Cylinder misfire??

Question

ok, ive got a 99 nissan frontier 4cyl 2.4l i believe. the c/e lights been on for sometime now and i finally took it to the mechanic and they say the codes reading as cylinder 1 misfire. is kind of on and off... does it when it wants to... :p weve done EVERYTHING that the mechanic said was a possiblity and it hasnt worked... lights still on. only idea he has left is the computer.... says it may need a new one... what do you think? the trucks at nissan right now (where the mech. told me to take it) and theyre being jerks... as usual =)

Answer 1

here's three possiblities that your 'mechanic' may not have considered: a leaking fuel injector or a hung EGR valve that is dumping air into the one cylinder or a burnt intake manifold gasket..

If the fuel injector is leaking or clogging it will have the same effect as a bad spark plug. You can check for a leaking fuel injector by doing a fuel pressure test . Pull the fuse for the fuel pump and start the engine to run it out of gas. Then clamp off the return line and connect the fuel gauge to the fuel rack. Then put the fuse for the fuel pump back in and start the engine. then shut the engine off and watch the pressure gauge. The fuel rack should hold pressure for 5 minutes. If it drops rapidly then you have a leaking injector.

The egr valves on nissans can get carboned up and hand. they usually affect only one cylinder when they dump air in. It is a longshot if it is a cylinder #1 misfire but it could be non the less.

another possibility is a burnt intake gasket that is causing an air leak to that cylinder. That is a realistic possibility on that engine. A leaking intake gasket can usually be spotted by spraying carburetor cleaner around the gasket with the engine running. If the engine speed picks up or the idle smooths out then you have a leak. Just don't spray it near the air intake or you'll get a false reading from the artifical fuel enrichment.

there is also the possiblity that there is a burnt valve in cylinder #1. A cylinder leak-down test can tell you if that's the case.

the "happens when it wants" is probably wrong as well. My guess is Its happening all the time but it takes two test cycles for the OBD II system to determine there's a fault to turn the light on if its a minor misfire (a major misfire would result in a flashing light). The test cycles are not consecutive trips; they occur when specific test criteria are met and may take a few days and several trips for the light to be put back on after the tech clears it.

running a scope test on the firing line using a hand held oscilloscope such as a Tektronix will show whether or not the misfire is there all the time. Again, my guess is that it is.

it is never the "computer".

hope that helps

Answer 2

What specific codes did they have besides a misfire code?
Has anyone done a compression test or leak down test on #1
cylinder? What parts has your mechanic replaced and why? What was his reasoning besides a misfire code? Did he erase the code and it comes right back? Or did he not erase the code even? How quickly does it come back on (the CEL) ? I doubt it needs a new "computer". If you can answer these questions, I and maybe someone else can be of more help. Good luck!

Answer 3

i might initiate by means of checking the spark plugs. in the event that they are burnt or in any different case in undesirable shape, replace them. whether they don't look to be the reason at the back of the mis-fire, spark plugs are a miles less high priced and common thank you to enhance a autos overall performance. on a similar time as your at it examine and replace the spark plug wires, they are much less high priced additionally, in simple terms confirm you diagram which cord is going the place till now you're taking them off because is extremely severe which you place them returned on good. next, attempt paying for some gas-injector-purifier. in simple terms pour the bottle into the gas tank till now you fill it, power till the tank is low. I had a truck that adjust into working truly undesirable as quickly as, the diagnostics substitute right into a cyclinder not fireing. I had a gas-Injection cleansing provider executed for below $a hundred and the truck ran great afterwards. Ever considering that then i exploit a bottle of gas injector purifier on the 1st tank of gas after each and each oil substitute. this retains the gas injectors from cloging up interior the 1st place. utilising greater useful high quality gas will help with this additionally (greater useful sort, not greater grade) it would additionally be the distributor, take off the distributor cap and notice no rely if it truly is burnt, coroded or in any different case undesirable. you additionally can call some vehicle-shops, describe your issues and that they are going to help confirm what it ought to be, in simple terms act like your involved in understanding what maintenance are mandatory considering which you opt to comprehend how a lot it is going to fee.

Answer 4

Bad cylinder coil. Mine did that for 4 years until I had it changed. Some will tell you its a bad sensor but most of the time the sensors are doing their job and telling you something is wrong. Have someone run a full diagnostic or check the cylinder coil.

Answer 5

i own a repair shop ,and have they even checked the fire on it to actually see if was getting any at all i would think on this one it could be a bad coil pack,if the computer was that bad it wouldn't run at all hardly and just a miss on one cylinder makes me think it is a bad coil pack,i think you need a new mechanic ,because usually mechanics are easy to work with,and if yours isn't being reasonable id find me another one to deal with,good luck with it i hope this helps.

Answer 6

the ka24 has egr ports on the intake manifold which get clogged up with carbon .. to clean remove tappets 10mm allen head get a can of carb cleaner to clean excessive carbon from manifold

Answer 7

Replace the computer, the engine and the mechanic. Not necessarily in that order.