If the regulator is stuck open, it just pours fuel down the return line, right back into the tank, with no or low fuel pressure.

 

..and maximum pressure when it's closed -- no vacuum to diaphragm; what you should get when starting.

Thank you for posting your fix.

 

They told me that it probably wouldn't be the injector because that doesn't kick on until it gets below 32 degrees outside.

Can any of the experts confirm or deny this?

I was about to replace my cold start valve because my truck is hard to or impossible start when it's cool or raining outside, it would sputter/buck progressively with the amount of throttle(becoming more and more lean), then ran perfectly soon as it was warm(after about almost 3 miles), as if a switch was flipped now I don't know if I should replace that or the FPR.

 

Before you can properly diagnose a problem you need to have at least a decent understanding of how what ever it is works.

The cold start injector most certainly works at temperatures above 32deg. The cold start injector time switch provides a ground circuit for the injector that allows the injector to spray fuel during cranking to help start the engine. The time it allows the fuel to spray is based on what the temperature is. So if it is 32deg it will spray longer than if it is 100deg. But it still only sprays while you are cranking the engine. As soon as the key moves to the run position there is no longer a power supply to the injector.

The fuel pressure regulator is a spring loaded valve that allows fuel to return to the tank once the set pressure is reached. It has a diaphram that is linked to the intake manifold with a vacuum line so the the pressure drop across the injector is always the same regardless of the pressure in the intake manifold. measuring the fuel pressure will show quickly if it has a problem. you should get proper furel pressure almost immediatly after you start to crank the engine and when you turn it off it should hold pressure without dropping for at least 10min.

 

Does that mean neither one of those are the problem, since it continues to not get fuel when it fires up, eleminating the cold start valve as the problem? Or is there a reason a failing FPR would not give enough fuel when the engine is cold but work perfectly with a warm engine?

 

Hold it< hold it< hold it!!!!

HOLD IT EVERYBODY!!!!!!!!!!!
I wasent going to post a reply on this but after i saw brandon3155s post, i had to. Well about 2 weeks ago when i though everything was fixed IT WASENT!!!! After replacing the FPR, AFM, Temp sensor, fuel filter, checking for codes, replacing the coil, replacing the spark plugs back to factory spec ones, checking vacuum switches, checked distributor, checked idle speed, check EGR system, checked the cold start time switch and valve itself (ohm tested only) and lots more. I even went up to Toyota numerous time for advise, pretty much did everything you could possibly do to no avail. I was about ready to toss in the towel when i had an accident. While i was painting the frame of my truck i noticed a small amount of coolant dripping from the from differential. I finished what i was doing and followed the trail of coolant to a coolant return hose (the metal one that wraps behind the engine) that connects underneath the intake manifold and is held with two 10mm bolts. About 5 months prior to that, i replaced the head gasket so i was very familiar with what each part was for and where it went, i remember cleaning the metal pipe prior to installing the new gasket and second guessing myself on whether the gasket mating surface was clean enough, so to be sure i put this gasket sealer stuff on it to be sure it dosent leak. Well it started leaking. I figured this isent to bad, just drain some coolant, take out the bolts, replace the gasket. Nope i couldn't be that easy, when trying to take the bolts out, both bolts snapped off in the intake manifold, so now i had to pull the ENTIRE intake assembly to extract the bolts. (THIS IS WHERE IT GETS INTERESTING)!!!! I started to dissasembe the everything off the intake plenum when it got time to remove the cold start injector. When i pulled it out i noticed a drop of gas at the tip of if, dident think much of it. I got everything off and pulled the plenum off the runners. When i pulled it off what i saw shocked me, there was a puddle of gas in every on of the runners. I panicked, thinking it was all of my primary injectors leaking at once, then i tought to myself how common is it for all four injectors to fail at the same time? So i called a shop to get an opinion, it just so hapend that the guy i was talking to was an expert on the 22re and told me its very rare for all four to fail at once and that if i even had one injector fail it would be causing drivability issues (which i dident, only starting issues) he also added that the injectors on my engine are pretty reliable and he has never seen injectors on a 22re engine ever have to be replaced. He said its my cold start valve and that alot of 22re engines have this problem. He told me that the valve would get weak over time and start to leak constantly because even when you shut the engine off you still have 40psi of fuel pressure in the lines. That combined with a leaking valve = starting problems and flooding out. Finally i thought to myself, so i got the bolts extracted, put a new gasket in, put everything back together and my test drive was up to Autozone to pick up a cold start injector. In stalled it and to this day, my intermittent starting / flooding problems have not been back. Its weird but i think if i hadent have sheared those bolts off, i probably would have never found the starting issue. Its ashame i had to go through all that trouble but looking back on it now i like to think i fixed two problem at once. Brandon 3155, REPLACE THAT F!$#ING COLD START INJECTOR IF IT HASENT BEEN REPLACED BEFORE!!!!!!!!!!!!!!!

