Pinging
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Pinging
I have a 94 b4000. I have been geting a code 186 ( to long a fuel pulse) for awhile now. Not being able to hear well I had the wife listen for pinging in the engine. On long hills it is Pinging. I just replaced the fuel filter and fuel pump(what a job). Stil getting the code 186. Only thing else I can think of is the Pressure regulator. Any one have any Ideas what else it could be?
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Joined: Jan 2004
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From: SW Va
Low fuel pressure can cause a lean squirt of fuel. So I'd do a fuel pressure check. It kinda fits in with the code your getting. So I agree with your suspecions about the regulator
Also, a dirty MAF sensor, will mess with the signal the computer is getting & cause it to think the engine isn't ingesting as much air as it really is & this will cause the air/fuel ratio to go lean & ping, as the computer doesn't add enough fuel as you open the throttle to climb the hill.
A unmetered air/vacuum leak too, so check the air tube down stream from the MAF sensor, this would include the PCV system & all vacuumlines & fittings.
A dirty air filter might be on the suspect list too.
The wrong heat range plugs (too hot) can figure in on this.
Maybe even the wrong octane or poor quality fuel.
Just some additional thoughts.
Let us know what you find.
Also, a dirty MAF sensor, will mess with the signal the computer is getting & cause it to think the engine isn't ingesting as much air as it really is & this will cause the air/fuel ratio to go lean & ping, as the computer doesn't add enough fuel as you open the throttle to climb the hill.
A unmetered air/vacuum leak too, so check the air tube down stream from the MAF sensor, this would include the PCV system & all vacuumlines & fittings.
A dirty air filter might be on the suspect list too.
The wrong heat range plugs (too hot) can figure in on this.
Maybe even the wrong octane or poor quality fuel.
Just some additional thoughts.
Let us know what you find.
Post Fiend
Joined: Feb 2003
Posts: 6,940
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From: Eastern WA
The three most common causes for engine knock on a 4.0, in no particular order are:
1) Carbon build up which can be addressed by implementing the TSB noted here: https://www.ford-trucks.com/forums/s...hreadid=100739
2) MAF sensor needs cleaning
3) Lower intake bolts need to be retorqued.
The correct octane gas to use is 87; higher octane gas increaes the likelyhood of pinging. This is noted in the TSB.
1) Carbon build up which can be addressed by implementing the TSB noted here: https://www.ford-trucks.com/forums/s...hreadid=100739
2) MAF sensor needs cleaning
3) Lower intake bolts need to be retorqued.
The correct octane gas to use is 87; higher octane gas increaes the likelyhood of pinging. This is noted in the TSB.
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Maf sensor has been cleaned twice. I do not use High Test gas I can not afford it. I have run injector cleaner though the truck 3 or more times. I have battling this for about 6 months now. I don't use the truck but once or twice a week when I do it is on dirt and country 2 lane roads.
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Joined: Jan 2004
Posts: 13,851
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From: SW Va
OK, good feedback on the MAF sensor cleaning.
Billy has a good point about the lower intake manafold leak. Seeing as how this engine is prone to leak there, it too would be a good canidate for your suspect list.
An air leak, even though it's not sensed by the MAF, is likely sensed downstream by the O2 sensors, so they'll tell the computer there's too much O2 in the exhaust & to enrich the A/F mixture.
So the code suggests the computer has run out of programmed pulse width for the injectors & maybe it's because of an upstream air leak, the system can't quite compensate for.
So it would suggest you need to look carefully on the intake side of things for any signs of a vacuum or unmetered air leak downstream from the MAF sensor.
Billy has a good point about the lower intake manafold leak. Seeing as how this engine is prone to leak there, it too would be a good canidate for your suspect list.
An air leak, even though it's not sensed by the MAF, is likely sensed downstream by the O2 sensors, so they'll tell the computer there's too much O2 in the exhaust & to enrich the A/F mixture.
So the code suggests the computer has run out of programmed pulse width for the injectors & maybe it's because of an upstream air leak, the system can't quite compensate for.
So it would suggest you need to look carefully on the intake side of things for any signs of a vacuum or unmetered air leak downstream from the MAF sensor.
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