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Backing up earlier comments throughout 100+ pages of this thread that stated often times the problems with FiTech are really problems outside of the unit.

About 4 weeks ago I hit a possum doing 80 mph (I was the one doing 80...) and that thing rocked my car, bending one of the header tubes and nearly tearing out the o2 sensor wiring so it was a good hit. I still have possum hair stuck to my header collector bolts and other sharp surfaces under the car. Fast forward to tonight, since the possum hit, I've been chasing misc problems such as once in a while popping through the throttle body while trying to start the car, or throttle response just didn't seem right. Zero error codes so no help there. The breakthrough came tonight when I tried to start the car and all electrical quit at the same time, no electrical fans, no electric water pump, no FiTech. I traced it back to the positive battery wire at the battery terminal. Barely a trace of corrosion could be seen on the terminal; however, I cleaned it and all back to normal. Quick startup. Good throttle.

My best guess is that the jolt my car took from hitting that possum impacted the wire connection / corrosion on the battery terminal. It's a 2 year old battery and has been having trouble keeping more than a 12.6v charge on it in recent weeks which could suggest yes, there was a poor connection. Tomorrow I'm going for a new battery, anti corrosion rings, and the gel. All my fat wires are soldered to large copper lug connectors which I bolt to the battery connectors. In fact, based on comments on this forum, months ago I soldered all my connections throughout the entire car.
 

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If it really hit the O2 sensor and pulled the wiring you might want to think about replacing the sensor. They are sort of delicate.
 

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If it really hit the O2 sensor and pulled the wiring you might want to think about replacing the sensor. They are sort of delicate.
I have two sensors. The wideband for FiTech is on the passenger header tube and did not get hit. I still have my old narrow band (single wire) on the drivers side that feeds a small gauge inside the car. That sensor is bent but still works. I was using narrow band as it was cheap ($8 and the gauge was $35) which helped me tune my holley carb for several years. I thought I was the sh!t as after 30 some odd years finally able to fully tune a holley. Now with an EFI unit, that thing is the sh!t -- best purchase in recent years. I will never go back to a carb.

The narrow band gauge is basically an LED light bar with yellow/green/red. I left it in place just as a visual aid just to see what is happening which is kind of nice to have.
 

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The narrow band gauge is basically an LED light bar with yellow/green/red. I left it in place just as a visual aid just to see what is happening which is kind of nice to have.
Does the narrow band on the other side of the engine match up well to the wide band the FiTech uses?
 

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Funny I seen a video for another Brand Efi and they say for auto to adjust the Iac when the car is in drive with your brakes on at idle.... wonder why fitech says adjust when in park at idle wonder if it would run better if you did it when in drive since thats how it will be all the time when driving? makes me wonder....
 

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Funny I seen a video for another Brand Efi and they say for auto to adjust the Iac when the car is in drive with your brakes on at idle.... wonder why fitech says adjust when in park at idle wonder if it would run better if you did it when in drive since thats how it will be all the time when driving? makes me wonder....
In theory, I'd agree and even originally had my Fitech set that way...with IAC counts at 7 or so in gear...which meant they were at zero in neutral for me...can't say it idled any better or worse, but it did start a bit harder until I reset it in properly, in neutral.

One big thing I noticed, the IAC counts are always different on my car when compared between warmed up sitting still, and an actual drive to warm it up.

Fwiw, my idle has 8-9" of vacuum and ran its best on Cam#2 setting.
3 was noticeably richer pretty much at all times, and setting 4, which Fitech would recommend for me, was absolutely, positively, not even close... Ran horrible...

Also fwiw, I have 3" Pypes X pipe and Race Pro mufflers.
My car has never, ever droned whether I had the Fitech, the Holley Sniper I have now, or any carb that was ever on it...have used 850 and, for about a year, 900 as my commanded idle rpm. That was also with tailpipes, and now, without. Just my experience with that setup...
 

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In theory, I'd agree and even originally had my Fitech set that way...with IAC counts at 7 or so in gear...which meant they were at zero in neutral for me...can't say it idled any better or worse, but it did start a bit harder until I reset it in properly, in neutral.

One big thing I noticed, the IAC counts are always different on my car when compared between warmed up sitting still, and an actual drive to warm it up.

Fwiw, my idle has 8-9" of vacuum and ran its best on Cam#2 setting.
3 was noticeably richer pretty much at all times, and setting 4, which Fitech would recommend for me, was absolutely, positively, not even close... Ran horrible...

