1999 Toyota 5VZ-FE 3.4L V6 Hot Hesitation

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  #1  
Old 04-15-07, 03:14 PM
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Question 1999 Toyota 5VZ-FE 3.4L V6 Hot Hesitation

Was wondering if anybody out there has had any experiences with a 1999 or similar Toyota 5VZ-FE 3.4L V6, hesitation or engine stumble on hard accelleration when warm / hot. Engine typical to 4Runners, Tacoma, Tundra, others...


System stats;

120k miles on vehicle.
(2nd) timing belt replaced at 120k miles, with new tensioners / idlers.
Front end v-belts replaced at 120k.
fuel filter replaced at 120k.
New OEM air filter at 115k.
MAS cleaned (out of air intake) at 120k (with lube free CRC contact cleaner).
OEM plugs at 120k, gapped to .043 spec.
Plug wires replaced at 120k.
All old plugs removed showed similar tan color and similiar electrode wear (no obvious oil fouling or indications of leaky valve seals, etc...)
Throttle body scrubbed out with a good quality 3M throttle body cleaner.
Fuel system hit with two sequential (full tank) doses of Seafoam.

Problem synopsis (happened before aforemetion work - much of which was regular maintainance interval scheduled);

Cold starts fine. Excellent hard accelleration when cold, no engine stutters or stumbles (misfires).

Once engine has warmed up, normal accelleration is fine, however hard accelleration (wide open) is labored. If you stay down on the acccellerator, the MIL light will flash and of course if the operator persists will stay lit. CEL code P0303, misfire cylinder 3 always results. After some additional driving, the MIL indicator always goes out.

This vehicle has three (3) igniter coil packs, each with a remote spark wire to the remote head / cylinder. Only cylinder 3 shows the misfire. Cylinder 3 is paired with cylinder 6, which shows OK operation, no relative codes.

Also tried switching coil packs 2 and 3. Problem stayed with cylinder 3, which rules out the igniter coil pack. Primary side coil resistance measures same across all coil packs (supply leads disconnected).

I'm ruling out fuel pump as it would be a problem at start, cold, and hot operation.

Next logical steps would be to check compression on all cylinders and fuel rail pressure. There is a vaccum operated fuel regulator on the fuel rail, connected to the air intake noise damper box. Based on where the vaccum connection is made, I expect the fuel regulator would open up when the throttle plate is wide open. No obvious leaks or cracks found in the intake tube or related vaccum lines. Manual vaccum operation on the fuel pressure reg line, at idle) didn't prove much.

Anybody have any suggestions or relative experieces with this engine?
If there's a known common direction that might save me from cracking the air plenum and fuel rails, I'd surely appreciate the feedback.

Thanks,
 
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Old 04-15-07, 03:25 PM
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I'm researching this, but so far, it looks like a common problem with Toyota. Let me looks some more...
 
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Old 04-15-07, 03:47 PM
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1999 Toyota 5VZ0F# 3.4L V6 Hot Hesitation

Thanks man!

Been all over the net on this one.

Let me describe the hesitation a bit further. It's not as severe or consistent as say a good old SB Chevy 350 with the timing port disconnected or advance retarted. The only true nature of the hesitation is that it happens when the engine is warm to full ambient hot operating temp.

The temp guage is operating where it always had since the truck was new. I know this isn't a true temp measurement, but it's not wildly off at any rate.

Per the OEM shop manual, fuel pressure can be felt in the flex hose by pinching it. I don't own my own code reader with live monitoring, so I can't read the fuel pressure transducer (just yet anyway).
 
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Old 04-17-07, 06:32 AM
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Thumbs up 1999 Toyota 5VZ-FE 3.4L V6 Hot Hesitation

Compression tests good.

All cylinders within 5~10 PSI variance of each other around 174 PSI specification, full open throttle crank test.
 
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Old 04-17-07, 01:32 PM
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After reading some information, the problem "may" lye within the transmission. The transmission can cause sensation that the engine is at fault, when in actuality, it is the tranny. I wish I could help you more.
 
