borz170

I have a '94 4runner SR5 that has developed a problem starting. It starts up fine at a cold start, but the problem occurs after the engine warms up. If I drive until the engine is warm, stop at the jiffy store for 5 minutes, the engine will start up quickly. If I stop for longer than 15-30 minutes after the engine has reached operating temperature, it will have a difficult time starting. In this situation, I try to remember to turn the key to the run position, wait 5 seconds, turn off and repeat 2-3 times prior to attempting a start. This usually results in a quick start, but rarely a smooth start. The engine will stumble before smoothing out after a second or two. It will then run fine at all speeds.

I have changed the wires, plugs, cap and rotor. The fuel filter has less than 5k miles on it. The K&N air filter has just been cleaned with no help starting (although the engine sounds stronger). I have no check engine lights on. I was thinking it could be the fuel pump, but I don't want to change parts for no reason. I have been told that it could be the air sensor that is connected to the air filter box(forgive me, I don't know the exact name).

I was hoping someone had some experience with this problem and could point me in the right direction. I plan to check the fuel pressure, as well as clean the sensor I mentioned above. It almost feels like the engine is losing its fuel prime, like there is a small leak in the line. There is no smell of gas though, and I know that the fuel filter is tight.

Thoughts?

yoterr

do you have a 3vze or 22re? might be a bad cold start injection (letting to much fuel in when warm??) or like you said the AFM (Air Flow Meter)

borz170

Thanks fort the reply. It is the 3.0. Is the cold start injection a hard part to chjange/diagnose? What would you do if you were in my shoes at this point, other than cleaning the AFM?

Borz

abecedarian

The CSI is not particularly hard to troubleshoot.
Disconnect the electrical harness from it then connect a voltmeter or test light across the two wires in the harness and have someone turn the key to start the engine. There should be power on the plug only while cranking the engine and the coolant temp is below approximately 60-65F.
-- Voltage when not cranking and < 60-65F implies ignition switch or related wiring issue.
-- Voltage when not cranking and > 65F implies ignition switch or related wiring issue AND cold start injector time switch issue.
-- Voltage when cranking and > 65F implies cold start injector time switch issue.
If everything's fine with the harness / voltages, next thing you'll need to do is get the cold start injector out of the intake manifold, turn the key to on and put a jumper between the FP and B+ terminals of the diagnostic check connector (to turn the fuel pump on) and check the cold start injector for fuel leaking. If it leaks, you may be able to clean it otherwise you'll need to replace it. If it doesn't leak... something else is going on.

borz170

Thanks, I am going to get to work. This has been very helpfull.

borz170

[quote=
-- Voltage when cranking and > 65F implies cold start .[/quote]

I performed the diagnostics and found that I do have voltage in the above situation. From what you wrote before, I am lead to believe that I have a faulty cold start injector timing switch. The problem I have now rests in finding the faulty switch. I followed wiring harness that connects to the CSI. It seems to run under the intake manifold to the main wiring harness, toward the distributor, then down toward the oil pan? This could be all wrong though. I need help locating the faulty switch.

Thoughts?

Thanks in advance!

mmcpeck

Anybody have an answer to this?

I am having the exact same problem on the same engine. Very hard start and long cranking when it has sat longer than say 20 minutes after reaching operating temp.

I am going to do the above diagnostic procedure, but can somebody say where the CSI time switch is?

Thanks.

borz170

I read a manual at Advanced Auto Parts and it stated the CSI timing switch is located in the thermostat housing, but If I recall correctly, the waterpump covers the thermostat, it's housing and probably the CSI timing switch. In order to replace this switch, I will have to pull the timing cover and everything (including the intike manifold/radiator, fan, etc) in order to get to it. Can anyone confirm this?