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

[from6to8]

All signs point to me having everything set up correctly. When I called the tuner tomorrow I'm going to be very curious to see what he has to say about my situation. I would think that if the fuel pump was weak or something the car wouldn't want to start it would drive crazy you know and fuel pressure might be spiking you know up and down not just a little bit over time but maybe fluctuating going kind of crazy lol. No one

Also have on the list to try the my oil filled pressure gauge too because I want to see once I shut the car off how fast the fuel pressure is taking to actually bleed down to zero

 

[Noobz347]

Umm... Hmmm.... That appears to be [after] the SC.


What do your install instructions say about plumbing the FPR?

 

[from6to8]

Umm... Hmmm.... That appears to be [after] the SC.


What do your install instructions say about plumbing the FPR?

There are actually no instructions about plumbing the regulator from vortech.

I might need to give them a call but I think I actually did and was told that, well it might have been actually in reference to the bypass valve and where that needed to go but I will give them a call tomorrow and see what they say.

 

[Noobz347]

There are actually no instructions about plumbing the regulator from vortech.

I might need to give them a call but I think I actually did and was told that, well it might have been actually in reference to the bypass valve and where that needed to go but I will give them a call tomorrow and see what they say.

Good Call. I'm not familiar about how their bypass valve works.

 

[from6to8]

Good Call. I'm not familiar about how their bypass valve works.

Also I want to point out that when I last talked to the tuner and asked him about the 255 pump being large enough as in at the max potentially in he was like no and in fact he had to pull some fuel away. Reminder 2:55 high current pump with the 60 lb injectors.

I would have thought that if there was anything going on with the pump potentially I mean I'm not sure but you know I'm not sure if he could have saw it losing pressure due to voltage drop potentially or the pump possibly being flawed itself...

 

[Noobz347]

losing pressure due to voltage drop potentially or the pump possibly being flawed itself.

This is possible. We hit on this some over the phone.

 

[from6to8]

This is possible. We hit on this some over the phone.

I'm hoping he will tell me tomorrow that that's something he would have seen during the tuning process.

How would you check the voltage drop I mean I'm guessing the tank will have to be dropped and is there a way or do you have to even check it while the car is running and warming up as well to see it drop at certain intervals?

 

[Noobz347]

I outlined one method above. Get a reading on it with the car running and start turning on accessories. That should tell you something about the wiring etc...

 

[from6to8]

I outlined one method above. Get a reading on it with the car running and start turning on accessories. That should tell you something about the wiring etc...

But that's at the inertia switch though. I believe someone suggested that in order to see voltage drop it would actually have to be at the fuel pump itself or no?

Well I guess that's one way to verify that the inertia is getting plus 12 but I wonder if there could be a point between the inertia switch and the pump if that's where it comes from the front of the car. Isn't there something else some wiring or something running under the car as well under the underbody going to the fuel tank?

 

[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?

Vortech says the fp vacuum at that spot should be fine.

I called you this morning by the way and sent you a text, not sure you text though lol. So as to the car sitting and idling and the fp eventually over the course of about 15 minutes ish dropping from 35 to 25 but the vacuum rising from -5 to -13, if there was voltage loss occuring at the pump what would cause that voltage drop if the car is just idling? Just curious because I know under a load and driving the car and more demand for fuel as you open up the throttle I can see how that would cause the voltage drop as you are doing those things. I will test later this eve as well as to the accessories being on while the car is running and check the voltage at the inertia.

and the same thing for the pump itself if the car is just sitting there idling if the pump for whatever reason is or something is wrong with it, why would it do that after the car is warmed up and not right off the bat?

 

[Noobz347]

I'm sorta like a vampire.

over the course of about 15 minutes ish dropping from 35 to 25 but the vacuum rising from -5 to -13, if there was voltage loss occuring at the pump what would cause that voltage drop if the car is just idling?

As the Vacuum rises, the fuel pressure should fall off. So, I don't see an inherent issue with that. That's how the FPR should work.

If however, you discover that it is not consistent, then that would be an issue.

This goes back to what we talked about before about setting your Fuel Pressure when the car is heat soaked vs. cold. This also the reason for wanting to try an OEM style non-adjustable FPR to make sure that the vacuum source is correct at idle and when in boost.

The FPR should not see boost. At 0 vacuum, you should be seeing your highest/best fuel pressure (whatever you set it to with the vac off).