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Old 04-20-07, 06:05 PM
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Talking 1999 Toyota 5VZ-FE 3.4L V6 hot Hesitation

I lucked out. Fortunately not transmission related. Since the diagnostic code kept kicking up on cyl 3, and I didn't have the appropriate fuel pressure test gear, I spent $80 for a pro diagnosis. Injector intermittance on injector 3 confirmed. The shop wanted way too much for the parts and labor, so I'm procuring the parts from a local dealer. Just one inector and a couple plenum gaskets. Going to take the top end and fuel rails apart tomorrow.

Shop advised me that newer oxygenated (alcohol blended) fuels can eat away at the electric solenoids (coils) in the injectors. Apparently, the coils are fuel wet to keep them cool. Didn't know that.

I was searching for injectors and found many companies that supply refurbs at significant cost reduction. Like half of a new injector. However, none seem to replace the coils, just clean, test, and refit with new o-rings.

So I'm going with a new OEM part. Can't really afford to replace all six at $130 each, but the air plenum is easy enough to remove again and again, if I have to.

Thanks for the suggestion threads. I'll let you know how this turns out.
 
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Old 04-20-07, 06:08 PM
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Definetly keep us posted!
 
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Old 04-21-07, 12:02 PM
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Talking 1999 Toyota 5VZ-FE 3.4L V6 Hot Hesitation Solved

Aside from the damage to the old wallet for a new injector, the new cyl 3 injector replacemenet was completed in about an hour.

There is a good manual for this engine on the TTORA website. Just google TTORA.

#1 - remove neg batt connector.

#2 - blow the intake off good with comrpessed air. Miniscule amounts of road grit will collect around the injector seals.. blow it out good.

#3 = remove the six (6) 10mm bolts from the plastic timing belt cover. slip the upper radiator hose clamp back about 10 inches to allow the timing cover to retreat forward towards the radiator. Gives you clearance to reach the front (odd bank) fuel rail banjo bolt (18mm) front and rear.

I lucked out with Cyl 3, as this whole fuel rail can be reached by only splitting the top half of the air intake (plenum) runners off. Four 12mm bolts and two 12mm nuts (15 ft/lb retorque). Had it been the even bank, one would have to remove the bottom plenum half also.

The vaccum lines were minimal, removed, and tucked aside for the duration of the job. Had to remove the throttle, trans kickdown, and cruise cables, and tucked aside.

Only think to look out for are the two 3/8" coolant lines that run to the base of the throttle body. They won't weep much coolant, but have a rag around to pick up any spillage and a good pair of pliers to work the clamps back. After 120k miles, they like to set themselves into the neoprene hose.

Fuel rails have banjo style fittings on both ends so they get dual feeds front and back, both banks in parallel. The banjo fittings have fine flat washers. Keep an eye on em.. They can disappear quick, and you need em!

Once the bajno bolts are backed out the rail is held by two 12mm bolts (25 ft lb retorque). Once these bolts are out, the rail will wiggle on the inector tips. VERY, VERY, VERY, patiently, work this with all due kindness until the rail pops off the o-ring injector tips.

Have some rags on hand to soak up about 50 cc of fuel that will leak.

STOP. Get your shop vac!

When removing the injectors from the intake, a fair amount of road grit will remain around the base injector seal. Have a vaccum handy to keep this junk from going down the injector port and to the head.

There should not be any amount of leaked fuel, so running the vac shouldn't be an issue (potential fireball hazard).

The injector, pair of intake gaskets (one spared), and a spare injector rail side o-ring ran about $225. My local shop wanted that alone for just the injector and included no labor.

For less than the cost of the labor, I added a new torque wrench to my tool collection. This task is easlily accomplished. Just don't be in a hurry.

After you get the whole mess back together, promptly check for any fuel leaks. I had none. Let the engine warm and retorque the intake. Other than that, just drive it and let the ECM recalibrate itself.
 