Also fwiw, I have 3" Pypes X pipe and Race Pro mufflers.
My car has never, ever droned whether I had the Fitech, the Holley Sniper I have now, or any carb that was ever on it...have used 850 and, for about a year, 900 as my commanded idle rpm. That was also with tailpipes, and now, without. Just my experience with that setup...
I have full pypes with X pipe and the street pro mufflers mine made a hum at the 800rpm stock setting... 850 900rpm is that kind of high? you have a auto don't they say in drive the rpm should be at like 800rpm or something?
I have a Chevy ZZ4 crate motor cam set to 2 it never seems to run good always studders some times ...maybe I should try cam setting 3 maybe more fuel will make it run better as it used to smell much more like raw fuel with the carb out the exhaust?
 

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Kind of a random question, but I am still working through issues with a lean spike (followed by 10.4 AFR rich compensating for a few seconds) on moderate to fast tip-in. I thought I kind of fixed it by cranking my accel / fast pump way up, but really only partially masked the issue, and makes the rich issue after the fact worse.

Per FiTech's suggestion, I hooked up a fuel pressure gauge right before before the throttle body and watched at quick snaps of the throttle (no FCC, using Tanks Inc setup and LS1 filter/regulator). Given the motor is not loaded in that situation so it may not be truly apples to apples, but I do see a good 5-10 (saw ~20 once) psi drop and I have no idea if that's normal from what anyone else has seen. I also see that at idle, my pressure is reading ~10 psi higher than the 58 psi that I thought the system needed, and I have no idea if that's a separate issue or an issue at all. Vent hose I have running from the tank up to next to the filler cap, although it is sitting about an inch lower than the cap now that I look again...

I hope to hear back from FiTech tomorrow, but in the meantime, I wanted to see what you guys thought as well. In the below video, at about 0:50 to 1:00 is where I got the pressure to drop the most on throttle snap, and almost killed the motor for a second.

 

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Why the LS1 filter/regulator? The FiTech has a regulator in it already. I would ditch that setup and just run a return line to the tank from the throttle body.
 

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I have full pypes with X pipe and the street pro mufflers mine made a hum at the 800rpm stock setting... 850 900rpm is that kind of high? you have a auto don't they say in drive the rpm should be at like 800rpm or something?
I have a Chevy ZZ4 crate motor cam set to 2 it never seems to run good always studders some times ...maybe I should try cam setting 3 maybe more fuel will make it run better as it used to smell much more like raw fuel with the carb out the exhaust?
I don't know who "they" are, but I do know my car likes a 900 rpm idle speed. ;)

I'm not going to pretend to know what your car will like. That is something you need to find out, with trial & error, to learn what it likes.

If you don't think the Cam setting you have now is "right", simply try another...just make sure you also do a relearn/start over, so you'll get accurate information. Like I said, according to Fitech's recommendation, I'd need setting #4, but in real world use, the car ran terrible with that setting.

Ran very well at #2, where "they said" it shouldn't/couldn't/wouldn't. ;)

Your car will tell you what it likes.
 

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In all honesty I forgot the TB had its own regulator, may very well do that, thanks
Quick test you could try is pull the return line off the regulator and install a temp one into a safe container. You could have some sort of restriction in your return not letting the regulator work correctly.

I do like the idea of using the one built into the TB but if you have a line issue it won't help. Went through this a few years ago on one of my cars.
 

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I don't know who "they" are, but I do know my car likes a 900 rpm idle speed. ;)

I'm not going to pretend to know what your car will like. That is something you need to find out, with trial & error, to learn what it likes.

If you don't think the Cam setting you have now is "right", simply try another...just make sure you also do a relearn/start over, so you'll get accurate information. Like I said, according to Fitech's recommendation, I'd need setting #4, but in real world use, the car ran terrible with that setting.

Ran very well at #2, where "they said" it shouldn't/couldn't/wouldn't. ;)

Your car will tell you what it likes.
So you think I should try a higher idle RPM first? mines set at 730RPM now.
Thanks
 

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I don't know who "they" are, but I do know my car likes a 900 rpm idle speed. ;)

I'm not going to pretend to know what your car will like. That is something you need to find out, with trial & error, to learn what it likes.

If you don't think the Cam setting you have now is "right", simply try another...just make sure you also do a relearn/start over, so you'll get accurate information. Like I said, according to Fitech's recommendation, I'd need setting #4, but in real world use, the car ran terrible with that setting.

