Running On 3 Cylinders!, i've replaced plugs and wires...no go Options

[blankenship]

my 2.4L is only running on 3 of 4 cylinders...it's #4 that's the culprit, because when i remove that plug wire, i get no change in running.
i just replaced plugs and wires, and no change!
i do get some spark when i hold that plug wire near the engine...

the distributor cap and rotor have been replaced recently and look darned good.
what the heck's going on here?

[thomcasey]

my 2.4L is only running on 3 of 4 cylinders...it's #4 that's the culprit, because when i remove that plug wire, i get no change in running.
i just replaced plugs and wires, and no change!
i do get some spark when i hold that plug wire near the engine...

the distributor cap and rotor have been replaced recently and look darned good.
what the heck's going on here?

Clogged/bad injector or possibly a burned valve?

[blankenship]

for some reason i was under the impression that the 2.4L "MPI" system only used (2) injectors...IF that's the case, (does anyone know?) can we rule out injectors b/c it's only the 4th cylinder that presents this symptom?

how do you check for a burned valve?
any chance it could be ignition coil related?

ps: engine has 118k and NO warning light has come on...

[Az3g]

there are defiantly 4 injectors, if you look at the back side of the engine you can see all 4 coming out of the fuel rail. so don't rule it out.

[waynerwats]

Do a compression test.

[blankenship]

just did compression test. results:

cyl 1: 129
cyl 2: 133
cyl 3: 130
cyl 4: 145

so, the #4 cylinder that's not hitting has the divergent compression, but it's not LOW!
any new thoughts?

(of course, you're right about the (4) injectors)...if the #4 injector was bad, why the heck wouldn't i get a 'warning' light on the dash?
how would you go about testing that injector?

[HMatt]

In a round about way... you could pull that one off and swap it with another cylinder. Then if the new cylinder is messed up, you have found your problem!

[BigJohnson9796]

Your injectors are not clogged unless someone put something in your fuel tank. Injectors dont just clog up somethin has to stop them up. I pointed towards clogged injectors and I was corrected quickly. You could have something electrical wrong with the injector. Other than that I dont really know what it could be. I was just wanting to help ya out that injectors dont just clog up.

[HMatt]

^these are 87 and 88 mitsu vans. With them being that old, any number of things could have clogged them over the years. Hell, just crappy gas can build up stuff in there to clog them. Most likely though, it is an electrical problem.

I doubt it's a coil, if it was, all the cylinders would be out because it's a singular coil on a distributor. Now, if it runs well at idle but cuts the cylinder under load, it can be the coil depending on how your intake mani is made. The cylinder closest to the throttle body is going to have a little more pep than the others and because of that, it may be cutting out and leaving the other 3 alone because they are not as strong.

[BigJohnson9796]

if he drives them normally still it shouldnt clog up. You can try it though

[piggylover1985]

do you a cam sensor or something ? sound kindda wierd but my 4g63t was doing that before, i tried adjust the cam sensor, and it went away.

[blankenship]

re: cam sensor ::: my books mentions a "Crank Angle Sensor," but it doesn't appear to be adjustable?

anybody thought about why it could (or couldn't) by my distributor?

the injectors definitely have an electrical component...man, that #4 looks really tough to access...like i've got to take off the throttle body and "fuel rail" and god knows what else to even get to it to test.
anybody got any tips about doing this?
the manual says something about needing to get "new insulators" for mounting the "delivery pipe" to the intake manifold (among other things)...

[BigJohnson9796]

take it to a shop have them fix the problem

[Az3g]

take it to a shop have them fix the problem

the point of this forum is for people to avoid the shop

[waynerwats]

Well your compression isnt the culprit which kills the idea of burnt valves. Its not exactly the best and is probably getting down to the service limit though. I dont know the specs on the vehicle though so that would have to be checked. The vehicle is old enough it might or might not give a warning light. I would start looking into the injector being clogged or defective. If you have a DMM you can ohm out the injector and compare it to either one that you know is good or if you have the Ohm specs for it compare it to that. You could get a stethoscope and while the vehicle is running listen to see if it the injector is actuating. Other then that take it out, connect a fuel line to it with a fuel source, and hit it with power and ground. If it sprays you know its good.

