Anonymous
Unregistered
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Okay, I've been down this road before & so I thought perhaps it was the same problem resurfacing - '90 3.0L won't start or dies whenever it gets really wet out with the problem previously being poor fuel pump contacts & moisture related shorts at the fuel pump harness.
Lately (as in a couple of times over the past month or so) my poor beast would die at particularly inopportune times (like accelerating from a stop) whenever it was very wet out. This morning, it simply wouldn't start up at all (pouring/freezing rain mix outside). After wasting a bunch of time checking fuel pump connectors, etc., I finally just checked for spark & there was none. I checked for error codes and there was none. I took the coil off & checked it with the multi-meter & these are the values I got:
Primary Coil Resistance
standard value should read 0.72 - 0.88 Ohms my reading showed 1.1 Ohms
Secondary Coil Resistance
standard value should read 10.3-13.9 kOhms my reading showed 11.66 kOhms
Obviously, the Primary Coil resistance is out of range, but is it out enough to cause complete lack of spark?
I know there's a few things that can go wrong within the distributor, but don't each of those produce error codes? (Like the crank angle sensor).
Before you ask/suggest, the Dizzy Cap gasket is only about 16 months old & I did replace the cap itself sometime in the last 3 years (can't remember exactly when).
I'll repeat that this only happens when it is sufficiently moist outside.
TIA
Shawn
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DougB
Roll Me Over
Reged: 11/08/02
Posts: 4123
Loc: Terre Haute, IN
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Rotor? Otherwise I would suspect the crank sensor. If it hasn't been throwing code, maybe the bulbs burned out?
I would say dizzy first, coil 2nd. What about the power transistor?
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FrankR
Web Wheeler
Reged: 02/01/04
Posts: 10225
Loc: Columbia, SC
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I would think you'd still get spark. It's not like an open or shorted coil primary.
Dampness suggests the possibility of the coil wire from the distributor to the coil. Try cleaning the coil wire contacts. Take off the distributor cap and check for corrosion and/or wear on the cap inner contacts and the rotor. You may need to replace the cap, rotor and wires.
Another suspect could be the power transistor, but unless the case is cracked it shouldn't be affected by moisture. Examine it it carefully for cracks in the case. Spray some electrical contact cleaner inside the electrical plug and examine the wiring at the end of the plug.
Good luck,
Frank
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'89 G-Raider Supercharged 3.0L, MegaSquirt 2, lockup A/T, 2.5" exhaust, 155k, Cibie H4s/Oscar SCs, Hella Micro DE fogs, Cobra CB, Superwinch hubs, LSD rear/Aussie Locker front, Bilsteins, 165A alt., Lifeline AGM, Rust-Oleum
Edited by FrankR (02/14/05 10:07 PM)
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Anonymous
Unregistered
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Well, as far as wires go I replaced all the plugs & wires in November of '03 (so around 16 months ago). I did check the inside of the cap & everything looked normal, but sprayed some WD-40 in there for good measure. The power transistor is the only thing I have not checked yet - still trying to figure out how!
I'd be ready to suspect either the internal dizzy sensors OR the ECU itself, but I'm getting the regular 'sweep, sweep, sweep', A-OK signal from the computer. Has anyone ever had an ECU that appeared normal but was actually shot? How about one that failed to report codes for a known failed sensor? I s'pose all that is moot anyway since it would fail regardless of weather whereas mine just doesn't like getting damp...
TIA
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FrankR
Web Wheeler
Reged: 02/01/04
Posts: 10225
Loc: Columbia, SC
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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.
Frank
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'89 G-Raider Supercharged 3.0L, MegaSquirt 2, lockup A/T, 2.5" exhaust, 155k, Cibie H4s/Oscar SCs, Hella Micro DE fogs, Cobra CB, Superwinch hubs, LSD rear/Aussie Locker front, Bilsteins, 165A alt., Lifeline AGM, Rust-Oleum
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Anonymous
Unregistered
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I'm assuming that the terminal would be read left to right if you were looking at the Power Transistor as it is mounted on the coil tower , right? The 'transistor itself has them labeled as "IB", "G" and "OC". I ask this because I tested the the transistor the way I thought you'd traditional label them 1, 2 & 3 (looking at the terminals from the harness POV with 'OC' as #1, 'G' as #2 and 'IB' as #3)) and the transistor failed the test. BUT , if I reversed the connectors (IOW, 'OC' becomes #3 & 'IB' becomes #1) it passed the test. AAARGH!
After this both conclusive and not conclusive result, I thought I'd double check & to see if the coil was getting juice to the distributor. I won't go into the details of this test  , but let's just say my left hand tells me there's definitely power going to the dizzy from that primary coil wire. This may sound stupid, but if there's enough juice flowing from the coil to make my arm jiggle like a stuck pig then there should be enough for spark, right?
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DougB
Roll Me Over
Reged: 11/08/02
Posts: 4123
Loc: Terre Haute, IN
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Quote:
I won't go into the details of this test , but let's just say my left hand tells me there's definitely power going to the dizzy from that primary coil wire. This may sound stupid, but if there's enough juice flowing from the coil to make my arm jiggle like a stuck pig then there should be enough for spark, right?
That's a completely different test, but you passed and welcome to the club!  
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Anonymous
Unregistered
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Okay, I'm an idiot. I must have just not been grounding the plug well enough because I am getting spark  after all.
Now I've got myself wondering if the sound I'm hearing from the fuel pump is the right sound. When I first checked it, I sort of had a thought in the back of my head that it didn't quite sound right but I chalked it up to being so long since I fiddled with it that I'd just forgotten. But when I listen to it now that I've verified spark, I'm beginning to think it s'posed to really whirr when you give it juice (12V via the check circuit) and instead I'm hearing a faint hum.
I know this is subjective, but for those of you who've had your ear to the fuel pump on the 3.0L would you say it's definitely loud, moderately audible or just a faint hum?
Once again, TIA -
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FrankR
Web Wheeler
Reged: 02/01/04
Posts: 10225
Loc: Columbia, SC
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1 = OC
2 = G
3 = IB
You did it right the first time. You have a bad power transistor. Just to make certain, I checked mine.
Check the dealer price, but a JY unit should be fine so long as you test it first. Those parts (new or used) could last 100 years or 10 minutes.
BTW, I know you're trying to be exact, but it isn't necessary to hold the coil wire to verify the meter reading! Feels good, eh?
Frank
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'89 G-Raider Supercharged 3.0L, MegaSquirt 2, lockup A/T, 2.5" exhaust, 155k, Cibie H4s/Oscar SCs, Hella Micro DE fogs, Cobra CB, Superwinch hubs, LSD rear/Aussie Locker front, Bilsteins, 165A alt., Lifeline AGM, Rust-Oleum
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FrankR
Web Wheeler
Reged: 02/01/04
Posts: 10225
Loc: Columbia, SC
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I think you have a failing power transistor - if you did the test correctly. As previously stated, the case may be cracked which allows moisture inside. As it dries, it could start working again - it also could work intermittently. Test one from the JY and install it - see if it stops the problem when it rains. If not, you're only out a few bucks and can look elsewhere for a solution.
I'll bet your truck will start now.
Frank
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'89 G-Raider Supercharged 3.0L, MegaSquirt 2, lockup A/T, 2.5" exhaust, 155k, Cibie H4s/Oscar SCs, Hella Micro DE fogs, Cobra CB, Superwinch hubs, LSD rear/Aussie Locker front, Bilsteins, 165A alt., Lifeline AGM, Rust-Oleum
Edited by FrankR (02/14/05 06:03 PM)
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