Ran very well at #2, where "they said" it shouldn't/couldn't/wouldn't. ;)

Your car will tell you what it likes.
Do you think I should raise the idle higher first before changing the cam setting? my idle is at 730-RPM now?
THANKS
 

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The return line from the Fitech to Tanks Inc. EFI tank....I know people just reuse the stock line. It's obviously a combination of hard line and rubber. Will that cause an issue to go rubber to hardlines to rubber and connect up at the return port? What I'm getting at is it won't be under pressure since it's a return line right? Just needs a wide open tube for gas to run back into the tank?
 

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The return line from the Fitech to Tanks Inc. EFI tank....I know people just reuse the stock line. It's obviously a combination of hard line and rubber. Will that cause an issue to go rubber to hardlines to rubber and connect up at the return port? What I'm getting at is it won't be under pressure since it's a return line right? Just needs a wide open tube for gas to run back into the tank?
The return has minimal pressure on it, but it does have pressure. Otherwise the fuel wouldn't return. Not a concern using hard line and fuel injection rubber hose if you use the right size hose and fittings. I used my old hard line for the return and the hard line ends are just straight cut. I pushed the rubber hose onto the hard line 3 inches and clamped it with fuel injection style clamps. No leaks. If your hard line is flared it is even less likely it would ever leak.
 

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Do you think I should raise the idle higher first before changing the cam setting? my idle is at 730-RPM now?
THANKS
Changing the idle is not going to fix stumbles. It's also doubtful changing the cam setting will either, unless you get real lucky.

Given how long you've been having issues, I'd guess it's an air leak in the intake or exhaust before the 02 sensor, or both, a fuel delivery problem, or an electrical problem. 99.9% of the issues brought up in this thread are not the FiTech unit itself. Could be as simple and not having the throttle body torqued down right, or a couple of bad plug wires. If it were a minor learning issue, the system would have figured it out by now.

You may have to do some manual tuning of the fueling parameters if you think all the elements of your install are correct. If you still haven't figured out how to use the handheld, it's gonna be rough.
 

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The return has minimal pressure on it, but it does have pressure. Otherwise the fuel wouldn't return. Not a concern using hard line and fuel injection rubber hose if you use the right size hose and fittings. I used my old hard line for the return and the hard line ends are just straight cut. I pushed the rubber hose onto the hard line 3 inches and clamped it with fuel injection style clamps. No leaks. If your hard line is flared it is even less likely it would ever leak.
Maybe a dumb question, but did you use -6 AN going to your return line? My hard return line is a bit smaller and I'm not sure if clamping down the -6 hose will still clamp/seal well enough or if I need to look at a smaller hose going off of the TB...
 

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Changing the idle is not going to fix stumbles. It's also doubtful changing the cam setting will either, unless you get real lucky.

Given how long you've been having issues, I'd guess it's an air leak in the intake or exhaust before the 02 sensor, or both, a fuel delivery problem, or an electrical problem. 99.9% of the issues brought up in this thread are not the FiTech unit itself. Could be as simple and not having the throttle body torqued down right, or a couple of bad plug wires. If it were a minor learning issue, the system would have figured it out by now.

You may have to do some manual tuning of the fueling parameters if you think all the elements of your install are correct. If you still haven't figured out how to use the handheld, it's gonna be rough.
Thanks i just checked the bolts holding the Efi on and they where kind of lose so I snugged them up maybe it was leaking by the gasket.
 

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I am having an issue finding my return line -6an fitting to leave the throttle body (not sure if I got one) and can't find any info on FiTech's site. Does anyone have the thread size/pitch for the return line fitting off-hand, or a fitting that works? I am hoping I can run to the local speed shop tomorrow and pick one up with any luck.

The thread size of the return plug is about 3/8" but I'm assuming I'm spec'ing it wrong, since I can't find a 3/8" to -6AN male fitting. Thanks for helping a noob


Edit: Sounds like the fitting is 10mm x 1.25 pitch ( FITECH fits with PTFB Drop Base!!! ), however it's weird I can only find one of these even on Amazon (Amazon.com: Speed-SupRex -6AN 6 AN -6 Male Flare to Male M10 x 1.25 Metric Thread Straight Fitting Adapter: Automotive) and is going to be 6 weeks shipping from Hong Kong. I must be missing something.
 
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