 

HOLD IT EVERYBODY!!!!!!!!!!!
I wasent going to post a reply on this but after i saw brandon3155s post, i had to. Well about 2 weeks ago when i though everything was fixed IT WASENT!!!! After replacing the FPR, AFM, Temp sensor, fuel filter, checking for codes, replacing the coil, replacing the spark plugs back to factory spec ones, checking vacuum switches, checked distributor, checked idle speed, check EGR system, checked the cold start time switch and valve itself (ohm tested only) and lots more. I even went up to Toyota numerous time for advise, pretty much did everything you could possibly do to no avail. I was about ready to toss in the towel when i had an accident. While i was painting the frame of my truck i noticed a small amount of coolant dripping from the from differential. I finished what i was doing and followed the trail of coolant to a coolant return hose (the metal one that wraps behind the engine) that connects underneath the intake manifold and is held with two 10mm bolts. About 5 months prior to that, i replaced the head gasket so i was very familiar with what each part was for and where it went, i remember cleaning the metal pipe prior to installing the new gasket and second guessing myself on whether the gasket mating surface was clean enough, so to be sure i put this gasket sealer stuff on it to be sure it dosent leak. Well it started leaking. I figured this isent to bad, just drain some coolant, take out the bolts, replace the gasket. Nope i couldn't be that easy, when trying to take the bolts out, both bolts snapped off in the intake manifold, so now i had to pull the ENTIRE intake assembly to extract the bolts. (THIS IS WHERE IT GETS INTERESTING)!!!! I started to dissasembe the everything off the intake plenum when it got time to remove the cold start injector. When i pulled it out i noticed a drop of gas at the tip of if, dident think much of it. I got everything off and pulled the plenum off the runners. When i pulled it off what i saw shocked me, there was a puddle of gas in every on of the runners. I panicked, thinking it was all of my primary injectors leaking at once, then i tought to myself how common is it for all four injectors to fail at the same time? So i called a shop to get an opinion, it just so hapend that the guy i was talking to was an expert on the 22re and told me its very rare for all four to fail at once and that if i even had one injector fail it would be causing drivability issues (which i dident, only starting issues) he also added that the injectors on my engine are pretty reliable and he has never seen injectors on a 22re engine ever have to be replaced. He said its my cold start valve and that alot of 22re engines have this problem. He told me that the valve would get weak over time and start to leak constantly because even when you shut the engine off you still have 40psi of fuel pressure in the lines. That combined with a leaking valve = starting problems and flooding out. Finally i thought to myself, so i got the bolts extracted, put a new gasket in, put everything back together and my test drive was up to Autozone to pick up a cold start injector. In stalled it and to this day, my intermittent starting / flooding problems have not been back. Its weird but i think if i hadent have sheared those bolts off, i probably would have never found the starting issue. Its ashame i had to go through all that trouble but looking back on it now i like to think i fixed two problem at once. Brandon 3155, REPLACE THAT F!$#ING COLD START INJECTOR IF IT HASENT BEEN REPLACED BEFORE!!!!!!!!!!!!!!!

