98 3.4L 4 Runner wont rev over 3500 - Detailed!!
Oct 29, 2015 | 11:38 AM
#61
Registered User
Joined: Jan 2005
Posts: 404
Likes: 3
My 3.4 had a serious issue with power much like you're describing.
You've tried everything else, try this:
Tighten the bolt for the crankshaft pulley to 217 ft/lbs. It feels tight? Do it anyway!
Don't use an impact gun, Don't use a breaker bar and go by "feel". Get a torque wrench and take it to 217.
If this fixes the issue get a NEW crank bolt from Toyota and put it in.
You've tried everything else, try this:
Tighten the bolt for the crankshaft pulley to 217 ft/lbs. It feels tight? Do it anyway!
Don't use an impact gun, Don't use a breaker bar and go by "feel". Get a torque wrench and take it to 217.
If this fixes the issue get a NEW crank bolt from Toyota and put it in.
Oct 30, 2015 | 10:15 AM
#62
Had this same problem as well I've preached it in other threads. If the crank pulley backs out the timing ring that is behind the pulley will come out too. The crank sensor won't be able to get a good reading on it.
Nov 15, 2015 | 02:20 PM
#63
Registered User
Joined: Jul 2006
Posts: 51
Likes: 0
From: NE
Had a similar problem on a 97, guy who did my TB for me didn't get the crank pulley tight and it created problems. I'd do as recommended above, if you haven't checked it with a torque wrench I would do that.
Oct 6, 2019 | 12:20 PM
#65
Registered User
Joined: Dec 2012
Posts: 5
Likes: 1
Bringing this back.
Ive got the sam exact thing happening to me. Almost to the T.
97 4runner 3.4L. Rebuilt motor/heads with 4,000 miles. 2x4 converted to 4x4, retro fit e-locker. J shifter with locking hubs. Trd supercharger, 7th injector kit( now deleted)
List of parts:
New exhaust, cat, headers
new fuel pump (came with 7th injector kit)
new fuel filter
new injectors from toyota
new knock sensors
new spark plugs(came with 7th injector kit)
new coil pack and wires
new trd supercharger
When issue started, i was getting on the interstate, full throttle, low on fuel and the truck started popping like it was hitting rev limiter. I shut her down and got drug off the interstate by a friend to the gas station where i filled up and checked for spark but the truck would not fire. It would only crank. So there she sat for 6 months.
Work performed:
checked all fuses and wires for shorts. All good
1: replaced crankshaft sensor
- still did not fire
2: removed 7th injector kit, leaving fuel pump, plugs and thermostat.
-truck fired up!
—went for a drive and noticed it cutting out at 3500rpm
3: swapped out ecu
- nothing changed
4: put old crankshaft sensor back in
- nothing changed
5: hooked up a scanner
- everything reads normal
-throttle position read 13.7% at 0 throttle, and 77% at full throttle?
6: swapped out tps
-no change
7: cleaned MAF
-no change
8: checked fuel pressure
- has good fuel pressure read about 60 while reving it up
9: torqued crankshaft bolt to 217lbs was not loose
- nothing changed
10: put scope in crankshaft sensor hole
-all looks good
Nothing looks out of the norm, all wires and hoses look ok. Exhaust fumes smell rich.
no codes showing
im guessing the op sold his with out fixing. I think i have tried everything.
Anyone every find a fix for this problem?
97 4runner 3.4L. Rebuilt motor/heads with 4,000 miles. 2x4 converted to 4x4, retro fit e-locker. J shifter with locking hubs. Trd supercharger, 7th injector kit( now deleted)
List of parts:
New exhaust, cat, headers
new fuel pump (came with 7th injector kit)
new fuel filter
new injectors from toyota
new knock sensors
new spark plugs(came with 7th injector kit)
new coil pack and wires
new trd supercharger
When issue started, i was getting on the interstate, full throttle, low on fuel and the truck started popping like it was hitting rev limiter. I shut her down and got drug off the interstate by a friend to the gas station where i filled up and checked for spark but the truck would not fire. It would only crank. So there she sat for 6 months.
