3.4 1999 hard starting, stumbling, and not wanting to rev

So I think I've figured out the issue.
I think the fuel pressure regulator is faulty.
I had to remove the Intake Silencer earlier and i noticed that it had gas in it! It may have this whole time and I just never tipped it all the way to have it spill out when removed! This means a bad FPR, correct?
So...I hope that I don't blow up or something while I order a new FPR.

Other question: should I go OEM (even used goes for like $60) or will an aftermarket be OK?

Like this:
Universal Red Adjustable Fuel Pressure Regulator Gauge JDM FPR 1 1 0 140 PSI | eBay
 
Is there a vacuum line running from the FPR to the air intake or throttle body? If yes double-check all hose routing to make sure a fuel or air hose wasn't accidentally switched around.

If not, then you migh have a bad FPR that is leaking and somehow feeding fuel into the throttle body or air cleaner and collecting. That's a ton a fuel though, since fuel evaporates quickly. I've never heard of that happening though.
 
gamefreakgc said:
Is there a vacuum line running from the FPR to the air intake or throttle body? If yes double-check all hose routing to make sure a fuel or air hose wasn't accidentally switched around.

If not, then you migh have a bad FPR that is leaking and somehow feeding fuel into the throttle body or air cleaner and collecting. That's a ton a fuel though, since fuel evaporates quickly. I've never heard of that happening though.
Click to expand...


I've never seen that particular failure mode either, but I don't know that I've ever looked for it. I usually just slap a gauge on it first thing and go from there.

Given the fact that there's really just a diaphragm or o-ring separating fuel from vacuum it's not hard to imagine that it could happen. This is generic diagram, but the regulator on our trucks works the same way.

faq_fpr_image021.jpg
 
gamefreakgc said:
Is there a vacuum line running from the FPR to the air intake or throttle body? If yes double-check all hose routing to make sure a fuel or air hose wasn't accidentally switched around.

If not, then you migh have a bad FPR that is leaking and somehow feeding fuel into the throttle body or air cleaner and collecting. That's a ton a fuel though, since fuel evaporates quickly. I've never heard of that happening though.
Click to expand...


Yeah, there's a line running from the top of the FPR directly to the front/driver side of the Air Intake Silencer. It's the line that has to be TEE'd to engine vacuum if I do the Intake Silencer Removal mod. Runs right under the intake plenum to the FPR. I was under the impression that this is stock.
I checked all the vacuum lines per the diagram on the inside of the hood of the truck (very useful) and everything looked good to me.
 
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Well, it's gotta be the FPR, I can't imagine anything else being wrong.

And yes, those diagrams are super helpful! Exept on the 3VZ-E engine... since there's about 30 vacuum hoses...

I recommend staying OEM though. That one you linked a few posts back looks like cheap china stuff. I bought a cheap china catch can a while back and it leaked air on every single joint on the whole thing.
 
gamefreakgc said:
Well, it's gotta be the FPR, I can't imagine anything else being wrong.

And yes, those diagrams are super helpful! Exept on the 3VZ-E engine... since there's about 30 vacuum hoses...

I recommend staying OEM though. That one you linked a few posts back looks like cheap china stuff. I bought a cheap china catch can a while back and it leaked air on every single joint on the whole thing.
Click to expand...

Neato. I ordered a used OEM off eBay for $40. It should be here Friday. This part usually doesn't go bad, so I feel rather safe getting a used one.

If you wanna get crazy with the vacuum hoses, look at a late model Jeep (Grand) Wagoneer. This was the last carbureted vehicle in America (with the exception of one Isuzu). I have a mid 80's model and it originally was just a giant spaghetti bowl. It really does look like someone just grabbed a pile of hoses and chucked it at the engine. I took most of the emission's stuff off for ease of use. If one hose broke/leaked on the original setup, it ran like duck crap. It's now back to the original mostly emissions free 60's/70's setup. I love Texas and their 25yo or older and no emissions inspection law.
 
AntleredRuin said:
Neato. I ordered a used OEM off eBay for $40. It should be here Friday. This part usually doesn't go bad, so I feel rather safe getting a used one.

If you wanna get crazy with the vacuum hoses, look at a late model Jeep (Grand) Wagoneer. This was the last carbureted vehicle in America (with the exception of one Isuzu). I have a mid 80's model and it originally was just a giant spaghetti bowl. It really does look like someone just grabbed a pile of hoses and chucked it at the engine. I took most of the emission's stuff off for ease of use. If one hose broke/leaked on the original setup, it ran like duck crap. It's now back to the original mostly emissions free 60's/70's setup. I love Texas and their 25yo or older and no emissions inspection law.
Click to expand...

