Corolla doesn't start on first self

[salman108]

I would take that in fair sense, maybe if that smiley wasn't there.
What do you think ?

I am willing to talk reason.

[Xulfiqar]

Great!

So what reason do you want to debate?

[Xulfiqar]

This engine would show tdc corelation errors if it were not timed right.

And if a mechanic cannot time a plain jane toyota 4cyl engine, Then he should take up some other skill to earn money.

Timing a toyota engine is dead easy simple and only requires a working pair of eyes (even one eye would suffice too), there are no special timing tools for this engine.

[salman108]

@Xulfiqar
Here is my problem,

a,. Whichever mechanic he went to, i am almost certain he would not have pressure gauge to measure fuel pressure,
even if he did, it would be a cheap knock off, thus the readings cannot be trusted.

b. Which ever mechanic he goes to, chances are he wouldn't have a time gun. most toyota engines are TDC a few degrees before zero.

c. Even if the mechanic had some understanding of TDC, I can bet he won' t be able to tell compression from exhaust stroke, and thus time the engine on the wrong turn.

All that said, since the car starts on second attempt, It's either the fuel return valve, or the fuel pump that would be the problem.
However as per the author, those are eliminated and are performing well ( read a and b ).

Lastly, debate is not reasoning,
reasoning is how to perform debate and build logic.

[Xulfiqar]

Checking timing with a timing light on an efi corolla is not worthy of anything except checking if the ecu is stuck in some other mode than normal.

There is nothing to adjust while shooting a timing strobe to the crank damper,

The only timing that matters is the crank to block to chain and camshaft wheel to head to chain markings and installing the timing chain correctly which is extremely easy on these engines. The chain tensioner is very easy to work with too.

The problem here is that the pressure regulator in the fuel jug is bad or the engine has a leaking injector that slowly bleeds down.

The crux is that most customers in Pakistan opt for a scrapyard part as “good replacement”

Mechanics with tooling like pressure gauges etc exist but customers dont want to visit them because their charge is more expensive than “andaaza ustaad”

[salman108]

I can only base my opinion on the data that the user is sharing.
I agree and suspect the same, that the fuel return valve, or pump, or leaking injector maybe the case.

As far as timing etc is concerned, maybe i am a bit mathematical in my approach, but my belief is that
if something can be calibrated to 2 decimal places, then it SHOULD be calibrated to 2 decimal places.

People can keep going to Andaza ustaad and types,
they don't realize that the loss of performance, fuel efficiency, and general lack of pleasure in driving is worth much more than a few thousand Rs.

[Xulfiqar]

You cannot time a toyota engine with mathematical precision like you want, thats the beauty of it, - its done to make repairs easy.

The reason is that there are no timing tools to lock anything in place unlike mazda or bmw engines where they rely 100% on friction fit of the cam and crank timing wheels to the cam and crankshaft. (They dont use a woodruff key system - just a diamond crusted friction washer and a stretch bolt tightened to plastic range) is that it can be timed with basic hand tools and a working pair of eyes (or even just one eye)

Now doing timing on the above engines, you need a specific timing tool set (it costs money - which the mechanic doesnt want to spend in Pakistan) and requires new bolts, washers and fasteners (which the customer doesnt want to buy in Pakistan)

[pwuser149950754995]

Yes, the mechanic has the fuel pump pressure gauge and i saw the reading myself, so, not solely depending upon the mechanic. It stuck around 39 - 41 once the they stopped giving the pressure, not sure if the gauge was of good quality or not. Plugs got already changed so i don't think they are creating the fault. I too think the injectors here are at fault but I read somewhere that if your injectors are faulty or something, engine sign comes on but my car is giving no engine sign. I got it checked from various electricians and mechanics and some of them deal with insurance companies too(big names).

Btw, how to check or really know if wiring is faulty as one of them said that your wires may be at fault. The only confusion I have is why car worked perfectly for a day after changing the fuel pump regulator and the issue came back afterwards

[salman108]

Please first understand the problem.
The fuel pump's job is to pump in fuel and maintain a certain pressure in the fuel distribution line.
The excessive pressure is relieved via the fuel return valve.

Now, a few things can happen that can go wrong here.
a. The fuel return valve is not functioning well; and thus the fuel pressure is not maintained properly.
b. The injector(s) are leaking thus the fuel pressure doesn't maintain.

a is more likely than b.

if one or more injectors are leaking, then have a look at the plugs, excessive fuel will leave behind excessive carbon.
Also, can you tell me, when you start in the morning,, does it take 2 attempts ? and once the car is warned up, you shut it and start again within a minute, and half a minute, does it start properly ?
If it starts properly after warm up, then it is almost definitely a problem of the fuel return valve.

Do this step first please, and then we will talk about more complex stuff.
regards.

[pwuser149950754995]

does it take 2 attempts ? and once the car is warned up, you shut it and start again within a minute, and half a minute, does it start properly ?

Yes, but how come the fuel pump pressure is correct than and after changing its regulator it worked correctly for a day. I will go to another mechanic tomorrow and will share your perspective with him.

Thanks for your support

[pwuser149950754995]

Just a quick update for anyone who might need help, changing the injectors did the trick for me.

[Xulfiqar]

you had a leaky injector? did your mechanic verify this or just replaced them on "tukka"?

[salman108]

Please try and understand.
The fuel pump's job is to maintain a certain fuel pressure in the fuel rail.

If the injector is leaking, or the fuel return valve is faulty, then the pressure drops,
and you start the car, it takes 1/2 attempts to build up the pressure again.

When you will open the plugs, you will notice one plug that has more carbon than others.
that maybe the injector leaking.

If not then it is the fuel return valve that needs changing.

regards.

[pwuser149950754995]

TBH, he replaced them on "Tukka" i would say as he said after fuel pump the only culprit left is the fuel injectors. Though, I'm pretty sure he couldn't find corolla 1300 cc injectors and put some other fuel kabli injector (mine original was blue and after a lot of searching and back & forth he came up with some yellowish fuel injectors). Anyhow, my car is working fine except average dropped by 1 - 1.5 / per km which is fine with me as i don't use this car on long and barely drives it 30 - 40 km/day as long as car keeps running fine.

[helper_learner]

Yellow and blue injectors are different.

@Hassan1991

[Hassan1991]

Yes. Many specs can be different.
Like cc, impedance, dwell time, resistance, flow rate, and even flow pattern.
Fuel maps got injector tables filled according to specs.

[pwuser149950754995]

is it something to be worried about ?

[Hassan1991]

Log the fuel trims in different driving states if they are in range then it's okay, nonetheless i will still suggest oem injectors.