the carbies i followed the step layed out in the Yellow trackor book (the Scans river gave me).

The GT40 coil doesn't use a resistor

Question what the chances of point causing a miss under load?

they can miss, but only if they are pitted or you havnt set the points gap if they have been takenb out or a new set put in. pitted i mean both contact surfaces not flat or smooth.

vacuum advance will only affect low revs and be a flat spot down low.

[Celica_73]

Have to admit problem is looking to be in the Carbies. Billzilla mentions something about the auxiliary venturi falling out. Looked up the book to see where they were located. I found large and small venturies which seem to be held in by a screw and a lock nut from the bottom is this correct? If so the screws are all tight.

Also check the dizzy shaft today and baiscally no movement there luck to be 0.5 of a mm at the top.

What are common faults with the Solex carbies?

[Celica_73]

Ok reguarding points i used a point file on them and reset the gap and igntion timing before the carby tune. They were a little pitted but i filed until a flat surface was showing

[kingmick]

do exactly what bill said and then check floats and needles. i have not played with a 2tg at all and bill has so his would be good advice to check

[Celica_73]

Just pulled the tops off the carbies to find what look to be sand in the bottom of the bowl. The sand looks pretty fine and don't think it would block the jets as they are huge. As yes i did check the jets for blockages. As well as sand up around the needle and seat. But the little filter, which i did even know of had a lot of sand on it. Haven't tested it yet i'd take it for a run later and let you all know it that was the cause.

In some ways i hope it's that simple.

[YelloRolla]

I didn't see if you've replaced the points - I had a similar problem with the wire tail to the points - changed the points and problem solved.
Check in-tank fuel filter sock thingy (if it has one).
Change spark plugs again - if they've fouled due to whatever caused the miss (like the coil that you've replaced), then the plugs should be cleaned before re-testing the engine.

Good luck

[Celica_73]

10 Point to Billzilla Pulled the air cleaner off again and look at the venturies. No 1 Cylinder's was boken off and hard up againt the butterful.

Ok now the questions is where can i get venturies from as number 2 is looking suspect too.
Don't think it can be repaire due to the fact it looks like cast Alloy. How it broke was the side of the screw holding it has the side missing.

Thanks for your help everyone

[Billzilla]

10 Point to Billzilla Pulled the air cleaner off again and look at the venturies. No 1 Cylinder's was boken off and hard up againt the butterful.

Ok now the questions is where can i get venturies from as number 2 is looking suspect too.
Don't think it can be repaire due to the fact it looks like cast Alloy. How it broke was the side of the screw holding it has the side missing.

Thanks for your help everyone

Yeah, POS Mikuni's .....

[Celica_73]

Have to say a BIG WARNING to all those with solex carbies check your ventruies on every service as it appears to be a very common fault with these carbies from everyone I've spoken to chasing these parts.

Even if the screw and nut are tight give the venturi a touch to see if it's loose