| Baldylocks |
| (Getting the Wheeling Fever) |
| 09/08/07 12:03 PM |
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More starting help please
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Original Post earlier today:
"My 90 Montero has left me stranded again. She turns over just fine but when I remove one of the spark plug wires while trying to start her….no spark. Then I removed the short wire to the coil, still no spark. What is the resistance of the coil? And what is the input voltage to the coil and where does it come from? Are there any other checks I can do to isolate this problem?"
I recieved an outstang reply to my question so I went to check everything. It checked OK so I actually started the Montero. But as she got up to operating temp, she started missing badly and then she went for another couple of blocks and quit again. I tried to start it but it turns over fine and tries to start. It like it is missing ,missing, then it will sputter like it wants to start and dropps out again.
So the coil seems to be good as does the input voltage. I wonder what is causing this stopping. It just came on all of a sudden. Any more ideas would be very helpful.
Oh yeah, how do I check the Power Transistor and the ECU with limited tools? If there is another topic started on these please refer me to the link.
Thanks
Pat
| FrankR |
| (Web Wheeler) |
| 09/08/07 01:22 PM |
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Re: More starting help please
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Searching, searching, searching.... [+power +transistor +test]
Quote:
If the coil passes those tests, the power transistor is suspect. The power transistor is what triggers the coil, much like points in an older vehicle. The Haynes manual has no information I can find on the power transistor, so I'm giving you the test procedure from the '89 FSM and I'm assuming the power transistors are the same. Check as follows:
The power transistor is the black, flat contraption mounted next to the coil on the coil bracket. Remove the 3-wire connector. As you look at the 3 electrical connections, mentally number them 1,2,3 from left to right.... they have letter designations on the topside of the unit, but my truck isn't here right now and I can't give you the designations that way - so -
With your test meter set on "ohms", check between terminal 2 (middle) and terminal 3 (right).... there should be no continuity (high reading in ohms).
Connect the negative (-) side of a 1.5v flashlight battery to terminal 2 (middle terminal) and the battery positive (+) to terminal 1 of the power transistor (you'll need some small alligator clips) - Now there should be continuity (zero ohms) between terminal 2 and terminal 3.
If you connect and remove the battery (+) lead, you should see the meter move back and forth between continuity and no continuity just like a switch - which is what the power transistor is acting as when voltage is applied.
This test is difficult to do because of the tight quarters, but be patient and get whatever clips you need to get good readings without the clips touching each other. If it's easier for you, remove the coil bracket so you can do the test on a table or workbench.
If the power transistor fails this test, you've likely found the culprit.
If the power transistor passes, remove and check the coil wire with your meter leads on each end - I don't have a handy reference on ohms/foot but guessing it should be somewhere around 2K ohms max for the short lead.
Let us know when you've tried these tests.
Oh, if either the coil or the power transistor fail the tests, I'd suggest getting a complete assembly from a junk yard as electrical components can last for 10 seconds or 100 years.
web page 1
Searching, searching, searching.... [+power +transistor +test]...
Quote:
The power transistor has 3 contacts - labeled #1/#2/#3 from left to right. Connect the negative end of a 1.5v flashlight battery to terminal #2 on the power transistor. Connect the positive post of the flashlight battery to terminal #1. There should now be continuity between terminal #3 and terminal #2. When you remove the voltage from terminal #2 there should be no continuity between #2 and #3.
If the transistor doesn't perform in the prescribed manner, replace it.
web page 2
Dadgum - that search stuff really works!
Frank
| Baldylocks |
| (Getting the Wheeling Fever) |
| 09/08/07 01:32 PM |
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Re: More starting help please
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When I search I didn't know that I had to go
+power +transistor +test
I just wrote it out
Sorry bro but now I know.
Newby stuff
Thanks
Pat
| FrankR |
| (Web Wheeler) |
| 09/08/07 01:57 PM |
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Re: More starting help please
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No problem.
I'm in the middle of pulling my engine to make way for another and ran into a nightmare left by the transmission shop when they rebuilt the transmission..... stripped bellhousing threads, overtapped threads with SAE sizes, pulled thread-serts, over-torqued everything, missing transmission stay block bolt, loose transmission stay bolt.... you name it, they screwed it up - never seen such a Goober job.
I didn't mean to sound testy, but I guess I needed someone to scold and you were convenient.....
Let us know if you need more help.
Frank
| 89IsMine |
| (Rock Warrior) |
| 09/08/07 03:22 PM |
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Re: More starting help please
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Quote:
No problem.
I'm in the middle of pulling my engine to make way for another and ran into a nightmare left by the transmission shop when they rebuilt the transmission..... stripped bellhousing threads, overtapped threads with SAE sizes, pulled thread-serts, over-torqued everything, missing transmission stay block bolt, loose transmission stay bolt.... you name it, they screwed it up - never seen such a Goober job.
I didn't mean to sound testy, but I guess I needed someone to scold and you were convenient.....
Let us know if you need more help.
Frank
Maybe you need to line your wrenches up on the bench and give them a good talking-to again
Sorry to hear about the goober job with your transmission. That kind of stuff drives me nuts! C'mon... how hard is it just to do it right?
However, I have complete faith in the Jedi-Frank abilities to deal with this and have the result better than new Eric W.