[Harleydsg]

So today I dove in to replace the PCV valve and plugs, I was doing this because it had a erratic idle that would happen intermittently and was idling high. So a new Motorcraft PCV valve, new tube and rubbers, new Autolite spark plugs gaped to .050. Replaced the intake gaskets and a new EGR gasket. Started up and idled like it should of, took for a test drive, had a misfire and flashed the check engine light under heavy load but was ok under cruise conditions, returned home and shut it off to check for loose spark plug wires. Once I went to restart it it would catch then immediately die, only way it will run is if you throttle it once it fires but it doesn't run well, misfires, pops and chugs but will die it llf you let off the gas. I pulled code P0171 and P0174 but that could be from before this happened. Anyone have a clue as to what has gone wrong? Seems odd that it was fine then suddenly this happened.

 

[rjacket]

Based on the information you've provided, it could be several things. You've also not provided some information eg year and engine.

The codes are lean on both banks. Which means more air than fuel. Since you've taken things apart, you might have not sealed things up correctly and have unmetered air going into the engine.

Your spark plug gap of 0.050 inch is wrong for both the Duratec and the Vulcan engines.

How did you retrieve the codes? If you have access to a scanner then you should be able to pull up other data that can help the diagnosis.

 

[Harleydsg]

My mistake It is a 2002 with a DOHC.

There was also code p1151, p1131

 

[Automender12345]

First guess without and data is a massive vacuum leak. Make sure your sparkplug wires are connected correctly.

 

[rjacket]

My mistake It is a 2002 with a DOHC.

There was also code p1151, p1131

Those codes are also to do with too much air.

Spark plug gap for DOHC is 0.054". Range is 0.052" to 0.056" so 0.050" is not too far off but it will result in weaker combustion.

 

[chartmaker]

So today I dove in to replace the PCV valve and plugs, I was doing this because it had a erratic idle that would happen intermittently and was idling high. So a new Motorcraft PCV valve, new tube and rubbers, new Autolite spark plugs gaped to .050. Replaced the intake gaskets and a new EGR gasket. Started up and idled like it should of, took for a test drive, had a misfire and flashed the check engine light under heavy load but was ok under cruise conditions, returned home and shut it off to check for loose spark plug wires. Once I went to restart it it would catch then immediately die, only way it will run is if you throttle it once it fires but it doesn't run well, misfires, pops and chugs but will die it llf you let off the gas. I pulled code P0171 and P0174 but that could be from before this happened. Anyone have a clue as to what has gone wrong? Seems odd that it was fine then suddenly this happened.

I have done '01 and 3 '-3's. I always take the intake off. Hard to do plugs, wires, coils and such, also PCV best done with the intake off. In the pic, right side see the vertical hose. I have left this off more than once. PCV hose to intake, and to engine can leak. On the back of the intake there is a hose that goes to the EGR solenoid. I have had one fall off the nipple. Check the hoses from the accordion to the valve covers, the rear is hard to feel and check. If ll hoses are OK get a stethoscope and listen for the leak.
-chart-

 

[helifino]

And if you pull the upper intake, might as well change the gasket o-rings. They're quite cheap and a simple installation.

 

[sheila]

And if you pull the upper intake, might as well change the gasket o-rings. They're quite cheap and a simple installation.

He said in his 1st post he replaced the intake gaskets.

 

[chartmaker]

He said in his 1st post he replaced the intake gaskets.

There is a s hopping list of things that can leak vacuum on G-4/G-4.5 Bulls. I have done 4 as I remember, maybe 5 if I count the '05. Never replaced intake gaskets, never had an issue except for hoses left off. I seem to have a talent for leaving hoses off. Fair share of hoses fail.
-chart-

 

[Harleydsg]

Those codes are also to do with too much air.

Spark plug gap for DOHC is 0.054". Range is 0.052" to 0.056" so 0.050" is not too far off but it will result in weaker combustion.

It's easy enough to pull the front bank and reset it.

 

[chartmaker]

It's easy enough to pull the front bank and reset it.

