LT1UltraZ

It fires right up when cold. After it warms up it takes a while to fire up (takes about 10-15 sec or so to catch) and when it does , the idle is rough and low. Clears right up after bliping the throttle. Jumping the fuel test connector and leaving the pump running for few seconds before trying to start has no effect. I can hear the pump humming, so it comes on fine. The COR clicks just fine as well.


Last weekend i went to a friend of mine that has a 85 4runner that cranks right up hot or cold and we switched all the usual "fixes: for the condition i am experiencing.

1. Coil/Igniter
2. cold injector switch
3. coolant switch
4. AFM
5. ECM
6. Injector solenoid
7. EFI fuse
8. COR
9...i have put in a brand new pump


non of it helped....all the parts of my truck were put on my friends and it continued to start right up....


Timing is set at 5 with the jumper in.
New plugs
new wires
new distributor cap/rotor
new fuel filter
fuel pump has been changed by previous owner.



i am out of ides...other then the starting problem, truck runs great.

updates:

cold start injector is not stuck nor it is firing when engine is warm.

cold start injector is firing fine in the morning ( 55 degrees outside)

annoyingrob

So you're SURE that the cold start injector is NOT firing when hot? Like if you un-plug it, the truck still stumbles a and is hard to start when hot?

xcfunrunner

When you say it takes 10-15 seconds to catch, do you mean for the starter to catch? Or do you mean that it takes 10-15 seconds of cranking until it fires up?

LT1UltraZ

yes, i am positive the cold injector inst firing. I cranked the truck for good 15 sec and pulled the plugs out and they were dry?

i would think they would be wet if the injector was stuck open?

LT1UltraZ

it takes 10-15 sec for it to fire...starter is spinning just fine.

LT1UltraZ

truck is warm in this video

[YOUTUBE]GKXZNlfBxiE[/YOUTUBE]



here is another one right after turning it off


[YOUTUBE]ZzCy_YjIbnk[/YOUTUBE]

ill add the cold start up video once the truck cools off

toastyjosh

iTrader: (1)

Does it start with starting fluid?

crawler85

i am having the same issue.

fires right up when cold.

when warm, if i turn it off and immediately and try to turn it back on, it will crank but not start.

if i wait a few minutes, it will start right up.

i will post if i figure mine out.

LT1UltraZ

just to be sure i pulled the injector out of the manifold and hooked a clear hose to it so i could see if it was squirting fuel. Cranked the truck up few times and there is 0 fuel coming out of it.

LT1UltraZ

should the COLD start injector be firing when the engine is warm?
at what temp does the cold start switch engage the injector?


also i can get it started quicker when its warm by turning it off/on about 3 times....what i mean by that is, crank it for a sec, turn the key off, crank it for a sec, key off and usually on the 3rd try it will start to catch and with little bit of gas pedal moderation it will start and run rough until i blip the throttle.

crawler85

CSI switch should read 40-60 ohms when at operating temp (above 40C 104F). if it is in that range, it will not fire the CSI.

my problem has disappeared for now. it fires right up every time when warm.

i had an EFI main relay out of specs.

Replaced that ($12 from dealer) and threw in a used TPS (for a different problem) and my problem solved itself.

Pull your EFI main relay under the driver side panel, see if it reads 60-80 ohms

between the two pins (top and bottom) on the right (pg. FI-64 on FSM). the two on the left should be infinite.

crawler85

check your resistance on the coolant temp sensor that sits next to the CSI switch.

there is graph in the FSM. you should see roughly 1.5k ohms at 70F, and it should increase as the engine gets hotter. should be roughly less than 200 ohms when at operating temp (100Fand above).

LT1UltraZ

coolant sensor is fine....

EFI relay checks out fine too...69.7 ohms

snobdds

Well the blue VSV on top of the valve cover is specifically designed for start-up when the engine is hot. It keeps the gas in the fuel rail from boiling by adding pressure to increase the boiling point. It's operated off of manifold vaccume.

It connects from manifold vaccume to the VSV to the fuel pressure regulator.

The problem has become Toyota has stopped making them, at least for my 88 I know for sure. The only part on mine that has broken off is the little black filter, but it still operates. There is a way to by-pass it by just running a vaccume line from manifold vaccume directly to the port on top of the fuel pressure regulator. You will just have higher fuel rail pressure, but no harm. Your cold starts will be the same due to the cold start injector.

When mine finally breaks, this is how I will by-pass it...

crawler85

jumper the fuel pump test plug on the driver side under the hood, so it starts sending fuel immediately when the ignition is on (as opposed to when it senses air going through the AFM).

perhaps the fuel pump is always a little late in turning on, and the CSI is "filling the gap" of no fuel when the engine starts up cold.

LT1UltraZ

already tried that

LT1UltraZ

just went out and tried it...didnt help

crawler85

did you verify your tps is good and adjusted?

seems like a stretch but that was the other part that i swapped out that made the issue go away.

LT1UltraZ

actually i did...i readjusted mine yesterday and the truck idles much better..but it had no effect on the starting issue

i really have no idea what else could it be...i guess the only thing left is the fuel pump.

what were your EFI relay readings?

i am going to my buddies this weekend again and i am going to swap the COR and the EFI fuse with him....after that i guess it's time to pull the fuel pump?

snobdds

So you bypassed the blue VSV and ran a new piece of 3mm vaccume tubing from the intake to the fuel pressure regulator? A new piece of 3mm vaccume tubing is not easy to find especially in that lenght and usually needs to be ordered off of the internet.

So...did you really by-pass it because if you did...you would have fixed your problem.