Diagnosing pip issue.
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Diagnosing pip issue.
I have a question for you. Repairing a '91 460 with an intermittent starting issue. At first I pulled the cap and rotor and found tons of corrosion and gunk so I replaced plugs wires cap rotor and boom. Started right up. Issue persisted however. When it won't start there is no spark coming from the coil. My question is given that it is an intermittent issue. Would this be a pip problem or should I be looking elsewhere. Furthermore how do I diagnose a pip issue when the truck does want to start. Is there a voltage range I should be looking for. When I connect my voltmeter to the pip based on subfords writeup I get 2.5v to 5v alternating.
Of course when I want to diagnose it the damn thing won't act up. Soon as I hand it back its gonna go wonky again.
Of course when I want to diagnose it the damn thing won't act up. Soon as I hand it back its gonna go wonky again.
Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
That is not normally how a PIP sensor goes bad.
A bad one will never start the engine or it will always start the engine and the engine will quit down the road about the same distance each time. A bad PIP sensor will almost always set a code in the computers CM.
If it does not have a remote mounted ICM then I would replace it. But it is very hard to find out why it will not start sometimes if you never have it do it while you are working on it.
It could also be a bad computer as we have seen the computer do this also with bad capacitors in it or could even be a bad Ignition coil or Ignition switch.
A bad one will never start the engine or it will always start the engine and the engine will quit down the road about the same distance each time. A bad PIP sensor will almost always set a code in the computers CM.
If it does not have a remote mounted ICM then I would replace it. But it is very hard to find out why it will not start sometimes if you never have it do it while you are working on it.
It could also be a bad computer as we have seen the computer do this also with bad capacitors in it or could even be a bad Ignition coil or Ignition switch.
Fleet Mechanic
Joined: Jan 2013
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subford ... your tester looks like something that is worthy of a sticky .
can i assume that a) the connector you are using is a salvaged connector that matches the one coming from the distributor and b) failure of the led to light up during cranking indicates a bad pip ?
also, does it have to be an LED or will any 12v lamp do the job ?
also, do the numbers 16 .. 48 ... etc. have any significance for testing purposes ?
thanks.
can i assume that a) the connector you are using is a salvaged connector that matches the one coming from the distributor and b) failure of the led to light up during cranking indicates a bad pip ?
also, does it have to be an LED or will any 12v lamp do the job ?
also, do the numbers 16 .. 48 ... etc. have any significance for testing purposes ?
thanks.
Fleet Owner
Joined: Aug 2005
Posts: 23,667
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From: Easton,Ks
The LED is more dependable with a built in resistor and and I do not think a 12V lamp will work.
This tester is modified from another wiring of a PIP tester.
http://easyautodiagnostics.com/misc-...ht-test-tool-1
This tester is modified from the wiring of the PIP tester below.
I do not know where to get the LED now that RS went under.
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mehigh
1987 - 1996 F150 & Larger F-Series Trucks
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Nov 16, 2014 03:34 PM
