MGB Starting problems, running problems
Michael Daley
Its a 1980 MGB GT 1800 with twin SU carbs.
The main problem is that it just does not want to start, I have to turn the
engine over for ages before it fires. I've replaced the points, rotor arm,
distributor cap, HT leads and put some bosch super 4 plugs in, but to no
avail. The carbs seem to be adusted fine.
Please help, I'm getting desperate now!
Cheers
Andrew W. MacFadyen
Check the needles aren't set to low in the carb pistons
Use a thin engine oil in the carb dashpots
Check the coil polarity (- termminal goes to the points)
Check the voltage coil is getting power while the engine is cranking ( it is
possible the ignition switch is incorrectly wired) it should get just over 10
volts.
If this dosen't work re-post we will come up with more
Andy M
Dave Plowman
<mic...@daley77.freeserve.co.uk> wrote:
>
> I'm starting to get a little bit annoyed with my car now.
> Its a 1980 MGB GT 1800 with twin SU carbs.
> The main problem is that it just does not want to start,
I /think/ these have a cold start circuit. Have you checked, when
cranking, you get full battery voltage at the coil? I would then check with
a volt meter between battery pos and coil pos /during cranking/ and would
expect no more than a fraction of a volt. Running, this should be around 3
volts. Do the same check between dissy body and a good chassis earth, should
be only a fraction of a volt or less. The next thing would be a check of the
actual HT voltage. Check also /both/ chokes are moving to the fully rich
position if it's only a cold start thing.
--
Dave Plowman dave....@argonet.co.uk
RIP Acorn
Kippy
fault transpired to be a broken wire from the alternator to the distributor.
Paul Tatam
Michael Daley wrote in message <79b22p$i2o$1...@news5.svr.pol.co.uk>...
>I'm starting to get a little bit annoyed with my car now.
>Its a 1980 MGB GT 1800 with twin SU carbs.
Dumbass
little brown cylindrical relay on the offside inner wing. On my car this
had power to the fuel pump passing through it, and one of the wires inside
had become loose. Winding the engine over for ages would cause the wires to
contact and it would eventually start, but whilst running it would break
contact intermittently and starve the engine of fule, causing the car to
run erratically. It's a bit of a long shot, but it might be worth checking.
These relays are pretty hard to get hold of, so on your next visit to the
local scrapyard check out all the old Austin Allegros, they have the same
relay - grab a few and keep 'em as spares. It has 'Lucas' written on the
top, and a small circuit diagram.
Attila the Hun
ley77.freeserve.co.uk> writes
>I'm starting to get a little bit annoyed with my car now.
>Its a 1980 MGB GT 1800 with twin SU carbs.
>distributor cap, HT leads and put some bosch super 4 plugs in, but to no
>avail. The carbs seem to be adusted fine.
>
Take the air flter/s off and squirt carb cleaner into the ports of the
carb then crank it over with a bit of throttle. If it fires straight
away then the choke is probably the culprit.
At this age of car the carbs could have been changed for scrap yard
models. Is it fitted with HS of HIF? HS's have the jet under and outside
the carb. HIF - the bottom of the carb is flat.
--
Attila the Hun
"Our future depends upon whether or not we learn lessons from history"
- Kurt von Schussnig.