you need to check the voltage to the coil plug ends on those 2 cylinders, sounds electrical if you are certain the engine is not damaged .....
I need some ideas?!?
- Thread starter BLOWN00GT
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my brother and i checked the voltage when we pulled the #5 coil pack out... the car was running and when i pulled it out i got zapped like 25 times in 2 seconds... we also checked the power to the plug. but i can't remember what it was getting. does anyone know what voltage is supposed to be getting to the plug. i will check with my brother and he may remember.
i know that nothing is wrong with the motor. i know its sounds naive... but it starts and idles fine. no noises and was fine before the valve seal job.
let me know if anyone can think of anything or if anyone knows of a similar problem...
i will post the voltage to the plug...
i know that nothing is wrong with the motor. i know its sounds naive... but it starts and idles fine. no noises and was fine before the valve seal job.
let me know if anyone can think of anything or if anyone knows of a similar problem...
i will post the voltage to the plug...
have you replaced the plugs , maybe they are not firing , and if they are you are going to have to pull the heads to find out whats going on ......
i am bringing back this thread...
i did what was recommmended by doing a compression test. originally the #3 and #5 cylinders were missing. so i tore the car down(intake hose off and plugs out) so i could check compression. what i found was that the #5 cylinder was only putting out 30 psi, which was WAY lower than the others. the #3 however was putting out the same as the other cylinders. i found that odd so i quickly assembled the car again and started it up. putting the coil packs in no particular order. when i started it, i was dumbfounded to see the #3 cylinder was nolonger missing. although it was before i did the compression test. this coil i never swapped because it was harder to get to and i figured whatever was wrong with #5 was wrong with #3. so anyways, the #5 is still not firing. so i am now running on 7 cylinders instead of only 6. 1 down 1 to go. i have reason to believe its not the bottom end because it ran fine before i did the valve seals. ever since then it has been missing. what i would like to know is what valve is exhaust and which one is intake(front or back valves on the #5 cylinder).
also i would like to know what i may be able to do to figure out which valve i am having problems with... assuming that is what it is! both valve go up and down as i spin the crank!
also remember that i have longtubes and can't simply tear it apart... unless anyone has ever pulled a head off with MAC LT's before. i was looking and there may be enough clearance to pull the head off with the header still attached. but i am not positive!
any advice appreciated! thanks for any input guys.
i did what was recommmended by doing a compression test. originally the #3 and #5 cylinders were missing. so i tore the car down(intake hose off and plugs out) so i could check compression. what i found was that the #5 cylinder was only putting out 30 psi, which was WAY lower than the others. the #3 however was putting out the same as the other cylinders. i found that odd so i quickly assembled the car again and started it up. putting the coil packs in no particular order. when i started it, i was dumbfounded to see the #3 cylinder was nolonger missing. although it was before i did the compression test. this coil i never swapped because it was harder to get to and i figured whatever was wrong with #5 was wrong with #3. so anyways, the #5 is still not firing. so i am now running on 7 cylinders instead of only 6. 1 down 1 to go. i have reason to believe its not the bottom end because it ran fine before i did the valve seals. ever since then it has been missing. what i would like to know is what valve is exhaust and which one is intake(front or back valves on the #5 cylinder).
also i would like to know what i may be able to do to figure out which valve i am having problems with... assuming that is what it is! both valve go up and down as i spin the crank!
also remember that i have longtubes and can't simply tear it apart... unless anyone has ever pulled a head off with MAC LT's before. i was looking and there may be enough clearance to pull the head off with the header still attached. but i am not positive!
any advice appreciated! thanks for any input guys.
you can simply follow the ports to figure out witch valve is witch. It sounds like you have a bent valve or a valve that isnt closing completely. and what did you do for the valve job?
not sure what exactly you mean on that question. but i tore off valve covers and simply replaced the seals. and reassembled! no big deal really. i could see one not being seated correctly! but bent? i have no idea. i hope someone has an idea for me to check it!
thanks
thanks
betcha 10 bucks you are missing part of that piston on number 5 , and it probably but a groove in the valve seat as it got chopped up and spit out the exhaust pipe .........could have bent that valve as well........
i'll bet that you are right!!!! I'll bet that piston just broke up into little pieces and flew right out my exhaust. no doubt that is what happened. considering the last time it ran on 8 cylinders it hasnt even moved from the garage. no high rpm's, no nitrous, it just sat at idle.
lets get real!
anyone with useful info and who doesnt feel the need to bet on what is wrong with cars... that would awesome...
thanks!?!
lets get real!
anyone with useful info and who doesnt feel the need to bet on what is wrong with cars... that would awesome...
thanks!?!
You said you had the chains off, I'm guessing that you may have gotten off a tooth or two when putting it back on. Either way, I'd start by pulling the valve covers and visually checking everything as your turn it over by hand.
Try pouring a little oil in cylinder 5, then turn it over a few times and try the compression test. When the cylinders get washed down with fuel that isn't getting burnt, it can show low compression. If that doesn't change the compression at all, then pop the valve cover and make sure that both rocker arms are still on that cylinder. One fell off of the intake valve on my buddy's Crown Vic, and it only did 30psi. If everything is in order under the valve cover and putting oil in the cylinder didn't change the compression, then you may be looking at a bad head gasket or something much worse. When you did the bottom end, did you change the pistons too? You have to make sure that the rings' gap on the side don't all line up with eachother.
some good advice guys!
i did do new pistons and i made sure that each ring wasnt in line with the next ring.
the timing is pretty easy to set and i know it jumps links pretty easily but i get my brother to hold the chains in place while i put on the tensioner on. i did this right after the rebuild and had no problems either.
i do have that valve cover removed and both rockers and valves move with the cam like they should.
