HELP! Car shutting off for no reason, SDS Engine Mgmt. I think might be the cause?

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Sid3ways S13
Posts: 218
Joined: Thu Jun 19, 2003 3:29 pm

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Well I'm having problems with my SDS Enginemanagement system. The cars has run flawlessly up until yesterday when I started having this problem.

I just was driving down the road no problems whatsoever and the engine just turns off. All of the electronics stay on, everything acts normal but the motor itself just shut off. :confused: Ok, that has never happened before, I am checking the SDS control unit and nothing looks out of the ordinary, engine temp looks perfectly fine, air temp may be a little hot but the motor itself wasn't overheating by any means. Get out of the car and am not leaking any fluids, visual inspection of the engine bay and everything on the outside looks perfectly fine. Ok try to start the car and it won't start back up right away so I let it sit for 5 minutes. After 5 minutes it started back up and I drove away.:confused: Then about another half hour later the car does the same exact thing, normal driving and it shows no sign whatsoever of running hard or rough or any preliminary symptoms that something is about to happen. It starts back up after a while and now it runs for maybe a mile before it shuts off again.

Well anyways I get to the car show and the car sat for probably 6 hours or so and leaving was a *****, a normally 1 hour drive took 3 hours because the car died so many times on the way home. But a few times I found on the way home that when the car goes into its "limp mode" or whatever you want to call it if I let off the gas and coast while in gear the car will coast normally but when I hit the gas again the car actually slows down quicker like it is worse for the car when I give it gas. One of the times also when the car was about to die I turned the knob all the way to the rich setting which is 50% more fuel at idle and it saved the motor from completely crapping out, it had a really rough idle for like 2 minutes and then it went back to normal for about a half hour:confused:.

Bottom line is I would love to get some feedback if anyone has and information if they think it could possibly be something else. It also feels like I'm losing spark or something possibly, I'm going to check the spark plugs and wires to see if they are still good and one of them isn't fowled up. I can't imagine it has anything to do with the engine itself, it runs cherry and I can beat on it all day long when it runs fine, but just out of the blue it goes into this "time to turn off" mode. I'm starting to learn more about this SDS system everyday but if anyone has had this problem, or if my unit is going bad you think, please give me some feedback. Thanks guys.


240_Keyy
Posts: 1310
Joined: Wed Dec 04, 2002 6:45 am
Car: '90 240 Fastback
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my friend had this exact same problem with his SDS system. As it turns out, the problem is that over time the magnetic sensors in the crank pulley lose their magnetism and the sensor can no longer read the crank position from the magnets. After some random amount of time, the ecu begins to be unable to compensate with the weak signal and it shuts off the car. Then if you let it sit for a while, it will start back up exactly like you describe. Then it will work fine for a while and get confused again and turn off.

I think you can order spare magnets from SDS really cheap, so you might want to check with them on that one. This started happening so frequently to my friend that he bought a whole buttload of magnets and just keeps them in his car incase it ever happens to him again.

Hope this helps...

Sid3ways S13
Posts: 218
Joined: Thu Jun 19, 2003 3:29 pm

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Well honestly that sounds exactly like what my car is doing so I'll call up SDS and order a few more. I can't thank you enough if this fixes my problem, I am clueless! :confused:

Sid3ways S13
Posts: 218
Joined: Thu Jun 19, 2003 3:29 pm

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Well I called up SDS and they told me to check the fuel pressure, which I didn't even think about looking at. Yup, turns out that after about 45 seconds now, I can hear the HKS fuel pump just turn off and the car slowly dies off. I'm going to check the wiring to see if it is the pump itself that needs replaced or I have a short somewhere. I'm glad at least I found the problem. Thanks for your help.:ylsuper

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slw240sx
Posts: 3303
Joined: Thu Aug 08, 2002 9:39 pm
Car: 1990 Ca18det 240sx Hatch

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where in ohio are you?

Sid3ways S13
Posts: 218
Joined: Thu Jun 19, 2003 3:29 pm

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Maumee (Very close to Toledo)


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