Piranha

yeah, I downloaded the factory manual, but I don't have a pump like that. where do I get one?

HAILERS

Its a cheap item called a MITTYVAC that I got at Autozone or PepBoys. By the way, I've been editing the last post I made. Did you read the last edit?

HAILERS

Here is a site that shows a graph of the output voltage of the boost/pressure sensor at different psi. If one had a digital meter and had it connected to the input wire to the ECU, he could put pressure on the boost/pressure sensor and compare voltage readings with the graph. Although the MITTYVAC's gauge shows only vacuum, it will put pressure on whatever you wanna put pressure on. It just won't show the pressure on the gauge, but if you had your aftermarket boost gauge tee'd in you could see the pressure output of the Mittyvac.

Piranha

got it Hailers, I'll do that tomorrow. Thanks Sooooooooooo much... it sucks not to have my car working right.

HAILERS

I forgot to install the url for the graph: http://www.teamfc3s.org/info/articles/fcd/diy_fcd.htm

HAILERS

Is your timing correct??? Have not advanced it too much, maybe? Just a thought. I saw your figures for fuel boost at idle and cruise, how about a little boost figure?? Say at 5psi on your boost gauge. What is the fuel pressure???

Piranha

I haven't changed the timing, I'll have to check it. I am going to go to the store in a little bit to buy the vac line, then put it back together. we'll see. I actually think I'm going to mount the sensor before the engine inlet. there is no room for a Tee by the fuel rails, and the pressure should be the same all around, fuel being a liquid and all

Piranha

Alright, I just checked my boost sensor voltage. I used an air compressor, but used a gauge to get the right pressure. I used 1.95ish psi, it is hard to tell, and got 2.55 volts off the signal terminal of the boost sensor. without any pressure it was 2.25v. Also, I got an error code for once, I just left my error code checker in, one long, one short. I don't know what that means, so I'm going to look it up now.

Piranha

oh yeah, duh, I have my intake off hooo hooo heee heeeee. I was just happy that the checker actually works :P

HAILERS

So when you put pressure on the boost/pressure sensor, do you get any movement out of the factory boost gauge????

And with that outfit you have, can you put say 5psi on the fuel pressure regulator and take a look at you fuel pressure gauge you had tee'd in and see if the pressure of the fuel pressure gauge rose????

Piranha

oh yeah, haven't checked that one yet. I should be able to do that. I finally got the gauge hooked up and with the jumper wire in (to prep the fuel system) it was about 60 psi.

HAILERS

I missed something here. You jumpered the fuel check connector and applied some pressure to the fuel pressure regulator and then looked at the fuel pressure gauge and it read 60psi??? Thats what I read.

And the first sentence meant that you did not take a look at the factory boost gauge while applying pressure to the boost sensor????????? And you are going to do that.

Is what I wrote above right?????

Piranha

yeah, my conversion was wrong. whups Well, I rechecked it, it is around 37 psi when I put 5 psi on the regulator, and around 31 when I have no pressure or vacuum. It may be off, I'm reading in KPa's and converting. Yeah, I'm going to go check the boost gauge now. I had a fuel leak and fixed it.

Piranha

Okay, I was wrong about it, I just went out to the garage to check. when under 7 psi of boost, the fuel pressure was at 350 kpa, and at atmospheric pressure 310 kpa. 310 converts to 44.96 psi, and 350 converts to 50.76. This is while the yellow plug is jumpered.

Also, I turned the key to on, and had my dad put pressure on the whole hook up, aftermarket boost gauge, pressure sensor, and fuel regulator, and at 5 psi and 8 psi according to my boost gauge the *stock* boost gauge didn't even move. it is plugged in.

HAILERS

Well, it seems to me the fuel pressure is good and the fuel pressure regulator is doing its job.

Theres some doubt in my mind if the ECU is getting the output of the pressure/boost sensor. It'd be good if you had a digital meter and could put it in the back of the signal wire from the boost/pressure sensor to the ECU, at the ECU with the plugs all hooked up. It would be the center plug on the ECU, bottom row, last wire on the far right. A brown wire with a red stripe.

If the voltage on that wire, at the ecu plug, rises and falls as you put pressure on the boost/pressure sensor, that would be a good thing, and we can just forget about your factory gauge.

If that proves good..........you've got me why your car pings!or detonates. It'd be great if you could monitor your fuel pressure while driving to see if its falling and not staying above 40 psi under boost. You've got to make sure that the fuel pressure regulators vac/boost hose is going to a nipple that is downstream of the throttle plates for the fpr to work right.

Another thought is the fuel pump may not be switching to 12v when under boost. Normaly the pump is supplied with approx 9-10 psi when not under a load, but when at boost and above about 3500rpm it should start to get a full 12v, which in turn makes its output rise. Then again, if you had a fuel pressure gauge that you could look at when you are boosting, you could see the sudden jump in pressure as the pump starts getting 12v instead of the nine or so that it gets when not under boost.

Get that fuel pressure gauge hooked up and running so we can see what you have under boost above 3500rpm!

Piranha

Hey Hailers, the fuel pressure gauge is permanent, at least for now. I was also pinging under 3000 rpm, it would be just when I was getting spooled, like 1 or 2 psi, in a higher gear, like 4th at 40 mph or so.. something like that. I was thinking the same thing with checking the ecu to see if it was getting the signal. I am going to do that tomorrow morning, I'll post after.

I also checked my AFM for the helluvit, and it came up fine.

Piranha

Alright, I took a wire, pushed it into the back of where the signal wire goes into the ECU and I didn't get anything. I made sure I had a connection, and I still didn't get any. The funny thing is, the 2nd time I did that my ECU error code lights gave me the code for pressure sensor. I tried it a 3rd time, and it was ok.

I then ran a new wire straight from the sensor to the ECU. It looks like the previous owner had hacked the hell out of the signal wire putting in an FCD or something. Yuck. Now I see why.. who needs good connections when you can twist and use electrical tape? Not my logic.

I have had a helluva time; I created a major vacuum leak at the BAC valve because I torqued it down too much and broke the metal, so I'm also fixing that.

Today I went for a cruise and fuel pressure was ranging from 210 kpa to 300 kPa which is around 43 psi. at cruise it was right in between. when I would floor it, albiet at 1500 rpm in 5th gear, the fuel pressure would jump accordingly.

Thanks a bunch Hailers, I'm about to take it out and check it!

HAILERS

Hope its fixed. I'm out of ideas. Looks that way.

Piranha

Hey... it isn't fixed actually. Got the vacuum leak straightened out, but I got the detonation again. Whats strange is that it only occurs around 3000K, when the secondaries come on I don't get it in the higher RPMs. Anyone else have an idea?

Piranha

Okay, it did come on in the higher RPMs this time. It seems like it is very intermitent.. sometimes I can boost, sometimes I can't. The problem seems like it is gradually getting better; before I would boost a little bit, and I would get it, now I don't get it until 4 psi or more.