[HMatt]

^that is also a good way to set fire to your car and yourself. That's why I suggested just swapping it out with another cylinder. OHMing it out is a good idea, but it can just be stuck somehow, so that could give a misleading result.

Now, to the man with the van:
You don't have a cam angle sensor, you have a distributor, and your cam angle sensor basically tells the coil when to fire. Now, it has just 2 firing points because the crank turns twice as fast as the cams, so therefore twice as fast as the distributor. From that information, you can see that the same spot on the cas fires the 1 and 4 cylinders and the other spot fires the 2 and 3 cylinders, when it does this, the coil just knows when to fire, and the distributor lines it up with the proper plug wire and sends the spark down the line. SOOOOO if it was your cas, your car probably would run at all because all a CAS is, is a metal plate with a little sensor that picks up on the gaps in the metal plate. At least this is from what I know about those old 2.4 vans. the old 2.4 truck/van motors are a pretty interesting animal to say the least. HAHA!

All those insulators are, are the little plastic spacers where the fuel rail bolts to the intake mani. I doubt seriously that's your problem because I have seen people lose them and then bolt the rail down without them just tight enough to hold the injectors and rail in and drive around like that until the spacers came in at the stealership. The delivery pipe is just the little hard fuel line that goes to the fuel rail, if that's not leaking and the other cylinders are firing, that is not the issue.

That being said, yes, it can be your distributor cap or possibly the wire or the plug itself not giving that cylinder enough juice, or the injector is bad not giving the cylinder enough fuel. If it is easier, you can just run the motor for a bit, then pull the plug out of the problem cylinder and see if it is black and/or wet and smells like gas. That would mean that it is not getting the spark. If it is dry and white and doesn't really smell like gas, but more like burnt gas, it's not getting fuel.

Every problem like this is either fuel or spark, and there are only a few things that are specific to that cylinder and I guarantee you that one is your problem.


Happy wrenching!

[BigJohnson9796]

the point of this forum is for people to avoid the shop

Well some things mechanics need to fix at shops where they have the right tools and equipment for some jobs. This one sounds like it could be multiple things

[HMatt]

^eh... you can usually rent a "special" tool, or make one with a cut-off wheel for some of them. You would be surprise what you can do with a jack, stands, basic tools, and a little time. Now, it WILL take longer for you to do without special tools or shop, or 100% knowledge of the vehicle, BUT anything is possible.

There is no test in my previous post that he can't do. I mean hell, even if he can properly diagnose a problem, that will save time for the the mechanic he takes it to and therfore, MONEY!

Oh, and I pullled and rebuilt the motor in my elipse with a set of tools, borrowed ring compressor and torque wrench, $60 cherry picker off of craigslist, a buddy, beer and 2 weekends. Nothing is hard if you have enough time.

[BigJohnson9796]

^eh... you can usually rent a "special" tool, or make one with a cut-off wheel for some of them. You would be surprise what you can do with a jack, stands, basic tools, and a little time. Now, it WILL take longer for you to do without special tools or shop, or 100% knowledge of the vehicle, BUT anything is possible.

There is no test in my previous post that he can't do. I mean hell, even if he can properly diagnose a problem, that will save time for the the mechanic he takes it to and therfore, MONEY!

Oh, and I pullled and rebuilt the motor in my elipse with a set of tools, borrowed ring compressor and torque wrench, $60 cherry picker off of craigslist, a buddy, beer and 2 weekends. Nothing is hard if you have enough time.

Is there anything at all besides injectors that will fit onto the gst from the evo 8?

[onesickgst32]

if he drives them normally still it shouldnt clog up. You can try it though

no not necessarily. i work on motorcycles with carburetors and they will clog over the course of 2 weeks without a crank. think of an injector as a jet in a carburetor, if something gets in it it will obstruct flow (which can even be something as small as years of crappy gas) and injectors do get clogged and dirty over time, just like jets, just not as easy. i mean even injector cleaner manufacturers use that as their number one pitch for their products.

dont get me wrong, i know injectors are more efficient than carbs, but saying they cant clog is not true.