Schrade
Well-known member
Good try there, honey-bunch...
What does THIS tell anyone?
Still listening here... Is that good? Bad?
And, now that he got Ohms, that you wanted, what does he measure, or do, NEXT???
Good try there, honey-bunch...
What does THIS tell anyone?
Still listening here... Is that good? Bad?
And, now that he got Ohms, that you wanted, what does he measure, or do, NEXT???
boomdriver
Well-known member
Absolutely !
when these things go south...there is no rhyme or reason as to the symptoms or headaches they can cause. Mystery ailments.
Last summer I chopped my left bank injector harness out and replaced wire and connectors. At the moment, I have stable oil pressure readings, BUT if I move that harness section I'll get 80 psi when off, 60 at idle and 25 psi on the freeway. All because the splices are now coming apart and there is wire exposed to each other and the elements. Interferrence or grounding..I don't know. The wire is just rotten. It can all be repaired if the source can be pinned down to that 6" of harness where all this stuff splits apart.
There must be close to 20 splices within 6" and if that car ever got steam cleaned or someone used a degreaser....I would bet the insulation is brittle and cracked on the individual wires and the splices are corroded and breaking, creating higher resistance to just about everything.
I found a GM bulletin on the harness shorting on a casting edge on the trans, and heard that there was another regarding chemicals and the wire insulation but I never actually saw that one.
I know on mine that I can effect the idle by moving the harness around.....I can see a new engine harness the next time that motor comes out.
vetteoz
Well-known member
With the meter set on the 20,000 ohm scale he is getting a reading ( continuity ) between the pump wiring and the ground (A) when he should be getting open circuit , nothing , zilch
Not exactly rocket science
He needs to identify where in the circuit the short is , process of elimination by testing individual sections of the pump wiring until he finds it
How does Voltage relate to a short? Lower voltage is the result of resistance in the wiring
A fuse blows because the current (Amps) draw is higher than the fuse is rated at ; no because of a voltage change
I am starting to see why you got banned on CF.
We are trying to help a guy out here and your ignorance of basic auto electrics is not helping
John Robinson
Gone but not forgotten
Just a comment on what boomdriver is saying on the wires and the way they have bundled the grounds. this last year I went crazy trying to get my car to run without misfiring and acting like it was always lean. It would hunt and peck between closed and open loop on the road. I discovered one of the ground bundles on the right side for the TPS, MAP, and other sensors. It was covered in black tape and badly corroded. with brittle insulation. After removing the bad sections and soldering in new wire with heat shrink I was then able to get to the real problem and that was an O2 sensor. One thing I learned from this is that the grounds are the key to everything on this car.
One more thing I use the seat frame as the ground with an alligator clip jumper wire when checking G on my ALDI I do not go to A for the ground. I often just use a test light and not the voltmeter to look for voltage on that circuit.
One more thing I use the seat frame as the ground with an alligator clip jumper wire when checking G on my ALDI I do not go to A for the ground. I often just use a test light and not the voltmeter to look for voltage on that circuit.
Schrade
Well-known member
And you DO understand auto electronics? Basic electronics?
Current (in amps) is about equal to voltage / impedance (ohms).
If voltage is lower, and ohms is the same, then the amperage will be lower too. But that's not the case, because the fuse is blowing (amperage is HIGHER).
Which means, SINCE THE VOLTAGE IS LOWER, the ohms is MUCH LOWer (or '0') .
If he measures OHMS on an energized circuit, he could blow the multimeter. If he measures ohms on another circuit, that has nothing to do with the problem, then he'll get no reading, and know nothing.
If he finds a circuit with wrong (low) voltage, he's onto the problem.
If you know different about law of electricity, please explain (I think it's called Ohm's rule, if you want to google)
Current (in amps) is about equal to voltage / impedance (ohms).
If voltage is lower, and ohms is the same, then the amperage will be lower too. But that's not the case, because the fuse is blowing (amperage is HIGHER).
Which means, SINCE THE VOLTAGE IS LOWER, the ohms is MUCH LOWer (or '0') .
If he measures OHMS on an energized circuit, he could blow the multimeter. If he measures ohms on another circuit, that has nothing to do with the problem, then he'll get no reading, and know nothing.
If he finds a circuit with wrong (low) voltage, he's onto the problem.
