does any one know if the new or even rebuilt maf have the hot wire. I have replaced two recently and was still getting code. took it to my mechanic and he said the hot wire has been eliminated any one else come across this problem and if so how do I clear the code hat the dreaded service engine soon light. also replaced both relays for maf. thanks. I need your help

 

Try and get a good used one, do not trust a maf that is not a correct Bosch maf sensor. The ecm uses the wire to measure airflow, how can one without this wire work?

I had this happen years ago was totally different inside did not work, had to find a correct Bosch sensor it worked perfectly.

Should look like this inside, if you cannot see the wire avoid it. I would look for a good used original 👍




Not like the crap below ..... That is what the so called new one was like, didn't work and the seller will say no warranty as is electrical part. They throw you under the bus with that nonsense, even tbough their part was clearly not a genuine bosch maf. A copy that looked the same outside, only later found out I needed a modified ecm to run those type of mafs...... Be very careful look at your maf part number on bottom panel get an exact replacement, there are different part numbers for the 85 to 89 mafs.

 

Try Mirrockcorvette.com

 

Contact Tequila Boy .......

 

What year car?

 

thanks for the info. really appreciate it

 

Well, appears it's code 36 season! Plenty of posts have discussed for 15+ years, search and read for yourself.
Short answer, there are other options then spending a bunch of money on an "original" MAF design. More modern MAF designs don't need constant cleaning to work well, and the code 36 can be disabled.

A Google search string that will find these if not interested in using the site's search, literally copy and paste:

"c4 corvettes" site:corvetteforum.com code 36

My recent comments (as in last couple weeks):
https://www.corvetteforum.com/forums...post1608905996
https://www.corvetteforum.com/forums...post1608908511
https://www.corvetteforum.com/forums...post1608927548

I just remembered, one item additional item I had disabled via MEMCAL change was the VATS code. No key no worky for me!

 

Phobos84 Profile Says 1988

 

So for an 88 a new Delphi MAF is $150. I've heard good things about the Cardone MAF but never tried one personally. They run about $130.

One weird question though. About 20 years ago it was the latest and greatest thing to eliminate the MAF and run speed density. I even helped a friend of mine back then to convert his IROC to speed density. Is this not a thing anymore? Back then it seemed like everyone was doing it. After I LS swapped I only used a MAF sensor for a short time before I went speed density and got rid of it. It seems like if you TPI guys are having trouble finding good working MAF sensors it might be worth looking into.

 

If I could find someone who knew how to do that I would change my setup to speed density. I'm dealing with a code 34 now.

 

From what I've read the new style sensors are supposed to have a circuit to fool the ecu into thinking the burn off circuit is still working, which electrically speaking wouldn't be difficult.
I see a lot of reports that they don't though, which seems weird since it sets a code. I wonder if the sales volume on them is just so low now they don't care?
I'd be glad to be rid of the afm myself, though for whatever reason other cars with them don't seem to have much issue outside of normal.
My LT1 has 250K on the stock one, seems like it's a wire type too but I haven't looked at it in so long I wouldn't swear it.
I've had dozens of 80's Bosch injected euro cars with functionally identical air flow meters as the TPI cars use and while
they do crap out now and again it's really not a big issue.

 

There is no adverse functional effect of a code 36 other than the SES lamp (and code 36 itself), but it will mask other codes if also present.

Here is an old log from a Callaway with a code 36 present that is also setting code 36 again after ign off: https://datazap.me/u/tequilaboy/puzz...rk=283-334-346

See the yellow markers showing the ignition off and burn-off events (27 to 33 seconds into log). Note the behavior of the unlimited airflow signal during the burn off cycle. 147 gm/sec is about 3.8 volts and 80 gm/sec is about 2.9 volts (which is too high).

The maf is working just fine and the car is running just fine with the code 36 present. The voltage during the burn-off is just too high with this particular maf (so the code is repeatedly being set).

Note: this particular maf is also being limited a bit by the max airflow vs rpm table, so it is possible that this maf just has a poor calibration that is resulting in unusually high voltage during normal use and also during the burn-off cycle, but keep in mind that it is a Callaway and likely flows more than would normally be expected. I don't think the turbos are spooling with these short bursts of throttle.

Sorry, I don't have many logs with Code 36 present, but here is another log showing a successful burn-off cycle: https://datazap.me/u/tequilaboy/burn...&mark=38-64-67

Codes 33 and 34 will run a bit differently since the actual mass airflow signal will be replaced by the default airflow calculation but even this mode can run pretty well (beats walking).

 

Incorrect, code 36 will result in static tune from the ECM.
-- Witness, me, with my '87 running like **** until I reset the code 36 and running like **** again when code 36 popped back on the next start.

