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1993 mitsubishi won't start
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sophistocat
New User
Aug 9, 2013, 11:30 AM
Post #1 of 2
(1627 views)
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1993 mitsubishi won't start
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1993 Mitsubishi Mighty Max pu w/ 4.2 -4cyl-2wd won't start. I drove to the store and parked. re-entered the truck, started it, put it in reverse and let my foot off the brake and it died. It turned over but wouldn't start. Compression sounds normal, shot starting fluid in the air inlet and still no pop.Figuring it's a spark issue I started changing parts. So far I've changed plugs, wires, cap and rotor, coil, distributor, ecu and ecu relay, several fuses, and fuel pump for good measure. it still won't start. 12 v at the coil, no spark to the plugs. Parts guy suggesting ignition switch. really?
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Hammer Time
Ultimate Carjunky
/ Moderator
Aug 9, 2013, 12:44 PM
Post #2 of 2
(1614 views)
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Re: 1993 mitsubishi won't start
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We call that the "dartboard" method of diagnosis. Just keep throwing stuff at it until something sticks. Nothing ever sticks.
Here is the diagnostic method.
All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.
Every engine requires spark, fuel and compression to run. That's what we have to look for.
These are the basics that need to be tested and will give us the info required to isolate a cause.
1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.
2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.
3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.
4) If all of these things check good, then you would need to do a complete compression test.
Once you have determined which of these functions has dropped out,
you will know which system is having the problem.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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