If you know different about law of electricity, please explain (I think it's called Ohm's rule, if you want to google)
- Moderator
- #46
vetteboy86
Well-known member
OHMs law states that E=IR
Where E is voltage, I is current and R is resistance.
Where E is voltage, I is current and R is resistance.
boomdriver
Well-known member
John,
I completely "get" what you;re saying..
I had an ongoing problem that took months to figure out. I was thinking I had a burnt valve or some other mechanical issue when it was just worn out wire. Mine had a 'misfire' that moved...yes, one day it was #7 and the next time I started the motor the mis would be on #3. Made me crazy until I got lucky one day and just yanked on the harness when I was beyond angry...and the idle suddenly smoothed out !
From there it took a few more days but I was able to pin down the real problem and work to correct it. The only remaining problem is the oil pressure wires splice to the main harness and that is almost inaccessable with the engine in place. I hesitate to chop into the harness there, and risk not being able to have enough working space to complete the soldering and insulating. So, it works for now, and I know exactly where to look if/when something quits...
P'd me off too,;squint: bought a new OP sender thinking that was behind the weird display numbers.:eyerole
Schrade
Well-known member
I knew it was something like that...
And more 'basic' electronics, which I already mentioned - you DON'T measure VOLTAGE (or a circuit that might have VOLTAGE) with an ammeter / ohmmeter / multimeter set on 'Ohms'.
vetteoz
Well-known member
And for the trillionth time ,if you could READ a circuit diagram you would see that there is NO power on that circuit with the key OFF
Conversely if the circuit did had power the pump would be running full time with key OFF
The 9 volt reading he got was when he supplied it from the battery when testing voltage with the DVM as per your instructions.
Batt Pos to terminal G
It was not voltage " present " in the pump circuit
The fact he got 9 volts shows he has a path to ground from that circuit where he should have NONE; hence he has a short in that circuit
Schrade
Well-known member
kANT REED 2 gud dOOd - whent too pUBLiK sKool. 
(and besides - Manic doesn't have a circuit diagram; he's got VOLTAGE somewhere that he shouldn't. If he finds it with his multimeter set on Ohms, like you're telling him - he COULD blow the MM).
(and besides - Manic doesn't have a circuit diagram; he's got VOLTAGE somewhere that he shouldn't. If he finds it with his multimeter set on Ohms, like you're telling him - he COULD blow the MM).
vetteoz
Well-known member
He can always refer to post # 6 and 30 unless he is doing by Braille
Schrade
Well-known member
Key on, or key off, whatever the circuit is that's not SUPPOSED to have power, it's getting where it ain't supposed to. Don't test for it with an Ohmmeter - set it on VOLTS. You can blow the multimeter (for the trillionth +1 time).
Manic - if you want to set the MM on Ohms, dis-connect the battery.
But if you have a water leak, it's easier to find with the water ON.
Manic - if you want to set the MM on Ohms, dis-connect the battery.
But if you have a water leak, it's easier to find with the water ON.
Schrade
Well-known member
... and if you're offended there oz, by 'honey-bunch', then I apologize.
vetteoz
Well-known member
No offense taken ;spend enough time on the Forums and you are bound to get up someones nose.
But ,
I still say checking for voltage is wrong way to find a short
boomdriver
Well-known member
There is some irony in this most recent page of this thread....
The OP goes by "manic" .....and the response has been appropiate
otflvetteoz
Well-known member
I resignThere is some irony in this most recent page of this thread....
The OP goes by "manic" .....and the response has been appropiate
If the OP runs a new wire from the tank connector along the outside of his car to the battery the pump will run without blowing any fuses
( car may burn to the ground however)
rayquayle
Active member
Mmmmm, Carbecue!
boomdriver
Well-known member
:ugh
Burn or explode...? :W
either way, solves the fuse problem for the time being.:ugh
AllState man----->
right.
Burn or explode...? :W
either way, solves the fuse problem for the time being.:ugh
AllState man----->
right.- Thread starter
- #59
M
manic
Guest
I've been meaning to give an update. I replaced the fuel pump and the problem was resolved. Thanks for all your enthusiastic help. Now on to my next problem. I have to repalce the starter. What a year - I have replaced the alternator,water pump, fuel pump, and now the starter.
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