76MM C&L volts goe up when RPM goes down

[TT331FB]

Hi Tuners, I have been chasing a problem and I think I have discovered a significant clue. Normal idle is 800 RPM, about 22 KG/HR, .7 volts.

When the fan comes on, the engine usualy dies. I data logged this and saw that the MAF voltage went up as the RPMs went down. see below

RPM 800 700 600 500 400 300
MAFV .7 .71 .72 .78 .8 .85

Maybe it's time to give up on this C&L meter and go back to stack or a Pro Air meter.

Input?

Thanks, Eric

[QWKSNKE]

Ditch that junk meter. Italian and I have seen at least 3 of these 76 meters cause problems. One of them being on his car. It was very erratic and hurt his power.

Swap over to a PMAS 80mm and be done with it

[Italian LX]

Yeah, when I had my C&L, I gave them the benefit of the doubt and tried to make it work. I ran into way too many consistency issues and MAF wash problems. I finally ditched it in favor of a Pro-M univer (which worked a lot better). Now I run a PMAS Velocity meter and love it!

[coupe]

Agreed. Getting the C&L to be in a perfectly directed stream is the only way for it to work. Too bad it's nearly impossible to achieve this on our cars.

The sampling method is just too sensitive on the meters IMO...especially if you have a bunch of stuff done to the car.

[TT331FB]

Ditch that junk meter. Italian and I have seen at least 3 of these 76 meters cause problems. One of them being on his car. It was very erratic and hurt his power.

Swap over to a PMAS 80mm and be done with it

Do you have a specific recommendation to replace the 76MM C&L which, I think is 3" in/out?

Eric

[coupe]

The 80 like they use will be fine. They've tested it and it's not giving any troubles. Also, if you can find one, the old ProM 75mm is a great setup. May be a different name now.

[Italian LX]

Yeah, call Anderson Ford Motorsports for a PMAS meter. That's were Lee got his 80mm and I got my 95mm. Real good people and pretty good price.

[QWKSNKE]

yep. the PMAS 80mm MAF will work fine. I have been very pleased with mine.

[Cougar5.0]

I've had excellent results with the C&L w/tuner tube - it draws air from the center of the airstream using a venturi effect - much better than the straight-through sample tubes. Can measure to 2700 kg/hr on my 80mm meter as well. I am impressed with how clean the signal is and how I have not had to adjust the provided MAF curve at all.

Edit: BTW, the voltage rising as the engine dies has nothing to do with the C&L tube, though the electronics may be messed up. I would guess the fan coming on (electrical) and the voltage to the MAF varying have something to do with the problem. Blaming the "meter" is not logical really since the 70mm Cobra meter uses a straight-thru tube just like the C&L and the same electronics (slightly different calibration).

[Italian LX]

I've had excellent results with the C&L w/tuner tube - it draws air from the center of the airstream using a venturi effect - much better than the straight-through sample tubes.
That's interesting. Is this something that C&L sells? Sounds like a good idea, but they should've got the word out if they were fixing a problem.


Blaming the "meter" is not logical really since the 70mm Cobra meter uses a straight-thru tube just like the C&L and the same electronics (slightly different calibration).
The Cobra MAF isn't much better. For close to stock motors, those meters do fine, but it seems like I had more and more issues as the mods went up.

The PMAS 95mm Velocity meter that i got has a similar straight-thru sampling but the meter is ultra accurate. It's designed very well. :nice:

[QWKSNKE]

I've had excellent results with the C&L w/tuner tube - it draws air from the center of the airstream using a venturi effect - much better than the straight-through sample tubes. Can measure to 2700 kg/hr on my 80mm meter as well. I am impressed with how clean the signal is and how I have not had to adjust the provided MAF curve at all.

Edit: BTW, the voltage rising as the engine dies has nothing to do with the C&L tube, though the electronics may be messed up. I would guess the fan coming on (electrical) and the voltage to the MAF varying have something to do with the problem. Blaming the "meter" is not logical really since the 70mm Cobra meter uses a straight-thru tube just like the C&L and the same electronics (slightly different calibration).

