VTEC sputtering/quits after 2-6 hits
07-29-2013, 11:22 PM
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VTEC sputtering/quits after 2-6 hits
This has been going on for months now, we've tried every fix we can think of, and I can't find anyone reporting this exact issue.
Symptoms:
VTEC usually engages normally the first time, but each successive use within the same run gets worse by sputtering (the VTEC engagement, not the engine) at the crossover point and sputters worse and worse throughout the upper rev range until it stops going into VTEC at all after about the 4-5th hit and triggers limp mode after about 7th/8th attempt to rev past 6k at full throttle. (engine won't rev past 6k in limp mode, resets by turning the ignition off/back on.) Otherwise the engine runs smooth when not at full throttle and will rev all the way to red line smoothly.
Sometimes during this failing VTEC process, there is an odd sound like paper flapping in the wind...it's quite loud and I'm not sure if it's coming from the exhuast or the engine bay.
Remedies we've tried:
*EDIT - NEW*
Replaced oil pump with new unit.
Still no cure...starting to think something in the head is causing it now....
Oil level is good, car is warm.
We have 2 AP1s, my wife's hits VTEC every time, strong.
We swapped VTEC assemblies.
We swapped MAP sensors.
Tried the MAP whack.
Cleaned all electrical connectors and zip-tied the MAP sensor connector.
Removed air intake to rule out air filter issues.
Changed spark plugs.
Ran injector cleaner.
Cleaned VTEC module and screen. (no dirt)
Removed valve cover and inspected/checked valve lash.
Unplugged VTEC module completely - Motor pulls smooth to redline but triggers limp mode after about 2 pulls with a "VTEC Failure" code showing.
At this point I'm starting to think the oil pump is not supplying enough pressure. Oil is not lightweight, 10w30, and oil light never comes on, but the car has 140k miles. Engine was rebuilt about 30k miles ago (VTEC worked fine first 20k miles or so) and oil pump was not replaced since it was working fine and they're so simple. The rebuild was done as a result of failing bearings though, (GET magnetic drain plugs for your cars, engine savers!) and there were pieces of brass/steel in the oil pan and oil pump that were cleaned out.
Another indicator of oil pressure issues is a Timing Chain Tensioner (TCT) SOUNDING rattle but not at idle like normal. I have a new TCT, sandblasted the worm gear and inner housing to eliminate idle rattle, but now it SOUNDS like TCT rattling at 2500-4000rpm...maybe higher but I can't hear it over exhaust/road/wind noise.
I'm open to any suggestions at this point before we tackle replacing the oil pump. I plan to verify oil pressure issues first with a pressure gauge, but haven't done that yet. Any other areas you guys can suggest we investigate?
Symptoms:
VTEC usually engages normally the first time, but each successive use within the same run gets worse by sputtering (the VTEC engagement, not the engine) at the crossover point and sputters worse and worse throughout the upper rev range until it stops going into VTEC at all after about the 4-5th hit and triggers limp mode after about 7th/8th attempt to rev past 6k at full throttle. (engine won't rev past 6k in limp mode, resets by turning the ignition off/back on.) Otherwise the engine runs smooth when not at full throttle and will rev all the way to red line smoothly.
Sometimes during this failing VTEC process, there is an odd sound like paper flapping in the wind...it's quite loud and I'm not sure if it's coming from the exhuast or the engine bay.
Remedies we've tried:
*EDIT - NEW*
Replaced oil pump with new unit.
Still no cure...starting to think something in the head is causing it now....
Oil level is good, car is warm.
We have 2 AP1s, my wife's hits VTEC every time, strong.
We swapped VTEC assemblies.
We swapped MAP sensors.
Tried the MAP whack.
Cleaned all electrical connectors and zip-tied the MAP sensor connector.
Removed air intake to rule out air filter issues.
Changed spark plugs.
Ran injector cleaner.
