I have a 2001 PoorRunner with a 3.4. I experience hard starting due to flooding, caused by leaking injector(s). This is according to two different Toyota mechanics. The thing is, I have sent the injectors out for leak testing, and there were no leaks detected. These were refurbished OEM injectors I purchased on Ebay. This is the second set of injectors that are leaking that I have tried. My only possible hunch is that there is something wrong with the wiring or the ECM that is telling and injector to stay open after the vehicle is turned off?? The mechanic says my fuel pressure regulator is testing out fine. Whant should I try next?

 

The poor 4Runner, so 2 Toyota Mechanics said the old and the new injectors where leaking causing flooding in every cylinder, ok, but these are the 2nd set new tested injectors, i assume the same Mechanic told you the fuel pressure regulator was ok, something is a miss here, maybe they don't like you at the shop you are visiting, or maybe they are so busy working on a hundred different cars a week that they just say what they think not digging into it further. How long have you owned this 4R, I would check some basics, maybe toss a FPR in, check plugs are correct style, wires, coils, fuel filter, fuel pressure, fuel pump, Battery terminals and associated wiring, test Battery, check OBD system, take a peek at the ECU for water damage. Not all Toyota Mechanics are created equal, and some don't give a ˟˟˟˟ about 20 year old 4R's, let alone offer sound tested diagnostic advice to customers.

 

Thanks for your response. It is definitely flooding out after it sits. Not sure if it is ALL the cylinders. If it just sits for 30 minutes, no flooding; if it sits for longer, flooding; if it sits overnight, no flooding, because I assume that the gas that trickled into the combustion chamber had time to evaporate, etc. overnight. Here is what I have tried replacing so far. FYI, no failure codes on the scanner are ever noted. Fuel pressure check performed, and it points to pressure loss out of injectors. Could something in the wiring be telling the injectors to stay open after the vehicle is shut off? I will check the ECU; cranking amps are more than plenty. I don't know what an FPR is.

REPLACED SO FAR:
1) Coil packs
2) Spark plugs
3) Spark plug wires
4) Air cleaner
5) Fuel filter
6) MAF sensor
7) Vapor canister purge solenoid
8) Replaced used throttle body off a known running vehicle, thinking that it could be the throttle position sensor.
9) I was going to investigate the cold start injector, but I don't think it has one.

 

If the old injectors and new injectors were tested good by your refurbisher, they're probably fine. FPR is the fuel pressure regulator. Pull the vacuum hose off of it and see if its wet with gas. If it is, replace it. Try isolating the leak. Put a pressure gauge on it. Using a pair of needle nose vice grips with some fuel line on the end pinch off the fuel return line. If pressure holds, its the FPR. If not pinch off the feed line. If pressure holds now, its the check valve in the pump. If it still doesn't hold, pinch of the both of them. It could be a combination of the two. If it still doesn't hold then its either the FPR leaking into the vacuum line or injectors. This info is only valid if there isn't an external leak of course.

 

Thanks, I will definitely try those suggestions. So, if I am leaking fuel from any of the other areas that you are suggesting (and I am not pouring fuel into the combustion chambers from the injectors themselves, as what the dealership thought), would your other potential leaking areas also cause my hard-starting issues? Remember that I have good starting after the vehicle is shut down for no longer than 30 minutes; and hard starting if the vehicle sits turned off between 45 minutes and 5 hours; and good starting after the vehicle sits for longer than 5 hours (the presumption again was that, after the car sits turned off for longer than 5 hours, the leaking fuel has eventually all evaporated or migrated somewhere else, and thereby eliminating the hard-starting issues.). Thanks

 

If the FPR is leaking through the vacuum line, then yes, it will flood the engine. The other places no they won't flood it, however, these test will determine if the hard start is even actually caused by flooding. It may be an entirely different problem.

 

Thanks. I will try to figure out what type of leak-tester to use, and give it a try this weekend.

 

You said you already checked fuel pressure? The same gauge used for that is what you will use for isolating the leak.

 

The clowns at the Toyota dealership checked it. I don't know anyone in my town who has a fuel pressure gauge with a fitting that attaches to these old-skool banjo fittings on my fuel rail, but I will figure something out. Thanks.