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Old 02-13-2001, 07:53 PM   #1
Pipercub
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Post MAF matters

I don't think I have seen any posts about MAF failures in a long time. Wonder if this could be the confirmation of the bad batch theory?

Now Marcus PMed me with a good question. Why not use the MAF off a 98 instead of the 99 MAF? Of course the mountings may be different but the readings generated are what is really the issue. Does it generate the same reading per CFM accros its range?
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Old 02-13-2001, 07:56 PM   #2
tom@kartboy
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unfortunatly the 99 use a HOTFILM and the 98 use a HOTWIRE. they are not compatable...

i looked into this, then i woke up and got a tec-2
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Old 02-13-2001, 08:11 PM   #3
Buckbomb
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Cobb tunning is working on an aftermarket MAF for the '99's, that is more durable. When it comes out, I want it!!!
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Old 02-13-2001, 10:16 PM   #4
Revision
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Post

12,000 miles and 6 months and still counting on a MY99 and Rallispec intake /w SAFC.

And I still havn't cleaned that Pipercross filter yet.
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Old 02-13-2001, 11:14 PM   #5
markus
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Question

What exactly is the incompatibility between the 98 and 99 MAF's? Is it strictly a physical incompatibility that some custom made intake system could handle or are the volatge readings and electronics involved totally different?

If it were an electronics issue, I suppose someone could try to get a 98 "black box" with the compatible MAF and transplant it into a 99 car. Not sure if this would be do-able, affordable, or if I'm strictly grasping at straws.

Would appreciate if one of the tuners like Shiv or Trey could provide their input here based on their experiences/knowledge.
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Old 02-14-2001, 04:14 AM   #6
Pipercub
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And if it were a somewhat linear difference it would seem that an SAFC would be able to compensate. Lets say it reads 5% over at 1k and 13% over at 3k and 17% over at 5k then you could just add that to your SAFC settings.
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Old 02-14-2001, 04:46 AM   #7
wac
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Quote:
...if it were a somewhat linear difference it would seem that an SAFC would be able to compensate.
Unfortunately not. The S-AFC allows you to add corrections according to RPM and TPS, but not actual MAF readings. What you really need is a signal conditioning circuit that remaps the MAF voltage before it even gets to the S-AFC.

In theory, you should be able to use any MAF at all in closed-loop mode. The ECU is supposed to compensate for environmental changes, manufacturing tolerances, etc. However, you may end up with grossly lean or rich A/F ratios in open-loop mode. Or the ECU may throw a code because it notices that it's running much too lean/rich, and assume that your MAF is broken.

-WaC
Wayne
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Old 02-14-2001, 05:31 AM   #8
Rich L
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Post

Pipercub

I already consulted a few people (including Rallispec) on swapping MAFs.
There appears... there are a few barriors between compatability, including different connections and engine characteristics (99s run leaner)
My maf blew 3 days after the turbo install.
So bottom line, you need a new one and hope for the best (until Trey gives us another option)
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Old 02-14-2001, 05:38 AM   #9
Revision
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Post

The only reason to run a SAFC on a 99 is to compensate for the lean run at full throttle at 5500 rpm.

At partial throttle, there is no lean run, all the way up to rev limiter.

At full throttle, lean run doesn't even start until 5300 rpm.

The ECU compensates very well thank you. And even on a 99 you WILL have to reset the ECU as it learns the new run settings. Something ont the order of.. Hmm.. so far for me, every 6 months.

I'm running an A/F meter and have figured out how to read it.
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Old 02-14-2001, 06:08 AM   #10
tulit
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Hi guys.

Ive actually finished prototyping a 98-99 MAF adapter. I hope to have it on a test car shortly, and have it available to everyone soon after that. It allows you to interface a 98 MAF adapter with the 99 ECU.
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Old 02-14-2001, 06:42 AM   #11
Pipercub
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Post

That is good news. How much does a 98 MAF run anyhow? And how much might this adapter system go for? I believe I have a pretty good MAF, it has 27000 with an aftermarket intake and now 4 days with a turbo. I have it braced prety good but the turbulence is still an issue, and that BOV venting 5 inches behind it is also a concern. But uf it pops it pops. I am really interested in this 98 MAF though.

I do find it interesting that the MAF failure postings have dropped to almost nothing. I haven't seen one in about 6 months.
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Old 02-14-2001, 08:04 AM   #12
cvalle-sd
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I have 42k on my original MAF -about 30k with a K&N cone filter, no "big" filter, and the stock intake plumbing - still going strong.
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Old 02-14-2001, 08:11 AM   #13
GTBGUY
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One of the cars up here in Calgary (a '99RS) that's been turbo'd for more than 25,000kms is still running on the orginal MAF, no probs at all.
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Old 02-14-2001, 10:06 AM   #14
2.5GT
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Angry

I paid ~$350 for a new MAF sensor for my 97 GT last year. What puzzles me the most is that I had to replace the HOT WIRE MAF sensor. Everyone had posted how that particular type of MAF was very sturdy compared to the 99 MAFs. For the record, I had a minnam intake on for about 30,000 miles before failure.

I noticed I had done damage when I had upshifted from first to second gear at 6500rpm. After reaching that rpm I let off the gas hard before flooring it in second. Once I started gassing second, the car started surging like something was wrong. The computer instantly threw a CE light which I later found to be attributed to a MAF failure. My suspicion(sp) is that the blow back from the abruptly closing throttle body caused a surge of air back towards the MAF, thereby disbling it. I say this because the MAF was bolted down tightly to the frame and the filter had not been oiled for 10,000 miles (which may cause failure due to oil contamination).

Given the circumstances, I am reluctant to try another intake due to the cost of replacing the MAF again. I'm holding out for the Cobb intake in hopes that they will address the pulse induced MAF failure problems.

Jason
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Old 02-14-2001, 05:29 PM   #15
tulit
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The system will run approx $70 + the cost of the MAF sensor. The 98 sensor costs the same as the 99.

2.5GT, the hot wire MAF is the problematic one. The hot film (98) is the sturdy one.
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Old 02-15-2001, 05:13 AM   #16
2.5GT
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According to kartboy, the hotfilm MAF is the problematic MAF.

Jason
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Old 02-15-2001, 07:20 AM   #17
STiShawn
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Tulit, your turned around...the 98 Hot Wire is the good one while the 99 Hot film is the weak link.
Trey, are you reading this post and have anything to contribute?
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