Weird miss fire and idle HELP!!!

[joshcasey0791]

hey i have just recently purchased a 91 talon 4g63 non turbo and it was a weird miss fire. i pulled cylinder 4 plug wire off and it didnt change how it ran but i was getting spark outa the wire and there was water in the tube. i blew out the water and let it dry then i pulled the plug out and it was fouled out bad. so i replaced it ### im just tryin to get it running right. and when i replaced it the idle lopes and then when i give it gas or drive it, it still miss fires the same. and suggestions on when i should look at next?????

 

[dented_coffee]

Is your check engine light on? Try swapping out the MAFS. Is your fuel filter bad? Take the connector off the injectors and make shure none of them are burnt out and are all in spec with a multi meter. They should be reading arround 13-16 ohms at arround 68* in temp.

Also it might be your ISC as well. They tend to go bad alot when people try ajusting the BISS improperly. To test the ISC you read the ohms of resistance between the terminals in this order of sequences. The * is showing the top of the connector for reference.

*
1 2 3
4 5 6

1 and 2
2 and 3
4 and 5
5 and 6

All of them should be reading 28-33 ohms at 68* in temp.

 

[Calloflunacy]

Another thing that would be worth while to check is do a compression check on the motor, bad compression could be your issue.

 

[joshcasey0791]

im pretty sure compression is ok i did a tune up to it and it ran great a little miss when just starting out but other than that it was great...then it started running like crap and i replaced the fuel filter and it didnt help at all.. ecu maybe?

 

[Calloflunacy]

I doubt it is the ECU, when it goes the car ussually won't do anything. I would still check the compression to be sure since it is really easy. other then that check the plugs or the fuel injectors like coffee said. I would troubleshoot the possibilities to figure out what is the problem, if one of your cylinders isn't firing, make sure your getting fuel, so test the injectors, take them out and look at them, plug them in and turn the car over see if they sprays. Check your spark plugs take them out, plug them in, lay them on your valve cover and see if they spark. And you need good compression for it to fire. Try to rule out what it isn't then once you have it narrowed down we can help you better.

 

[joshcasey0791]

I doubt it is the ECU, when it goes the car ussually won't do anything. I would still check the compression to be sure since it is really easy. other then that check the plugs or the fuel injectors like coffee said. I would troubleshoot the possibilities to figure out what is the problem, if one of your cylinders isn't firing, make sure your getting fuel, so test the injectors, take them out and look at them, plug them in and turn the car over see if they sprays. Check your spark plugs take them out, plug them in, lay them on your valve cover and see if they spark. And you need good compression for it to fire. Try to rule out what it isn't then once you have it narrowed down we can help you better.

ive replaced the plugs and wires and then the wires kept falling off so i replaced them again along with the plugs and the car runs by itself after i backed the idle screw off a little and if i touch the gas it kinda sputters and bogs out and backfires and doesnt increase the rpm unless i just barely touch the throttle. and it smells like its running extremely lien.....ive replaced the fuel filter as well and it didnt help and i pulled the injectors out and they looked very clean so im just not sure where to go from here ### i keep getting responces from my brother who is a fellow dsm owner that has more experience in the dsm world than me to replace the fuel pump because we ran some tests on it and it sounds like a dying cat or something its not a smooth hum like its supposed to be.

 

[iron bird]

i had similar problem and my ecu was fried

 

[Calloflunacy]

Now when you say it backfires, is it actually like a pop, or just a miss. If so, is it backfiring out of the intake or the exhaust? because that sounds like a timing issue.

As for the fuel pump, that could explain the missing cylinder, my GS had the same problem before. The fuel pump was going out and I could hear it from the driver seat when I turned the key, they get really loud when they start to burn out. You can disconnect the main fuel line and turn the key and watch the fuel spray out and try to gauge how well the pump is working if you don't have the connector for the pressure gauge. How I did it though was I disconnected the air intake tube from the throttle body and sprayed some starter fluid in the intake, hooked the tube back up and started the car. if it starts up great and runs for a couple seconds without missing then I would look at the fuel pump.

 

[Chazz1978]

Its always a good thing to test compression across the board. Could be possible minor headgasket. Try replacing the plug. Next step if it occurs again I would make sure fire is strong and fuel to and coming out of injector is good. If its only one cylinder more than likely its not mas related. It can be intake gasket leak. Bad coil or wire. Also bad injector could cause misfire. So recap single misfire could be caused by bad injector, plug, plug wire, and or coil. Also if all other cylinders are good may not need to worry about fuel delivery either.

 

[XiKeiyaZI]

Have you checked your MAF? What you explained in your first post, sounds like it's not metering the amount of intake it's getting and compensating with Fuel.

Do realize that Lean means too Much Air.
Rich Means Too Much Fuel.

 

[joshcasey0791]

yeah i was a mechanic for 6 years i know what the diffence is between rich and lean and on these types of fuel systems i cant just turn the key on and let the fuel flow.....i have to crank it..so i did and it doesnt have alot of pressure

 

[Karnag3_0kc]

Did you check the spark plug gap? Maybe that's an issue?

 

[joshcasey0791]

i actually just replaced the fuel pump 2 days ago and that fixed it thanks for all ## help guys!!!!!