Work performed:
checked all fuses and wires for shorts. All good
1: replaced crankshaft sensor
- still did not fire
2: removed 7th injector kit, leaving fuel pump, plugs and thermostat.
-truck fired up!
—went for a drive and noticed it cutting out at 3500rpm
3: swapped out ecu
- nothing changed
4: put old crankshaft sensor back in
- nothing changed
5: hooked up a scanner
- everything reads normal
-throttle position read 13.7% at 0 throttle, and 77% at full throttle?
6: swapped out tps
-no change
7: cleaned MAF
-no change
8: checked fuel pressure
- has good fuel pressure read about 60 while reving it up
9: torqued crankshaft bolt to 217lbs was not loose
- nothing changed
10: put scope in crankshaft sensor hole
-all looks good
Nothing looks out of the norm, all wires and hoses look ok. Exhaust fumes smell rich.
no codes showing
im guessing the op sold his with out fixing. I think i have tried everything.
Anyone every find a fix for this problem?
Last edited by Famous; Oct 6, 2019 at 02:00 PM.
Oct 9, 2019 | 05:22 AM
#66
Registered User
Joined: Apr 2005
Posts: 1,436
Likes: 95
From: Frederick, MD
I would start with the TPS. Try to figure out why that isn’t going from zero to 100. Is the throttle plate all boogered up? Is the shaft binding?
Next I would get a decent scan tool that can monitor fuel trims. This vintage is starting to show prone signs of injector failure. About 2 years ago there was at least a dozen threads about injectors dieing during heat soak.
You said this all started one day getting into the highway with low fuel. Going back to that event, were you accelerating harder than normal? Was there anything different about that event?
Next I would get a decent scan tool that can monitor fuel trims. This vintage is starting to show prone signs of injector failure. About 2 years ago there was at least a dozen threads about injectors dieing during heat soak.
You said this all started one day getting into the highway with low fuel. Going back to that event, were you accelerating harder than normal? Was there anything different about that event?
Oct 9, 2019 | 07:39 PM
#67
Registered User
Joined: Dec 2012
Posts: 5
Likes: 1
I would start with the TPS. Try to figure out why that isn’t going from zero to 100. Is the throttle plate all boogered up? Is the shaft binding?
Next I would get a decent scan tool that can monitor fuel trims. This vintage is starting to show prone signs of injector failure. About 2 years ago there was at least a dozen threads about injectors dieing during heat soak.
You said this all started one day getting into the highway with low fuel. Going back to that event, were you accelerating harder than normal? Was there anything different about that event?
Next I would get a decent scan tool that can monitor fuel trims. This vintage is starting to show prone signs of injector failure. About 2 years ago there was at least a dozen threads about injectors dieing during heat soak.
You said this all started one day getting into the highway with low fuel. Going back to that event, were you accelerating harder than normal? Was there anything different about that event?
Also going to take a look at the timing.
And because im ocd ive got new tps, maf, crankshaft sensor and fuel pressure regulator ordered.
Maybe ill hook up the fuel pressure gauge and go for a drive and see what it does at 3500rpm.
I understand new parts can go bad. But the fuel system is all new with oem fuel injectors.
The event was normal. I was pinned getting on the on ramp. It was raining pretty good and i do have the deck plate mod. It is a 22 year old gas tank im sure it not good to run it low.
Ive read multiple diagnoses like this with each one fix being different then they other. I feel ive tried everything brought to the table. There has to be a common factor. Or maybe each failing part show the same signs. IDK i will get to the bottom of this.
Thanks for the response.
Oct 10, 2019 | 12:03 PM
#68
Registered User
Joined: Apr 2005
Posts: 1,436
Likes: 95
From: Frederick, MD
You might want to start your own thread so new people don’t confuse the OP’s symptoms with yours. In the meantime, to get some clarity, does your truck run at all? OP only had trouble getting to higher rpms.
