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Discussion Starter · #1 ·
k so i have a 87 7mgte in a 85 pickup. i converted it to a 3in gm maf 2 weeks ago using a fullthrottle maf tanslator

link:
http://www.fullthrottlespeed.com/itemdesc.asp+ic+050SUPRA3MAFT+eq++Tp+


engine runs fine, idles cruses but when you got WOT the engine will cut out or surge at aboot 4500 rpms.

never did this running my stock afm(which i would put back on but its wrecked). ive turned back the boost to 10psi, was tickling the fuel cut at 13-14psi of boost and would only cut out at winter time in the extreme cold(-25,-30C)

when it cuts out and does not surge it codes 34, but aboot 9 out of 10 times it just surges and will still keep pulling.

im positive i do not have any boost leaks, my afr is around 11-12 under WOT.

i never had any of these said problem running the stock afm and all these problems accord once the motor was running on the maft.

any ideas? bad MAF? translator?
 

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weaksauce, work on it...
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and the 7m oil pump said AAAAAAGHHHHHHH!!!! as you nearly caught air on that jump... exhaust note doesnt sound too bad ither.

about the maf translator... who wired it? and what wideband are you using?
 

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weaksauce, work on it...
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the xd gauge? or the innovative gauge? I ran maft pro myself and used the same wideband last year... got sooooo sick of free air calibration for the sensor. went with the aem wideband so i wouldnt have to go through the calibration bs ever again, then ended up going to the aem ems aswell...

nother question, what year harness/ ecu? what im getting at is did you need to do the hac mod for the 89+ ecu? how similar was the setup to this?
 

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weaksauce, work on it...
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659 Posts
nice, something new... mine was the L-c1. good to see they have more options.

is the new wideband still compatible with the maf translator? maft pro had a short list of compatible widebands, possibly its not giving correct #'s to the unit... also, is your factory o2 plugged in?
 

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Discussion Starter · #9 ·
im just running the translator.... not the pro. no O2 inputs or that.

heres the manual/install
http://www.fullthrottletech.com/showthread.php?t=1102

so i just got back from a test.... like a dumb ass i still have the HAC plugged in, so i unplugged it... work awesome for about 4 or 5 pulls then it was right back to its old tricks. surging, fuel cut and leaning out. like always i try adding more fuel and still nothing changes
 

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NO SOUP 4 U
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1,683 Posts
Little more info needed about the afm you put in. You said you were running a stock one. Now? Lexus afm? larger air flow = have to re-tune the fuel map to compensate for the higher air flow.
Its possible the set screw is out of adjustment on the afm as well. Or you have a crap afm. Time to get the meter out to test it.
For those running the Maft Pro..... we would just run in speed density mode (without a afm).
 

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Supra Tech
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Um don't u mean 3 bar?
MAF not Map

He's on an older translator, which I believe can run in SD.

OP if your running a translator with a GM MAF then you don't need the stock AFM anymore. Thats the idea with a translator it "fakes" a stock AFM signal to the TCCS after reading the air on a MAF or MAP and an IAT. Test your MAF? Are you blowing through your MAF or is it before your turbo?
 

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NO SOUP 4 U
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Ok.... My brain saw MAP.
Anyhow.... When you took the stock AFM out, and installed the larger AFM did you make the setting changes in your translator?

I saw this when reading in to it.
Controls:
The Translator has the following controls:
MODE SWITCH – a 4 section “dip switch” for setting the basic vehicle/translator parameters. Turn the engine off when making changes to the MODE switch.
BASE – this 16 position (0-F) dial is used to set the general airflow scaling. This adjustment affects the entire operating range and is generally used to match the Translator and MAF to the selected injector size.
IDLE – This 16 position (0-F) dial is used to adjust the airflow signal during engine idle conditions. It can also be used to compensate for modified PCV (crankcase vent) and fuel pressure setups.
MID - This 16 position (0-F) dial is used to adjust the airflow signal during moderate acceleration conditions.
WOT – (WOT=Wide Open Throttle) This 16 position (0-F) dial is used to adjust the airflow signal during heavy acceleration conditions.
AUX - This 16 position (0-F) dial is used to adjust the airflow signal during heavy acceleration conditions when the purple TRIGGER wire is activated. This mode is active above 8 psi boost (approximate)
(The AUX dial is also used for selecting the base settings)
RPM Mode, WOT Fine Tuning setup:
• Once the BASE settings are done, switch MODE 4 ON. This will save the base settings and allow the use of the dials for RPM/WOT tuning. (wait at least 5 seconds after your last base adjustment, then turn the ignition off before making changes to the MODE 4 switch)
• The dials are now 2% steps of the scaled airflow. Refer to the picture below to see how the settings are the “breakpoints” or “corners” of the flow correction graph. Base adjusts 3000rpm and lower, idle is 4000, mid is 5500, and WOT is 6500 and greater.
• If the RPM signal is not connected, the correction dials will be selected based on airflow.
• These corrections are enabled as long as the airflow Hz is over 600 at RPMs below 3000, and always when the RPMs are above 3000.
• These corrections are added to the BASE adjustments set in the initial MAF mode setup.
The Manual is here. http://www.fullthrottletech.com/showthread.php?t=1102
 

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Discussion Starter · #18 ·
this is probably a newb question but..... im hitting fuel cut, not leaning out or acting funny. the truck will pull fine now but im running straight pressure off the turbo to the wastegate and im hitting fuel cut above 4k. the wastegate just cant dump off the pressure. at lower rpms it will hold at 7psi but keeps climbing. i had a grainger valve as a boost controller but i removed to knock the boost pressure down and the has got me to where im at now.

so the question is where do i go from here? (really look from someone to hold my hand) so do i put in larger injectors and adjust the maft to a larger injector size and that will get me past my current boost cut....

heres my current set up. fully rebuilt 7mgte, arp head bolts, cometic headgasket, arp rod studs, stock turbo, stock injectors, 3in gm maf, maf translator, 3inch intake and a 3inch divorced downpipe
 

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Supra Tech
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oh yeah, tested the maf, it works fine. and im running before the churbo
If you have a VTA BOV anywhere after the MAF then all the air your blowing off has already been "Measured" and the TCCS will dump fuel for it. You should "blow through" you MAF. Place it somewhere in between your BOV and TB, this way when you blow off the air hasn't been measured yet.

About FC, it sound like you have a boost creep at higher RPM's because of the free-er flowing exhaust and intake. A simple solution is to hone out the wastegate hole in the stock housing. You can remove sooo much material to make the wastegate larger. If you can lean out some of that mixture while keeping you Vf happy then you can add that fuel to the top and raise the boost up accordingly. But I would get my creep issue under raps first. I know its sacrilegious but try putting a silencer/restricter in your muffler to add some back pressure and see if the creep is better or fixed, if so then there's your problem
 
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