 

[from6to8]

I'm sorta like a vampire.



As the Vacuum rises, the fuel pressure should fall off. So, I don't see an inherent issue with that. That's how the FPR should work.

If however, you discover that it is not consistent, then that would be an issue.

This goes back to what we talked about before about setting your Fuel Pressure when the car is heat soaked vs. cold. This also the reason for wanting to try an OEM style non-adjustable FPR to make sure that the vacuum source is correct at idle and when in boost.

The FPR should not see boost. At 0 vacuum, you should be seeing your highest/best fuel pressure (whatever you set it to with the vac off).

ok hence the 35 fp at startup yesterday and -5 vacuum.

consistent as in the numbers I saw yesterday even when the pressure went to 25 and the vacuum about -13. If it consistently does that then I might be fine? But of course I want to verify that everything is fine and if so I might be. Talking to a few guys on fb yesterday they said they believe their fp does the same thing with their setup and they will verify; I believe they've had their setup for awhile. I'm going to call Vortech again to ask another question. I'll put the fluid filled gauge on when I get home and begin the checks and see how that gauge does under the same circumstances. It should slowly bleed down at around an hour mark ish maybe a little before an hr ish as I've had a fluid fill for over 20 yrs with my NA setup.

 

[Noobz347]

consistent as in the numbers I saw yesterday even when the pressure went to 25 and the vacuum about -13. If it consistently does that then I might be fine?

I don't see a problem with how the FPR is acting. It appears to be doing the job it is intended to do.

 

[from6to8]

I don't see a problem with how the FPR is acting. It appears to be doing the job it is intended to do.

Okay so got home and put on the mechanical gauge and started the car and a fuel pressure was 38 and vacuum - 11. Yesterday the fuel pressure was 35 and the vacuum was -5. I've noticed lately when I started the car it fired up but it's it kind of idled a little low like it wanted to cut off almost and then it leveled out after about 10 to 15 seconds.

After about 4 minutes of running now at 125°, the idle sounds better fuel pressure at 34 vacuum - 11. I noticed the vacuum never changed like it did yesterday. Went on a very short drive I mean probably 3 to 4 minutes and got back home and the fuel pressure is holding it was at about 36 and the vacuum I believe was - 11. Another thing I noticed is with the mechanical gauge on there the fuel pressure is bleeding down slowly like it's supposed to it's not just going straight to zero within a matter of minutes.

However, what I did notice and by the way checked the volts and it was about 11.50 11.75ish. I didn't do it with the accessories on because what I noticed is the car started back to driving a little erratic on taking off with feeling like it didn't have power and then going through the gears it didn't feel smooth or it just felt like something was off. I'm probably going to just not mess with it anymore tonight and start back fresh tomorrow when I get off and take it on the drive and see how it does.

I'm not sure if it's a sometimey thing that is doing but I may end up just getting it back to the tuner and letting him check everything out and maybe make some changes or whatever. I did send the chip back to him for him to make some changes after it was driving just like it's doing today after I got the car back home from the dyno tune. It's crazy how it drove nice and smooth yesterday even with the fuel pressure reading lower with the glow shift digital gauge and the only thing I did today was put a mechanical gauge in place.

I did somehow start the car up with the trickle charger still on the car which I never do but that should not have heard anything

What I'm going to do tomorrow as well I'm going to swap the coil from my other car to it just to see. I might even try a different TFI module as well I have another one lying around and hopefully it's one of those two things that's the issue before I well I'll see what the tuner says tomorrow when I call him but hopefully I don't have to take the car back and it's one of those things potentially.

 

[AeroCoupe]

Again, I am not a supercharger guru but wouldn't the vacuum source for the FPR need to be after the throttle body?

The other thing you did not look at or at least failed to mention is what was the voltage at the battery when testing the voltage at the inertia switch connection? If there is a wiring harness connector for the fuel pump and sending unit just above the tank and behind the bumper you should be testing the voltage on the pump side of that connector. Closer to the pump is better. If the voltage continues to be sketchy then just run a dedicated 14 ga wire from the battery (with a fuse) to a relay in the trunk. Cut the wire on the pump side of the inertia switch and use that to trigger the relay and wire the pump output from the relay back to the pump side of the wire you cut on the inertia switch. Ground the coil side of the relay in the trunk to a good ground.

