89 GXL. mazdaspeed intake. rb street header, presilencer. new fuel pump and filter. new plugs and wires. regrounded + ground kit. new batt, new alt.

during WOT car runs around low 12 afr then hits 6k and leans out insanely and will not go past that point. for experiment purposes, i let the car wind up 1st gear with partial throttle and it went all the way to the red with 12-13 afrs. will rev all the way in neutral but sounds like it's breaking up at the top end, doesn't feel like it wants to rev all the way.

notes: 6pi system does not activate when revved in neutral (not sure if it has to have load, don't know how to test)

suspect: air pump issue? ecu issue? sensor? timing? this was automatic converted to manual BUT it did not have this problem until recently, it came out of nowhere.

I absolutely appreciate any help on this, I am completely baffled

 

Check the vacuum lines to the Ports,..on an s4 the ports are activated under load.Can't open in neutral or Revving in the Driveway.I am not sure about the s5's though.

 

any idea how to check it under load....? but either way, 6pi working or not, car should still rev past 6

 

Might be the ole boost sensor. You can check it by removing the vacuum hose to it, plug the hose, disconnect the TPS sensor electrical plug and this will simulate load and then try reving through the 6000 level.

 

satch: GXL = NA
thanks though

 

Boost sensor = pressure sensor. It's the same thing. So there.

 

is that the one somewhat behind the passenger headlight? ok, will try that

 

Yes, and the process I mentioned earlier helps to simulate load on the engine so it could be applied to checking other things related to engine performance besides the boost/pressure sensor as well that requires "load" w/o having to leave the driveway.

 

Hey I didn't know this, so I can simulate load and still have the car free revving on the driveway lmao this is good stuff !!

Thanks for the tip.

 

i would check for codes (they do not all turn on the light) and then check the TPS. a stock ecu car should be richer than 12's

 

satch:

disabled pressure sensor and disconnected tps. revved car and it held solid afrs with no leaning on wot, but ports didn't budge at all. even tried moving them with pliers, seem seized.

i took for a test drive with tps disconnected and car DID go past 6k all the way to red, but struggled a lot getting there. afrs stayed solid, but it was very choppy, most likely since tps was disconnected and ports aren't opening.


j9:
no CEL and no codes appeared when grounding green code checker. car is technically not stock since it has intake and exhaust mods with a mild streetport, but either way, it seemed to be just under 12 at wot with tps disconnected

all readers:
WTB: tps and pressure sensor

 

anybody?

 

i'm having this same issue. have you resolved this yet?

 

New thread going here: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/fuel-problem-troubleshooting-930631/