Only firing on 2 cylinders?

[skipjim]

Ok,

A few weeks ago my 2000 Galant 2.4l coasted to a stop on the highway. Towed it to my buddy's garage figuring on replacing the fuel pump.

Did that. Still wouldn't start. Replaced the Cam Position Sensor, still nothing, replaced one of the two spark packs nothing.

Opened up the timing belt cover to discover that the balancer belt had come apart, replaced that and the timing belt, and the crank position sensor. We also replaced the spark plugs too (yes they're gapped properly).

Now the car will actually start, but it will only fire on cylinders 2 & 4 and 1 & 3 aren't firing at all. We pulled the codes off the car and got one for random misfires, nothing else comes up.

Where do we go from here? All four of the cylinders still have compression (125psi for 1-3 & #4 has 100psi), all four are getting spark.

Do we check the injectors on the two cylinders that aren't firing or do we bite the bullet and tear off the top half of the engine assuming that now we've got valve work to do?

Any suggestions would be greatly appreciated, I'm running out of money to throw at this car.

[seth98esT]

Thats really low compression. Dumb questions, have you check spark on all the cylinders?

[skipjim]

There are no dumb questions with this @#$@# car =]

Yes we checked for spark on all four. The odd thing is it's firing one cylinder from each spark pack...

As far as the compression test I'm not 100% sure they did it per the manual (I wasn't there that night) but I guess the point is that the cylinders are all holding pressure.

[duh2150]

lets see, im gonan take some wild easy guesses.... are they even hooked up? lol to the packs?, are they all the way down into the engine? use a mutimeter to see if theres a full current can be conencted through the lines on plugs 2 and 4, its a problem with the wires it sounds like not the packs itself, if it was a problem with the pack it would at least have one working fully, its like really hard to believe that both packs and both side thingys are not connducting right..

check plugs
check wires
multimeter the wires
put them fully in press down a bit somtimes its hard to get in.. give them a good push lol youll here then snap in place kinda,
also see if the thinsg are in good shape
post pics :)

[lonestar22]

injectors? idk im an idiot

[Stewi]

Dump a cap full of engine oil into each cylinder and do the compression test over again, if the compression doesnt rise at least 10psi per cylinder, you either have bent valves, cracked pistons, or both. Like seth said, the compression #'s you posted are super low. The motor may still run, but it doesnt mean its not hurt.

[skipjim]

I'll have him check the pressure again tonight with the oil in there. When he told me the numbers the other day I started to wonder why they were so low, on the other hand the cylinder with the worst compression is one of the two that is firing.

I know he's got a meter there so maybe I'll check all the wires and injectors while I'm there too.

Pictures...uhg they're not going to be pretty. I'll see what I can do tonight.

What I'm trying to do at this point is avoid having him pull the valve cover off if we don't have to. Mostly it's denial because if we go that far I'm probably going to end up either yanking the engine and getting one from a junkyard (they take kids in trade don't they?) or rebuilding whats already in there. Either way is going to cost me more than I've got right now (buying a house next week).

I'll try and post more information and maybe some photos tonight.

Thanks for the advice so far.

[WarmAndSCSI]

Dump a cap full of engine oil into each cylinder and do the compression test over again, if the compression doesnt rise at least 10psi per cylinder, you either have bent valves, cracked pistons, or both. Like seth said, the compression #'s you posted are super low. The motor may still run, but it doesnt mean its not hurt.

He's not going to see 100+ PSI with bent valves. Even slightly bent valves will show 60 PSI max. That's a ring sealing issue, be it a cracked piston or just worn rings.

[RedGalant2k1]

Dump a cap full of engine oil into each cylinder and do the compression test over again, if the compression doesnt rise at least 10psi per cylinder, you either have bent valves, cracked pistons, or both. Like seth said, the compression #'s you posted are super low. The motor may still run, but it doesnt mean its not hurt.

He's not going to see 100+ PSI with bent valves. Even slightly bent valves will show 60 PSI max. That's a ring sealing issue, be it a cracked piston or just worn rings.

Though it doesn't tell you why its not firing.

I'd say ignition module. Though you should make sure the plug wires and coil packs are installed in the proper firing order.

