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Discussion Starter · #1 ·
so I pick up this cirrus drove fine first day . Next day in the morning I turned it on . About a minute went by and it shut it self off . Thought maybe it sat awhile before I bought it . So drove it to work and with in 25 minutes came to a light and it shut off at the light .started right up . Still doing the same thing . Replaced the alternator because it failed voltage regulator. Swapped the auto shut off relay . Cleaned the throttle body and cleaned the iac . No change . No codes no lights on dash . Any ideas ?
 

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If you're serious about solving this it would help you tremendously to acquire a factory service manual, or a web based information database subscription such as ShopKey for example. Get access to service information, and do some real tests and inspections.

Based on the information you've provided (which isn't much in terms of making a positive diagnosis over the internet) I would verify that your Crankshaft Position Sensor is functioning within specifications.

It can be difficult to diagnose an intermittently failing CPS, so if it is cheap and you can afford to gamble the money, in this case, I would almost go as far as to say that you could try throwing that part at it.

-Ziu
 

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1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
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The coil is inside the distributor. The early Mitsubishi distributors were known for failure. It may not leave fault codes behind, but a good scan too can tell you whether the cam sensor or crank sensor signal is lost or missing while it's in no-start cranking. Diagnose first.
 

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If you have a multi-probe oscillscope and read wave forms, testing the Crank/Cam sensors simultaneously is a great way to see visually if they are working properly on their own and in relationship to each other as they should.

Here is a link to a fairly competent article concerning Crankshaft position sensors.

Crankshaft position sensor: how it works, symptoms, problems, testing (at https://www.samarins.com/glossary/crank_sensor.html )

The 2-wire (magnetic) CKP can be tested using a multimeter switched to Alternating current. Back probe the signal wire and ground. Remove a fuel pump fuse or relay so the car will not start, and then crank the engine while taking your voltage measurement. If you get a good reading when the CKP is working, you can use that as a reference point to spot a variation in voltage if you are lucky enough to get a reading when it does decide to fail. (This is a simple logical deduction I use in some cases if exact service specs are unavailable.)

You can also resistance check the CKP, but it's not a guaranteed test for an intermittently failing CKP.

Also take note as mentioned in the article that what can appear to be a defective CKP, could in fact be a faulty flex plate, reluctor ring, or even the crankshaft itself.

It's variables such as these that can make for a wild goose chase if you're not thorough and informed.

Another example being that a catalyst whose honeycomb substrate has super heated and fused together can form a heavy duty blockage/barrier, causing exhaust flow restriction and backpressure into the cylinders, which depending on the severity of the blockage can cause issues such as overheating, stalling, misfiring, damage to gaskets, etc. You can have someone step on the gas to about 2,000 RPM, and feel for a hot, restricted flow, or any sulphuric smells.

I do not know if this applies to your vehicle or not, but in certain vehicles a faulty 02 sensor will shut down the engine, in which case the engine will generally need to cool before it will start again. However you should find a code stored for your o2 if this is the case.

When dealing with any stalling engine or crank but no start, it's usually a great idea to always cover your basics. Air intake and vaccuum, Fuel, filter, pump, pressure check, injectors, etc. Compression, spark/plugs/wires/coil(s)distribution...all are worth looking into.

I had a 95 Geo Metro with a bad magnetic type CKP, and no matter what I did, it would not die or fail to start for me whenever I was testing the CKP! However it would randomly die, and fail to start here and there, or run for hours without an issue. Long story short, the water pump was leaking onto the CKP. The CKP and water pump were replaced, fortunately solving the problem.

I hope you get it figured out.
 

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The coil is inside the distributor. The early Mitsubishi distributors were known for failure. It may not leave fault codes behind, but a good scan too can tell you whether the cam sensor or crank sensor signal is lost or missing while it's in no-start cranking. Diagnose first.
Unfortunately the distributor is the first thing I thought of.
 

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Discussion Starter · #12 ·
I did noticed some odd self acceleration while I was leaving work . Pulled like I was pushing the gas down .
 

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I know you said you cleaned the IAC, but you may want to test this further. Is the vehicle idling erratically? Is this vehicle equipped with cruise control by chance?
 

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I know you said you cleaned the IAC, but you may want to test this further. Is the vehicle idling erratically? Is this vehicle equipped with cruise control by chance?
The idle is smooth only when you drive does it get low coming to a stop almost stalling or just stalling outright. In park it’s fine . As for cruise control. I not sure . I drove it for about 4 days . And haven’t explored the options yet . It’s parked till I can figure this issue out .
 

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All good to know. The more information you can think of the better.

You said in the OP there are no codes (another reason I suggest looking at the CKP) BUT just for clarity sake, did you check for codes? (Key cycle 3x, ending in the on position) Because you also mentioned no MIL/CEL. So just wanted to make sure you did not assume there are no codes stored just because the MIL is not on.

It's also possible the symptoms you've described could be related to a vacuum leak of some kind.
 

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When you said that you cleaned the IAC, did you also thoroughly clean the housing where it resides?
 

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I'm sorry, disregard the last statement on code retrieval. OBDII/Scan tool only. But there is a possibility the key method could work with the emergency brake fully engaged, and the transmission in park/neutral. If you do not have a scan tool you can try this but the odds are low.
 

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I also wanted to ask if you've had any more issues with the alternator or voltage regulation? Do you have a voltage meter in the car? And if not have you verified it is charging at 14v to the battery?

I am also curious if you replaced the auto shut down relay just to replace it or did you find a problem there?

Was the ASD fuse blown or compromised?
 

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Is this the engine where the distributor wiring runs under the intake manifold? There were problems with those due to chaffed wiring.
 
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