Vaccum Problems!

[Vigilante]

Aren't they great? lol

So, every time I think I have solved a problem, I seem to find something else that could be contributing to the larger portion. Now for instance, I notice a vaccum hose in the cab that goes through the firewall (above and just to the left [looking towards the front of the car] of the accelerator pedal) and connects to the rear facing vaccum point. This hose ran through my firewall and was wound up under the dash and was plugged by a rather large bolt. My Chilton's doesn't tell me much on vaccums and what it does the image is far too small to read.

Ok, have to throw this in too.

At the front of the air intake manifold (towards the front of the vehicle) there are 2 vaccum ports. One is for the Mass air flow sensor, the other is for the air cleaner box (I think?). My car idles much smoother when these are disconnected in park or neutral but when the car is in gear it runs rough until I plug in ONLY the Mass air flow sensor.

So heres the first pic showing my main vaccum hub on the drivers side of the engine at the back, closest to the cab. The blue painters tape is to mark the port that the 'unknown' vaccum hose goes to. It was easier to just plug it here than to connect it and plug the line.

So this is where the 'unknown' vaccum hose goes through the firewall. At the point where the hose goes through this reinforced rubber component, the vaccum hose itself is reinforced with a copper tube that is roughly 4 inches long and sticks out about 2 inches and goes into this reinforced point through the firewall.

And lastly, this is where the 'unknown' hose comes through the firewall in the cab. The metal component on the right is the accelerator and the black rubber boot is the steering column. You can see the hose goes out of the picture but comes back around into the pic. I did this to try to show that the hose was not cut. It is a thicker black hose with a yellow stripe on it. I cannot find anything in my vaccum diagrams or in my manuals that indicate what it may be. I am under the impression that it could be Air Conditioning or something?

She idles around 900 rpm for about 20 seconds and then starts to bogg and the rpms climb just so she can keep herself alive. I believe I am running lean on the fuel because when I open up the throttle she will die, or she clears up but then shuts down when the rpms reach 3500. The Idle Air Controller I removed and it checked out to manual specs (but it is an original Ford part). And the Mass Air Flow sensor was replaced, but when I unplug the MAF sensor from its vaccum port on the front of the intake manifold, it runs better than when it is connected. I have no check engine light while the car is running either.

And is there any way to tell which vaccum hose goes where and what exactly they do? I would like to write this down and draw myself a better picture than what it is I have been able to find.

This morning I tried a new approach. I plugged all the vaccum ports (besides the ones that I know are going to their respective locations) as well as the main air intake, and she idled beautifully at 800 rpm for more than a minute before she got rough and died. I've had vaccum problems on my old Explorer, but it was never as bad as this and I am still at a loss to figure out what exactly is going on with it, lol.

 

[IMenriched]

At first my thought was for climate control...(if that is what is used) but wow that is a big line for that.

nope not for climate control....ran out side ...took a gander at my 86'.

It went to the brake pedal, up High on it, really had to crane my head around to see it....pumped the brake a few times (engine off) & i could hear it weez abit,, each time I hit the brake the pedal got firmer.

 

[Vigilante]

Got it, brake pedal. Im going to go check that out.

Thanks a lot!

 

[Original_Ranger84]

I would clean the MAF sensor too, your probably running lean because of the leak. Brake I believe is directly connecte to the Mastercylinder I thought? I know on my 84 I don't have anything like that. and the brake hisses because of a leak around the connection.

 

[Vigilante]

the MAF is brand new, I just replaced it 2 days ago. Im wondering if it could be the IAC or the FPR or something.

 

[Psychopete]

MAS and MAP sensors are quite a bit different - there are 2.9Ls with a MAF ECM, but they are sort of rare (California Emissions) and measure air flow coming in from the air box between the intake tube as opposed to manifold vacuum. From what you describe, it sounds like you are referring to a MAP sensor.

Does your FPR have a vacuum line running to it?

I was under the impression that cruise control uses vacuum, that would be my next thought. I don't know a whole lot about this system as I've never ran into one on an '88. Maybe someone will chime in on that...

