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Double 2bbl Webers to Fitech 30003 four barrel TBI
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'67 Dart 270
Turbo EFI


Joined: 23 Nov 2011
Posts: 1862
Location: SF Bay Area

Post subject: updates (Tue Sep 12, 2017 8:29 am) Reply with quote

No, I had to stop for another issue. My master cylinder brake boost rod was adjusted incorrectly, my brakes were grabbing a bit. I readjusted that and I also noticed my alignment didn't seem right, looked visually like the toe was out, so I took it to my local shop for alignment check, but the old school guy who does my alignment is out sick. Hope to get it back this week so I can play with it on the weekend. I do plan to convert my fuel command center (FCC) to low pressure recirculation back to the gas tank to keep the FCC cooler. Hopefully that will be sufficient. I'll do some test driving first though, see if the alignment is OK, I can report back on performance from those test drives.

Brian
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'67 Dart 270
Turbo EFI


Joined: 23 Nov 2011
Posts: 1862
Location: SF Bay Area

Post subject: performance (Tue Sep 12, 2017 8:32 am) Reply with quote

I can tell you that it ran well enough that I already sold my Weber setup...so I'm confident that it'll be my setup going forward.

Brian
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'67 Dart 270
Turbo EFI


Joined: 23 Nov 2011
Posts: 1862
Location: SF Bay Area

Post subject: update (Mon Sep 18, 2017 8:49 am) Reply with quote

Got it back from the alignment shop, wow it is so much better now, the toe was out, not sure what else, but boy that made a huge difference in handling. FYI when I first went to pick it up, my guy had the front end up higher than when I brought it in. I said, "hey, did you adjust my torsion bars?" he said, "I couldn't get enough camber without doing that". I gave him a pshaw, and told him to do it again. Now it's dialed in and at my preferred height.

Took it for a highway drive, it ran pretty good, but was doggy. I had the timing at TDC since I installed the TBI. I advanced it about 10 degrees, as you might imagine it made a huge difference, runs much better. Still, it is not performing as well as the Webers did. I need to play with the programming I'm sure, e.g. I have a rich condition on deceleration. I am very happy with it so far though, it starts instantly and I can sit in the garage at idle forever and no more weber boil over issue.

Still, the fuel command center will have to be replumbed for recirculation (low pressure through the FCC) to keep it cooler. I went on a long drive yesterday and it was fine (it was only 80 degrees outside), but recall on that really hot day that I was previously testing the TBI system, the FCC low pressure gauge stopped reading, I think it was the gas boiling into the vent line. The high pressure line to the TBI was still reading 58 psi, but I have a feeling if I had driven much longer in that heat it would have starved the FCC for gas.

Also noted that the computer is reading my RPM's about 500 more than my tach. It's not linear, when I'm on the highway at 60 mph my tach is reading 2100 rpms, but the TBI computer is reading 2600 rpm. At idle the difference less than 100 rpm difference. I tend to believe my tach, by ear that is. I'm running 2.76 gears in the chunk. Could be they're both wrong, but I suppose the electronic gizmo reads more accurately. My Cadillac has a six-speed manual and at 60 mph it's tach shows just under 2000 rpm in sixth gear, I need to run 70 mph in sixth gear to get over 2000 rpms in the caddy.

Brian
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Pierre
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Joined: 08 Feb 2003
Posts: 4347
Location: CA

Post subject: (Mon Sep 18, 2017 6:59 pm) Reply with quote

Non-linear rpm difference is electrical noise, likely coming from secondary ignition. Prime suspects - non-resistor plugs, plug wires with poor shielding, worn coil.... also keep all sensor wires as far away in as you can from ignition in parallel runs. This needs to be fixed first before anything else is done. 500 rpm is a big chunk percentage wise.


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'67 Dart 270
Turbo EFI


Joined: 23 Nov 2011
Posts: 1862
Location: SF Bay Area

Post subject: thanks Pierre (Mon Sep 18, 2017 8:25 pm) Reply with quote

Pierre wrote:
Non-linear rpm difference is electrical noise, likely coming from secondary ignition. Prime suspects - non-resistor plugs, plug wires with poor shielding, worn coil.... also keep all sensor wires as far away in as you can from ignition in parallel runs. This needs to be fixed first before anything else is done. 500 rpm is a big chunk percentage wise.


I have resistor plugs - check

plug wires are shielded well - check

coil is new - check

will check parallel runs of sensor wires with ignition wires (you mean the plug and/or coil wires running parallel to the tach or TBI sensor wire?)


Brian
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'67 Dart 270
Turbo EFI


Joined: 23 Nov 2011
Posts: 1862
Location: SF Bay Area

Post subject: hmmm (Mon Sep 18, 2017 8:35 pm) Reply with quote

tach wire and the wire for the TBI run from my coil down and away from the coil wire (the coil is mounted horizontally so the coil wire is on the side), about 2 inches away from the coil wire and never closer. They run down from the coil (mounted on the passenger side inner fender) and behind the valve cover on the fire wall, over to the bulkhead terminal block (the tach wire stops there) the TBI wire goes on, under the master cylinder bracket and over to the drive side inner fender where I have a plastic box holding all the TBI connectors.

Could it be that the tach wire and the TBI sensor wire run parallel to each other and are interfering with each other's signals? They are hooked to the same terminal on the coil (as you might guess).

See the blue and green wires in this pic: https://www.flickr.com/photos/151192512@N07/36503763523/in/dateposted-public/


Brian
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Pierre
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Post subject: (Mon Sep 18, 2017 8:50 pm) Reply with quote

Nope... but are those low resistance msd superconductor wires?


