My workin on the car face
I am so stumped, i have never had a challenge like thos
Ok, i found out that my motor has only been running on 5 pots instead of 8. Its pots 2,3 and 4. But heres the twist; the leads are sparking, a nice blue spark. Ive checked the dizzy cap and its all good. Ive checked the gap on the plugs which are fine. I even switched a firing plug with a non firing and there is no difference. DIJM8 thinks its the LPG system, which may be since its 2,3 and 4 in a row.
i have no idea how to solve this.
Originally Posted by <TVR-161>
Ecotech Power
Leads/Plugs can spark fine when removed, but wont fire under compression (installed), but if swapping plugs and leads and it still happens on those cylinders then you can eliminate that.
Dizzy and Coil is a possibility, it may not be strong enough on those cylinders to spark under compression, but unlikely.
Do a compression test to make sure theirs not something wrong with those cylinders, could be stuffed rings, unlikely... more likely to be a cracked head gakset between those cylinders if compression is low.
Other wise yes it could be LPG not getting down their for some reason.... Sorry dont no **** about LPG.
My workin on the car face
Ive got an oil pressure gauge and its getting great readings if that adds anything.
oh and also, when i was doing my exhaust manifold gasket, on the drivers side i undid a bolt to get the gasket out and all my coolant flowed out of it. It was only the one bolt that did it i believe but im sure its not normal...
Ecotech Power
Shouldn't really relate to your ignition problem, but good to double check you are getting oil pressure.
Have you got a compression tester?
My workin on the car face
no but my dad does, what about that coolant problem when changing my exhaust gasket. Could that be a head gasket problem?
Ecotech Power
Im not familiar with these motors, but Im pretty sure thats not normal lol.
Ecotech Power
Grab the compression tester and do the test and post back.
Im not to sure on the coolant leaking out, ill leave it for someone else to answer.... But i dont think it should be happening, and it maybe a crack somewhere on the head, or could be the head gasket... A compression test would answer a bit, also you can get a mechanic to hook up a thing to the radiator and it will tell you if the head gasket is gone.
dah dut dut da dah
check your firing order
1-2-7-8-4-5-6-3
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My workin on the car face
did that, all in the right spots. I took the dizzy cap off as well and checked inside of that and all good.
Banned
How high is the oil pressure?
iv got another car running on 3 cylinders of the 4 as it needs a new piston ring. Not only does it run ****, but iv got blow by (check for smoke coming from the oil. Its exhaust smoke) and the oil pressure went from 40psi to 60psi when the ring broke.... its a possibility i guess
on holiday
what do you mean by 2 3 and 4 do you mean all on one side of the engine cause 2and 4 are on the same side but 3 is on the other side
America just kicked in yo
is the manifold bolt on the same side as the cylinders that are not firing? (could be a cracked head)
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My workin on the car face
yea 2 3 and 4 as in one on one side and two on the other.
Oil pressure is high when revving it and accelerating but idle is middle of the gauge.
My workin on the car face
i did tighten the 2 front valley cover bolts just as a tighten them to make sure they dont go any where thing. Those bolts i tightened up are in the same ares as the non working pots.
and yea, the area where to coolant came out was next to one of the non working pots
Last edited by Paiste402; 05-08-2008 at 10:38 PM.
born in the FB era
Sounds like its now a process of elimination. Rip the rocker covers off and check for broken rocker posts or bent pushrods. Worn cam lobes or cracked head mebbe. Even an inlet manifold gasket or a crack in the inlet manifold itself. Without the correct anti-corrosion inhibitor recommended for holdens the inlet manifold may be corroded around the water galleries. Keep us posted hey.
on holiday
the manifold will be a dual plane ie split into 2 lots of 4 cylinders half the carby going too one set of four other half to the other 4 are the 3 that arnt going all linked to the same one half of the manifold could be a stuck inlet valve in one cylinder stopping suction to the other cylinders should be able too see if the dead ones are connected buy looking at the outside of the manifold and following the runners to each cylinder they will look like a bit like an H pattern some runners going to each side of the engine
My workin on the car face
she has a new cam in her but i will check everything else. I am rather tempted to take it to a mechanic do to this sorta work since inside the heads are quite sophisticated n all.
thanks for the help guys, im gonna try and narrow everything down.
Donating Member
are you meaning the in dash one? if so those things generally arnt telling you the full story and are known to give inaccurate readings.
We got rep back, yaaay!
Maybe burnt or sticking valves . Turn the motor over till the offending valves are closed and check to see if there is any "play " in the rocker gear . Maybe the valves are not closing
there are three types of people in the world , those who can count and those who can't
My workin on the car face
i borrowed a comp tester but typically it didnt hold pressure very well but i got this info.
I tested 4 pots, 2 that worked and 2 that didnt. The 2 that did work gave the gauge a reading even though the pressure just escaped. The 2 that didnt had no reading at all, the needle didnt budge. If thats anything at all...
My workin on the car face
also i want to add that the car runs, it idles no worries with the remaining 5 cylinders and ive been driving it for a while i reckon like this. No over heating and the coolant stays in the radiator (the radiator is in quite bad shape though after all those years not going anywhere). Is it possible that a few valves are stuck down after 3 years of not moving.
And no, there are no unusual noises in the engine when its idling with this problem.
Take off the rocker covers and get someone to crank the motor and have a look at the valve gear and see whats happening .Check to see if the valves are fully opening and closing ,make sure you disconnect the coil so it doesn't fire up .
there are three types of people in the world , those who can count and those who can't
I had a similar problem once it was that a few lifters had collapsed and broken the pushrods put in new lifters and replaced the broken pushrods off it went again but on all 8 cylinders
My workin on the car face
mystery is over, its the head and gasket. Found the milky stuff under the oil cap and its all chocolate milk looking in the sump. New gaskets and maybe new heads to fix it. Im now looking around town for some 2nd hand heads that are good to use and then have to get a mechanic to put them on for me.
thanks fellas for the help
take your heads to a machine shop and have them crack tested only cost about $80 then if they are ok get them to machine them you need to do this with any second hand heads before fitting them anyway
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