Progress Thread Progress Thread- From6to8's 1994 Cobra Supercharger install

[from6to8]

So... Start recording your vacuum when FP is normal and when it's not. Note the temp on the gauge too.


Also: See if you can rig up some way to reference your voltage at the fuel pump. Maybe at the FP relay under the pass seat?

Whatever that wire is you were talking about ,around the fuse... Fix that to eliminate it as a possibility.

ok I will start recording that.

the 94 95's have the fp relay under the seat?

yes in the morning once I put the adj. regulator back on I'm going to note the fp at cold start then go ahead and make that wire permanent or actually make permanent then start the car.

 

[Noobz347]

the 94 95's have the fp relay under the seat?

I keep forgetting this part. I think your is behind the kick panel near the EEC?

 

[from6to8]

I keep forgetting this part. I think your is behind the kick panel near the EEC?

Yes lol

Here's a video I was just looking up some stuff on YouTube in this video explains checking the inertia switch making sure plus 12 voters coming in and out. The way the video is set up someone in the comment name drag radio performance explains how it really should be done with the checking to make sure 12 vote is coming in and going out. Going to read up a little bit on this tomorrow and try some stuff to make sure see if I can see if I'm getting good voltage there.

Did hit a deer in October and installed the Vortech shortly after that so did not drive the car much after the car was repaired. To my knowledge with the inertia switch though if a jolt does something to it it's supposed to not let the car start up at all I don't think it could be partially down or anything to where it's not causing proper voltage?



View: https://youtu.be/42ZMipfjZfU?si=RMsx8lnkNXlAZeJw

 

[nicholase]

Have you checked your FP with anything besides the new guage? If not I'd go rent a mechanical guage from the parts store (or buy one). Screw it on the schrader valve and double check if it's actually low. Could be a fuel system problem, could also be a sending unit, wiring, or guage malfunction.

If the mechanical guage and new digital guage read the same them carry on. But I'd rule that out first.

https://www.harborfreight.com/fuel-injection-pump-tester-58760.html

 

[from6to8]

Have you checked your FP with anything besides the new guage? If not I'd go rent a mechanical guage from the parts store (or buy one). Screw it on the schrader valve and double check if it's actually low. Could be a fuel system problem, could also be a sending unit, wiring, or guage malfunction.

If the mechanical guage and new digital guage read the same them carry on. But I'd rule that out first.

https://www.harborfreight.com/fuel-injection-pump-tester-58760.html

I do have a fluid filled pressure gauge screws in to the straighter location that I was thinking about trying and monitoring. Would yield the same diagnosis right?

 

[from6to8]

I keep forgetting this part. I think your is behind the kick panel near the EEC?

When you were talking about the car going in closed loop after it warms up if the car is just sitting in the garage idling for however long that's the same thing as me driving it and it going in closed loop correct because I was going to probably after I check some other things today let it run for however long see if the pressure is going to drop.

 

[Noobz347]

It will reach that stage idling in the driveway but it will take a bit longer.

 

[from6to8]

It will reach that stage idling in the driveway but it will take a bit longer.

Gotcha. I'll probably drive

 

[from6to8]

Checking the voltage at the inertia switch and something seems off with it. There's a green wire and a brown wire one of those wires I should be getting 12 volts with the car just switched to the on position correct?

I know unplugging the wire and checking the volts it's definitely not showing 12 it's showing around 7 and the gauge showed 8

Edit-
Okay it seems the inertia switch will only see voltage for 2 seconds once the key is switched on so I will need a helper or just fire the car up and check

 

[from6to8]

It will reach that stage idling in the driveway but it will take a bit longer.

Update-

Just wanted to say that yesterday I actually put the OEM regulator on and when I switch the car on but no start the fuel pressure was 24 or 25. The car was still warm ish some from my trip yesterday and it was getting dark so I wanted to diagnose that quickly. Actually had an issue and I don't remember if it was me or the person who put the adjustable regulator on long long time ago when I was a rookie back in the early 2000s LOL. But the bolt hole nearest the intake was stripped and there was a bolt with a nut. I actually found the original bolt and fastened and it felt like it was getting decently tight but when I switched the car on there was a leak.

