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Ryguy92503

1989 Buick Reatta Blackout.

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Hello I have a 1989 Buick Reatta, I've been having a battery drain problem ever since I bought it but recently the drain grew so I put a kill switch in it. Now my car is fantastic.... Except for the past 3 days.... I'll be driving and all of a sudden EVERYTHING in my car shuts off, and then a few seconds later turns back on like all of my computers are restarting themselves, this will happen while I'm driving. But my computers don't seem to turn off because my mpg number doesn't reset or my trip number doesn't reset. It happens if I go over a small bump or so ermines I don't even need a bump. Yesterday I was driving on a smoothish road and all of a sudden my car does it again but this time my engine cut off... So I had to put it in park and restart my car. I don't know if it's the kill switch I don't believe it is but if anyone can help me I'd really appreciate it. I do not know where to even start....

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You should go to this link to find help with your problem.

I had a similar problem a few years ago that turned out to be a battery cable with a bad connection. You can read about it here.

  1. Start by doing the Battery Cable Checks & Repair procedure.
  2. Then you should read Ground Terminals & Junction Box Location to learn how to clean and tighten the ground wires. There are also some ground wires connected to the intake manifold.
  3. Once you have found the problem with the engine dieing you can go here to learn how To Measure Battery Drain that will assist you in finding why the battery keeps going down.

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This is going to be a process of elimination. FYI, this problem is likely not related to your battery drain issue. You may ALSO be experiencing multiple separate issues.

FYI, if you don't have the '89 GM Field Service Manual, GET ONE. With vehicles of this complexity and age, trying to work on them without the FSM is virtually an impossibility. You can get a soft copy of the '89 FSM at www.reatta.net (click on documentation and the fill out request). It may be just my personal preference, but I would NOT be without a hard copy of the FSM as it cross references itself a LOT and doing so online tends to get confusing. The online version is great for getting specific pages that you want to print out so you actually need both.

If you are not really comfortable with both typical automotive systems and complex electronics, the Reatta is not a good place to learn either. The car was WAY ahead of its time. It has proven to be a pretty reliable design in all aspects, but when there are issues, they can really wrap you around the axle at times. I am not trying to dissuade you from tackling this problem, but it is always good recognize your limitations. Finding someone that can troubleshoot the Reatta can be a challenge due to its age and again, the GM FSM is going to be key for ANYONE trying to work on it (independent technicians will NOT have access to the FSM as a rule, so it is BYO affair.

I would start with the various grounding connections as they are notorious for corrosion. Start with the negative battery connection itself as it can develop internal corrosion. Then check the two grounding posts mounted just forward of the battery. Then verify the large grounding post that is on the passenger fender just aft of the battery. Finally follow the negative cable from the battery to where it connects to the engine itself. I would removed the nuts at each of these connections and look for corrosion as well as clean the lugs and then coat them with a good dielectric silicon grease (found at any FLAPS) and reinstall.

Faulty grounds are the root cause of many of the Reatta gremlins. So it is VERY important that you inspect all of them carefully.

Obviously you need to verify that the kill switch you installed was not the culprit in the latest incident. As I assume that you installed the kill switch to totally disconnect the battery, the easiest way to clear the kill switch is to ask yourself if the trip and mpg readings reset after the engine died.

Once you have cleared all the grounds, it never hurts to verify the +12 connections at the battery terminal (again internal corrosion) and at the isolated +12 post located behind the red plastic cover just aft of the battery on the passenger fender. These don't give as much issue as the grounds but it is a good idea to verify their condition.

If not for the most recent failure you mentioned (i.e. engine completely dying) I might suspect the CPS (central power supply) as it supplies a regulated and filtered voltage AND ground to ALL the electronics with the exception of the ECM (engine control module) which has it own internal power supply. If the CPS is failing, the info maintained between starts of the car (mpg, trip, etc) would be maintained by the +12 keep live circuits. The CPS is located up behind the instrument panel and you really just need a spare in order to test if that is the problem since the problem is intermittent. However, I don't believe that the CPS failing could explain the engine dying, since as I mentioned, the ECM and its associated circuits power directly from the battery.

The engine just dying has all the earmarks of a failing crank sensor, but since the rest of the car died if I understood you correctly, then I would not chase that squirrel until you eliminate a few other things. FYI, some crank sensors fail totally, outright and others are intermittent, so the fact that it restarted does NOT clear the crank sensor and the associated ignition system just yet, but again, see if you can solve the other issue first.

I am sure that others on the forum will remember something that I have forgotten to mention. You have found the BEST place for keeping your Reatta road worthy and a joy to own.

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Thank you guys very much! I really appreciate the tips! I'm going out now and looking at EVERYTHING. I'll write back if I find anything or if something is corroded. Thanks again for the help!

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I had the same problem when I first bought my Reatta, turned out to be loose battery connections.
That was my problem too. The battery bolt that held the negative cable to the battery was stripped and so were the threads in the battery. Mine required a new bolt and battery to cure it once and for all. I tried to chase the threads and tighten the bolt but it would loosen rather quickly. I have also read here about some bolts bottoming out and not allowing a tight connection to the battery. I hate side mount batteries.

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