Diego toyota

Happy new year to everyone. Well gentlemen, I'm starting the new year with new issues, but I luv my 91 22re, it's still taking me places, or should I say distance. Ok then. This is it. I am now questioning my self if it's a cold start issue.
The reason I tested and changed the cold start injector, and cold start injector switch was because my 91 toy had to turn over a couple of times before starting. It might not start on the 1st or 2nd swing but never go beyond the 3rd before it starts. I am somewhat familiar with how these switches work, and how to test them.
My question is, and why I doubt myself is, I drove the Toyota for 200 miles non stop, when I decided to full up on gas, thinking it would start right up because it was hot enough, it would do the same thing,turn over 1,twice before starting. Am I looking in the wrong place where the issue lies? Can someone help me? thanks.
By the way, I am in Tennessee, and as cold as It was, 20 degrees it started right up on the 1st turn. When it was 90 degrees it took 1,2 but always starts on the 3rd swing. What should I be looking for. Thanks for the help.

scope103

A possibility is the check valve in the fuel pump, and the power of the fuel pump. When you shut off, the check valve in the fuel pump will hold up the fuel rail pressure for a few minutes. (The spec is "above 21psi for 5 minutes." http://web.archive.org/web/201003261...87fuelpump.pdf Mine only makes it to about 3 minutes.) When you restart in that time frame, the pump only needs to raise the fuel pressure a bit to get it to start. Unless the check valve goes south.

But you probably can't fill up on gas (and candy bars and sodas) in 5 minutes anyway. Then the fuel pump has to bring the rail pressure up from (near) zero. If your pump is "weak" but otherwise can do the job, it may take longer to re-pressurize the rail.

Personally, I wouldn't put much effort into this, unless the re-start time starts getting longer. You can probably test it directly with a fuel pressure gauge. You might want to run the pump with the jumper (to take the injector load out of the equation). At the same time, you need to get a sense for how little fuel pressure it takes to get the truck to start; it's less than you might think.

Co_94_PU

iTrader: (-1)

Whomp, whomp, vroom! Really wouldn't concern me personally.

Saggy battery, bad wires, lose or dirty connections. There is a minimum RPM required, but I can't find the specs. Opening the throttle plate tends to make the engine spin easier.

There is also from memory a sync required of the Ne signal that takes one full revolution.

RAD4Runner

+1

Even brand-spanking new CSI and CSI timer switch would not work WELL IF the switch does not get ground. It gets its ground from the thread on the block where CSI timer switch screws into. On later models, I think the ECU also grounds negative side of the CSI, IF it thinks it's cold enough. All of the above means, all temp sensors and mountings should be cleaned thoroughly. This is very easy and quick to do and if done at least once every 30 years (LOL!), you eliminate doubts on temp sensing.





THIS IS TOO OFTEN OVERLOOKED
CSI Timer Switch gets its ground from the block through this thread. No ground = No Go... Clean to bare, shiny metal with battery terminal steel brush. Do not use insulating teflon tape...




In order to monitor fuel pressure and eliminate doubt on the check valve, other members and I installed fuel pressure gage piggybacked on CSI

L5wolvesf

This is what I was thinking re the battery etc.

ChinkTruck

Have you by chance recently replaced spark plugs with the "platinum" variety? I had this issue when i purchased some of these. One turn and VROOM! was concerned with hard starting so I went back to factory spec plugs. Turns out the hotter plugs caused this for me, given my truck was a carb so I dont have any insight on the electrical aspects for you.

Diego toyota

It's a brand new fuel pump I installed 3 months back. I'll test it over the weekend thanks.

wyoming9

iTrader: (1)

Maybe I am looking at this wrong

Do you need to crank the engine 3 times before it starts??

The engine rotates 3 times on the first crank before starting ?? Which is not to shabby !!

coryc85

I'm not 100% certain what the OP means, but from my perspective he must mean that he turns the key to start, engine cranks but does not start, he releases key, turns key to start for second time, engine cranks but does not start, and releases key, and then does it all over again for third time and engine starts. Otherwise, if he literally means the engine only needs to turn over 3 times on the first key turn to start, then I don't think there is a problem.

Diego toyota

i need to crank it 2, some times 3 for it to start.

Diego toyota

you got it!

Co_94_PU

iTrader: (-1)

FSM ~90
Eg1-192, circuit opening relay

Try bypassing it, jumper "FP" to "B+" at the diagnostic port. It doesn't isolate it to the COR but it will isolate to the startup fuel system

Diego toyota

by jumping it, what will it do exactly?

Co_94_PU

iTrader: (-1)

bypasses the circuit opening relay.. or hot wires to fuel pump to run as long as the key is on.

Do NOT drive the vehicle while the pump is hot wires, if something goes wrong it's a very dangerous fire risk!

It bares repeating. Do not drive it like this, you are not just risking harm to you but people around you, first responders and my loved ones..

OK now here is how the system works.

When you turn the key to the start position the COR (circuit opening relay) closes the circuit and provides power to the fuel pump. When you release the key back to the run position if the engine is running the switch inside the VAFM takes over and holds the relay circuit closed and continues to provide power for the pump until it no longer senses air entering the engine.

​​​​​​So if this part is faulty you don't get reliable power to the pump during cranking. You'll get intermittent power provided by the air flow meter switch which makes the fuel pressure take longer to reach the level required, requiring you to flip the switch between start and run repeatedly before there is adequate fuel to start.

magnet18

Heads up that link is bad

Co_94_PU

iTrader: (-1)

Its part of the internet usage license testing, did you pass or do we sent over the goons to confiscate your electronics..

Link for piggy back.

RAD4Runner

LOL! Edit link in original post, too