91 240 running on 3
91 240 running on 3
...sometimes. This is a really wierd problem. Occasionally my 240 runs on 3 cylindars. It'll be vibrating like mad and you can pull the plug wire out of the #1 cylendar and nothing changes. I've replaced cap rotor and plugs. Ran ohms on the wires, tested for injector pulses, ran codes on it -there were none, and spit and cursed at it multiple times. What i'm thinking is thats its a computer problem. I know its getting air and spark, and fuel, to a point (more on this in a second) When it's in it's pissy mode, which really isnt very ofen, most of the time it runs fine, it feels like it has no power, and vibrates violently at idle. It also backfires when you let off the throttle. So my theory is that sometimes, for whatever reason, the computer screws up the injector pulse timing to the #1 cylendar, so its like it still injects fuel, just at the wrong time, so it doesnt ignite and just gets blown out the exhaust, therefore leaving only the other 3 cylendars making power. Now tell me how cockeyed my hypothesis is and what I can do about this problem
well first you said you checked injector pulse, then you hypothisized it didnt have a correct injector pulse?? which is it?. I am thinking your injector itself is malfunctioning, when it goes on its trip ohm check the injector and see how many ohms it is, it should be in the teens any higher or lower then its probably got cicuitry problems inside.
Re: 91 240 running on 3 (RipShift)
A friend of mine has this exact same problem with a 90 240sx....only its cylinder #2...he had the head worked,swapped injectors,wires,plugs,everything except another computer.....he says there is a good spark on #2 when the problem is happening...thinks maybe it isnt firing at the right time...oh yes,he even swapped the distributor and the problem stays on #2.....being a nubie as far as 240s go,I had no other suggestions....he says there is no way to check the computer but I dont really 'buy' that...is this true?...thanksRipShift wrote:...sometimes. This is a really wierd problem. Occasionally my 240 runs on 3 cylindars. It'll be vibrating like mad and you can pull the plug wire out of the #1 cylendar and nothing changes. I've replaced cap rotor and plugs. Ran ohms on the wires, tested for injector pulses, ran codes on it -there were none, and spit and cursed at it multiple times. What i'm thinking is thats its a computer problem. I know its getting air and spark, and fuel, to a point (more on this in a second) When it's in it's pissy mode, which really isnt very ofen, most of the time it runs fine, it feels like it has no power, and vibrates violently at idle. It also backfires when you let off the throttle. So my theory is that sometimes, for whatever reason, the computer screws up the injector pulse timing to the #1 cylendar, so its like it still injects fuel, just at the wrong time, so it doesnt ignite and just gets blown out the exhaust, therefore leaving only the other 3 cylendars making power. Now tell me how cockeyed my hypothesis is and what I can do about this problem
Re: (NISTECH)
NISTECH wrote:well first you said you checked injector pulse, then you hypothisized it didnt have a correct injector pulse?? which is it?. I am thinking your injector itself is malfunctioning, when it goes on its trip ohm check the injector and see how many ohms it is, it should be in the teens any higher or lower then its probably got cicuitry problems inside.
what i was talking about with the injector pulse was that the injector is getting a signal to fire from the computer, that much I know. What i dont know is whether or not the signal is comming at the right time. It's the timing im questioning. How do you run ohms on an injector? Or which prongs do you touch to check it I mean, there are 4 I think.
Re: (NISTECH)
lol yeah after posting that i went out to test it anyway and discovered there were only 2 prongs 2,3 and 4 are all at about 12.5 which is good I guess. 1 deosnt even show a reading on the dvom, so im guessing its cooked, correct?
almost forgot, one other thing. How do you get the bloody thing out of there to replace it? As far as I can see, its just those 2 phillips head screws that hold the cap in place over the top of the injector. These are completely stuck on my car and I cant get them out without stripping them out. Any suggestions?
thanks
almost forgot, one other thing. How do you get the bloody thing out of there to replace it? As far as I can see, its just those 2 phillips head screws that hold the cap in place over the top of the injector. These are completely stuck on my car and I cant get them out without stripping them out. Any suggestions?
thanks
Use a #2 phillips bit in an impact driver to break them loose. Impact driver is one of those things you hit with a hammer, not to be confused with an impact rachet. Thats the easy part too. getting the injector out takes a bit of finness. You have to gently pry on it and let the seal work its way out of the bore if you pry to hard you will break the injector and it will become a real pain to get the injector out.
And yes that injector is open ,so its no good.
And yes that injector is open ,so its no good.
Re: (NISTECH)
Ok, thanks for the help Nistech. Sadly I wont be able to work on it for about a week, but as soon as I can I'll get that injector replaced ...expect more questions then
Re: 91 240 running on 3 (RipShift)
oh where to begin... replaced the #1 injector, after some fiddling with a bunch of stuff, heres where I am. Running on 4 cylinders, hard to start (have to blip the gas to get it to start) plugs are fouled (all black) blowing whitish smoke, it doesnt have a lot of low rpm throttle response (it'll bog for a second if its idling in neutral and you blip the gas) but up high it feels fine. the smoke is what im most worried about at this point, theres lots of it. I'll try to answer any more questions you have to help get a diagnosis on this. thanks