Yeah, pretty much like that! And when you get a leak it takes FOREVER to find it.

When I got rid of my Pickup and got my current 4Runner I was overjoyed on how simple the engine was! I just laugh when people complain about the 5VZ-FE engine being hard to work on. :spit:
 
gamefreakgc said:
Yeah, pretty much like that! And when you get a leak it takes FOREVER to find it.

When I got rid of my Pickup and got my current 4Runner I was overjoyed on how simple the engine was! I just laugh when people complain about the 5VZ-FE engine being hard to work on. :spit:
Click to expand...
Seriously! They must not have worked on ANY engines before then! I do love the 2.0 on my '03 Rav4 though. Spark plugs are just about the easiest thing in the world to access. Simply open the air filter box to get the front out of the way and the 4 plugs are right there, smack dab center of the engine bay facing right at you. A drunken baby could change them. :lmao:
Of course, replacing the alternator on it was a PITA. Transverse engines.....
 
Ok so update finally! Don’t want to say for sure yet, but things look to be better (in a way; I’ll expand on that in a minute).
Got the FPR in the mail, and set out Saturday morning to remove the old one and replace with the new. I got the Air Intake baffle, TB, Top and Bottom air intake off pretty easily. Just a bit time consuming. I also managed to crack the driver’s side plastic wiring harness cover up pretty good, so I very carefully inspected and made sure to clean any plastic bits up. Stuffed small rags into the intake manifold to keep any crap out. So now I can see the old FPR at the back of the fuel rail on the driver’s side. I could not remove it directly from the fuel rail with the fuel rail in place on the manifold. The little 10mm bolts holding the FPR on were in there GOOD even with PB Blaster and WD-40. I could only access them with a small wrench, and could not apply that much pressure at that angle. I was starting to strip them, so I set about looking for how to remove the fuel rail.

After a bit of Googleing, I saw that you can remove the 4 bolts holding the fuel rail down and lift straight up. It came up, but in the process, I managed to break the front driver’s side fuel injector. CRAP. I lifted the injector up, and saw the small injector head sitting there in the hole. I tried to suction it up, but it would not work. I very carefully tried to pull it out with needle-nosed pliers…and pushed it into the intake manifold. Well, now I had to remove the intake as well to keep the injector out of the valves! After much cursing, I called around and found another injector close by.

I proceeded to remove the other injectors CAREFULLY to avoid breaking them as well. The fuel rail was loose, but still had the primary and return lines wrapping around and through wiring harness and like 4 different vacuum hoses. I was able to get the hoses out of the way, but I really didn’t want to remove the whole wiring if I could avoid it. So, I disconnected the main fuel line from its spot near the charcoal canister. I ended up having to cut the return fuel hose attaching straight to the FPR so I could get the fuel rail out of the engine bay. To remove the FPR from the rail, I had to sit to with the rail in my lap, and wrench at it with a 10mm socket on each bolt with a crescent wrench around the body to hold it in place. Those were honestly the hardest bolts/nuts for this entire project. Got the new FPR on, and now I needed about 6” of new fuel line to replace the bit I cut.

Well, to remove the intake, I had to drain the radiator of coolant. This needed to be done anyways, because I noticed when I bought it that it had orangeish green in it. I already had a bottle of non-diluted Toyota red ready to go.
I got radiator drained, and took the radiator hose and the top timing cover off to allow clearance for the intake manifold. I noticed that the Cam Sensor was very dirty so I sprayed it down with electrical contact cleaner, and then covered the timing belt area with a large towel to keep debris from getting in. I got the Intake manifold off, and found the tip of the injector just sitting there on one of the valves.
kbqdzs.jpg

I was very apprehensive about trying to reach in there to grab it; I didn’t know if my pliers were long enough. So I held a very bright LED light in my mouth and ‘started playing Operation’. And I did NOT make it buzz! Woohoo!

I had also bought a new PCV valve to replace the old brittle one, and of course manage to break the old one like crazy. Don’t worry, I had another towel covering the intake area. So, I removed the valve cover (after removing the spark plug coil packs.) and started fishing with a pair of pliers. After tilting the valve cover all over the place, I was able to get the old PCV out. I put the new gasket and valve in, applied some new RTV to keep the molded gasket in place, and put the valve cover back on.

Question- how loose are the valve covers supposed to be? These were so loose (all bolts) that I originally thought my socket was too big. When I reattached the cover, I tightened them, but not super tight. On the driver’s side too.
I got the new injector and bit of fuel line, as well has new O-rings for the current injectors. I was soaking the current injectors in gasoline to help clear any crap out.