Anyway I got that all sorted out now and ended up having to use the bolt and nut and I just went ahead and put the adjustable regular to back on. Also to point out I put the distributor cap off of my other car which even though the car was used that sucker looks new. My rotor button looked fine but the MSD cap was not too bad but it did have some rust looking marks on it and I guess that's from age but it's not super super old but it might be old enough so I wanted to try it. Also had a couple of questionable wires where the metal clip inside the boot came off and so I just put on two of my old Ford racing wires and the car actually drives better so I'm going to end up getting a set of wires and a distributor cap and rotor button.

Now on to the checks for today. I could not check the voltage at the inertia switch by myself since I discovered you only get voltage for 2 seconds once you switch the key on so I started the car and the fuel pressure was 35. Vacuum was -5 and for some reason it seemed the voltage at the green wire of the inertia switch was 10.20 and the brown wire was 10.94 but that was using a safety pin which is a little bit difficult sometime to check the votes and you got to keep it still and don't let it move. The car when I fired it up it sounded like it wanted to cut off but it leveled out and I don't know I did prime the fuel pump 4-5 times after swapping The regulators to. I think since I've gotten it tuned when I first fired it up it kind of does that for a few seconds or so then levels off.

After a few minutes a few pressure was 33 and vacuum -9.

At about 140° the fuel pressure was 32 and vacuum - 11

At 180°. Still using the paper clip I got 9 volts at the brown wire in the green wire was 10.80 to 11 fluctuating. Fuel pressure was 32 and vacuum - 10. The car sounded more alive between 150 and as it warmed up good. (Definitely will monitor again tomorrow as I start the car and see if it sounds the same up on startup until it warms up).

Little past 180° the votes at both wires 11 plus to 12 and this is with pushing the clips straight into the harness connector without using the safety clip. That's noted for future reference to just try and use the connector from the meter if it will fit. The fuel pressure was at 31, 30 and vacuum - 10.

After a few more minutes for your pressure 29 vacuum - 11

Maybe after another 5 minutes or so fuel pressure 29 vacuum - 11, 29 then 28, 28 vacuum -12. Maybe after about 3 to 5 minutes fuel pressure 27 vacuum -13 and all of this is just sitting and idling vacuum - 12 to -13 at this juncture, fluctuating some. So - 14 and a fuel pressure 27, - 13 fuel pressure 26 and air fuel 14.20 ish. In my notes all of this is after 5 plus minutes running idling.

At 307 p.m. fuel pressure 25 vacuum -13 air fuel 14.50 to 15

At 3:09 p.m. fuel pressure 24 vacuum - 13 - 14

Leaving garage in until I get to the end of the driveway fuel pressure 25 vacuum -10 to - 11.

After taking off probably after a few minutes fuel pressure is at 21 vacuum - 17 at 45 mph air fuel 15-ish.

After a few more minutes of driving fuel pressure 23 vacuum -13.

After a few more minutes got to the stop sign fuel pressure 22 vacuum -14 air fuel 13.75

Pulled back into garage at 323 p.m. fuel pressure 21 vacuum -13 air fuel 14.11 at 200° on the gauge
Green wire 12 plus volts brown wire 12 plus volts

15 minutes later switched on not start after crimping the wires and uel pressure 22 vacuum 0 of course.

So it seems that once the car is good and warm the fuel pressure is much lower but I thought I read something as well where with a tune and if you are showing negative vacuum the fuel pressure is going to be lower something about there's a trade off or something I think I think that's what I read something along those lines where your fuel pressure is actually fine for what it's showing on the gauge according to what the vacuum is.

Thoughts?

 

[Noobz347]

After a few minutes a few pressure was 33 and vacuum -9.

At about 140° the fuel pressure was 32 and vacuum - 11

So, it looks like your fuel pressure is tracking with vacuum. I also don't see anything in your data that suggests a vacuum leak.

The voltage readings that you got, however, are suspect.

See if you can hook the volt meter up so that you can read it with the car running. Let the idle stabilize (doesn't matter at this point if it's hot or cold). Turn on all your accessories: Healights, interior lights, A/C, etc... and see if there is a voltage drop at the inertia switch/pump power feed.

 

[from6to8]

So, it looks like your fuel pressure is tracking with vacuum. I also don't see anything in your data that suggests a vacuum leak.

The voltage readings that you got, however, are suspect.

