" how to check ohlms/resistance?"
Thread Starter
Racer
Joined: Aug 2005
Posts: 469
Likes: 1
" how to check ohlms/resistance?"
hi there guys,
i was just wandering please , when i measure the ohlms resistance on my fuel injectors on my 1991 l98 engine, do i measure the resistance at the wire end or the injector end?
does it matter where the positive and negative lead is situated when i test the wire or injector?
it seems that the injectors are ok as they all come up around the 16 ohlms mark, that is if i tested it ok!
also i tried to test the plug wires and was told the plug wires should measure 5,000 ohms per foot, well that test didnt go well at all!
when i test the plug leads for the ohms, do i put one lead at one end and the other lead from the multimeter at the other end of the plug?
any help,tips would be great thnaks!
thanks
glen
i was just wandering please , when i measure the ohlms resistance on my fuel injectors on my 1991 l98 engine, do i measure the resistance at the wire end or the injector end?
does it matter where the positive and negative lead is situated when i test the wire or injector?
it seems that the injectors are ok as they all come up around the 16 ohlms mark, that is if i tested it ok!
also i tried to test the plug wires and was told the plug wires should measure 5,000 ohms per foot, well that test didnt go well at all!
when i test the plug leads for the ohms, do i put one lead at one end and the other lead from the multimeter at the other end of the plug?
any help,tips would be great thnaks!
thanks
glen
Thread Starter
Racer
Joined: Aug 2005
Posts: 469
Likes: 1
hi smokeshow,
thanks for the quick reply and info!
what about if the injectors were hot or cold,does it matter?
also r.e how to measure the plug leads?
i didnt get a good result on plug leads, how do i go about testing the leads please?
thanks for all your help mate!
glen
sxyvet
Australia
thanks for the quick reply and info!
what about if the injectors were hot or cold,does it matter?
also r.e how to measure the plug leads?
i didnt get a good result on plug leads, how do i go about testing the leads please?
thanks for all your help mate!
glen
sxyvet
Australia
Last edited by sxyvet; Nov 7, 2006 at 03:06 AM.
Melting Slicks
Joined: Apr 2002
Posts: 2,118
Likes: 0
From: St. Charles, MO Route 66 Corvette Club
skyvet: you should be measuring the resistance between the two terminals on the inector WITH the engine wires removed from the injector. Do not check the resistance of the injector engine wires with the ignition on as this could damage the ECM. You can check voltage on one of the injector wires and this should be 12 volts. The other engine injector wire will go to ground.
Thread Starter
Racer
Joined: Aug 2005
Posts: 469
Likes: 1
hi sam lam,
thnaks for the reply mate!
yep i checked the injector with the ignition off, thanks!
they all came up as around 16 ohms, which im told is ok?
i just finished checking plug lead ohms as follows
(1) was 1.290 k ohms
(2) was 2.060 k ohms
(3) was 2.261 k ohms
(4) was 1.654 k ohms
(5) was 1.270 k ohms
(6) was 2.025 k ohms
(7) was 1.284 k ohms
(8) was 1.3 51 k ohms
i was told to work out move the deciamal point three places to the rite, is this correct at all?
what do these figures mean, are the plug leads bad at all?
if so which ones please?
the average plug lead is about 2/1/2 feet long or more in length!
any help please at all with this stuff!
the plug leads are only about 8 months old!
thnaks guys
you are all a great help to me very much!
cheers
glen
Australia
thnaks for the reply mate!
yep i checked the injector with the ignition off, thanks!
they all came up as around 16 ohms, which im told is ok?
i just finished checking plug lead ohms as follows
(1) was 1.290 k ohms
(2) was 2.060 k ohms
(3) was 2.261 k ohms
(4) was 1.654 k ohms
(5) was 1.270 k ohms
(6) was 2.025 k ohms
(7) was 1.284 k ohms
(8) was 1.3 51 k ohms
i was told to work out move the deciamal point three places to the rite, is this correct at all?
what do these figures mean, are the plug leads bad at all?
if so which ones please?
the average plug lead is about 2/1/2 feet long or more in length!
any help please at all with this stuff!
the plug leads are only about 8 months old!
thnaks guys
you are all a great help to me very much!
cheers
glen
Australia
Thread Starter
Racer
Joined: Aug 2005
Posts: 469
Likes: 1
hi kalister1 and smokeshow,
thanks for your replys guys r.e ohlms!
dont you think though that some of those plug lead numbers are a bit low though?
only #2 ,#3,#6 came close to the 5,000 ohlms! needed to measure per lead !,any other helpful hints please guys?thanks all!
the leads i have also are top gun racing leads, 8.8 mm diamater also!
glen
Australia
thanks for your replys guys r.e ohlms!
dont you think though that some of those plug lead numbers are a bit low though?
only #2 ,#3,#6 came close to the 5,000 ohlms! needed to measure per lead !,any other helpful hints please guys?thanks all!
the leads i have also are top gun racing leads, 8.8 mm diamater also!
glen
Australia
Last edited by sxyvet; Nov 7, 2006 at 04:41 PM.