I got everything patched back up, and was very relieved to see that I had not miss ONE bolt or hose. Haha. I also put some plastic wire loom cover over the driver’s side wire harness by the fuel rail for heat protection.
I filled the radiator back up with distilled water, and added to radiator cleaner. I started it up, and after about 5 seconds or cranking, it fired up! I ran the cleaner + water through until a couple minutes after the heater kicked on, then let it cool, drained the radiator of the roughly 1 gallon, and then topped it back off again with more distilled water. I kept an eye on the temp gauge, and it DID fluctuate a bit, but it never overheated.

I did this 5 times until the radiator was draining clear. Then, added the full 1 gallon of Toyota Red to the radiator. There was already roughly a gallon of pure distilled water already in the system, so this would make it about 50/50. This time, I was STUPID and forgot to top it off. I took it for a test drive around the neighborhood and noticed that the heater was not coming on. As I was at the back of the neighborhood, the temp gauge shot all the way up so I shut it off immediately. I had brought another gallon of distilled with me, so after about 5 minutes, I popped the radiator lid (with a rag just in case), and after 30 minutes or so after that, topped the radiator off with the distilled water. NOT cold; it’d been in my garage for a few weeks. It was hard to start this time, but the heater kicked on instantly, and the temp gauge leveled out to normal. I got home just fine, no more issues. After it cooled, I took it out for another test drive, not just in the neighborhood and no issues at all. No leaks, no significant noises, nothing. I changed the oil filter just in case, and ensured that the oil level was topped off.

NOW, today, I’m noticing something else. It starts up great, and revs a whole lot more easily, so the FPR fixed those issues (I hope), but now I’m hearing a bit of clatter in the engine when in park (around 1100 – 1400 rpm) that I did NOT hear yesterday even after the overheat incident. It does not have a pattern, but is regular. It stops when in moving gear (drive, reverse, etc) when the idle is lower, and I don't hear it when getting on the gas with the windows open. I don’t hear it in the cab, so it’s not SUPER loud, but I can hear it with the hood closed. What does a clattering fuel injector sound like? I made sure to install the new fuel injector in the front passenger side slot for ease of access if the injector was bad, so I can replace it if necessary. I don't have a stethoscope, but it sure sounds like its coming from the new injector. It almost sounds like clattering porcelain dishes like when you bang on the kitchen cabinet or something.

*update* Now, after driving back to the office from a client's, I made sure to drop into neutral and lower the windows at every full stop to raise the RPMs to see if I can hear the noise, and it is definitely decreased. I checked it when I got to the office. Put it in park, popped the hood. The noise is still there, but very irregular. Instead of several times a second, it's only every few seconds; still no pattern. Seems quieter when it's happening as well. Do fuel injectors have a break-in period?

Sorry for the novel.
 
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Lol, that reminds me of my first few attempts to work on the ol' Pickup. Broke as many things as I fixed. Hope I can help with some of your questions:

1. The injectors are set at an angle, so not surprised you broke one. Next time, get the right tools for the job (ratching wrench, 6 point or 12 point socket, etc.) and save yourself the headache. Trust me... it just makes things a whole lot easier. Toyota's are all metric so your tools should also be metric, not standard.

2. Valve covers should be loose, but not enough to leak. The bolts are to be at 6 lbs/ft or 72in/ft, per the FSM. Don't overtighten them, they will strip real easy. The gasket should be compressed but not smashed to bits, if that makes sense. Make sure the pressure is uniform and use Black RTV or FIPG material where directed or it may leak down the road. If you missed the FIPG don't sweat it unless it leaks.

3. Pull the EFI fuse and relay in the fuse box under the hood for a few minutes when off and then put them back in. The engine is getting more fuel than it used to (no more leaks) so the ECU needs to re-adjust the fuel trims, this will expedite the process. This may eliminate some of the noises/stumbling you are hearing.

4. Does it idle at 1100 RPMs in park when warmed up? If yes that's really high... but a separate issue.
 
gamefreakgc said:
Lol, that reminds me of my first few attempts to work on the ol' Pickup. Broke as many things as I fixed. Hope I can help with some of your questions:

1. The injectors are set at an angle, so not surprised you broke one. Next time, get the right tools for the job (ratching wrench, 6 point or 12 point socket, etc.) and save yourself the headache. Trust me... it just makes things a whole lot easier. Toyota's are all metric so your tools should also be metric, not standard.

2. Valve covers should be loose, but not enough to leak. The bolts are to be at 6 lbs/ft or 72in/ft, per the FSM. Don't overtighten them, they will strip real easy. The gasket should be compressed but not smashed to bits, if that makes sense. Make sure the pressure is uniform and use Black RTV or FIPG material where directed or it may leak down the road. If you missed the FIPG don't sweat it unless it leaks.

