A couple of issues after initial startup - Please help

[gottadiesel]

Background - fresh re-build, all new vacuum, coolant and oil lines, fresh rebuilt turbo, 90% of the wiring has been inspected and gone through for any needed repairs.

So I finally got the car ready for start-up last night and after a couple of minor issues she started up, no oil leaking, no knocking... off to a good start.

I am running Lexus AFM/550 injectors, AEM WB, with a Neo piggyback controller (not for this forum but I set Neo at 69L/70H, everything below 70 is set to zero compensation). Here are the two issues that I have: (also fyi - no codes reporting)

Running lean - off the gauge at idle >18, if I rev it up a little it will stutter at first as it is starving for fuel, but then will come down to 16-17. By the way running an aeromotive FPR set at 35 psi with no vacuum, also tried 40 made a little difference.

If i compensate with the Neo at idle it will come down to the 14.8 with 50% compensation...

2nd issue -

Do not think they are related. I have a spot in the throttle that the engine acts like it is hitting a fuel cut or something. Let me explain, it is right around 3.5% throttle (so just feathering) at a standstill that is about 2000rpm, but is linked to throttle % not rpm, as tested on the road. If I am just sitting and try to hold it right at 3.5% it will act like it is going to die, drops to 800-1000 rpm then jumps back up to 2000, it will do this every 1 second or so continuously.

The thought I had was the TPS, but I set it per the TRSM, also I would think if it were that it would not report the % position correctly to the Neo, but then it appears the is just an open/close switch for idle, would that be different reaction if not set perfectly in position? Maybe TPS has nothing to so with it...

If you could offer any suggestions on either one / or both issues I would GREATLY appreciate it, it as been off the road since last November so very anxious to get the wrinkles ironed out...

Thanks

 

[89supra7mgte]

When the car stutters what do your afrs read? I am kinda having the same issue. if i hold steady throttle the idle jumps not near as bad, and the afrs peak to 21.9 back and forth, almost like a dead spot in fuel or something.

 

[gottadiesel]

It jumps off the meter, I think my AEM max read is 18 then it just reads -- ... yeah similar issue, but yeah mine is bad, if I am driving and it does it, it lurches, when not moving, it sounds like it is going to die but then comes right back up in a steady on off on off on and so on... well perhaps someone who has had a similar issue and found a resolution will chime in and help both of us...

 

[jdub]

Eliminate the Neo as the cause of the problem...i.e. completely disconnect it and run the stock ECU wiring.

With the Lex/550, FP needs to be ~30 psi with vac ON.

Test the TPS per the TSRM:
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?S=FI&P=101

Make sure you get a smooth increase in VTA as the TPS is moved from closed to full open.

Run the car and check for codes after all this.

 

[IJ.]

Sounds a bit like a faulty AFM or wiring, are there any codes?

 

[jdub]

I was thinking the same thing, but in post #1 he says there are no codes.
Taking the Neo out of the loop should show a code if the AFM is at fault...it could be masking it since the Neo modifies the Vs signal.

I would check the AFM connector to make sure it's secure

 

[IJ.]

I was thinking the same thing, but in post #1 he says there are no codes.
Taking the Neo out of the loop should show a code if the AFM is at fault...it could be masking it since the Neo modifies the Vs signal.

I would check the AFM connector to make sure it's secure

I concur

 

[gottadiesel]

Thank You guys - damn I missed that point, I did take the neo out of the picture already... just disconnected and wired the Karman signal back together... still no codes... I will check wiring on AFM again, I will back track color coding to make sure I didn't screw up, as I had to extend wires to get to the AFM location. I will also set the pressure up to 30 with vac on, as it is only about 25 or so...

As for the TPS, with the just ignition on, not running I have tested the TPS via the NEO, voltage is consistent throughout the movement of the throttle, but I will also check with meter to make sure... If I remember right went from .285volts to 3.3volts

Thanks for the info!

 

[gottadiesel]

Seems to running pretty good now, need to put fenders, bumper and hood back on so that I can do more than drive on the back road we live on... so here is what I did -

To get AFRs where I think they should be, correct me if I am wrong, I am hanging out at 14-15 while driving, throttle no more than 20% at this point... idle sits at about 17 @ about 700 rpms, i at first bumped the pressure with vacuum to 30, still a little lean, bumped to 34-35 and seems perfect, so is that ok, or am I compensating for a different issue?

