How To Test Tps And Afm?

[GT888]

Hi all,

I have tried to do a search for some answers and have not been successful.

I have a S2 R33 gtst. When I drive my car on half throttle it will revs out and boosts fine but when I have it on full throttle it will hesitate for like 1/2 a sec and feel powerless reving out. So I'm pointing the finger at either the TPS or the AFM.

Question is how do I check if my TPS is rooted? Also how do I checked my AFM without having to swap it with another one as I have no means of getting my hands on a spare and don't want to buy another just incase my one is fine.

Thanks in advance,

James

Edited June 1, 2009 by GT888

[Adriano]

Check trouble codes, either will throw a code if stuffed. Is it stock?

[mad082]

i highly doubt it will be either of what you have said. without knowing your mods and boost level i'd say more than likely it is going to be a spark plug or coil pack issue. how old are your plugs? and do you know what sort they are and what gap they are?

if you don't know i would recommend going to your local repco, autobarn, etc and getting some new plugs. the ones you need are part number BCPR6ES. they are ngk copper plugs and are about $5 or $6 each. put them in and see what happens. you have your coil packs out changing the plugs look at them for signs of arcing out. if that hasn't solved the issue then pull the coils back out and tape them up (there is a thread in here about how to do it somewhere). don't do it at the same time as doing the plugs otherwise if it fixes it you won't know what the problem was. then see if that causes the issue. if it makes it better but doesn't fix it then you need new coils.

if you are running higher boost (about 11psi or more) on a stock ecu then you may be encountering rich and retard. this is a protection in the ecu which you can't get around without changing the ecu to an aftermarket one. however from my experience with rich and retard it normally won't happen throughout the rev range when you floor it. it sort of comes and goes as you rev up.

[mad082]

ok just saw in another thread that you have split fire coils and platinum plugs. well firstly i would recommend getting rid of the plugs. not a fan of platinum plugs. do you happen to know what heat range they are? they may be too cold (or hot).

also just because it has splitfires doesn't mean they aren't shagged. i know someone who had splitfires go bad on him.

also to test the tps and afm all you need is a multimeter, or a consult cable (better option). with the multimeter you just tap in to 1 of the wires (not sure which one) when the igntion is on (car doesn't have to be started) and get someone to push the accelerator to the floor. it should read between 4 and 5v. the afm is a bit harder to test but again works off the same principle. you can only test it and idle and reving, you can't test it at full throttle unless on a dyno (or feel like sitting in the engine bay while driving, which i don't recommend, LOL). you could tap into it at the ecu plug though, but then you have to find the right wire. i would recommend getting a consult cable. they are about $50 or $60 (depending on which one you get) and there is plenty of free software to go with it. there is a member on here who sells them. then you can check afm and tps while driving as well as check the ecu for fault codes, etc.

[paulr33]

then the car to ON, but don't start it

with consult mash the accel pedal, TPS should go from 0.3v to around 3.4v

AFM should 0.5v at ON, but not running and when running should be 1.1v idle

agree with mad082, it wont be TPS or AFM

go see a mechanic, save guessing

[GT888]

It has:

Turbo back 3" exhaust

Spitfire coil packs

Greddy Profec B II

FMIC

Walbro pump

Boosted to 12psi

Have changed over to copper plugs, heat range 6 gapped to 1.1. Have tried 0.8 but felt it pulled stronger on 1.1. Plugs and coil packs look ok too.

Codes say OK. Also have reset ecu.

Am currently saving up for a PFC. Maybe will have to stick it out till then.