3. Pull the EFI fuse and relay in the fuse box under the hood for a few minutes when off and then put them back in. The engine is getting more fuel than it used to (no more leaks) so the ECU needs to re-adjust the fuel trims, this will expedite the process. This may eliminate some of the noises/stumbling you are hearing.

4. Does it idle at 1100 RPMs in park when warmed up? If yes that's really high... but a separate issue.
Click to expand...


1. The injectors are set at an angle, so not surprised you broke one. Next time, get the right tools for the job (ratching wrench, 6 point or 12 point socket, etc.) and save yourself the headache. Trust me... it just makes things a whole lot easier. Toyota's are all metric so your tools should also be metric, not standard.

I used almost exclusively for this whole project: a 10mm socket, a 12mm socket, and a 6" extension when necessary. Makes it very easy to look at a nut/bolt and know that 98% of the time it'll be one of the 2 sizes. I saw online that you can loosen the fuel rail with a 17mm wrench, and THAT's what really broke my injector. Twisted the whole damn rail. That's when I decided to just remove the whole thing. Is there another way to do this?

2. Valve covers should be loose, but not enough to leak. The bolts are to be at 6 lbs/ft or 72in/ft, per the FSM. Don't overtighten them, they will strip real easy. The gasket should be compressed but not smashed to bits, if that makes sense. Make sure the pressure is uniform and use Black RTV or FIPG material where directed or it may leak down the road. If you missed the FIPG don't sweat it unless it leaks.

They were definitely finger loose; like I said, I originally thought the socket I was using was too big and just spinning over them. I reused the gasket; it looked just fine. Just put a few dabs of RTV in the gasket 'gutter' on the cover and pushed the gasket back in flush all the way around. I don't have a torque wrench (i know, i know), so i pretty much finger tightened them back down and gave a very tiny tweak with the ratchet.

3. Pull the EFI fuse and relay in the fuse box under the hood for a few minutes when off and then put them back in. The engine is getting more fuel than it used to (no more leaks) so the ECU needs to re-adjust the fuel trims, this will expedite the process. This may eliminate some of the noises/stumbling you are hearing.

4. Does it idle at 1100 RPMs in park when warmed up? If yes that's really high... but a separate issue.

I had the battery unplugged for the whole project so I thought that'd be good enough, but I reset the EFI yesterday anyways. The clatter noise is gone and it now idles at about 900-1000 when warm.


OK. One last question: related to all of this, but I don't think I've even mentioned it yet. When idling in gear (around 650-800) there's a very faint regular 'whuph' noise. It's not a knock (at least not any knock that's I've ever heard). It goes away around 1000rpm and does not come back at all until idling again.
I'm pretty sure this has been going on since I change my spark plugs after I bought the truck. I know I would not have bought it had I heard this noise during the test drive, and I didn't notice it for the first week I drove it before I did some maintenance the next weekend. What does a misfire sound like in these engines? I'm only used to hearing misfires in my old Jeep when I was playing with the timing and they were a whole lot louder, but of course, that was a carbureted engine.
I'm pretty sure it's the spark plugs. I used the dual ground NGK, but I was not very nice to them when gapping them. I just used a gapping coin and had to yank on them pretty hard. Any suggestions on a certain tool to gap these dual ground plugs with? I'll just buy new plugs if I need to. Unfortunately, I did not keep the old ones to just toss back in and see.
I had hoped that it was a weird issue at with the fuel pressure at low idle that the new FPR wpuld fix, but obviously not.
 
Last edited:
A 10mm and 12 mm socket will pretty much do everything in the engine bay, where a 14 mm will do basically everything else in the vehicle lol! It's so easy. Glad to hear that you did catch the little things, including the RTV on the valve covers. That one gets a lot of people and they wonder why it starts leaking again. In regards to the valve covers, not very many people have a torque wrench that is accurate under 10 lbs/ft, I don't either. Basically it just need to be tight enough not to leak but not so tight that the very small, fragile bolts break or strip (been there done that). If it's not leaking then you did it just fine.

Misfires can be felt, in a sense since the engine will not be firing in sync. They don't make a sound per say, unless it's really bad. Will sound like the enging is loping, almost like a beefed up muscle car at idle with performance cams, but not quite that pronounced. Often when idleing the most obvious sign is if you watch the engine it will shake periodically. No engine with these sorts of miles will stay PERFECTLY still, but you can tell when it's more than normal. Sometimes it can also be seen or felt on the 4x4 shifter if it's the J-type shifter. Unless major enough to throw a check engine light, misfires can be hard to track down.

