Engine Foxbody idle/throttle issues

[red5.0fox]

So I took my upper intake off to get a better idea as to of how I’m going to do my vacuum setup. I also removed both the solenoids on the passenger side and removed the vacuum reservoir in the fender (NOT the AC ball). I’m going to put a plate over the EGR port on the EGR spacer and just leave the connector unplugged. 90% sure my EGR valve doesn’t work properly anyways. Gonna put it back together in a bit and see what happens.

 

[AeroCoupe]

I'm pretty sure you need the vacuum reservoir?

 

[red5.0fox]

I'm pretty sure you need the vacuum reservoir?

The only vacuum that goes into the reservoir in the passenger fender connects to the solenoids and the EGR valve itself. There is no vacuum going anywhere else from it.

 

[red5.0fox]

Okay so all the stuff is deleted, no change in how it runs. Except I think maybe it idles better. Now that I have vacuum crossed off the list, I’m honestly leaning towards timing. I don’t think I’ve ever properly set the timing in this car. My goal has always been 12-14°, so I’m working on that currently

 

[red5.0fox]

Okay so all the stuff is deleted, no change in how it runs. Except I think maybe it idles better. Now that I have vacuum crossed off the list, I’m honestly leaning towards timing. I don’t think I’ve ever properly set the timing in this car. My goal has always been 12-14°, so I’m working on that currently

So I’ve made myself a line right around 13ish° and it runs like crap when it’s set there. Pops in the intake and everything. The only place it seems to run decent at all is way off all of the timing marks.. what do I need to do here?

 

[AeroCoupe]

Put the motor on top dead center and see if the rotor is pointing at the #1 cylinder post on the cap.

You will need to get the motor on the compression stroke on the #1 cylinder and verify that the piston is all the way at the top of the cylinder. This is TDC.

 

[AeroCoupe]

Also, are you pulling the spout connector to set the base timing?

 

[red5.0fox]

Put the motor on top dead center and see if the rotor is pointing at the #1 cylinder post on the cap.

You will need to get the motor on the compression stroke on the #1 cylinder and verify that the piston is all the way at the top of the cylinder. This is TDC.

Okay, honestly didn’t think I was off enough to have to do that again lol. guess tomorrow I’ll grab the big breaker bar and shove some paper towels in the cyl1 port lol. And yes I was pulling out the spout when I messed with it.

 

[AeroCoupe]

I’m just throwing it out there but it sure sounds like you are off a couple teeth.

I usually pull all the plugs so it makes it easier to roll the motor over by hand.

 

[90sickfox]

I just thought I'd add something here. The factory harmonic balancers can slip over time causing marks to be way off. Bring to TDC and mark the balancer with white out. Check the distributor. Make sure your number one wire is actually running to the number 1 spot on the cap. I've had people think you could put number one anywhere as long as the firing order was correct. That isn't true. Make sure you are using the HO firing order for a mustang 5.0. Wouldn't hurt to try the non HO firing order also. A bunch of lincoln and f150 engines have found their way into swapped 4 cylinder cars....even if they have gt40 heads.

 

[90sickfox]

I just thought I'd add something here. The factory harmonic balancers can slip over time causing marks to be way off. Bring to TDC and mark the balancer with white out. Check the distributor. Make sure your number one wire is actually running to the number 1 spot on the cap. I've had people think you could put number one anywhere as long as the firing order was correct. That isn't true. Make sure you are using the HO firing order for a mustang 5.0.

 

[red5.0fox]

I’m just throwing it out there but it sure sounds like you are off a couple teeth.

I usually pull all the plugs so it makes it easier to roll the motor over by hand.

okay cool, I’ll reset it all tomorrow

 

[red5.0fox]

I just thought I'd add something here. The factory harmonic balancers can slip over time causing marks to be way off. Bring to TDC and mark the balancer with white out. Check the distributor. Make sure your number one wire is actually running to the number 1 spot on the cap. I've had people think you could put number one anywhere as long as the firing order was correct. That isn't true. Make sure you are using the HO firing order for a mustang 5.0.

I’ll definitely check that out. I remember when we first swapped it we tried both firing orders. I believe it was the HO that wound up working correctly. I’ll go through the whole process after work tomorrow and update you guys

 

[AeroCoupe]

If the balancer comes up suspect and you are just looking to go back stock then Power Bond is a really good brand.

https://www.summitracing.com/search/brand/powerbond/part-type/harmonic-balancers?N=engine-balance%3Aexternal-50-oz-imbalance

Obviously if you step up to the street its a little better and the race is SFI but you are getting into that dollar range where you should look at other brands like Romac.

 

[TwoRockTwo]

Okay so, blue comes from the metal line off the backside of my intake. Green comes off the splitter, and runs into the FPR. Yellow comes off the tree and goes into my EGR valve. Ignore the uncapped areas on the splitter, I just uncapped them.

You should have direct vacuum on the fuel pressure regulator. So the blue, directly off the intake to the fuel pressure regulator.

You also had the EGR wrong in the above photo, applying a direct vacuum like pictured, opens the EGR valve at idle and causes misfires. The EGR should only be open at part throttle cruise. To correctly connect it, you supply a vacuum source to the vacuum bulb in the fender, and from there to the EGR solenoid in the fender, and finally from the solenoid to the EGR valve. The EEC activates the solenoid, which then supplies vacuum to the EGR valve.

 

[red5.0fox]

You should have direct vacuum on the fuel pressure regulator. So the blue, directly off the intake to the fuel pressure regulator.

You also had the EGR wrong in the above photo, applying a direct vacuum like pictured, opens the EGR valve at idle and causes misfires. The EGR should only be open at part throttle cruise. To correctly connect it, you supply a vacuum source to the vacuum bulb in the fender, and from there to the EGR solenoid in the fender, and finally from the solenoid to the EGR valve. The EEC activates the solenoid, which then supplies vacuum to the EGR valve.

I fixed the vacuum routing and tore out all of the rest of my EGR stuff and blocked the port off. I have one of those plugs LMR used to sell to “trick” the ECU so there is no CEL. Half of the vacuum lines on the TAB solenoids broke apart in my hands when I took them out lol, so I don’t imagine it was working anyway.

 

[AeroCoupe]

TworockTwo's comment got me thinking that I may have my EGR connected wrong so I looked at the vacuum diagram on one of the previous posts on page 2. Started noodling around and found the diagram below over on LMR which has a little more info in that it calls out what is connected to the vacuum tree. So with all that I also learned that the reservoir is not needed when you delete the EGR system so my apologies for thinking it was still needed.

 

[TwoRockTwo]

I fixed the vacuum routing and tore out all of the rest of my EGR stuff and blocked the port off. I have one of those plugs LMR used to sell to “trick” the ECU so there is no CEL. Half of the vacuum lines on the TAB solenoids broke apart in my hands when I took them out lol, so I don’t imagine it was working anyway.

You don’t want to trick the EEC into thinking the EGR is still present and working properly.
If you do, the EEC is still going to do what it’s programmed to do, pull fuel and add timing when it commands the EGR. It does that because exhaust gasses are inert and displace fresh combustible air.
In short your air/fuel will be lean, timing high, and combustion temperatures skyrocketing.

Allowing the CEL to illuminate because of a fault with the EGR effectively disables the whole function. The EEC knows there is a problem and just doesn’t use it anymore until the problem is fixed.

That’s one of the reasons nobody sells those plugs to trick it anymore.