O and i almost forgot, my truck had been sitting in the garage for 2 days without being started before i started the disassembley of the intake. So if i hadent of had to do my unexpected repair, it probably would have given me a hard time starting with as much fuel that was in each runner.

 

Ah, so when its warm and sunny out with truck being black, the fuel evaporates out of the intake runners, otherwise it floods, brilliant!

Also explains why it will eventually start with a lot of cranking even there is no more heat produced (at least around the cold start valve.)

But..... Would the pool of fuel be there for almost 3 miles, and cause what seems to be a lean condition with the engine bogging and bucking with more throttle?

I have ordered it and am going to replace it anyways. I'll let everyone know what happens.

 

I'm having a problem that's close to what you have and I am thinking it's my fuel pressure regulator; I just want some other opinions/ideas.

A few days ago I had another load of stuff in my truck headed to my storage unit, I pulled in the entrance and my truck developed a miss. I parked next to my unit and opened the hood and I could hear the miss and see the motor shaking a bit from it as well. I give it some throttle and it went away but I heard a ticking(sounded like a valve.) I unloaded the truck and started it up and everything was normal, and was until today; now when I start my truck cold everything it fine, but if it's at opertional temp and I start it it has a mis-fire, but if I give it a little throttle it goes away. But the ticking is always there; I am thinking it's the FPR becuase I hear the ticking coming from the left bank of cylinders(3.0 V6) toward the front of the motor; I grabbed my 12" 3/8 extension and used it as a makeshift stethascope and I there was no noise coming from the valve cover, I put the end on the injector(I believe that's #2) and I can hear the ticking, I put the extension on the FPR and it's louder than the injector. I can also feel the ticking when I put my finger on the FPR, but when I put them on the injector I cannot feel anything...

Any Ideas?

 

Well sorry to say, but im not familiar with the 3.0Ls. I dont think the FPR is suppose to tick as its not an injector and is only operated by engine vacuum. Beings that it only does this when its at operating temp, im leaning toward an ignition problem. When it starts to miss, try pulling spark plug wires one at a time until you pull the wire that has no effect on the engine, thats your dead cylinder. Example: Start you truck and let it warm up, when it starts to miss pull number one spark plug wire, if there is a change in engine performance, it stalls or it starts to really go crazy that means that isent the cylinder causing the problem, reinstall the wire and restart the engine if it stalled, continue this procedure until you pull a wire and there is no difference in engine performance then you have found your dead cylinder.

If you pull all the wires and nothing happens then its a fuel issue or an injector issue. Also be sure there are no codes(check engine lights)
This dosent sound like a FPR issue nor a Cold Start Injector.

 

89 3.0 won't stay running

Ok so one day when it was cold I started my truck and it reved high like it was in the warm up mode. Well I was in a hurry and took off and went a mile down the road.. I stopped and through some trash not a dumpster while the truck was running. I returned to the truck and put it in gear and it died.. I tried restarting it and it cranked for a long time and finally started and shuttered really bad and would die as soon as o put it in gear. Well that went on for a few minutes and then it would start and run beautifully for about 4 seconds then die like someone turned the fuel pump off.. So the next few days Ibought and took back a ton of parts and nothing worked.. Fuel pressure regulator, circuit opening relay you name it I bought it.. And to no avail. So.. I had a friend who said hey I had that same motor.. And a mechanic told him to put a piece of wire about 3 inches long into a horseshoe shape and open up the diagnostic box under the hood on the passenger side and put one end in the terminal marked (e) and the other end in the terminal marked (fp) so I did.. And it started and red fine.. The only difference I can notice is that sometimes when starting it, it cranks for two seconds then starts.. But that's only sometimes.. So my question is WHAT EXACTLY IS THATS PIECE OF WIRE DOING THATS MY TRUCK ISNT.. WHAT CAN I REPLACE THAT WILL ELIMINATE MY HAVING TO BASICALLY HOTWIRE THE FUEL PUMP?? Someone please help!!!!!!!