Any signs that there may have been a vacuum gauge installed in the cab?

Have you tried plugging that stray vacuum line to see if the problem goes away?

Might be worth while to pull codes even though you don't have a CEL present, bulb could be burnt or disabled.

Pete

 

[Vigilante]

The check enging light is working. After the vaccum suffocates the engine and it stalls, the CEL comes on.

From what I have figured out, my unknown line comes through the firewall and is supposed to connect to the brake pedal. After that it goes through the firewall and connects to the cruise control. Then there is a line that runs from the cruise control to the top point in the manifold. This is the line that shuts off the cruise control when the brakes are applied.

As far as the FPR, it does have a vaccum line running from it and it is plugged into the front (closest towards the front of the vehicle) vaccum port.

And lastly, my B2 was not originally sold in California, so it does not have the California Emissions regs on it.

 

[Original_Ranger84]

Pshh... I say take it off and plug the hole, then it will run fine and when you go to turn something on and it doesn't you know what you unplugged. Thats what I would do with my 2.8L will all its vacuum glory.

 

[IMenriched]

From what I have figured out, my unknown line comes through the firewall and is supposed to connect to the brake pedal. After that it goes through the firewall and connects to the cruise control. Then there is a line that runs from the cruise control to the top point in the manifold. This is the line that shuts off the cruise control when the brakes are applied.

.

Yes this is how the routing of vacuum line is on my 86' as well. only the vacuum line that goes through the firewall inside the cab hooks to the brake pedal.

agreed.....plug the line inside the cab...see how it runs from there. Pretty sure you just wont have cruse control...or it may still set, but you won't be able to shut it off with the brake...then hit OFF on the steering wheel.....but be ready if it won't shut off....that could be bad

 

[Psychopete]

the CEL comes on.

You probably have a CM code stored in memory. My Stang was having issues dying out, wouldn't throw a CEL, pulled codes and it had a fuel pump power loss code in stored memory (fuel pump monitor - but it is a '93 engine). Would have spent a long time trying to figure that out on my own.

http://www.therangerstation.com/tech_library/OBD_I.html

Just hook up the STI (small square plug) to the Sig-RET on the self test harness (trapezoid shaped plug) as shown on the diagram with a small piece of wire or paper clip. Hop in the cab and put the key on 'Run' and the computer will output KOEO codes (hard faults), single pulse, and then the stored memory codes through the check engine light. Each set of codes are repeated twice.

Pete

 

[Vigilante]

Ya, I need to go pick up my friends computer. I know where the EEC, I've pulled codes before but some of them were incredibly too far fetched to look into. I had one saying the neutral safety switch was bad when I could prove to myself quite easilyt that it wasnt, lol.

Now when I plug all the 'open' vaccum hoses, she idles right around 850 rpm, engine tag says 800 but its so damn close I dont want to mess with it. but when I get on the gas she still dies. Could this be the fuel pressure regulator? Shes not flooding because I dont smell any gas at all, so thats why Im pretty sure shes running lean. I can confirm that I get fuel pressure because I checked at the fuel manifold. I bought a tire pressure test gauge to test the fuel pressure. I probly broke it doing this, but I read a shot up to 20 psi upon start up and then it goes to 0, even though the engine keeps running smoothly and 20-30 seconds later, she starts shaking violently to stay alive and then dies.

 

[Vigilante]

Ok, so I replaced the Fuel Pressure Regulator and have had no improvements. I also capped some of the open vaccum points including the 'unknown' one. But she still lives for 20-30 seconds and then dies on me. So is it worth it to replace the Idle Air Controller even though it checked out? What about the O2 sensor as well, could that be it?

 

[IMenriched]

Ok, so I replaced the Fuel Pressure Regulator and have had no improvements. I also capped some of the open vaccum points including the 'unknown' one. But she still lives for 20-30 seconds and then dies on me. So is it worth it to replace the Idle Air Controller even though it checked out? What about the O2 sensor as well, could that be it?

Are your sure you are not loosing spark instead of fuel??
might be worth testing the TFI too

might want to trace the wires to and from the MAP sensor....it might not be getting its signal to the ECM