I doubt that your spark plug gapping is what did it, someone else just posted they removed original plugs from their engine after 200,000 miles on them. The gaps were at around .200" (stock I think is .043"?) and it still ran fine.

Drive it around for a week or so, the ECU will take time to adjust. Know that when warm at idle, it should be around 650-700 RPM. Any higher indicates and issue with the IAC. The idle speed is controlled electronically by the ECU and the IAC is how it adjusts. Sometimes it will seize up due to gunk and not open/close like it is supposed to. Eventually it gets to the point where it idles at very high speeds, or the opposite where it will stall at idle.
 
gamefreakgc said:
A 10mm and 12 mm socket will pretty much do everything in the engine bay, where a 14 mm will do basically everything else in the vehicle lol! It's so easy. Glad to hear that you did catch the little things, including the RTV on the valve covers. That one gets a lot of people and they wonder why it starts leaking again. In regards to the valve covers, not very many people have a torque wrench that is accurate under 10 lbs/ft, I don't either. Basically it just need to be tight enough not to leak but not so tight that the very small, fragile bolts break or strip (been there done that). If it's not leaking then you did it just fine.

Misfires can be felt, in a sense since the engine will not be firing in sync. They don't make a sound per say, unless it's really bad. Will sound like the enging is loping, almost like a beefed up muscle car at idle with performance cams, but not quite that pronounced. Often when idleing the most obvious sign is if you watch the engine it will shake periodically. No engine with these sorts of miles will stay PERFECTLY still, but you can tell when it's more than normal. Sometimes it can also be seen or felt on the 4x4 shifter if it's the J-type shifter. Unless major enough to throw a check engine light, misfires can be hard to track down.

I doubt that your spark plug gapping is what did it, someone else just posted they removed original plugs from their engine after 200,000 miles on them. The gaps were at around .200" (stock I think is .043"?) and it still ran fine.

Drive it around for a week or so, the ECU will take time to adjust. Know that when warm at idle, it should be around 650-700 RPM. Any higher indicates and issue with the IAC. The idle speed is controlled electronically by the ECU and the IAC is how it adjusts. Sometimes it will seize up due to gunk and not open/close like it is supposed to. Eventually it gets to the point where it idles at very high speeds, or the opposite where it will stall at idle.
Click to expand...

I don't even think the spark plug gapping is the issue; I triple checked the gaps before putting them in. I'm more concerned about the fact that I definitely 'made contact' with the center electrode piece on all 6 plugs. Something I just read you're apparently not supposed to do. You're supposed to pull away, not push out. The center electrodes did not break, but took some real punishment trying to get the plugs gapped.

I can hear the 'whumph' most of the time (very faintly) but it IS more of a feeling sometimes, like you mentioned. The muscle car cam lope comparison is accurate.
 
AntleredRuin said:
I don't even think the spark plug gapping is the issue; I triple checked the gaps before putting them in. I'm more concerned about the fact that I definitely 'made contact' with the center electrode piece on all 6 plugs. Something I just read you're apparently not supposed to do. You're supposed to pull away, not push out. The center electrodes did not break, but took some real punishment trying to get the plugs gapped.

I can hear the 'whumph' most of the time (very faintly) but it IS more of a feeling sometimes, like you mentioned. The muscle car cam lope comparison is accurate.
Click to expand...

I hope someone else with more experience with plugs than I will chime in... I don't even gap my plugs anymore unless after a quick visual they look bent. So I never touch the center electrode. Most spark plug. I have iridium plugs in mine which cannot be gapped due to the fragile nature of the small electrode.
 
[MENTION=129892]AntleredRuin[/MENTION]
Hey dude when you had this rev limiter problem
Would it be all the time no matter how you pushed the gas
Or would it only pass 3000 rpms when you would pound on the gas pedal?
 
giovannie23 said:
[MENTION=129892]AntleredRuin[/MENTION]
Hey dude when you had this rev limiter problem
Would it be all the time no matter how you pushed the gas
Or would it only pass 3000 rpms when you would pound on the gas pedal?
Click to expand...
It would be all the time, no matter what. Even when it didn't stall out when pounding the gas, it wouldn't get above 3000.
 
AntleredRuin said:
It would be all the time, no matter what. Even when it didn't stall out when pounding the gas, it wouldn't get above 3000.
Click to expand...

OK thanks for that
I was having the same problem you were having but it's gotten better the last couple days
At first I wasn't able to rev past 3000 no matter what but a couple days ago I punched the gas and now it revs past 3000 takes alot to get the rpms that high still tho..like it only will pass 3000 when I'm punching it
Maybe the fuel filter
 
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