The 70mm cobra meter does not have a straight through sample tube. The sample goes to the post in the middle of the meter which has a backing plate and forwards the sir down the post to the exit at the bottom

[Cougar5.0]

That's interesting. Is this something that C&L sells? Sounds like a good idea, but they should've got the word out if they were fixing a problem.




I'm not sure why they don't promote them more, but here is the page with the 85mm & 95mm Tuner MAF's http://www.cnlperformance.com/tunerMAF.html

I found out about the tuner tube while using Clint's EEC Analyzer - he had curves for the "Tuner Tube" and I then called C&L and got one as my meter was maxing out with the straight-through tube I was using. I was immediately impressed with the cleaner voltage signal and the lack of adjustment needed to get the car running with consistent near 1 KAMRF's. Yesterday I was lugging at 30MPH in 5th gear (1000RPM) and was quite impressed with the smoothness - pretty impressive with XE270HR cam I'm using.

[Cougar5.0]

The 70mm cobra meter does not have a straight through sample tube. The sample goes to the post in the middle of the meter which has a backing plate and forwards the sir down the post to the exit at the bottom

I do remember seeing one of those meters. My 70mm meter has a straight tube - I got it from a Supercoupe though - I guess I forgot about that difference. The electronics are the same however.

[SteedaChaos]

I think i need to dump my 76mm C&L too and get w/ the PMAS80mm! Mark wasn't pleased that i had the 76mm when he did my tune, but for a couple of weeks all was well, smooth ride at 17-1800rpm in 5th (4 me that's low), or sometimes she'd get great gas mileage, others omfg sheesh this thing chugging too much gas down wtf?! :bananahum :think:

But ya grab myself one and get a re-tune all should be well after that!

[TT331FB]

Hi Stangers,

I got tired, of messing with the 76MM C&L and decided to go back to the stock MAF. My plan was to get the car running real good and then try the C&L.

I was able to get the stock MAF running fine. Without changing any mechanical adjustments, I put the C&L back in, tweeced the new MAF curve, and gave it another shot. The tune was really close but I could tell the idle was not as good. The KMRFs were perfect though.

With the stock MAF, I was able to disconnect ICS, and the engine would drop to about 700 RPM. Trying the same trick, with the C&L, stalled the engine right away.

If you recall, my problem was that the engine would stall almost every time the low speed fan would come on. After I went to the cobra tune, with my stock MAF, those problems went away.

So, what do I think I have learned? Well, for one, the idle MAF was the same for both the C&L and the stock MAF. That tells me the MAF calibrations were good. By the way, I used Clints 76MM black tube 24# 70MM sensor curve from the EECA.

I think the C&L has problems at the low MAF flows, because the larger flow area, and the way the tube only looks ,at flow in one spot. the stock MAF sorta averages it because of the divider that goes across the MAF.

Where to go from here? The stock MAF is getting to about 4.8 Volts WOT. I suppose I could live with it. I probably will given that spending $200 would only get me about 10 HP. I probaly will put a K&N fliter in and call it good.

[QWKSNKE]

you are able to run a stock maf on a turbo car? What year MAF?

[TT331FB]

you are able to run a stock maf on a turbo car? What year MAF?

My sig is my Vintage Mustang. I'm talking about my '94 Vert.

To add confussion, I also have a 64.5 Vert and a 91 5.0 LX.

Eric

[gt90stang]

Hi all,

Well I don't know what could be going on, but I've tuned my 76mm C&L with three setups on my 90GT 306.

1. NA with MAC cold air kit.
2. NA with stock air box and K&N.
3. SC 8psi KB Blowzilla with stock air box and K&N.

All tuned very easily with an LM-1 WBO2 with rock steady idle and very smooth throttle response. Guess I'm just lucky.

Don