bad cdi box symptoms

Gav1n8 · #11 (**permalink**) 10-26-2009, 11:25 AM

okay most recent diagnosis. fuel pump pressure is perfect.

I think the cdi box is bad because when we first got it, it wouldnt start. we replaced battery, spark plug. still wouldnt start. but just last night me and my uncle flipped the cdi box upside down and it started? ran great for about 5 mins and then began to lose spark again and die. if you touch the cdi box at all while it starts up and runs for just a sec it dies. even if you just poke it it will kill the 4wheeler. thats why im thinking its cdi box.

Gav1n8 · #12 (**permalink**) 10-26-2009, 07:56 PM

does it sound like a cdi box problem since if you move it while its started it dies?

Stemmy450 · #13 (**permalink**) 10-26-2009, 09:08 PM

as said if its getting spark then its not your CDI, thats the whole purpose of the CDI to say when to give spark. I have a feeling its your fuel pressure regulator.

Jaydoggg · #14 (**permalink**) 10-27-2009, 06:04 AM

what was confusing to me is you keep saying cdi bad but "getting spark" total contradiction. Sounds like you might have either 1 or 2 problems. Wire harnes or connector for the CDI and the Fuel Pressure Regulator.

Pull the CDI and clean the connector terminals really good with contact cleaner. Put some dielectric grease on then check it with the manual. FPR just needs blown out.

ATP Racing Engines · #15 (**permalink**) 10-27-2009, 06:08 AM

Are you getting a check engine light? You could very well have a bad Tip over sensor that is causing you problems.

Obviously, anything can go bad, but for what its worth, I have nver seen a CDI go bad on an LTR.

Mike

Jaydoggg · #16 (**permalink**) 10-27-2009, 06:15 AM

Quote: Originally Posted by ATP Racing Engines

I have nver seen a CDI go bad on an LTR.

X2 They are rock solid.

Also, the kfx400, Arctic Cat DVX 400 and ltz400 were all the same quad MADE BY SUZUKI thats why they could share CDI's. The KFX 450 is actually made by Kawi, so that is why the CDI will not swap with the LTR.

the cdi's on those quads were shi*

Gav1n8 · #17 (**permalink**) 10-27-2009, 06:19 AM

how do u check fpr or can i use search engine and find out how?

I've never had a cdi go bad on anything but it just seemed the most logical since if you touch it thats what cause the atv to die. I can hit the fuel pump, pull wires, anything. but if i touch the cdi box at all it dies.

I will clean the terminals as u said, but really don't think it will help cuz its already really clean.

no im not throwing a check engine light.

**CQR** · #18 (**permalink**) 10-27-2009, 06:26 AM

The CDI is a tfi (Thick Film Integrated) unit, meaning that all the parts inside the box are encapsulated in a goo that helps prevent failure due to vibration and shock. The fact that it dies when you move the CDI, leads me to believe you have a bad connection or broken wire near the connector. Any part can fail, but the symptoms just don't point to a faulty CDI.

Testing the FPR is done by checking fuel pressure.

Gav1n8 · #19 (**permalink**) 10-27-2009, 06:42 AM

uncle said the puel pump and pressure is right on, its at his honda shop so i can't physically do any of this now, and am guessing he is checking this stuff right. I will tell him to clean terminals and hope thats it.

It really doesn't seem likely for a cdi to fail, i'm sure its happened before but I do see it hard to beleive also. I thought the cdi told the atv to keep giving spark which is why i think when u touch it, its may slightly disconnect a wire and cause it to die.

I'm definately interested in finding out what the problem is and letting yall know whats wrong with it.

Stemmy450 · #20 (**permalink**) 10-27-2009, 10:15 AM

sounds like somebody needs a service manual...

where is he checking the fuel pressure at? right after the pump? if so then yeah its gonna read good pressure. you might have something wrong in the wiring, bad connection someplace.