Cleaned VTEC module and screen. (no dirt)
Removed valve cover and inspected/checked valve lash.
Unplugged VTEC module completely - Motor pulls smooth to redline but triggers limp mode after about 2 pulls with a "VTEC Failure" code showing.
At this point I'm starting to think the oil pump is not supplying enough pressure. Oil is not lightweight, 10w30, and oil light never comes on, but the car has 140k miles. Engine was rebuilt about 30k miles ago (VTEC worked fine first 20k miles or so) and oil pump was not replaced since it was working fine and they're so simple. The rebuild was done as a result of failing bearings though, (GET magnetic drain plugs for your cars, engine savers!) and there were pieces of brass/steel in the oil pan and oil pump that were cleaned out.
Another indicator of oil pressure issues is a Timing Chain Tensioner (TCT) SOUNDING rattle but not at idle like normal. I have a new TCT, sandblasted the worm gear and inner housing to eliminate idle rattle, but now it SOUNDS like TCT rattling at 2500-4000rpm...maybe higher but I can't hear it over exhaust/road/wind noise.
I'm open to any suggestions at this point before we tackle replacing the oil pump. I plan to verify oil pressure issues first with a pressure gauge, but haven't done that yet. Any other areas you guys can suggest we investigate?
07-30-2013, 02:46 AM
#2
One thing i would have done that you didn't mention is pulling the valve cover to take a look inside ( roller, rocker, valve lash ect )
After maybe i would try and bypass that vtec solenoid just to see if the problem persist higher than 6k.
Maybe your oil pump didn't like eating all that brass and metal. I would buy a cheap guage and check for pressure fluctuation in " vtec "
That's all I can think of right now
Good luck
After maybe i would try and bypass that vtec solenoid just to see if the problem persist higher than 6k.
Maybe your oil pump didn't like eating all that brass and metal. I would buy a cheap guage and check for pressure fluctuation in " vtec "
That's all I can think of right now
Good luck
07-30-2013, 07:59 AM
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Thank you for the suggestions. I forgot to mention that we did remove the valve cover and inspect/check the valve lash, and we did unplug the VTEC completely and it runs smooth all the way to redline but triggers limp mode pretty quickly after one or two pulls with a "VTEC Failure" code showing. I'm going to edit and add those to the list of stuff we've tried.
07-30-2013, 11:59 AM
#6
I'd definitely look into the oil pump. What usually happens when bearing material is run through the pump is the lobes and walls of the pump get scarred up allowing blow-by and a lower oil pressure. Chances are the clearance has widened just slightly more from when the rebuild was done. Theres probably enough oil pressure to keep your light from coming on but not quite enough for VTEC to function properly. I'd say it's pretty clear cut and simple, replace the oil pump. I'm about 99.9% sure that's causing your issues. 
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08-28-2013, 10:58 AM
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Ok just an update for those who might be having this same issue in the future...
We swapped out the oil pump for a new one, no change. I'm starting to think it might be something in the head, so we me swap that out with a spare AP1 motor a friend has in the near future. Only other thing left to suspect is computer/controller but the fact that it only happens when things get heated up seems to contradict that possibility.
We swapped out the oil pump for a new one, no change. I'm starting to think it might be something in the head, so we me swap that out with a spare AP1 motor a friend has in the near future. Only other thing left to suspect is computer/controller but the fact that it only happens when things get heated up seems to contradict that possibility.
08-28-2013, 11:14 AM
#10
Did you reuse your oil heat exchanger in the rebuild?
Bearing material is generally non-ferrous metal, so a magnet won't do anything. They also generally do not take out the oil pump if caught quick enough because it is much softer metal. Measuring clearances after cleaning off bearing material will show you how healthy the pump is.
Bearing material is generally non-ferrous metal, so a magnet won't do anything. They also generally do not take out the oil pump if caught quick enough because it is much softer metal. Measuring clearances after cleaning off bearing material will show you how healthy the pump is.