 

Took my MAF off Tuesday and cleaned it well. I mean I sprayed the **** out of it. Let it dry for about an hour. Put back together and first start up it idled great. No codes. Went for a small ride around blocks to get up to temp and came back. At this point temp was 200. Turned it off and waited a min and started it back up. No codes *knock on wood*. Definitely could tell it was smoother idling and driving. I did have code 34 and prior a 36 but when I checked 36 wasn't present. My neighbor asked if I ran a K&N and I told him yea. He told me to get rid of it due to the oil. I told him I haven't had it out for sometime to re-oil it so don't think that was the issue. If it stays good for awhile I will clean that thing yearly.

 

On my 89, I can confirm no adverse effects (other than check light) for the 3-4 wks I ran a Spectra MAF before "tuning" out MAF burnoff at startup. Which is to say the Spectra "pintle" design DOES throw code 36 -- unless suppressed.

(Note: That means I can't recommend the pintle-style Spectra unless you don't care or can change your tune.)

 

What's the ecu looking for to be happy with a burnoff cycle? It's kicking a relay and supplying 12v+ to a resistive heater so voltage or resistance? Unless there is a thermistor or such checking things.

 

The ecm is monitoring the maf voltage during the burn-off cycle. The expected range is between 0.40 volts and 1.9 volts (which corresponds to unlimited airflow between about 5 gm/sec and 36 gm/sec with standard maf calibration).

;--------------------------------------------------------
; ERR # 36 Params
; >> MAF Burn off Diag <<
;--------------------------------------------------------
LC22E: FCB 3 ; 0.3 Second Dly prior to Burn off check, (sec * 10)
LC22F: FCB 6 ; 6 fails req for ERR #36
LC230: FCB 95 ; Fail Burnoff test if HLM A/D > 95
LC231: FCB 20 ; Fail Burnoff test if HLM A/D < 20

;----------------------------------------------
; MASS AIR FLOW TABLE #1
;
; ARG = GMS/SEC + (256/SCALAR)
;
;----------------------------------------------
LC5B3 FCB 23 ; TABLE SCALAR
;
LC5B4 FCB 8 ; 8 + 1 LINE TABLE
;
; g/Sec BIN VDC #/HR
;----------------------------------
LC5B5 FCB 93 ; 8.4 0 0.00 0
LC5B6 FCB 36 ; 3.2 64 0.18 25
LC5B7 FCB 50 ; 4.5 128 0.37 35
LC5B8 FCB 69 ; 6.2 192 0.55 48
LC5B9 FCB 93 ; 8.4 256 0.73 65
LC5BA FCB 121 ; 10.9 320 0.91 84
LC5BB FCB 155 ; 14.0 384 1.10 108
LC5BC FCB 197 ; 17.7 448 1.28 137
LC5BD FCB 248 ; 22.3 511 1.46 172
;----------------------------------------------


;----------------------------------------------
; MASS AIR FLOW TABLE #2
;
; ARG = GMS/SEC + (256/SCALAR)
;
;----------------------------------------------
LC5BE FCB 48 ; TABLE SCALAR
;
LC5BF: FCB 8 ; 8 + 1 LINE TABLE
;
; gms/SeC BIN VDC #/HR
;----------------------------------
LC5C0 FCB 119 ; 22.3 512 1.46 172
LC5C1 FCB 133 ; 25.0 544 1.55 193
LC5C2 FCB 147 ; 27.6 576 1.65 213
LC5C3 FCB 163 ; 30.6 608 1.74 236
LC5C4 FCB 180 ; 34.1 640 1.83 264
LC5C5 FCB 198 ; 37.1 672 1.92 287
LC5C6 FCB 217 ; 40.7 704 2.01 314
LC5C7 FCB 237 ; 44.5 736 2.10 343
LC5C8 FCB 254 ; 47.7 768 2.19 368
;----------------------------------------------

 

If it's just looking for a given voltage when the burn off relay energizes on a pin of the ECU that wouldn't be hard to emulate.
I'm assuming at least some of the new style maf's give correct flow numbers, I know some of them do not. Some extensive
discussions about such on 3rd gen I've read through. I've also read that some of the new style maf's have the circuitry built in to fool the ecu
into thinking burn off is occurring, probably the same way I'm thinking.

 

Why not put the correct part in and have everything work correctly?

 

It's becoming increasingly difficult to get the correct part apparently. To my knowledge there are no sources for new-new ones, just remanufactured
or the ones with the modern style sensor that may or may not function correctly regarding the burn off function and/or the airflow reported.
I've had a number of other vehicles with Bosch hot wire maf's over the years and the remans have always been hit or miss, just like the in the Corvette world
finding a good used one has always been the safest route. They are eventually going to run out though. I'm not an authority on such but there is
a boatload of discussion about issues finding quality replacements for everything GM of this era that used them.