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TopFuel SR20DET
12-09-2001, 02:51 PM
What's up everyone. I have an S13 SR20DET. My TPS is reading 14% with the TPS off the throttle body and without the motor even running! If you move the TPS a quarter of the way, it reads 100%. Anyone ever have this problem? I've already replaced the TPS and checked the wiring. Everything seems fine there. Anyone with any ideas, please help! http://www.freshalloy.com/

**DONOTDELETE**
12-09-2001, 03:12 PM
what kind of tps did it come with ? a big 6 wire one or a 3 wire small one ? what kind of tps plug is coming off the harness ? 6 or 3 wire ?

otherwise i have seen the throttle plate rod actually twisted before, before it goes out and goes into the tps. Was your throttlebody sorta sticky when you first tried opening it ?

TopFuel SR20DET
12-09-2001, 03:43 PM
Mine has the small 3 wire TPS and 3 wire connector. With the TPS actually removed from the throttle body, it still reads 14-15%. That's what is bothering me. I just don't understand how it is doing this. The car idles fine, but when you try to accelerate, it floods out due to it reading 100% at 1/4 throttle.

**DONOTDELETE**
12-09-2001, 04:35 PM
wait a minute... i thought you said you replaced it ? If you got a new one and it still reads 14 % disconnected, you are reading it wrong.

Later
martin s.

**DONOTDELETE**
12-09-2001, 05:12 PM
What device do you use to determine the TPS percentage? I am just curious cuz my SR is running very rich at idle.

<BLOCKQUOTE><font size="1" face="Verdana, Arial[/img]quote:</font><HR>Originally posted by TopFuel SR20DET:
What's up everyone. I have an S13 SR20DET. My TPS is reading 14% with the TPS off the throttle body and without the motor even running! If you move the TPS a quarter of the way, it reads 100%. Anyone ever have this problem? I've already replaced the TPS and checked the wiring. Everything seems fine there. Anyone with any ideas, please help! http://www.freshalloy.com/<HR></BLOCKQUOTE>

TopFuel SR20DET
12-09-2001, 05:37 PM
I replaced it. That's the new TPS's reading. I am using an Apex SAFC to read the throttle percentage. Any ideas as to why it's still reading 15% instead of 0% at idle? http://www.freshalloy.com/

Mav1178
12-09-2001, 05:41 PM
<BLOCKQUOTE><font size="1" face="Verdana, Arial[/img]quote:</font><HR>Originally posted by TopFuel SR20DET:
I replaced it. That's the new TPS's reading. I am using an Apex SAFC to read the throttle percentage. Any ideas as to why it's still reading 15% instead of 0% at idle? http://www.freshalloy.com/<HR></BLOCKQUOTE>

Why don't you stop using the SAFC until the problem is solved, so you wouldn't flood the enginee everytime you accelerate?

-alex

TopFuel SR20DET
12-09-2001, 05:57 PM
The reason I am using the SAFC is to lean the car out. I'm running 480cc injectors with an upgraded turbo. Sorry, I left that out of my original post.

BioSehnsucht
12-09-2001, 06:00 PM
Does the S-AFC know what kind of TPS it is ? If it's selectable double check what you have it set for. Maybe its misinterpreting the signal.

nismos13silvia
12-09-2001, 06:28 PM
I'm kind of having the same problem. My TPS reads 0% at closed throttle. But when you step on the gas, it starts reading and then goes all the way to 100%.

I'm using the Apexi S-AFC and I've got the 6 plug TPS.

SRFiveTen
12-09-2001, 07:20 PM
according to apex-i, at least the mafs selection, number of cylinders and throttle sensor selection need to be correctly designated for the gadget to properly function.

Mav1178
12-09-2001, 07:28 PM
<BLOCKQUOTE><font size="1" face="Verdana, Arial[/img]quote:</font><HR>Originally posted by TopFuel SR20DET:
The reason I am using the SAFC is to lean the car out. <HR></BLOCKQUOTE>

Obviously it isn't working.

-alex

SRFiveTen
12-09-2001, 07:53 PM
i have been lead to believe that ecu's had to be reprogrammed to work with other than stock injectors.

if s-afc can fool the ecu to believe that 480s are same as 370s, then how come there are people rewriting their chips?

12-09-2001, 10:47 PM
All the S-AFC does is modify the MAF signal. Thus, you can tell the S-AFC to put out a lower voltage than the MAF is actually putting out, so the ECU will fire the (larger) injectors for a shorter amount of time than it would with an unmodified MAF signal, thus leading to (ideally) the correct A/F ratio.

It's a neat little device, but I think it isn't really well suited to compensate for larger injectors because you'll still run into a limit whenever you reach the maximum voltage that the MAF can read...after that, all you're left with is RPM-based fueling...which may work ok, but it's not ideal. And, of course, the S-AFC can't adjust ignition timing.

Asad

<BLOCKQUOTE><font size="1" face="Verdana, Arial[/img]quote:</font><HR>Originally posted by SRFiveTen:

if s-afc can fool the ecu to believe that 480s are same as 370s, then how come there are people rewriting their chips?<HR></BLOCKQUOTE>

quest
12-10-2001, 02:15 AM
Bigger air flow meter - leans it out
Bigger injectors - fattens it up
AFC - strikes a balance
I can hardly think of a more sucessful tuning gadget... extremely popular. Lotsa wicked fast DSMs will be happy to show you how well they work, and they don't touch their ecu (oe progrmme) ... and its tunable.
Chips are good if written for your *exact* combo, but I sure as hell wouldn't pay $600 for one... guess coming from the GN world of $100 chip has me spoiled.
Now if ecu can be chipped / programmed for your specific car, on a dyno, for $200ish, as done abroad.... I'd spring for that

nismos13silvia
12-10-2001, 09:39 PM
Even though my TPS reads wacky, I still get a good mix at 13-15psi of boost. When running at stock boost, it runs rich. But that would be normal. Needs a turn off option like the S-AVC-R.

Number of cylinders and throttle sensor selection has been set. It still reads wacky. I've help installed and tune 2 other Apexi S-AFC. They work fine, mine is just working funny. But they're on different cars.

[ 12-10-2001: Message edited by: nismos13silvia ]

BioSehnsucht
12-10-2001, 09:53 PM
You replaced the TPS once right? And checked the wiring? Hrm.. Have you tried swapping out the S-AFC? Maybe its got something wrong either internally or with its electrical contacts ?

**DONOTDELETE**
12-11-2001, 09:16 AM
I'm totally confused http://www.freshalloy.com/
I don't have a SAFC hooked up yet, so I can just use the procedure in the FSM.
(backprobe the TPS and check voltage?)