The stumble was taken care of by re-adjusting the TPS, I tried twice to do with a feeler gauge .70mm but after tightening and testing did not like amount of movement required to open contact, so I did it by hand and sight and seems to work perfect... must have been telling ECU I was still at idle while giving fuel...

So far so good! A lot of money and even more time, I think she is ready to get on the road and start the break-in period.

Thanks to the both of you (IJ and jdub) for your always appreciated insight!

 

[89supra7mgte]

would fuel psi still be around 30 if you are using 560cc and lex?

 

[gottadiesel]

would fuel psi still be around 30 if you are using 560cc and lex?

Should be close to the same imo, it is only 10cc different than mine...

 

[jdub]

Seems to running pretty good now, need to put fenders, bumper and hood back on so that I can do more than drive on the back road we live on... so here is what I did -

To get AFRs where I think they should be, correct me if I am wrong, I am hanging out at 14-15 while driving, throttle no more than 20% at this point... idle sits at about 17 @ about 700 rpms, i at first bumped the pressure with vacuum to 30, still a little lean, bumped to 34-35 and seems perfect, so is that ok, or am I compensating for a different issue?

The stumble was taken care of by re-adjusting the TPS, I tried twice to do with a feeler gauge .70mm but after tightening and testing did not like amount of movement required to open contact, so I did it by hand and sight and seems to work perfect... must have been telling ECU I was still at idle while giving fuel...

So far so good! A lot of money and even more time, I think she is ready to get on the road and start the break-in period.

Thanks to the both of you (IJ and jdub) for your always appreciated insight!

That AFR at cruise is perfect...a bit lean at idle, but should not cause any problem. You could re-set the ECU by pulling the EFI fuse and let it start it's learned values from scratch. More important is what AFR shows during high throttle runs.

Adjusting the AFPR is setting a "global value" for FP across the range. Some motors need a bit more, some a bit less for the Lex/550 set-up.

If you want to check the TPS adjustment, jump the diagnostic block like you would for looking at codes. Check the CEL for a fast blink (no codes). Lightly press the gas pedal and a code 51 (it's a real time code) should appear...take your foot off the gas and it should stop. Make sure the AC is off during all this.

 

[gottadiesel]

That AFR at cruise is perfect...a bit lean at idle, but should not cause any problem. You could re-set the ECU by pulling the EFI fuse and let it start it's learned values from scratch. More important is what AFR shows during high throttle runs.

Adjusting the AFPR is setting a "global value" for FP across the range. Some motors need a bit more, some a bit less for the Lex/550 set-up.

If you want to check the TPS adjustment, jump the diagnostic block like you would for looking at codes. Check the CEL for a fast blink (no codes). Lightly press the gas pedal and a code 51 (it's a real time code) should appear...take your foot off the gas and it should stop. Make sure the AC is off during all this.

Yeah good point, I did not reset EFI after adjusting FP, I will do that this evening and see if that helps the idle AFR. Yeah the higher throttle stuff will come a little later, at this point I have my Neo set at 69/70 and do not plan to go past 70% or even 50% until I get passed my 5 heat cycles and re-torque the head... so yeah I will watch those close as I start to push it a little harder and make sure I am in the 10.8 to 11.5 I think is what I want to shoot for on the above 70% throttle...

Thanks for the tip on the TPS, good idea, I will just double check my setting with the CEL, but the falter issue I was having disappeared so headed the right direction if not at the right destination...

Thanks

 

[gottadiesel]

So did the test with the TPS using the CEL, yep got a code 51 with just a hair bit of throttle and went away after releasing.

Reset EFI, it helped a little, but not too much, about 16.8 - 16.9...

Did some 2nd - 4th gear pulls to 4k with it, felt real good, only went to 0 boost/vacuum... but I was getting some compressor surge, I heard the BOV open once when I boosted just every so slightly... like .5? gotta check the settings on BOV... sorry got off subject... Oh and I am still only at about -18 on the vacuum at idle, I know CajunKenny said he is seeing about -21... not sure if things still need to seat in a bit more or what, will check for any leaks but pretty sure there are none.

Thanks again for the help.