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Racer
Joined: Jun 2006
Posts: 408
Likes: 0
From: Elkton MD
Resistance ohms
In electrical engineering (ohms, amps, volts, etc.), a significant difference is often a factor of 10.
So 1 is different than 10
10 is different than 100 and so on.
Sometimes a small difference - like one part in a billion is significant.
For plug wires, yours are fine, rest easy.
The only reason plug wires have any resistance at all is to keep from trashing your radio reception and messing up all the TV's in the neighborhood.
So 1 is different than 10
10 is different than 100 and so on.
Sometimes a small difference - like one part in a billion is significant.
For plug wires, yours are fine, rest easy.
The only reason plug wires have any resistance at all is to keep from trashing your radio reception and messing up all the TV's in the neighborhood.
Last edited by IRAraid; Nov 7, 2006 at 05:09 PM.
Thread Starter
Racer
Joined: Aug 2005
Posts: 469
Likes: 1
hi iraraid,
thanks for your info/help!
im glad to hear that those numbers i qouted for my leads are ok then!
thanks alot mate!
so r.e my missing,spluttering,below 2,000 rpm, i have know checked the injectors/ok,plug leads/ok,tps/ok,ignition timing/ok,idle air control/ok,put in tank fuel injector cleaner/done,havent replaced fuel filter since 6 months ago,havent checked for vacuum leaks,or checked fule pump yet!
not sure what else it could be with the missing,back fire popping ,spluttering the engine is doing only up to 2,000 rpm?
thanks
glen
thanks for your info/help!
im glad to hear that those numbers i qouted for my leads are ok then!
thanks alot mate!
so r.e my missing,spluttering,below 2,000 rpm, i have know checked the injectors/ok,plug leads/ok,tps/ok,ignition timing/ok,idle air control/ok,put in tank fuel injector cleaner/done,havent replaced fuel filter since 6 months ago,havent checked for vacuum leaks,or checked fule pump yet!
not sure what else it could be with the missing,back fire popping ,spluttering the engine is doing only up to 2,000 rpm?
thanks
glen
Racer
Joined: Jun 2006
Posts: 408
Likes: 0
From: Elkton MD
Sputtering below 2000
Sputtering below 2000 rpm suggests you check IAC (but you already did), and the PCV and EGR valves. I had a bad PCV that caused terrible operation until 2 or 3000 rpm then smooth. Also lost a quart of oil in 500 miles and figured a ring was cracked. Eventually the car wouldn't run at idle and diagnostic led to PCV. (diagnostic was on a carb car and found that 1 7 4 and 6 weren't firing - that's the side of the carb that the PCV was connected to.) New PCV gave smooth operation and stopped the oil consumption.
My son's car had a sticky EGR that trashed his idle (sounded cool when it would run at all). But eventually that car wouldn't idle either. Diagnostic revealed sticky (intermittent failure) EGR.
So, check your PCV (cheap to just replace it) and EGR.
Check the EGR by applying vacuum (suck on the hose if you're brave - get a new piece of vacuum control hose so your lips don't turn black) and see if it moves smoothly and holds vacuum.
Good luck.
My son's car had a sticky EGR that trashed his idle (sounded cool when it would run at all). But eventually that car wouldn't idle either. Diagnostic revealed sticky (intermittent failure) EGR.
So, check your PCV (cheap to just replace it) and EGR.
Check the EGR by applying vacuum (suck on the hose if you're brave - get a new piece of vacuum control hose so your lips don't turn black) and see if it moves smoothly and holds vacuum.
Good luck.
Thread Starter
Racer
Joined: Aug 2005
Posts: 469
Likes: 1
hi cplonner,
how are you!
and hi to all !
my car was acting up wheather it was hot or cold!
and only up 2,000 rpm!
but guess what, i pulled all the 6 month old bosh platnium 4 spark plugs out and sure enough one of the spark plugs centre core around the electrode has split in half and is loose!
so $30.00 aus dollars later i brought 8 new ngk bcpr6es spark plugs and guess what guys, the problem is gone!
i m realy happy and it was a good learning curve for me all thnaks to all you helpful friends of mine!
thnaks heaps guys!
you have been great!
this is a great site!
cheers
glen
Australia
how are you!
and hi to all !
my car was acting up wheather it was hot or cold!
and only up 2,000 rpm!
but guess what, i pulled all the 6 month old bosh platnium 4 spark plugs out and sure enough one of the spark plugs centre core around the electrode has split in half and is loose!
so $30.00 aus dollars later i brought 8 new ngk bcpr6es spark plugs and guess what guys, the problem is gone!
i m realy happy and it was a good learning curve for me all thnaks to all you helpful friends of mine!
thnaks heaps guys!
you have been great!
this is a great site!
cheers
glen
Australia
