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problems after car overheated

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My 93 SE us version temp guage when almost to the red today. Very short time waiting in traffic and then cooled to normal. I do not think it was that bad. So a few minutes later the engine starts to run poorly. Looking it over I discover that if you pull number 1 and 4 plug wires off the engine still runs the same. It is getting fire so I do not think it is the coil. I swapped the plugs and no change. I plan on testing compression tomorrow. Any ideas?

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Compression check, which you are doing, and look for oil contaminating the coolant. Either one is sadly bad news. If those check out OK test the density of the spark, and the continuity of the leads, if the leads are more than 4 years old change them anyway. After that check coils, after that consult your local specialist.

Good luck

Roger

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checked compression as follows 1 cyl (at front of car) 155 , 2 at 142, 3 at 142 and 4th (toward rear of car) at 155. spark plugs on the middle cyls are sooted and the outside plugs are clean. No water in oil and no oil in coolant. Any idea headgasket?

Thanks Keith in Birmingham, Al.

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Plugs and leads? Over time the leads brake down, they get worse under heat and load, so either check them or replace them. Common coil? I'm not familiar with your car but I believe it has 2 coil packs, and I think the common plugs are 1&4 and 2&3, so there may be a clue there.

Roger

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its got 2 coil packs, held on by x2 5.5mm bolts (for each coil) you dont need to remove the air filter housing to get to them (its a bit tight and be careful not to drop the bolts) the one nearest teh fuel tank is 4 / 1 and the other is 3 / 2 (which seems to corroed more than the other one) take them off if there is green present there is a good chance that its gone inside (water gets in and corodes) mine was corroded in side the coil. clean the backing plate and the connectors and re-earth them some where else (bottom bolts provide the earth. if you stuck i have the 4 / 1 coil left (which could be used on the 3/2 i think) other wise you can get a set of performance ones from the states for about

Edited by mr.oogieboogie

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Thanks for the response! I have a set of spare coils. I changed the 1/4 coil out and there is no difference. I AM getting spark at the plugs, when I pull 1 and 4 off at the same time the engine runs the same when I pull 2 or 3 off it stops running. I can hear the fuel pump running and I have checked the fuel filter also.

Thanks again Keith in Birmingham, Al.

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Strange it should start after a brief spell at higher than desired temp, but as you've already found the cylinders with the issues are the ones with higher compression readings we can probably rule out head issues.

I'm thinking spark, and although you have a spark on 1&4, yo can get a weak spark which is incapable of firing correctly when the gasses are compressed.

Try cheating.

Take the plug wires from 1&4 and swap with 2&3, now swap the supply wires to the two coil packs so that the supply wires for 1&4 are supplying 1&4, just utilising a different coil pack.

Repeat you're method of removing plug leads while running. Does it still stall on 2 or 3 removed and not for 1 or 4 removed? I suspect the problem will have migrated to the other cylinders.

This would indicate an issue with either the coil pack (already ruled out it seems) or the backing board for the coils.

If it hasn't migrated then it could be the supply wires to the coils for 1&4 or the ECU (hope it's not). Either way you may want to borrow a spark tension tester or create one as somebody else has done recently.

Andy

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