|
|
|
|
|
|
Hi guys. I'm after some thoughts on my misfire please. It's my '68 Toyota Corona which I haven't had long. It drops down onto 3 cylinders at idle. No4 cyl drops out. You can pull the HT lead off and it makes no difference. Hold the lead away and you get a big spark across to earth or indeed to the plug connector
Rev it up, drive it or pull out the choke a bit and it's back on all 4, all the time. It's just hot idle it goes back onto 3
All cylinders have equal good compression with a compression tester at 120psi give or take. It's got one downdraught carb. New dizzy cap, new HT leads, rotor arm in good order, plugs cleaned and swapped.
What can I try next?
Cheers
Ferg
|
| |
|
|
|
|
|
|
|
|
|
|
i'd say plugs, even if you've cleaned them. atleast you know the leads are ok
|
| |
|
|
|
|
|
|
|
|
I've already swapped them
|
| |
|
|
loon
Posted a lot
Posts: 1,092
|
|
|
|
try swaping ht lead 4 with 3 (at both ends)  if there is a break in it there will be a delay in the spark that may only be noticeable at low revs just an idea |
| |
what the fcuk have you done lately
|
|
|
|
|
|
|
|
Done already, and renewed
|
| |
|
|
loon
Posted a lot
Posts: 1,092
|
|
|
|
|
have you changed the condenser? if you have then it may be faulty, not uncommon
|
| |
what the fcuk have you done lately
|
|
|
|
|
|
|
|
water or oil in the cylinder??
|
| |
|
|
|
|
|
|
|
|
ahh, just read that you've compression checked it!! oops!
|
| |
|
|
|
|
|
|
|
|
Could be the inlet manifold to cylinder head gasket leaking (air in)
|
| |
|
|
|
|
|
|
|
|
I haven't changed the condenser.
I haven't checked for leaking manifold gasket but that's a damn good idea I should have thought of! At idle, a small air leak could be significant enough to lean the mixture out to that one cylinder. I'll spray it with WD40 and see if I get smoke out the exhaust or anything changes. Thanks
It'll be at The Ace tomorrow evening, probably still on 3!
|
| |
|
|
|
|
|
|
|
Could be the inlet manifold to cylinder head gasket leaking (air in) Correct! Thank you. I sprayed WD40 around the inlet manifold gasket area while it was running and smoke came out the exhaust A few miles later, the exhaust gasket started to go too (as some may have heard at The Ace the other night The inlet and exhaust manifolds, plus the weight of the carb, air filter and exhaust downpipe are head onto the head by four bolts as standard which is pretty woeful The only part I can still get from Toyota is a manifold gasket. I have to make the one between the inlet manifold and exhaust manifold Thanks for your suggestions everyone Ferg |
| |
|
|
|
|
|
Jan 15, 2008 18:25:25 GMT
|
|
a bit late maybe, but a few years back i made a bracket/clamp for the exhaust manifold to support it further down from one of the lower bellhousing bolts after having similar/regular exhaust gasket problems.
|
| |
|
|
Snoozin
Posted a lot
Toyophile
Posts: 1,557
|
|
Jan 15, 2008 19:07:06 GMT
|
|
I have the same issue continually with my KP, due to poor design of the flange on the headers...
So I got angry, and am pulling the engine out to replace it with a bigger one....
|
| |
|
|
if there is a break in it there will be a delay in the spark that may only be noticeable at low revs