If it runs? What happens if you brake torque it? Does it miss and pop under load or will it build? Can you slowly rev up and how high will it go? Or does it cut out regardless of slow throttle or fast?
If it runs? What happens if you brake torque it? Does it miss and pop under load or will it build? Can you slowly rev up and how high will it go? Or does it cut out regardless of slow throttle or fast?
Oct 14, 2019 | 05:14 AM
#70
Registered User
Joined: Apr 2005
Posts: 1,436
Likes: 95
From: Frederick, MD
Hard ceilings like that are usually spark or fuel related. Spark isn’t as big of an issue with multipoint coil packs Now. Of you have a dying coil pack it just can’t fire fast enough or with enough energy to rev that high.
This brings me to fuel. If you are hitting a high limit, that sounds like it starving at high fuel volume. Wether the issue is a clogged fuel filter, (which would be a symptom of running the tank REALLY low and sucking up moisture or something), a dying pump that can’t move the volume, or injectors that are dying.
There are tests for fuel pump volume. I don’t have the spec in front of me, but you unhook the fuel line and time how long it takes to fill a set volume. You could measure this before and after the fuel filter to determine or rule out that as an issue. Or you can just replace the filter as a matter maintenance.
This brings me to fuel. If you are hitting a high limit, that sounds like it starving at high fuel volume. Wether the issue is a clogged fuel filter, (which would be a symptom of running the tank REALLY low and sucking up moisture or something), a dying pump that can’t move the volume, or injectors that are dying.
There are tests for fuel pump volume. I don’t have the spec in front of me, but you unhook the fuel line and time how long it takes to fill a set volume. You could measure this before and after the fuel filter to determine or rule out that as an issue. Or you can just replace the filter as a matter maintenance.
Feb 7, 2020 | 07:42 PM
#71
Registered User
Joined: Dec 2012
Posts: 5
Likes: 1
Just going to add some info that i have found. And i put a list together of all parts i think could be causing this issue.
Sounds like the vehicle put its self in limp mod and is cutting back it fuel due to one or more of these parts...
this is what i found others and myself saying...
ECU...People have swapped out with no fix
Throttle position sensor... Cleaned with no fix
Crank shaft sensors... Fixed! Also check also may be a short in the harness
cam sensor... checked no fix
MAF sensor... Cleaned with no fix
O2 sensor x2... Fixed not proven
knock sensor... checked no fix
fuel pump... replaced no fix
fuel filter... Fixed!
check fuel lines... Fixed! Due to crushed lines
fuel pressure... ranged from 44-60 problem persists
injectors... OEM/rebuilt, no fix
fuel pressure regulator... Fixed!
intake tube... checked no fix
PVC... checked no fix
Throttle body... Cleaned with no fix
cat... Fixed! due to honey comb burnt/clogged
muffler
Crank pulley bolt... Fixed
Timing... Fixed!, due to belt slipping and jumping a tooth check tensioner
timing gear... Fixed! due to loose crank pulley bolt and damaging the teeth causing belt to slip.
spark plugs... replaced no fix
coil pack... replaced no fix
spark plug... replaced no fix
wires... replaced no fix
igniter
leak down test... good with no fix
valve springs... Rebuilt heads with no fix
adjust valves... Rebuilt heads with no fix
open loop?
compression test... 140 and still no fix
"Check the FPS (Fuel Pressure Regulator).
This is mounted at the back of the fuel rail (driver side if I recall).
Mine failed right after I got the T4R. It has a vacuum line that runs under the intake plenum to the intake baffle. When my FPR failed, it just dumped all the fuel into the intake baffle through that vacuum line. It smelled really strongly of gas and just fell on it's face with any throttle. I could not get it past 2500 RPM no matter how hard I tried.
I got a used OEM from eBay for $35 with shipping because it's not a common failure part. 2 years later, no issues yet."