Plug gap is not critical, in fact there is a range of gaps acceptable. Pic off the internet, how is this gap and in fact it must have been still running. Ford used the exact same coil pack on Vulcans as DOHC but quite different gap. Best be in the recommended range of gaps. If there are other bad issues, they can make the gap important. New plugs should be factory gaped in the range of speds, if not return them. With the labor involved, best to use MC OE spec plugs.
Buying other brands can be risky as in the picture.
-chart-

 

[Lisfin]

A way I found my air leaks was took off air intake and put a bag on it after the mass flow sensor to seal up the manifold, than used a vacuum hose to blow cig smoke into engine to see where it was leaking from. If you don't smoke just don't inhale. It took me less than 2 puffs and 30 seconds to find my leaks with smoke.

Or make a DIY smoker. Glass jar with a old rag in it, fill with mineral oil and have a soldering iron sticking in from the top. Put a inlet hose and outlet hose and turn on and wait 5 mins for smoke to start. Use a bike pump or blow into inlet and watch the smoke find any leak in seconds! Good Luck finding them leaks!

Build your own smoke machine

 

[Harleydsg]

A way I found my air leaks was took off air intake and put a bag on it after the mass flow sensor to seal up the manifold, than used a vacuum hose to blow cig smoke into engine to see where it was leaking from. If you don't smoke just don't inhale. It took me less than 2 puffs and 30 seconds to find my leaks with smoke.

Or make a DIY smoker. Glass jar with a old rag in it, fill with mineral oil and have a soldering iron sticking in from the top. Put a inlet hose and outlet hose and turn on and wait 5 mins for smoke to start. Use a bike pump or blow into inlet and watch the smoke find any leak in seconds! Good Luck finding them leaks!

View attachment 222325
Build your own smoke machine

Thats a great idea. Thank for that.

 

[Architect]

flashed the check engine light under heavy load but was ok under cruise conditions

Perhaps it has something to do with the other thing both banks have in common: the fuel pressure. Can you drive the car and at the same time check the fuel pressure (parameter 0A = FRP) with a scanner? It should be around 40 PSI. When was the last time the fuel filter was changed?

 

[chartmaker]

Perhaps it has something to do with the other thing both banks have in common: the fuel pressure. Can you drive the car and at the same time check the fuel pressure (parameter 0A = FRP) with a scanner? It should be around 40 PSI. When was the last time the fuel filter was changed?

Car is '02 it uses variable voltage equivalent to the pump to satisfy the PCM. It it can't achieve desired pressure it will set a code. Unlike '01.
To confirm vac leak, see fuel trims at idle and at power cruise.
Vac will be high at idle, OK under load. Best be sure you have a leak before chasing it.
-chart-

 

[Harleydsg]

Got it fixed, turns out the new PCV valve tube that I bought came off the intake. Huge vacuum leak. Thanks to all for the suggestions.

 

[Steve83]

My mistake It is a 2002 with a DOHC.

So you never have to remember again, you should put ALL the car's details & history (as much as you know) into your signature so it shows with each post, as this page explains:

(click this text)


Phone apps don't always show signatures, so you may need to switch to a real browser in desktop mode on your phone, or just use a desktop/laptop computer. Put your location (nearest city) in your profile or signature & upload an avatar of the car. The more pics you post (NOT in your sig) of the car, engine, wiring, labels, & undercarriage, the more likely we can help you. Not all its details are relevant to these issues, but you don't necessarily know which ones are relevant, so just put everything in now.

Huge vacuum leak.

I highly recommend investing in this:

(click this text)

 

[soundu]

So today I dove in to replace the PCV valve and plugs, I was doing this because it had a erratic idle that would happen intermittently and was idling high. So a new Motorcraft PCV valve, new tube and rubbers, new Autolite spark plugs gaped to .050. Replaced the intake gaskets and a new EGR gasket. Started up and idled like it should of, took for a test drive, had a misfire and flashed the check engine light under heavy load but was ok under cruise conditions, returned home and shut it off to check for loose spark plug wires. Once I went to restart it it would catch then immediately die, only way it will run is if you throttle it once it fires but it doesn't run well, misfires, pops and chugs but will die it llf you let off the gas. I pulled code P0171 and P0174 but that could be from before this happened. Anyone have a clue as to what has gone wrong? Seems odd that it was fine then suddenly this happened.

make sure the larger vacuum hose to the brake booster is on and not cracked and leaking. dont ask me how i know....