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'67 Dart 270
Turbo EFI


Joined: 23 Nov 2011
Posts: 1862
Location: SF Bay Area

Post subject: plug wires (Tue Sep 19, 2017 9:14 am) Reply with quote

They are MSD 8.5mm superconductor wires, here is their description:

MSD's 8.5mm Super Conductor wire sets have a special helically wound core that has just 40-50 ohms of resistance per foot--but with an RFI suppression equal to a 1,500 ohm wire. In fact, each foot of finished wire features 40 ft. of tightly wound copper for superior conductivity. This winding procedure, combined with a ferro-magnetic impregnated center core, produces an extremely effective Electro Magnetic Interference "choke". This choke, or suppression capability, keeps the EMI inside the wire where it cannot interfere with other electronics on your vehicle.

Maybe I should take an external tach and check to see if it matches the dash tach or the TBI tach reading.
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'67 Dart 270
Turbo EFI


Joined: 23 Nov 2011
Posts: 1862
Location: SF Bay Area

Post subject: FiTech thread (Tue Sep 19, 2017 9:23 am) Reply with quote

I found some blurbs on FiTech's and tach signal, e.g. here is one about an MSD ignition box making issues:

Are you also having some slight hesitation problems, occasional hard starting and occasional poor idle? I also noticed that my tach was occasionally bouncing and reading different then the FiTech hand held screens tach. I spent the better part of 3 days checking grounds and all my other wiring thinking that I might of had a short somewhere. I'm running a 6AL and a 85551 dist. and was so frustrated that finally I tried disconnecting my 6AL and using the FiTech instead and man o' man once I bypassed the 6AL the car never ran so good! It only takes a few mins to wire it that way so it might be something you want to try and if it works you'll then have isolated what your problem was and you'll then be able to work on finding it a bit easier. I myself am going to wait for some rainy day or over the winter to try and reinstall the 6AL back in the system but for now my timing control works and I'm really enjoying the FiTech....finally.

reply:

If your going to leave in your 6al box and just try to isolate your tach be sure that the blck wire from your FiTech is connected to the correct "points Input" wire of your 6al box.

If your still having problems after trying to isolate the Tach like I did when using Figure 12 diagram... just for Tests Sake use "FIGURE 13" wiring diagram which eliminates your 6al box, I did and I finally got to see what all the praising FiTech was about.

I read another thread and they said having the ECU too close to the ignition box (coil in my case) can cause interference with FiTech tach signal. I can move my coil further away from the ECU. Also, I can try disconnecting the dash tach wire and test drive again to see if the FiTech tach signal changes to something more close to what the dash tach was giving.

Brian
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Pierre
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Location: CA

Post subject: (Tue Sep 19, 2017 5:56 pm) Reply with quote

Remind me what ignition setup you are using again? Or is the fitech driving the coil directly?

Unless it's a craptacularly low quality tach it's probably not an issue.

Those wires are suspect. Splurge for a magnecore set - if you don't want to go directly to that route then buy something cheap locally - higher resistance carbon core wires will emit less noise then those things. Cheap ones may not last long but make for good tests.


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'67 Dart 270
Turbo EFI


Joined: 23 Nov 2011
Posts: 1862
Location: SF Bay Area

Post subject: info (Tue Sep 19, 2017 8:07 pm) Reply with quote

Pierre wrote:
Remind me what ignition setup you are using again? Or is the fitech driving the coil directly?

Unless it's a craptacularly low quality tach it's probably not an issue.

Those wires are suspect. Splurge for a magnecore set - if you don't want to go directly to that route then buy something cheap locally - higher resistance carbon core wires will emit less noise then those things. Cheap ones may not last long but make for good tests.


I'm using a Flamethrower Pertronix coil with a built in resistor (no ballast needed). My tach is a VDO brand. Do you have a magnacore set in mind for an SL6?

Brian
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Pierre
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Posts: 4347
Location: CA

Post subject: (Tue Sep 19, 2017 8:51 pm) Reply with quote

What's driving your coil... what are you using as your ignition module? HEI? Oem points or electronic? Built into fitech?

I don't know the magnecore numbers off the top of my head... they have a catalog with the slant application in it with several different series of wire. They also had a special series of wire for ham radio users that had even better noise suppression then their regular good sets. You may need to call them to get a set in that though.


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'67 Dart 270
Turbo EFI


Joined: 23 Nov 2011
Posts: 1862
Location: SF Bay Area

Post subject: more info (Wed Sep 20, 2017 9:26 am) Reply with quote

Thanks, I looked up Magnecore, they have a specific part number for SL6 later models (no drool tube) but yes will make custom sets for you, nice.

I have mopar ECU (orange box) and electronic ignition, super six distributor.

brian
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Pierre
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Location: CA

Post subject: (Wed Sep 20, 2017 6:07 pm) Reply with quote

Those boxes are noisier electrically. If you want a super clean reliable signal to drive the efi then an ignition box like MSD's with a dedicated tach output is the easiest.

I'd start with the wires and go from there.

If you have one of those radio noise suppression caps from a points setup (goes from coil positive to ground, NOT coil negative...) use it.


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'67 Dart 270
Turbo EFI


Joined: 23 Nov 2011
Posts: 1862
Location: SF Bay Area

Post subject: Thanks Pierre. (Wed Sep 20, 2017 6:18 pm) Reply with quote

thank you for the tips, Pierre. I'm sure I'll figure it out from here.
b
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