i have not tried the oil in the cylinder yet but i did pressurize the cylinder. the air switched from exhaust to intake like i believe it should. i have not had a chance to see what it does on another cylinder but i will check to see if it is any different than what that one does when under pressure.
also with the fact that the #5 would be washed down with fuel and shows low compression would be strange because the #3 cylinder was also not firing but had good compression. after i reassembled the car i started it and #3 was no longer missing. so maybe the plug to the coil was messed up. i am not sure.
so my next step is to see if the #5 cylinder pressurizes the same as the other cylinders. if not than obviously there is a compression issue. but it would be nice if the low compression had to do with the fuel in the cylinder. i am betting it is a bent valve or something. maybe one got hung up and slapped a piston!
does anyone know if its possible to pull the motor and tranny at the same time with MAC LT's???? i would rather pull it up than drop it down with the k-brace. just my preference...
thanks...
i did do new pistons and i made sure that each ring wasnt in line with the next ring.
the timing is pretty easy to set and i know it jumps links pretty easily but i get my brother to hold the chains in place while i put on the tensioner on. i did this right after the rebuild and had no problems either.
i do have that valve cover removed and both rockers and valves move with the cam like they should.
i have not tried the oil in the cylinder yet but i did pressurize the cylinder. the air switched from exhaust to intake like i believe it should. i have not had a chance to see what it does on another cylinder but i will check to see if it is any different than what that one does when under pressure.
also with the fact that the #5 would be washed down with fuel and shows low compression would be strange because the #3 cylinder was also not firing but had good compression. after i reassembled the car i started it and #3 was no longer missing. so maybe the plug to the coil was messed up. i am not sure.
so my next step is to see if the #5 cylinder pressurizes the same as the other cylinders. if not than obviously there is a compression issue. but it would be nice if the low compression had to do with the fuel in the cylinder. i am betting it is a bent valve or something. maybe one got hung up and slapped a piston!
does anyone know if its possible to pull the motor and tranny at the same time with MAC LT's???? i would rather pull it up than drop it down with the k-brace. just my preference...
thanks...
here is an update:
i have the valve cover off and tore off the roller and removed the valve locks and springs on the #5 cylinder(which has low compression). i played with the valves to make sure nothing is wrong and all seemed very well.
i then decided to leave the rollers off so the valves would be totally closed. so then i pressurized the #5 cylinder to see if there was another leak through the bottom end or head gasket. i figured with the valves closed it should hold compression. and to my surprise it held the air without any leaks through the valves, bottom end or head gasket. but when i put back on the rollers and pressurized the cylinder again. i couldnt get the cylinder to hold the compression. as i spun the crank the air was constantly being forced out the intake or exhaust.
when pressurizing the other cylinders and spinning the crank, the crank eventually can't be spun anymore because the cylinders build pressure and will not allow the piston to be moved anymore.
the crank gets hard to spin when pressure is in the #5 cylinder. even though it gets tough to spin the piston still has free reign to go up and down under pressure. it seems the valves are opening at the wrong times.
anyone else thinking what i am thinking?!?
but can anyone explain why this would be the only cylinder affected?!?
i have the valve cover off and tore off the roller and removed the valve locks and springs on the #5 cylinder(which has low compression). i played with the valves to make sure nothing is wrong and all seemed very well.
i then decided to leave the rollers off so the valves would be totally closed. so then i pressurized the #5 cylinder to see if there was another leak through the bottom end or head gasket. i figured with the valves closed it should hold compression. and to my surprise it held the air without any leaks through the valves, bottom end or head gasket. but when i put back on the rollers and pressurized the cylinder again. i couldnt get the cylinder to hold the compression. as i spun the crank the air was constantly being forced out the intake or exhaust.
when pressurizing the other cylinders and spinning the crank, the crank eventually can't be spun anymore because the cylinders build pressure and will not allow the piston to be moved anymore.
the crank gets hard to spin when pressure is in the #5 cylinder. even though it gets tough to spin the piston still has free reign to go up and down under pressure. it seems the valves are opening at the wrong times.
anyone else thinking what i am thinking?!?
but can anyone explain why this would be the only cylinder affected?!?
I don't why your turning the motor over with air pressurizing the cyl. a leak down is with the cyl at tdc on compression stroke or with both rockers(valves closed) wih say 100 psi,if it holds 90 psi you have 10% leak(over simplifed).then you listen to pinpoint leak. make sure if you remove rockers to check,you only do the cyl your checking.,because if a head gasket is bad it still will allow the air to escape thru the adjacent cyl. again make sure to check leak at the top of piston travel
when i had the valves totally closed i didnt turn the motor. there was no need to. all i did was pressurize the cylinder. if it leaked anywhere i would have known it. but the cylinder built compression and then stopped taking air. which means there are no leaks anywhere. it doesnt matter if the cylinder is at TDC or BDC. if there was a leak in the head or bottom end you would here a leak and the cylinder would constantly be filling with air.
so i guess you could consider it a leak down test. and there is obviously no leak in the cylinder.
i only turned the crank with the rollers on. to see if the air pressure would give the enough resistance to keep me from spinning the crank(just like it does on the other cylinders). but with the roller on the valves are opened at the wrong time keeping me from getting any compression....
so for some reason the timing must be off a little. that is all i can think of! anyone else.
so i guess you could consider it a leak down test. and there is obviously no leak in the cylinder.
i only turned the crank with the rollers on. to see if the air pressure would give the enough resistance to keep me from spinning the crank(just like it does on the other cylinders). but with the roller on the valves are opened at the wrong time keeping me from getting any compression....
so for some reason the timing must be off a little. that is all i can think of! anyone else.
