My friend Owns a 91 240sx Hes been having problems left and right since he bought it. It was to be a project car. Well its one hell of a project car. I need you guys' help, Heres his post from the midwest240sx.com forum.

240sx post:: Does anyone know of any electrical problem that might cause my 91 to die whenever the MAF is CONNECTED?Whenever I have the MAF disconnected it idles fine as soon as you reconnect the MAF it sounds like someone is strangaling it, it shakes violently and dies. If you drive it, it drives fine, until you stop then it dies again. . . .

So far Ive repaced the ECU,MAF 3 times ,TPS, cleaned out the IACV, added 3 thick groundwires,the 02 sensor,new sparkplugs,new ignition wires,cleaned the intake manifold and throttlebody. Any Ideas????

I refuse to take it to Nissan as all I did was pay 300 for them to disconnect things and leave them undone and tell me that they think it has to do with the MAF circuit? ::


Please give any thoughts to the Problem I would really appreciate it
Help Me Anyone with any kind of idea.

 

because I have a Maxima and a 240sx at home, I guess I will lend a hand... but I'm not going ot be the one answering your buddy's problem because quite frankly... I have not friggin' idea what's the matter. You might take it into a trusty mechanic and just show him what kind of problems you're having. Some mechanics are cool like that.

Anyway, you should submit a post at www.240sx.org.
When you get to the home page, scroll down a little 'till you see the link "Info about joining"

After clicking that, scroll down some more until you see the bulletin board topics. BE WARNED however, they might be like this group... they don't like strays coming off the street and throwing questions up into their faces. READ the POSTING RULES.

Good luck.

 

As he said, check the 240 boards, but often times on problems like this you won't find help because (as on the altima board) most of the people there aren't exactly tech people. they're there to talk about intakes, exhaust, springs, wheels, etc...

Sooo, here's a bit of help- if it works, great. if it doesn't, at least it's a place to look.

I don't remember what engine the 240SX has in it, but my wife's alty has done some stupid stuff like that lately. KA24DE engine in it.. but it's got an intake manifold gasket leak. seems to be common on these cars and causes horrible idle problems, as there's air leaking into cyl #4 while the engine is at idle.. so the MAF doesn't see the air coming in to account for it and inject the fuel to burn it all...

so cyl #4 misses at idle because of it. floor it, and there's not as much vacuum in the engine, so the leak stops and all the air going into the engine goes through the MAF. runs fine that way.

In your friend's case, the intake manifold gasket could be leaking.. all of the probelms on the car indicate that it's getting air into the system and not running right. if you disconnect the MAF, the engine goes into a "failsafe" mode and relies on the o2 sensor and TPS in order to know how much fuel on inject. plug the MAF back in and it runs lean and dies.

give it gas, and the manifold leak stops as in my case, and the car runs fine.


make any sense? it's something to look at. certainly can't be any more messed up than swapping out sensors at several hundred bucks each.

 

You know what I asked him about this too and he said it was fine. Because like you thats What I think it is also. Ill tell him to make sure there are no leaks Like actually put a new gasket on. The thing is him and his dad just fixed the engine it had a blown head gasket so they put a new one in. I have a feeling youre right thanks Matt.