Help reguarding 2TG

[Celica_73]

Ok Car has mean runing fine until a couple of weeks ago when it developed a miss.

Since then I've
1. Replaced Spark Plugs
2. Retuned Carburttors
3. Disconnedted the Electronic Igntion box
4. Swaped Rotor and Disturbtor Cap
5. Measered the Ohms of Spark Plug Lead and Coil Lead
6. Check point gap
7. Done Compression test (low but unchanged from last time a year ago)

With no change so I'm hoping someone could tell me something I've missed or point me in the right direction as i have run out of ideas.

One thing i did find strange is there is only 6V across the coil is this normal?

Thanks
Jason

[RWDboy]

check over the alternator maybe

[Celica_73]

Alternator is about 8 months old since reconditioned.

Replace the battery the other day due to dieing 6 years old though.

Wouldn't the Charge light come on if not working corectly?

But i'll check the charging circuit tomorrow thanks for some ideas.

[RWDboy]

yeah aside from that, it could be crap fuel too ... ?

[Celica_73]

This is the second tank since it started and empty the first down to about 5 litres before filling up again. Must admit same fuel station and same pump. Although free fuel (work account) and only one pump with 95 at the station.

[river]

Hi,

Try a new air-cleaner element and a new fuel filter.

seeyuzz
river

[Celica_73]

Ok I forgot to say one thing it only missing under load.

But saying that looks like i found the problem. This morning the car wouldn't start. Open the bonnet and open and close to the point to see a nice blue park jump across my coil. And yes I did check the coil earlier by running the car in darkness with the bonnet up.

Getting a GT40 coil today I hope this is the problem!

[Invid]

I had something like this in my 22. Turned out to be the lead from the coil to the Distributor cap was not connecting properly. The coil had built up so much carbon from the spark having to arc the gap, that it was toatl blocked. The car would only miss fire at about 3000 revs.

Check your old Dizzy cap for any carbon build up as your lead may still be a bit dodgy too...

[Celica_73]

Ok new coil still a miss under load.
Cleaned air filters no different Don't think it's fuel related as there is no surging.
No sign of leaking spark anywhere else.
Swaped Dizzy caps as I had a spare one.
Cleaned points

And guess what still missing.

Anymore idea?

Bit more back gorund:

Mostly up hills is the problem rest foot on accelerator it is fine little bit more gas missing, back off fine. Leave foot down doesn't recover until you back off.
For those interested the Compression test was 155 PSI roughtly alround hight 165 lowest 150 I know it need work been like that since i've own first really dramas that i haven't been able to figure out.

[kingmick]

no water in the spark plug tubes? even a small amount makes a diffrence.and if you degreased the motor make sure there is no water up in the plug boot.
if you changed plugs did you gap them?
check coil earth and engine and computer earth?
make sure leads are not arcing against another lead or something metal.

[Celica_73]

No water in the spark plug holes
Didn't check the plug gap but the fatory gap for the plugs is the prefered gap. As the gap would be smaller then the older plug (same plug and not adjusted since new) the can't see the gap being an issue. I could be wrong feel free to tell me if i am.

As for coil earth if i'm not mistaken earthing the coil would stop the engine. The Jay Car special Electronic Igntion Kit is on the earth sid of the Coil. I dissconntect the unit to test to see if it was the problem which then moves the Earth point to the points. So I'm assuming this would inturn check the grounding of the Coil.

Computer??? Old tech 2TG Twin Carby

As for Lead had to check is they are arcing as it runs fine at idle. Lights off at night no pretty lights at idle.

Thanks

[kingmick]

with out hearing it in person its hard to tell if its spark or fuel miss!
check to see there isnt to much play in the dizzy shaft!
then onto the carby!

[Celica_73]

What you mean by play in the dizzy shaft?

I understand what you mean about hearing it in person. Don't worry my dad's a motor mechanic and can't work it out. His unsure if electrical or Fuel but suspect electrical after driving it. Not say it's not fuel as I've pretty sure the Igntion can almost be ruled out only Spark plug lead not sure on. but since they are 2.5 year old Top Gun 8mm Silcone lead that replaced the orginals i'd hope they would last longer then this.


Ok had I quick look at the carbies last night pulled the jets out and no blockages. Must admit the River still maybe right about fuel filter it's 4 years old just doesn't surge like you would expect when a fuel filter blocks up.

Air cleaner are Foam Pod style Ramfol think the name is. One Carby filter does have the Engine Breather on it and gets oily (Normally that cyclinder plug fouls first) Cleaned Filter Plugs are a nice light tan/white colour.

[kingmick]

the shafts can wear and when loaded up can push the shaft to one side and the gears and do the same at the top! moves rotor a bit so loaded they dont get full spark energy.
put a bit of pipe were the filter is just to give it a go first! then pull the dizzy out and check it for play.

[Billzilla]

I had a similar problem with the two 2TG's I worked with in the 80's.
Turned out to be the auxiliary venturi in the crappy Mikuni carbies falling out. They're not held in very well, and as soon as they start to move around they rapidly get loose and fall out. The engine still runs, but roughly.