17:1 at idle,now 11:1 at idle and all throttle

[ZR8ED]

As the title says.. cars screwed up.

 

Z31 VG30ET motor, Z31 harness and custom burned ecu, 370cc inj, t3/t4 turbo, 3" exhaust etc etc.

 

Car was running very nicely.. till last week or two.. drove it in the rain, when WAM... wideband O2 is pegged at 11:1 air fuel in all throttle positions except under deceleration with foot off the throttle... it then read 17:1.

 

I check lots of stuff.. Wiggle harness and the car runs better.. ok clean and check harness and all sensors.. ok.. lets just redo the entire harness to make sure..

 

Ok here I am. still idles near 11:1. Part throttle i get normal looking numbers, WOT see's 11:1, decel with foot off throttle 17:1. very light throttle, see's 11:1 a/f

 

I verified the O2, TPS, MAF, chts, dizzy, plugs wires, and ign.

fuel pressure is at factor settings 30psi with vac removed at idle.

 

I did notice my detonation sensor (factory inst) not working as described in the fsm. unplug it and the idle should drop and timing should retard 5 degrees... when I unplug it... nothing happens.?????

 

I'm unsure how to setup my tps.. manual shows bringing idle to 850rpm and set it up.. my car idles at 1000.. ( I like it there)

 

I redid the whole harness, unplugged the whole harness, unwrapped it, removed any wire no longer used (harness was from an auto matic 86 turbo...lots of electric gear) I redid ever ground, added some more to be sure, and removed wires all the way to the ecu that were not used. It took me 12hours to redo it all.

 

Car still runs as stated above. Even with all these wires/connectors etc removed.

 

 

It idles pretty smooth, starts well, drives not bad... it gets a bit "herky jerky" as throttle changes and air fuels jump around, but it will drive and will pull boost. 10psi at this point. Lots of rich smelling exhaust at the back of the car though!

 

Engine bay looks cleaner, and I now know my harness very well, but so far, no good.

[Bernardd]

set your tps to open at the same rpm difference as what stock says. example:

if the fsm says that the tps should open at 900rpm and idle is 750, then set the tps to open at 150rpm above what the idle is now.

[ZR8ED]

update.

 

Adjusted the tps. I still have a stumble from 2000-2500rpm when slowly increasing the throttle (neutral in the driveway)

 

Long story short.

 

Car idles at 12.8:1 air fuel, fp 27psi (vac removed and plugged) idles speed at 1000rpm. idle bypass screw all 3/4 way open to bypass air past the throttle plate. (factory equipment bypass)

 

The car drives around in the 12.5-13.5:1 air fuel. goes to 11:1 at WOT, and goes to 17 under decel in gear with foot off accelerator

 

I reset the timing to 20 degrees, lowered the fuel pressure 3-4psi, and opened up the idle air bypass 3/4, and lowered the throttle plate position (adjusting screw) to get to this level of performance.

 

I need to run the boost higher and see the air fuel ratio before I adjust the fp any more.

 

we'll see

[ZR8ED]

Ok another update.

 

MORE boost.

 

I cranked the dial a boost under the hood (to save my engine and myself ..no cockpit adj for me. hehehe)

 

I don't recall turning it back very far, but I have had to crank the dial 3 full turns to get from a solid 10psi to a nice 12psi in lower gears and 14 in top gears.

 

I still have some adjustments to go, and going slowly is better anyways. At least to keep track of each adjustment made.

 

I go out for a cruise with some 7mgte powered MkII supras. ok. The car is running much better. We had some fun with a Buick GN.. I guess he thought he would stomp some rice!! NOT!! we all waxed him.. even by me, and I was bringing up the rear!!

 

air fuels are still good, at full boost, air fuels are good as well. It looks as though I just need to get the car out and drive around with it. I'm going to crank the boost abit more and get it back to something around the 15psi mark. I am still not able to spin the tires when rolling into WOT 3rd gear, but I think that is due to my new suspension settings. The car is hooking up very strongly again.

 

I am feeling pretty good again, about working on the car. Confidence is back up after doing all that rewiring and then balancing my fp/timing/idle/idle bypass.

 

The only complaint I have at the momement is intown driving. The car either wants to coast or accelerate.. those very fine throttle adj have a "herky jerky" feeling to them, and my air fuels jump from rich (as I touch the throttle then it settles out), to full lean (17:1) as I coast in gear.???