running on 3 cylinders....

[240xGuy]

so my A/T 1990 240sx is boging out on me, and i know im running on only 3 cylinders, the first one is out. i switched injectors because i was told that could be it, but no difference. i switched spark plugs and no difference. so i figured it has to be compression, until i did a compression test and it has compression. im really lost, any help?

[s13redtaz]

check to see if your getting spark and check to see if your getting fuel.

[neverlift]

how are your plug wires? a short will give alot of trouble should be less then 30ohms(IIRC) fsm in my sig should cover it..

[edgartheace]

Yeah. Check the wiring that goes to each injector by pluging in a light bulb, as the car cranks it should fliker. if it doesn't then you have short, and that would explain why you don't have power in that cylinder because of lack of fuel. If that cheks out pull out each wire from the spark plug and cheack for a spark by putting the wire next to the block and look for the spark. if there is no spark check your wire by using a multimeter, or just switch wires and check for a spark. If the is still no spark, check your dist. cap for corrosion of broken points. I hope this helps.

[240xGuy]

i know there is spark and the wires are all new. the fuel is there but im not sure if it is pulsing. im going to try putting a test light to the wiring, thanks for the help and i will let you know if it works.

[240xGuy]

well, i tried the wiring and it is pulsing. i have no idea what it could be. im wondering if the intake valves are stuck closed and letting no air in to mix the fuel with. any other suggestions? anything that could be clogged as far a egr valve or anything?

[edgartheace]

The only other thing that I could think of is that your egr is stuck open. disconnect and plug the hose that runs to it and see if you car improves. If it does it means that your EGR control selenoid is not getting the signal to open and bypass the egr at idle.