"So I had a problem start a while back. I have a 96 Tacoma with the 5VZ engine and it started cutting out at around 3-4K RPM, not a stutter or miss but like completely cut out and not rev higher. It settled at 3000 RPM and did it hot or cold, driving or at idle. Since it did it cold I could rule out most sensors, and I didn't have a CEL come on. So I was a bit stumped. I finally caved in and took it to my local Dealer and within a few hours got the call the Tech said he had it narrowed down to the Crankshaft Position Sensor Circuit. $350 bucks later it turns out there was a bad spot in the wire for the Crank Sensor and it didnt trip the CEL, they fixed it and I am on the road again!"
"For those of you who have tried everything mentioned above or want to skip to a valid solution...
The problem is in the timing belt specifically in the tensioner.
If the pulley does not have the full range of operation like tightening the hex bolt too much, that can restrict the pulley causing the belt to operate too loose and you can skip a tooth or two, This affects the timing, causing the engine to act like the rev-limiter is activated or set at 3000 RPM.
Check if the marks line up and if the the tensioner has the full range of operation.
This worked for me and after looking into everything else other people have suffered and had a fix and said it resolved their problems. or other words $$$ later...
Cheers!"
"Dont rule out the CAT, the easy way to check is to remove the o2 sensors before the cats and run it around the block, see if it will drive under a load over 3000 rpm's if it does it's your cat(s), however most likely it will set the cel when your remove the o2 sensors."
"Just had in the toyota shop. They told me the water pump is failing and leaking fluid on the timing belt, which caused it to jump a kog or jump out of time by one notch and therefore when it hits a certain rpm the engine begins to miss-fire."
Guess I have my work cut out for the weekend, Will update once i find my culprit.
Sounds like the vehicle put its self in limp mod and is cutting back it fuel due to one or more of these parts...
this is what i found others and myself saying...
ECU...People have swapped out with no fix
Throttle position sensor... Cleaned with no fix
Crank shaft sensors... Fixed! Also check also may be a short in the harness
cam sensor... checked no fix
MAF sensor... Cleaned with no fix
O2 sensor x2... Fixed not proven
knock sensor... checked no fix
fuel pump... replaced no fix
fuel filter... Fixed!
check fuel lines... Fixed! Due to crushed lines
fuel pressure... ranged from 44-60 problem persists
injectors... OEM/rebuilt, no fix
fuel pressure regulator... Fixed!
intake tube... checked no fix
PVC... checked no fix
Throttle body... Cleaned with no fix
cat... Fixed! due to honey comb burnt/clogged
muffler
Crank pulley bolt... Fixed
Timing... Fixed!, due to belt slipping and jumping a tooth check tensioner
timing gear... Fixed! due to loose crank pulley bolt and damaging the teeth causing belt to slip.
spark plugs... replaced no fix
coil pack... replaced no fix
spark plug... replaced no fix
wires... replaced no fix
igniter
leak down test... good with no fix
valve springs... Rebuilt heads with no fix
adjust valves... Rebuilt heads with no fix
open loop?
compression test... 140 and still no fix
"Check the FPS (Fuel Pressure Regulator).
This is mounted at the back of the fuel rail (driver side if I recall).
Mine failed right after I got the T4R. It has a vacuum line that runs under the intake plenum to the intake baffle. When my FPR failed, it just dumped all the fuel into the intake baffle through that vacuum line. It smelled really strongly of gas and just fell on it's face with any throttle. I could not get it past 2500 RPM no matter how hard I tried.
I got a used OEM from eBay for $35 with shipping because it's not a common failure part. 2 years later, no issues yet."
"So I had a problem start a while back. I have a 96 Tacoma with the 5VZ engine and it started cutting out at around 3-4K RPM, not a stutter or miss but like completely cut out and not rev higher. It settled at 3000 RPM and did it hot or cold, driving or at idle. Since it did it cold I could rule out most sensors, and I didn't have a CEL come on. So I was a bit stumped. I finally caved in and took it to my local Dealer and within a few hours got the call the Tech said he had it narrowed down to the Crankshaft Position Sensor Circuit. $350 bucks later it turns out there was a bad spot in the wire for the Crank Sensor and it didnt trip the CEL, they fixed it and I am on the road again!"
