Corolla SE Saloon 2002 1NZ-FE Swapped

[hasankhurshid29]

As a preventive maintainence and facing some minor low idle issue, I opened the iacv few days ago. That day, 1 iacv scew gets stripped and the iacv gasket was in bad shape. So I fit it back somehow with 2 screws and bad gasket and ordered Tb gasket, iacv gasket and iacv screws from partscentral. They took a long time as 1 order was from UAE and 2 from Japan. On 4th Dec I recieved the order and installed it all on same day. The tb gasket was already good but still replaced.

Date: 4 December 2022
Odo: 187,773 kms

[nnabeel]

all of the roads in Karachi now are like mohen jo daro either due to new project construction in process, bad quality patching, rain damaged roads, pot holes and bumper to bumper traffic. even the new alto doesnt go over 16 kms/ litre here due to these issues.

[helper_learner]

mohen jo daro

Mohenjo daro was better but Karachi is more like moon,

Full of craters.

[hasankhurshid29]

As you all know, I am diagnosing the fuel average issue by myself so I bought a fuel pressure tester kit, costed me 4500. It has different sizes of quick connect fittings which is why I bought this kit because Toyota uses quick connect fitting inside the engine bay where you can easily connect it.

[hasankhurshid29]

This Sunday, I tried testing the fuel pressure. As my fuel pump is directly connected to ignition if I turn on the ignition (key on), the fuel pressure is 0.24 Mpa (34 Psi).

Specs: 44 to 50 psi for the 1NZ

MPa to Psi conversion Table
MPa Psi
0.00 0.0000000
0.01 1.4503774
0.02 2.9007548
0.03 4.3511321
0.04 5.8015095
0.05 7.2518869
0.06 8.7022643
0.07 10.1526416
0.08 11.6030190
0.09 13.0533964
0.10 14.5037738
0.11 15.9541512
0.12 17.4045285
0.13 18.8549059
0.14 20.3052833
0.15 21.7556607
0.16 23.2060380
0.17 24.6564154
0.18 26.1067928
0.19 27.5571702
0.20 29.0075476
0.21 30.4579249
0.22 31.9083023
0.23 33.3586797
0.24 34.8090571
0.25 36.2594344
0.26 37.7098118
0.27 39.1601892
0.28 40.6105666
0.29 42.0609440
0.30 43.5113213
0.31 44.9616987
0.32 46.4120761
0.33 47.8624535
0.34 49.3128309
0.35 50.7632082
0.36 52.2135856
0.37 53.6639630
0.38 55.1143404
0.39 56.5647177
0.40 58.0150951

[hasankhurshid29]

The fuel pressure with engine at idle without any load and gear in P with rpm ~1500 as it was cold start is 0.3 MPa (~43.5 Psi) but it starts to fluctuate when I turned on the AC and headlights. It fluctuate between 0.25 and 0.3 MPa (~36 Psi to 43.5 Psi).

Engine at Idle without load:

Fluctuations when AC and headlights is on and AC compressor cycling, Gear in P, Rpms above 1000:

[hasankhurshid29]

Then I tested with the gear in D, full load AC and headlights on and also tried with high rpms at 3k:

Again it fluctuates between 36 Psi to 42 Psi.

[hasankhurshid29]

After this test, I realized that after turning the engine off, fuel pressure is dropping quickly. I checked the fittings and there weren't any leaks. In 10 minutes, it drops to around 0.09 MPa (13 Psi):

It drops to 0 after few more minutes:

Here is a video how quickly its dropping after engine turned off:

[hasankhurshid29]

@Xulfiqar @rajaatta @xenerking @dani_kk @Hassan1991 @dayrider @capsat @syncview

Please read the above posts and give your analysis

[Xulfiqar]

You are facing a fuel starvation issue, if you put a longer hose and tape the gauge the windshield, put transmission in L or 2 and go full throttle you may see it dip to 25 or lower

Your filter is choked or your pump is dying.

[rajaatta]

Okay check the fuel pressure regulator in the fuel tank it's attached with the fuel filter assembly. Nothing more than that check it and replace it if needed

[TypeA]

fuel pressure regulator

also termed purge valve

[dayrider]

our filter is choked or your pump is dying.

1+

[rajaatta]

No no fpr

[hasankhurshid29]

Do you know the price of new oem pump?
It may cost 20k to 30k oy for oem pump

[Xulfiqar]

and why is that a problem? - you buy the car knowing its owning cost.

If 20 to 30K is too much after the car is 20 years old then perhaps dont own a car at all, hiring a cab would be cheaper.

[engnr.mubashir]

we have trust issues that's why we love to have premium products from kabul.

[Xulfiqar]

I prefer products from Jalalabad.

[Xulfiqar]

Use a better gauge, a wider one that can show you in actual 2 psi increments rather than this tiny item. The little fluctuation you see at idle is your fuel pressure damper not working right - due to the missing volume.

And this was not a full load test as you claim - a full load test can only be done when the car is on the road in a lower gear and you are at full throttle from 40% engine rpm range all the way to redline.

[aziz.rehan]

I have installed chinese denso fuel pump in Indus Corolla.It,s working good.Got it for under 2k with stainer.