Bosch relay wiring:

87 - Battery 12V+
30 - 12V+ to pump
85 - ground
86 - 12V+ from inertia switch

 

[General karthief]

Let me throw something out here....
A low voltage condition will effect how things work, like the fuel pump, among other things, you mentioned a low voltage reading in the last post, check and monitor your charging system.

 

[from6to8]

Again, I am not a supercharger guru but wouldn't the vacuum source for the FPR need to be after the throttle body?

The other thing you did not look at or at least failed to mention is what was the voltage at the battery when testing the voltage at the inertia switch connection? If there is a wiring harness connector for the fuel pump and sending unit just above the tank and behind the bumper you should be testing the voltage on the pump side of that connector. Closer to the pump is better. If the voltage continues to be sketchy then just run a dedicated 14 ga wire from the battery (with a fuse) to a relay in the trunk. Cut the wire on the pump side of the inertia switch and use that to trigger the relay and wire the pump output from the relay back to the pump side of the wire you cut on the inertia switch. Ground the coil side of the relay in the trunk to a good ground.

Bosch relay wiring:

87 - Battery 12V+
30 - 12V+ to pump
85 - ground
86 - 12V+ from inertia switch

The vacuum source for the fpr is after the throttle body it is on the elbow and there's a picture on the previous page of where it is. On that elbow and even on the factory setup there is a screw in tea or whatever that has three ports. There's a big Port that it's about a 3/8 I believe and that gets the big vacuum line from the tree in the corner on the driver side. The other one goes to the fpr and the last spot is for the boost vacuum gauge sensor. I called vortec and verified that's a good spot as well as others have said that vacuum spot is fine for the fpr.

The issue I was having lately that I was trying to verify was the fuel pressure and that was verified today with putting the mechanical gauge on it and having no pressure drop like I was with the glow shift digital gauge and sensor. Matter of fact I don't know how it happened and that might have been the cause of the glow shift gauge but when I went to loosen the sensor it was needless to say it turned easily, but it was not leaking any fuel. So when I get to another spot of diagnosing I will go ahead and swap that sensor back make sure it's good and tight and see if the sensor reads like it's supposed to.

The battery volts is good and I will verify what exactly it is tomorrow but I know the last time I checked it

I'm not having a or doesn't appear to be that I'm having a voltage issue with anything but I was checking voltage when I was having the fuel pressure situation. So tomorrow I will do some more diagnosing matter of fact the first thing I'm probably going to do is go ahead and swap the coil and maybe the TFI module but I will do one at a time and fire the car up and see if it does any better, I will start there.

 

[from6to8]

Let me throw something out here....
A low voltage condition will effect how things work, like the fuel pump, among other things, you mentioned a low voltage reading in the last post, check and monitor your charging system.

I'm going to do some checks tomorrow and matter fact I might actually take the car in to AutoZone and let them put the tester on the battery and fire the car up in check the entire system. I'm assuming you're talking about the 11.50 to 11.75 volts at the inertia switch. Should the volts hold steady at whatever it is or should it fluctuate? It was actually fluctuating going from that number to 12 something back to 11:00 I believe

my autometer volt gauge is holding steady at 14 plus volts and not fluctuating or anything by the way

 

[from6to8]

i did notice that lately the past probably 6 times I've started the car and since the SC install when I start the car there's almost a like a kinda screechy sound for a second or so coming from the engine bay. Another thing I noticed is that as the car warms up at about 125°it sounds better and smoother and more like the car should sound versus the first few minutes of it running after startup

Reading up on ignition coils and TFI modules right now and some of the symptoms that I am reading up on mine has so that's going to be an easy try tomorrow.

Also I'm running the OEM distributor and it's got a total of about 205k miles on it. It was mentioned in a thread that the magnetic trigger in the distributor could be shot.

I am running the stock ignition setup and the tuner told me to avoid spark blowout got the plugs at .25

I only mentioned that because this one thread I'm reading this guy had is at .32 and someone said that is way tight unless it is that tight for a weak spark having a blower. I'm pretty sure I'm fine and researching beforehand it seems a lot of people liked .28 - .32 for a blower

 

[Noobz347]

I don't recall what mine is but it is closed up. I also run a Boost-A-Spark to keep the coil saturated. Essentially the same function as the Boost-A-Pump for the fuel pump.

Checking/cleaning all of your wire connections and grounds can help with this too.

Do you run an OEM alternator or a 3G? It doesn't matter a [ton] unless you got e-fans or a huge stereo etc...