7mgte lex 550 lean under boost

[IndigoMKII]

Okay so a little history, with my previous setup before i went lex and 550 i was running pig rich. Roughly 10.0, but now that they're installed its running near 12-13. I only did one 14 psi pull and noticed the afrs so i creeped her slowly home. The idle afr is around 15.0 but i had to turn the base fp way up. Its near 44 if i remember correctly. I wont be running the car down the road anymore til i can figure out the problem.

Any suggestions?

And by the way, anyone thinking of running my mods and lex550 mod, around 14 psi, she comes to life QUICKLY.

 

[Dan_Gyoba]

TSRM FI-73 says that base fuel pressure stock should be 33-40 PSI, and I've always seen it closer to 40. (And I'd bet that exactly where in that range it sits will depend on altitude and local barometer.)

So... What's wrong then with setting your base fuel pressure there? What are you running fuel pressure at?

 

[Poodles]

Any other fuel mods?

 

[7M4EVR]

Slap a walbro 255 or mk4 pump in there and an afpr and FTW!

 

[IndigoMKII]

TSRM FI-73 says that base fuel pressure stock should be 33-40 PSI, and I've always seen it closer to 40. (And I'd bet that exactly where in that range it sits will depend on altitude and local barometer.)

So... What's wrong then with setting your base fuel pressure there? What are you running fuel pressure at?

ive always seen that lex 550 runs rich and most people reduce fuel pressure to compensate for it being pig rich.

 

[IndigoMKII]

Any other fuel mods?

yes, dm afpr kit with j tube deleted and walbro 255. i just installed the 550s 2 days ago but tore a o-ring putting them in. so i had to wait for a day to get a new o ring. my fuel system holds pressure well over 5 minutes.

 

[IndigoMKII]

Slap a walbro 255 or mk4 pump in there and an afpr and FTW!

i have both.

 

[IndigoMKII]

Im home with a fever but i will go outside and check the fp and try to pinch the rubber line and find my max fp.

i do believe its set near 44 though with no vacuum.

 

[Dan_Gyoba]

Do you have your Walbro running full-time 12V?

With my car, same fuel system mods, and base fuel pressure set to 40 PSI, it ran rich enough to get a film of soot on the rear bumper over the exhaust running a tank of gas in town. I didn't have a wideband, and so I was erring on the side of being rich.

 

[Poodles]

Depends how bad the o-ring is torn, but that could be a massive vac leak...

 

[IndigoMKII]

Depends how bad the o-ring is torn, but that could be a massive vac leak...

sorry for the confusion, she has a new o ring on the injector. my fuel system has no leaks nor restrictions anywhere in the system. i am also not running the 12v mod.
when i first changed the injectors and didnt mess with the fp at all she started at 15.0 afr and quickly went over to -- lean and the car stumbled badly. i gave her a few good turns of increased pressure to get her to idle. once i got it idling at 15.0 i took it for a drive to see it run lean at 14 psi.

 

[Poodles]

Something is up then... Where did you get the 550's?

 

[Dan_Gyoba]

I'd say you want to get those injectors flow tested. The TCCS is well known to run "pig rich" by default, and you can have a large variation in base fuel pressure (Assuming that your regulator works as it should, and adapts pressure based on manifold pressure) and it will adapt and still run pig rich.

Also, once warm, you should be idling at 14.7 AFR, which is stoichimetric and where the TCCS will keep the car in closed loop mode, assuming that your O2 sensor is correctly operational.

Because the TCCS adapts, you should also run it for some time in closed loop mode so that it can learn.

 

[D.J.T.]

I'm no genius. But I've read somewhere about injector impedance? something about there being 550cc with low impedance & 550cc with high? ::shrug::
Don't know if it would affect. I'll educate myself better tomorrow.

 

[thevork]

^D.J.T the 7MGTE has a low impedance circuit. You can use high impedance injectors in a low impedance circuit. No problem.
I removed the resistor pack to be sure it would be perfect, but you really don't have to do that. Low or high imp injectors in a 7MGTE, both will work.

@topicstarter:
Get the injectors flow tested as said in post #13.
Base FP 40 PSI without vacuum is not very strange on lexriemer mod.
Also, did you use your own afm electronics ?

 

[IndigoMKII]

Something is up then... Where did you get the 550's?

I bought the 560's off the forum. They're 560cc evo9 injectors, pink body. 2.3 ohms across the board.

 

[IndigoMKII]

I'd say you want to get those injectors flow tested. The TCCS is well known to run "pig rich" by default, and you can have a large variation in base fuel pressure (Assuming that your regulator works as it should, and adapts pressure based on manifold pressure) and it will adapt and still run pig rich.

Also, once warm, you should be idling at 14.7 AFR, which is stoichimetric and where the TCCS will keep the car in closed loop mode, assuming that your O2 sensor is correctly operational.

Because the TCCS adapts, you should also run it for some time in closed loop mode so that it can learn.

I got the injectors flow tested by DM before I even considered putting them in the car, while they were getting cleaned I also bought ev1 injector clips.

 

[IndigoMKII]

^D.J.T the 7MGTE has a low impedance circuit. You can use high impedance injectors in a low impedance circuit. No problem.
I removed the resistor pack to be sure it would be perfect, but you really don't have to do that. Low or high imp injectors in a 7MGTE, both will work.

@topicstarter:
Get the injectors flow tested as said in post #13.
Base FP 40 PSI without vacuum is not very strange on lexriemer mod.
Also, did you use your own afm electronics ?

The afm is in good condition, 560cc injectors are flow tested and in good condition and the reason I find near 40 psi weird is because normally the base FP is lowered, not raised for the injectors.

 

[IndigoMKII]

To sum everything up in one post.

560cc low impedance injectors 2.3 ohms across the board from a evo 9.
walbro 255 set at 44 psi with no vacuum regulated by the AFPR DM kit with the jtube bypassed.
Running a AEM UEGO to watch my AFR's.
At idle on base pressure(36psi) the car did NOT want to run after starting, would start at 15.0 and go full lean --.
At idle on base pressure(44psi) the car idles at 15.0 afr but runs lean at 14 psi(12.0-13.0)
Injectors are flow tested by DM and run #1 570, #2 560, #3 540, #4 540, #5 550, #6 540

 

[thevork]

What's your Vf signal doing?