"For those of you who have tried everything mentioned above or want to skip to a valid solution...
The problem is in the timing belt specifically in the tensioner.
If the pulley does not have the full range of operation like tightening the hex bolt too much, that can restrict the pulley causing the belt to operate too loose and you can skip a tooth or two, This affects the timing, causing the engine to act like the rev-limiter is activated or set at 3000 RPM.
Check if the marks line up and if the the tensioner has the full range of operation.
This worked for me and after looking into everything else other people have suffered and had a fix and said it resolved their problems. or other words $$$ later...
Cheers!"
"Dont rule out the CAT, the easy way to check is to remove the o2 sensors before the cats and run it around the block, see if it will drive under a load over 3000 rpm's if it does it's your cat(s), however most likely it will set the cel when your remove the o2 sensors."
"Just had in the toyota shop. They told me the water pump is failing and leaking fluid on the timing belt, which caused it to jump a kog or jump out of time by one notch and therefore when it hits a certain rpm the engine begins to miss-fire."
Guess I have my work cut out for the weekend, Will update once i find my culprit.
Last edited by Famous; Feb 7, 2020 at 07:46 PM.
Feb 9, 2020 | 07:09 AM
#72
Registered User
Joined: Sep 2008
Posts: 76
Likes: 1
Check your ground wires to the top of the intake plenum. once i was in a hurry and didn't get the bolt fully tight, holding the ground wires for the engine wiring harness. she fired up, cruised down the road no worries, then around 3500 it stumbled hard and had to idle down. did that to me several times until the grounds were making good contact.
Mar 7, 2020 | 12:13 PM
#73
Registered User
Joined: Mar 2020
Posts: 1
Likes: 0
Fix!!!!!!
I know this has been talked about in the past, I've searched many times on it.
I wanted to combine my info in my spot in the hopes of gathering some much needed support
I started a thread on another 4 Runner forum, but not much feedback so hoping this forum will yield more experienced responses.
Here's the scoop:
Previous owner was driving on highway and 60+ mph when it started stumbling at higher rpms. He was low on gas so filled it up and barely made it home. With the full tank, condition got worse. After sitting for approx 2 weeks, it started doing what its continuing to do now, running very rough at about 3500rpm with max rpm of about 4k. Conditions worsens the more gas you give it and it cant do any better than 4k, running very very bad at that rpm.
We've done the following:
Swapped ECU
Removed CAT - also dropped exhaust to make sure muffler wasnt the issue
Fuel pump replaced
Fuel filter replaced
TPS tested with meter - its good
Plugs, coil packs and wires replaced (ngk plugs)
Cam AND Crank Sensor replaced
Fuel pressure tested, no issues
Vacuum pressure tested - vacuum was smooth at 1000rpm increments, no fluctuation at all. At about 3600rpm the pressure started to drop, but still no fluctuations. Full throttle eventually brought the vacuum to zero. Even with the terrible condition that occurs at 3600, vacuum was steady at about 15.
MAF tested with meter and cleaned with MAF cleaner
Throttle body cleaned and seafoam engine cleaner as well
Timing belt, water pump and pulleys replaced. Timing is correct, cam marks, crank marks all line up as they should
It behaves in this manner whether its in park, neutral or if you're driving it in D, L or 2. It never changes, but pulls and runs normal up to 3500.
Hopefully I didnt leave anything out.
Oh....before anyone ask the obvious - NO CODES.....EVER.....
We can force a code by pulling the maf, tps etc, but no codes are generated with everything in place. CEL blinks at worst point of the issue, over 3600, but no codes are left.
We were thinking weak valve spring, valve float, but vacuum test doesnt indicate any issues at all.
