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1986 Ford Mustang engine idles rough and has lost power

Tiny
MUSTANGROOK5.0
  • MEMBER
  • 1986 FORD MUSTANG
  • V8
  • 2WD
  • MANUAL
  • 90,000 MILES
Im really good with cars and im about to sell this car. But anyways I have this mustang and it sounds like its running on four cyclinders, every other plug is black and doesnt really smell like its being drowned in gas I have run the codes and the ones that really come up are lik the evp indicates egr not closing and I changed the egr twice with ones that worked on other mustangs um other codes right ego sensor lean/ ego sensor indicates system lean. I have checked fuel pressure is good fuel filter new plugs new again cap and rotor new wires new have cleaned injectores and put new seal kit on them checked the conectors with noid light they all work changed coil thats good im gettin fuel spark air everything I have went through this car about 10 times and I cant seem to fix the problem and this motor use to run awesome and I erbuilt it cause I blew number 3 cyclinder and I tightened everything perfect I have perfect cyclinder pressure I dunno wat the heck it is im going crazy HELP
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Tuesday, March 30th, 2010 AT 3:34 PM

7 Replies

Tiny
MATHIASO
  • MECHANIC
  • 1,209 POSTS
Hello ,

Check the 95 °F (35 °C) EGR Ported Vacuum Switch (EGR-PVS),Spark Delay Valve (SDV) and Vacuum Check Valve (VCV)
Those are part of The major EGR/CSC system components .


https://www.2carpros.com/forum/automotive_pictures/46384_0900c15280073985_2.jpg



TESTING
EGR-PVS

# With a cold engine, the passage between the upper and middle ports should be open, and the passage between the lower and middle ports should be closed.

# With the engine at or above the EGR-PVS temperature (typically 95 °F), the passage between the lower and middle ports should be open, and the passage between the upper and middle ports should be closed.

Spark Delay Valve

# Disconnect the vacuum lines which run to the spark delay valve and connect a hand vacuum pump.

# Operate the pump and note if vacuum can be achieved.

1. A valve with one black or white side and one colored side is good if vacuum can be built up in one direction, but not in the other direction, and if the vacuum slowly decreases.

2. A valve with both sides the same color is good if vacuum can be built up in both directions before visibly decreasing.

Vacuum Check Valve

# Connect a hand vacuum pump to the vacuum (black) side of the valve.

# Apply 16 in. Hg (54 kpa) of vacuum.

# If vacuum remains above 15 in. Hg (50.7 kpa) for 10 seconds, the valve is acceptable.

The 235 °F (113 °C) PVS is not part of the EGR/CSC system, but is connected to the distributor vacuum advance to prevent engine overheating while idling.
(I'm sending the diagram to your email)
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Wednesday, March 31st, 2010 AT 5:12 AM
Tiny
MUSTANGROOK5.0
  • MEMBER
  • 4 POSTS
But car is carbureataed and this picture looks like its for a carb car
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Wednesday, March 31st, 2010 AT 12:19 PM
Tiny
MATHIASO
  • MECHANIC
  • 1,209 POSTS
Hello,
Help me

4 cyl. A 2.3 tbl
or
4cyli. 3 3.8 tbi or 4 cyl. M 5.0 lFI HP
which one is yours?
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Wednesday, March 31st, 2010 AT 1:07 PM
Tiny
MUSTANGROOK5.0
  • MEMBER
  • 4 POSTS
M sefi 5.0 ho
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Thursday, April 1st, 2010 AT 12:56 AM
Tiny
MATHIASO
  • MECHANIC
  • 1,209 POSTS
Hello,
what is your question?
What do you mean by"but car is carbureataed and this picture looks like its for a carb car"?
How can I help you?
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Thursday, April 1st, 2010 AT 1:31 AM
Tiny
MUSTANGROOK5.0
  • MEMBER
  • 4 POSTS
Engine Performance problem
1986 Ford Mustang V8 Two Wheel Drive Manual 90000 miles

im really good with cars and im about to sell this car. But anyways I have this mustang and it sounds like its running on four cyclinders, every other plug is black and doesnt really smell like its being drowned in gas I have run the codes and the ones that really come up are lik the evp indicates egr not closing and I changed the egr twice with ones that worked on other mustangs um other codes right ego sensor lean/ ego sensor indicates system lean. I have checked fuel pressure is good fuel filter new plugs new again cap and rotor new wires new have cleaned injectores and put new seal kit on them checked the conectors with noid light they all work changed coil thats good im gettin fuel spark air everything I have went through this car about 10 times and I cant seem to fix the problem and this motor use to run awesome and I erbuilt it cause I blew number 3 cyclinder and I tightened everything perfect I have perfect cyclinder pressure I dunno wat the heck it is im going crazy HELP

and my car is not carbuerated and the diagram looks like a diagram for a carbuerated car
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Sunday, April 4th, 2010 AT 10:15 PM
Tiny
MATHIASO
  • MECHANIC
  • 1,209 POSTS
Black fluffy carbon deposits indicate an overly rich fuel mixture or possibly a weak spark.
I found it is a 5.0L HO (302 cu. In.) Engine.
What are the cylinders that have carbon deposit on the spark plugs?
Give me the codes you got.
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Sunday, April 4th, 2010 AT 11:35 PM

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