Dreaded P0172 ‘99 1st Gen Supercharged

agreed mostly... my thoughts are this, the injector ms or the duty cycle is not adjustable, nor is the igniton timing the only other thing to do is adjust fuel pressure and by lowering the pressure the volume will lower too.

 

I know this is an old thread, but I have the same P0172 code and engine behavior almost exactly. As far as the Fuel pressure goes the Factory service manual indicates 31-37psi at idle, but the way the FPR is actually plumbed into the intake before the throttle body makes it so that it doesn't see vacuum at idle so you will see 45psi(it's the same as if you removed the vacuum hose). If you move the stock FPR vac line to the intake and cap the stock port on the intake box the fuel pressure will read between 31-37psi at idle just as the book mentions.

I installed the LCE fpr gauge kit myself. Comes with a pipe plug so that you can remove the gauge so it's not always installed in the engine bay.

 

Ok so did you ever figure out what's causing the code. I bought a 96 with a charger and swapped it onto my 02. I also put in a 7th injector and bigger fuel pump. I have the same p0172 the entire time. I just assumed it was because of the fuel pump and added injector

 

I've had the 7th injector with larger fuel pump for going on 6 years and have never gotten a P0172. Did it happen right after installing the supercharger or awhile after?

 

It came on as soon as I put it all together. I did everything all at once

 

Hm weird. Usually you hear of people getting a lean code (P0171) after the install because there's a vacuum leak somewhere, not a rich code. Did you put in the right spark plugs with it as well? 2 step cooler, IK22

 

Can be a MAF sensor issue,
Try cleaning it with MAF cleaner spray,

or fuel pressure regular issue,
How is the vacuum line coming off the fuel regulator?
To the supercharger?
Or intake?

 

I followed the toyota instructions to a T and have double checked everything. I got plugs from urd with the injector kit. Just to be sure I put a new toyota maf and both o2 sensors in

 

Fpr was new when I did the swap but I haven't checked fuel pressure. It's still not a hot rod so I'm about to peel all that crap off of it