 

It bypasses the circuit opening relay and the switch in the MAF. Those 2 switches need to be closed for the pump to work. Otherwise for trouble shooting you short the +B and FP for diagnosis. You may have corroded wire contacts at the COR or through the MAF. Did you replace the MAF?
Shorting +B and FP takes those 2 switches out of the system and put voltage directly to the pump, so if it starts then you either have a wire problem or one of the switches is bad, or both may be bad.

 

Bro every single person on 2 forums think it's a gas problem. The problem is electrical. When you get the trd fully loaded they add accessories and the cut freaking wires. You must always saughter your wires. The problem in all yalls trucks everyone of the hesitate start is the starter kill relay. 28 bucks. The guy I watched said just cut it out and tie back all the wires you feel like. It's under steering column. The diode burns on it.

 

Just waking up this old thread to share my story hoping it helps someone. 2 Toyota sites have kept my 1st gen '87 4runner on the road for 20 years, with only 270,000 on it so far. I've lived in Alaska for 45yrs, like those Wis and Min and NY and Maine people I've seen a lot of cold. Never have I had to use either to start my 22re, NEVER! Until 1 fine frozen day. These 2 sites, through hrs of learning taught me the cold start solenoid. Front of motor on the left are 2 plugs with wires going in. I don't remember which it was but a 13/16th wrench was what I had, bumped it with the heel of my hand, unscrewed it [few ounces of coolant leaked] and there was a long brass looking plug. $192 for that. This site and the other one said to shine it up with 600 grit emery. I screwed this now shiny brass looking thing back in and have NEVER had to use either again. Coolant starts dulling the surface to the point it doesn't know it's cold and send the signal to the cold start injector. May not be on topic for this thread but it might be worth a try if is somebody stuck. Through my 20 years I've learned a lot of tricks here, Thank You to those that post and I hope this helps.

 

I have a '96 Toyota Tacoma. The battery is turning the starter but it won't crank and no matter how much gas I put in the tank, it registers empty.

Charles

 

Well, after doing a lot of thinking i finally figured out my OUT OF THE BLUE HARD STARTING. It was my Fuel Pressure Regulator. At first i thought it was my ignition coil because the hard starting was intermittent and i ran a test on it and the Primary Resistance was way off spec, but the Secondary Resistance was spot on. So beings that it was out of spec i would replace it anyway even if it wasn't the cause of the problem. Well i replaced it and the problem was still there, so i knew it couldn't be an ignition problem, it had to be fuel related. Its just a shame i had to blow $50.00 on a part that wasn't the problem, but it was out of spec so no real loss. I then thought it was the fuel pump, but that couldn't be because as soon as it would start it ran perfect. It just gave me a hard time during the initial start up. So then it was down to the cold start injector and FPR. I went to Toyota to get a second opinion and more information about the cold start injector. They told me that it probably wouldn't be the injector because that dosent kick on until it gets below 32 degrees outside. That being said i knew it had to be true because before i left to go to toyota i started my truck up cold and unplugged the injector and there was no change in the idle speed. So now i was pretty confident that it was the FPR to blame. I went up to Autozone and picked on up. Let me tell you i was sticker shocked when he told me it was $70.00 for that little thing. Well i took a risk and bought it, installed it and presto. It fires up without hesitation every time. I think what was happening was that the Regulator was stuck open all the time and when it came time to start it when cold or warm, the engine was getting way to much fuel and thus it flooding out.

Thanks you guys sooo much for posting this issue and the fix...!! I also had identical issue on my 93 Toyota tacoma. Starting up flooded. Replaced the fuel pressure regulator. That indeed fixed it..! You guys saved me untold number of troubleshooting hours and... $$$$