See if you can hook the volt meter up so that you can read it with the car running. Let the idle stabilize (doesn't matter at this point if it's hot or cold). Turn on all your accessories: Healights, interior lights, A/C, etc... and see if there is a voltage drop at the inertia switch/pump power feed.

Okay just to point out I was checking the voltage while the car was running but not just I would have to see if I can get an alligator clip to clip the negative terminal to ground to be able to verify it with all of that stuff on or I could just turn everything on and then check again. But the voltage difference that you see is probably from using the safety clip to just pushing the prongs in the connector. By the way the voltage readings were with the car running because the only way you can check it when you just switch the car on as if you have someone to switch the car on for you because for my understanding you only get voltage for 2 seconds after the car is switched on at the inertia

 

[Noobz347]

Yeah, and it's important to get that reading while the car is running.

Remind me: Is the pump a new 255L?

 

[from6to8]

Yeah, and it's important to get that reading while the car is running.

Remind me: Is the pump a new 255L?

Yes new and it's the high flow

 

[from6to8]

Yeah, and it's important to get that reading while the car is running.

Remind me: Is the pump a new 255L?

I found this thread doing a little research earlier and it said something about indexing the fuel pressure regulator to boost and not vacuum I wonder if that's my issue.

Fuel Pressure Regulator Vacuum line? | Mustang and Ford Performance Forums https://share.google/PCzAj3I32iw7t09hv

 

[Noobz347]

That all depends on your tune and how it is setup.

On my KB setup, there is a pressurized manifold and an unpressurized manifold. There are two vacuum lines that come to a T and the one in the pressurized manifold has a check valve to keep the fuel regulator from seeing boost.

Most fuel regulators have no idea what to do with boost. There were not designed for it. In most cases, the EEC has no idea what the fuel pressure is. When the combo gets into boost, the tune resorts to pre-built air and fuel tables set up on the dyno, etc.

So... I'm not totally sure I follow what markolson is referring to about "Indexing" in the thread you posted.

That doesn't mean that somebody else here isn't more familiar. The KB kit [different] in a lot of ways though I do use an OEM FPR that has [zero clue] what a boost reference is.

 

[from6to8]

That all depends on your tune and how it is setup.

On my KB setup, there is a pressurized manifold and an unpressurized manifold. There are two vacuum lines that come to a T and the one in the pressurized manifold has a check valve to keep the fuel regulator from seeing boost.

Most fuel regulators have no idea what to do with boost. There were not designed for it. In most cases, the EEC has no idea what the fuel pressure is. When the combo gets into boost, the tune resorts to pre-built air and fuel tables set up on the dyno, etc.

So... I'm not totally sure I follow what markolson is referring to about "Indexing" in the thread you posted.

That doesn't mean that somebody else here isn't more familiar. The KB kit [different] in a lot of ways though I do use an OEM FPR that has [zero clue] what a boost reference is.

Got you. I'm going to call the tuner tomorrow maybe his explanation will explain a lot of things as to how he has it set up according to how or what he saw on the dyno and what the car was doing so maybe he has the computer tricked and hopefully he will bring some clarity in that I'm totally fine

 

[Noobz347]

I'm thinking back to things you said about your setup.


The vacuum line to your FPR should be attached to a vacuum source [before] the blower and not to your intake manifold where it will see boost.

Remind me where yours is connected again?

 

[from6to8]

I'm thinking back to things you said about your setup.


The vacuum line to your FPR should be attached to a vacuum source [before] the blower and not to your intake manifold where it will see boost.

Remind me where yours is connected again?

The vacuum line from the fuel pressure regulator is on the if you go back to some post maybe last week or so there was a picture I showed where there's a screw in Port thing that has three ports that gets vacuum. The fuel pressure regulator is going to one of those ports. The only thing that's going to the intake manifold is the bypass valve for the supercharger coming off of the discharge

 

[from6to8]

I'm thinking back to things you said about your setup.


The vacuum line to your FPR should be attached to a vacuum source [before] the blower and not to your intake manifold where it will see boost.

Remind me where yours is connected again?

I'm thinking back to things you said about your setup.


The vacuum line to your FPR should be attached to a vacuum source [before] the blower and not to your intake manifold where it will see boost.

Remind me where yours is connected again?

Ar one of these spots