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Old 04-27-07, 04:00 PM
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Question 1999 Toyota 5VZ-FE 3.4L V6 Hot Hesitation - Further DTC Codes

Well, the mystery hesitation on accelleration persists when soaked hot. So, I now own an Actron 9180 scanner of my very own. Yippee!

Captured some frame data triggered by the MIL upon event.

So here goes;

Same basic code P0303 - generic misfire on cyl3, no other codes.

Freeze data showed O2 sensors 1 and 2 ok.

However, fuel system codes varied between closed loop (02 sense feedback) and open1 and open2 reperesenting various stages of open loop fuel control during the event.

At face value, the fuel codes would point to an O2 sensor, however the O2 sensors report good, and no other DTC codes appeared aside from P0303.

The second oddity is that this happens after a consistent amount of running time, not just when the engine reaches quiecent operating temp. Which also leads me away from the O2 sensors and maybe towards a temp sensor, or some other sensor that's failing after themally soaking to some ambient under hood temp.

However from the data stream below, the temp sensor seems to be reporting a reasonable and consistent 190deg F.

Anybody have any insights from this. Again, vehicle has new wires, plugs, ign coils rotated (no problem migration from cyl 3), new timing belt, tensioners, etc. + new injector on cyl 3, new fuel filter, air filter (oem), cleaned MAS, check vaccum lines, cleaned TB when apart for injector svce), compression in-spec (shop tested);

As always... Thanks!


Data stream;************************
IM Monitors


Since DTCs Cleared

Misfire Monitor ok
Fuel System Mon ok
Comp Component ok
Catalyst Mon inc
Htd Catalyst n/a
Evap System Mon ok
Sec Air System n/a
A/C Refrig Mon n/a
Oxygen Sens Mon ok
Oxygen Sens Htr ok
EGR System Mon n/a

Codes

DTCs


P0303 Mod $10
Cylinder 3
Misfire Detected


No Codes Found



Freeze Frame

Frame 1 Mod $10
TROUB CODE P0303
ENG SPEED RPM 3486
CALC LOAD % 86.6
COOLANT F 190
IAT F 60
ST FTRM1 % 0.0
LT FTRM1 % 4.6
VEH SPEED MPH 69
FUEL SYS 1 OPEN1
FUEL SYS 2 N/A


Recorded Data

MIL STATUS OFF
ABSLT TPS % 64.7
ENG SPEED RPM 3436
CALC LOAD % 84.7
MAF FLOW g/Sec 99.26
COOLANT F 190
IAT F 60
IGN ADVANCE 11.5
ST FTRM1 % -1.0
LT FTRM1 % 4.6
VEH SPEED MPH 68
FUEL SYS 1 OPEN1
FUEL SYS 2 N/A
O2S11 V 0.895
ST FTRM11 % 0.0
O2S12 V 0.785
OBD2 STAT CA

Frame 0 Time 0.0


MIL STATUS ON
ABSLT TPS % 47.8
ENG SPEED RPM 3576
CALC LOAD % 82.7
MAF FLOW g/Sec 94.60
COOLANT F 188
IAT F 60
IGN ADVANCE 29.5
ST FTRM1 % -4.6
LT FTRM1 % 2.3
VEH SPEED MPH 72
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.455
ST FTRM11 % 0.8
O2S12 V 0.825
OBD2 STAT CA

Frame 1 Time 4.1


MIL STATUS ON
ABSLT TPS % 15.2
ENG SPEED RPM 2293
CALC LOAD % 33.3
MAF FLOW g/Sec 25.33
COOLANT F 188
IAT F 62
IGN ADVANCE 27.0
ST FTRM1 % 0.8
LT FTRM1 % 4.6
VEH SPEED MPH 68
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.805
ST FTRM11 % -2.2
O2S12 V 0.525
OBD2 STAT CA

Frame 2 Time 7.8


MIL STATUS ON
ABSLT TPS % 34.9
ENG SPEED RPM 2283
CALC LOAD % 74.9
MAF FLOW g/Sec 91.82
COOLANT F 188
IAT F 62
IGN ADVANCE 14.5
ST FTRM1 % 0.0
LT FTRM1 % 4.6
VEH SPEED MPH 69
FUEL SYS 1 OPEN1
FUEL SYS 2 N/A
O2S11 V 0.950
ST FTRM11 % 0.0
O2S12 V 0.905
OBD2 STAT CA