Previous owner says the MAF was swapped with a brand new one from NAPA when this problem started and nothing changed so the original was put back in. We've tested it with a meter and it appears to be good.
Ignitor?? Dont know how to test this - under the impression it either works or it doesnt or causes issues once hot. That doesnt fit our scenario.
Any info/suggestions at all will be HIGHLY appreciated.
Scott
- Adding that the injectors were sent to witchunter.com for professional cleaning and testing
I wanted to combine my info in my spot in the hopes of gathering some much needed support
I started a thread on another 4 Runner forum, but not much feedback so hoping this forum will yield more experienced responses.
Here's the scoop:
Previous owner was driving on highway and 60+ mph when it started stumbling at higher rpms. He was low on gas so filled it up and barely made it home. With the full tank, condition got worse. After sitting for approx 2 weeks, it started doing what its continuing to do now, running very rough at about 3500rpm with max rpm of about 4k. Conditions worsens the more gas you give it and it cant do any better than 4k, running very very bad at that rpm.
We've done the following:
Swapped ECU
Removed CAT - also dropped exhaust to make sure muffler wasnt the issue
Fuel pump replaced
Fuel filter replaced
TPS tested with meter - its good
Plugs, coil packs and wires replaced (ngk plugs)
Cam AND Crank Sensor replaced
Fuel pressure tested, no issues
Vacuum pressure tested - vacuum was smooth at 1000rpm increments, no fluctuation at all. At about 3600rpm the pressure started to drop, but still no fluctuations. Full throttle eventually brought the vacuum to zero. Even with the terrible condition that occurs at 3600, vacuum was steady at about 15.
MAF tested with meter and cleaned with MAF cleaner
Throttle body cleaned and seafoam engine cleaner as well
Timing belt, water pump and pulleys replaced. Timing is correct, cam marks, crank marks all line up as they should
It behaves in this manner whether its in park, neutral or if you're driving it in D, L or 2. It never changes, but pulls and runs normal up to 3500.
Hopefully I didnt leave anything out.
Oh....before anyone ask the obvious - NO CODES.....EVER.....
We can force a code by pulling the maf, tps etc, but no codes are generated with everything in place. CEL blinks at worst point of the issue, over 3600, but no codes are left.
We were thinking weak valve spring, valve float, but vacuum test doesnt indicate any issues at all.
Previous owner says the MAF was swapped with a brand new one from NAPA when this problem started and nothing changed so the original was put back in. We've tested it with a meter and it appears to be good.
Ignitor?? Dont know how to test this - under the impression it either works or it doesnt or causes issues once hot. That doesnt fit our scenario.
Any info/suggestions at all will be HIGHLY appreciated.
Scott
- Adding that the injectors were sent to witchunter.com for professional cleaning and testing
Feb 8, 2021 | 07:31 PM
#74
Registered User
Joined: Dec 2012
Posts: 5
Likes: 1
Fixed
vasinvictor
even though i re torqued the crankshaft bolt to spec, it had backed out enough to spin on the key. I should of caught it when checking timing, the mark on the crank pulley did not line up with 0. Even though it finally through a code of cam shaft sensor, it was in fact crankshaft bolt backing out. Hope this helps the next guy.
even though i re torqued the crankshaft bolt to spec, it had backed out enough to spin on the key. I should of caught it when checking timing, the mark on the crank pulley did not line up with 0. Even though it finally through a code of cam shaft sensor, it was in fact crankshaft bolt backing out. Hope this helps the next guy.
Thread
Thread Starter
Forum
Replies
Last Post
jonnydclark
Other Makes Cars/Trucks
8
Aug 9, 2014 05:38 PM
Archer1968
95.5-2004 Tacomas & 96-2002 4Runners
4
Jul 21, 2014 10:27 AM
Vantucky
95.5-2004 Tacomas & 96-2002 4Runners
17
Feb 19, 2011 07:22 AM
coolboatguy
95.5-2004 Tacomas & 96-2002 4Runners
10
Aug 21, 2006 01:02 PM