[WarmAndSCSI]

Dump a cap full of engine oil into each cylinder and do the compression test over again, if the compression doesnt rise at least 10psi per cylinder, you either have bent valves, cracked pistons, or both. Like seth said, the compression #'s you posted are super low. The motor may still run, but it doesnt mean its not hurt.

He's not going to see 100+ PSI with bent valves. Even slightly bent valves will show 60 PSI max. That's a ring sealing issue, be it a cracked piston or just worn rings.

Though it doesn't tell you why its not firing.

I'd say ignition module. Though you should make sure the plug wires and coil packs are installed in the proper firing order.

I wouldn't continue to run an engine with low compression unless I absolutely had to. Excessive blowby (acidic oil, gas, etc) is extremely unhealthy for an engine (since it gets sucked back in through the PCV or breather hose) as is the unbalance of the rotating assembly itself.

[RedGalant2k1]

I wouldn't continue to run an engine with low compression unless I absolutely had to. Excessive blowby (acidic oil, gas, etc) is extremely unhealthy for an engine (since it gets sucked back in through the PCV or breather hose) as is the unbalance of the rotating assembly itself.

Granted, I wouldn't either. I was merely stating it doesn't solve the firing issue.

[skipjim]

As far as I know he's got the plug order correct.

I'm going to try and get over to his house tonight maybe I'll try and swap the wires around and see if I can get it firing on 1 & 3. My wife is supposed to be bringing the digital camera so I'll take a few photos too so you guys can all point and laugh.

I'm not terribly worried about the low compression (at the moment) I'd just like to get the thing back on the road. I've been begging rides into work from a coworker who starts an hour before I do, thats getting old.

From the look of things we might just end up pulling the motor and finding one from a junkyard.

[skipjim]

I can't believe I'm asking this....

Is it possible to mount the V6 rather than the 4cylinder motor if we have to change the motor?

[Sleepervr-4]

I can't believe I'm asking this....

Is it possible to mount the V6 rather than the 4cylinder motor if we have to change the motor?

Any thing is possible with $$$ but it isn't worth it. You would need to swap to a v6 trans since the i4 trans wont bolt up to the v6. You would also need the front subframe since v6 is different also motor mounts and brackets and ecu and harness and engine. Not worth it imo when you could probably get a v6 for 4k. When you factor in the price for all that you could have got a stock v6 and had money to mod it too.

[skipjim]

Thats what I figured, but with the v6 only being a little bit more money from the junk yard the thought crossed my mind :D

Hopefully I'll have some pictures tonight, my buddy is supposed to be pulling the head off in a little while.

[silver_beast98]

mechanical issues dont explain two plugs are firing and not the other two... i hope the head hasn't been pulled before you read this... now my buddy has a 2g and im assuming the ignition system is relatively simular.. does it have a power tr unit? if so i think thats the culprit because his went out resulting in the car running on two cylinders and always trying to boost because the unburnt fuel from the other two was igniting in the exhaust mani! i seriously hope you get this before you take the head off because it has to be something electrical...

p.s. if it has a power tr unit and that in fact is the prob, they are expensive to buy new, but if you go to a u-pull-it and say its a relay, you can get it for about ten!!

[skipjim]

Nope, I'm pretty sure that he hasn't pulled the head yet.

I'm actually wondering now if it's not in the wires. The two cylinders that are firing are the ones that run directly off the spark packs. The two that aren't firing are the ones that run off the wires.

If it's something that simple I'm going to have to shoot him I think.

Pictures coming up in a moment.

[RedGalant2k1]

Nope, I'm pretty sure that he hasn't pulled the head yet.

I'm actually wondering now if it's not in the wires. The two cylinders that are firing are the ones that run directly off the spark packs. The two that aren't firing are the ones that run off the wires.

If it's something that simple I'm going to have to shoot him I think.

Pictures coming up in a moment.

Like I said its probably your ignition module.

Btw, I just read you are in michigan? Just outside Grand Rapids huh?

Up for a January Lansing meet?

[skipjim]

Yes I know I'm probably sinning by posting images of a dirty motor, sorry if I offend anyone








At least I didn't post photos of our new puppy :P

[skipjim]

Wouldn't the ignition module throw a code on the computer? the only thing that showed up there was for random misfires.

Yeah we're about 15 minutes north of Grand Rapids, I'm down there for work every day.