Frame 3 Time 11.4


MIL STATUS ON
ABSLT TPS % 65.8
ENG SPEED RPM 3720
CALC LOAD % 86.2
MAF FLOW g/Sec105.71
COOLANT F 190
IAT F 62
IGN ADVANCE 20.5
ST FTRM1 % -5.1
LT FTRM1 % 7.0
VEH SPEED MPH 75
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.380
ST FTRM11 % -7.5
O2S12 V 0.745
OBD2 STAT CA

Frame 4 Time 15.1


MIL STATUS ON
ABSLT TPS % 13.7
ENG SPEED RPM 2473
CALC LOAD % 25.4
MAF FLOW g/Sec 22.13
COOLANT F 190
IAT F 62
IGN ADVANCE 30.5
ST FTRM1 % 0.7
LT FTRM1 % 3.9
VEH SPEED MPH 74
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.730
ST FTRM11 % -1.0
O2S12 V 0.685
OBD2 STAT CA

Frame 5 Time 18.7


MIL STATUS ON
ABSLT TPS % 10.5
ENG SPEED RPM 2369
CALC LOAD % 10.1
MAF FLOW g/Sec 7.77
COOLANT F 190
IAT F 62
IGN ADVANCE 25.5
ST FTRM1 % 0.0
LT FTRM1 % 1.5
VEH SPEED MPH 71
FUEL SYS 1 OPEN1
FUEL SYS 2 N/A
O2S11 V 0.020
ST FTRM11 % 0.0
O2S12 V 0.085
OBD2 STAT CA

Frame 6 Time 22.4


MIL STATUS ON
ABSLT TPS % 12.5
ENG SPEED RPM 2324
CALC LOAD % 21.9
MAF FLOW g/Sec 17.79
COOLANT F 190
IAT F 62
IGN ADVANCE 30.5
ST FTRM1 % 0.7
LT FTRM1 % 4.6
VEH SPEED MPH 68
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.380
ST FTRM11 % 7.0
O2S12 V 0.115
OBD2 STAT CA

Frame 7 Time 26.1


MIL STATUS ON
ABSLT TPS % 14.9
ENG SPEED RPM 2192
CALC LOAD % 33.7
MAF FLOW g/Sec 26.21
COOLANT F 190
IAT F 62
IGN ADVANCE 22.5
ST FTRM1 % 0.8
LT FTRM1 % 7.0
VEH SPEED MPH 67
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.415
ST FTRM11 % -3.4
O2S12 V 0.680
OBD2 STAT CA

Frame 8 Time 29.8


MIL STATUS ON
ABSLT TPS % 18.0
ENG SPEED RPM 2234
CALC LOAD % 45.4
MAF FLOW g/Sec 31.15
COOLANT F 190
IAT F 62
IGN ADVANCE 25.0
ST FTRM1 % 1.5
LT FTRM1 % 6.2
VEH SPEED MPH 67
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.785
ST FTRM11 % -3.4
O2S12 V 0.370
OBD2 STAT CA

Frame 9 Time 33.4


MIL STATUS ON
ABSLT TPS % 17.2
ENG SPEED RPM 2228
CALC LOAD % 43.1
MAF FLOW g/Sec 32.60
COOLANT F 190
IAT F 62
IGN ADVANCE 24.5
ST FTRM1 % 0.0
LT FTRM1 % 7.0
VEH SPEED MPH 67
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.355
ST FTRM11 % -3.4
O2S12 V 0.180
OBD2 STAT CA

Frame 10 Time 37.1


MIL STATUS ON
ABSLT TPS % 17.6
ENG SPEED RPM 2214
CALC LOAD % 43.5
MAF FLOW g/Sec 33.94
COOLANT F 190
IAT F 62
IGN ADVANCE 24.0
ST FTRM1 % -5.1
LT FTRM1 % 7.0
VEH SPEED MPH 67
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.715
ST FTRM11 % -7.5
O2S12 V 0.365
OBD2 STAT CA

Frame 11 Time 40.8
 
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Old 04-27-07, 04:59 PM
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Could there be a problem with your ECM (engine control module)? This module controls almost everything going on with the motor. I'm not sure what else could cause this......
 
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Old 04-27-07, 06:17 PM
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Wow

Keep us up to date on what you find out. The scanner you have is it pretty user friendly? I have the basic actron scanner but want to upgrade to one that shows more info like yours does.
Do you take a laptop with you or do you download after the test? I have 3 OB11 cars so it will get used and I can use it on my friends cars as well.
Will that bad boy read trannie codes?
 
  #12  
Old 04-28-07, 03:45 AM
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Unhappy Interesting!!!

you wrote: Shop advised me that newer oxygenated (alcohol blended) fuels can eat away at the electric solenoids (coils) in the injectors.
What else haven't they told us...
 
  #13  
Old 04-28-07, 10:04 AM
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Talking TPS Sensor

Going for a TPS sensor.

I was looking over the aforementioned frame data stream and noted Wide Open Throttle WOT only registering 73%.

So I went back and looked at live data, Key on, Engine Off, wide open throttle.

The best report was about 74% WOT on throttle at full open.

Checked the pin resistances on the TPS sensor.

They were at the very bottom end of the factor spec, but still in spec.

Called a local Toyota dealer. They indicated I should see nearly 100% reported at WOT for the ABSLT TPS % measurement.

Hopefully this is end of this thread. Thanks for listening.
 
  #14  
Old 05-03-07, 05:10 PM
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Coil on Plug - Dielectric Grease

Ok, gonna make you all suffer through one more thread.

Hot hesitation persisted, very predictable after certian amount of drive time.

Only code P0303 cyl3 misfire.

Looked at coil over plug boot and new plug insulator.

Found signs of arcing on ceramic, indicating HV short.

Cleaned up the plug ceramic and boot, then gave it a good application of dielectric grease. This should put an end to the arcing and the hot soak hesitation.
 
  #15  
Old 12-22-08, 02:38 PM
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Help has arrived....

I too suffered with this problem..... Most likely a Blown HeadGasket... I tried all the above spent $$$ to diagnose the problem. try a sniffer to see if there is water vapor in the exhaust.
I have tried to swap all the igniter packs, new plugs, new wires, resetting the ODB codes after every attempt.

Hope this helps you out!
I just picked up a used engine to swap out with the original one in my 4Runner since the original has 198K miles!
Good luck
 
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Old 12-22-08, 03:16 PM
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It has been over 1 1/2 yrs since the issue....hopefully he got it figured out by now.....
 
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Old 12-23-08, 05:37 PM
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Ooops

I didnt pay attention to the date, I just saw that this was the same issues that I was having-
 
  #18  
Old 11-19-09, 04:40 PM
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Ignition Coil Cyl 3 Replaced 11/2009

So here's a late follow up to the old misfire problem. Since origniating this thread, and as per follow-up threads I had a couple issues. First, a bad injector on cylinder 3, and secondly a compromised ignition coil boot on cylinder 3.

The injector I replaced some time ago, towards the origination of this thread. However, I limped along with the problematic ignition coil ($100 OEM) for a couple years by doing the following;

Pulling the spark plug and cleaning the carbon arcing from the ceramic, then reinstalling with a dab of dielectric silicon grease on the ignition (coil over plug) boot. This would last for some 6 months at a pop. Occasionally, the dielectric grease would fail, the engine would begin stumbling on cyl 3 again and the process would have to be repeated.

I finally replaced the coil this month at about 154,000 miles.

I could have regreased it again and kept on going, but figured it was time to end the experiment.

So, for those old Taco owners out there, keep a small tube of dielectric grease and a 10mm wrench in the glove box.

Cheers.
 
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