4B11 engine failure documentation thread
Jan 13, 2010, 02:09 PM
#1
4B11 engine failure documentation thread
I know quite a few have lost engines with piston issues and plugs hammering closed, overrevs, etc, but it would be cool to have a master thread where we could keep up with it.
1) Mileage at failure
2) Symptoms of failure
3) Cause of failure
I know it takes guts to post up in this thread, but we can all learn from each other and hopefully save someone else's engine.
1) Mileage at failure
2) Symptoms of failure
3) Cause of failure
I know it takes guts to post up in this thread, but we can all learn from each other and hopefully save someone else's engine.
Jan 14, 2010, 01:35 PM
#2
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1.) 17000 miles @ failure
2.) Hole through side of block, at least 1 broken rod. Led to an oil fire which destroyed 1/3 of my engine bay. No symptoms up until catastrophic failure.
3.) Stock rod was either defective or they simply cannot handle 32+ psi on a CBRD BB-X turbo. From what I can see currently, the rod split clean in half and the big end is still in tact.
Moral of the story, the stock rods are weak as hell. I honestly spiked to about 36-38 psi 3 times on 3 partial pulls when I had some mapping issues with EcuFlash. That probably produced a torque spike of ~500 lb-ft which weakened one of the rods.
Oddly, the failure happened in 5th gear under 1/2 throttle while passing somebody going under the speed limit on I-29. I would convert back to stock and make the dealer fix it, but I honestly don't want another stock block that is incapable of handling a decent 450-500 WHP.
No tuning issues. 2-3 counts of knock max. 11.6 AFR with a large shot of methanol/water. Very conservative timing. 30-32 psi straight across from 3500 to 7500 rpm.
Must have just been too much for the stock bottom end to handle. *shrugs*
I'll find out soon if it was rod bolt failure, but it honestly doesn't look like that is the case. Nor should it have been because I neither make much torque nor rev past 7600 rpm.
edit: There are my modifications:
CBRD BB-X turbo, ported exhaust manifold & turbine housing, Invidia DP/TP/N1 catback, Cobb Intake + Inlet hose
Custom UICP, Snow Performance CH3OH/H2O injection, AMS inline fuel pump, 1000 cc/min DW injectors, Cossy fuel rail (doesn't matter, but just illustrating the adequacy of my fuel system), replaced OEM fuel relay w/ green one
2.) Hole through side of block, at least 1 broken rod. Led to an oil fire which destroyed 1/3 of my engine bay. No symptoms up until catastrophic failure.
3.) Stock rod was either defective or they simply cannot handle 32+ psi on a CBRD BB-X turbo. From what I can see currently, the rod split clean in half and the big end is still in tact.
Moral of the story, the stock rods are weak as hell. I honestly spiked to about 36-38 psi 3 times on 3 partial pulls when I had some mapping issues with EcuFlash. That probably produced a torque spike of ~500 lb-ft which weakened one of the rods.
Oddly, the failure happened in 5th gear under 1/2 throttle while passing somebody going under the speed limit on I-29. I would convert back to stock and make the dealer fix it, but I honestly don't want another stock block that is incapable of handling a decent 450-500 WHP.
No tuning issues. 2-3 counts of knock max. 11.6 AFR with a large shot of methanol/water. Very conservative timing. 30-32 psi straight across from 3500 to 7500 rpm.
Must have just been too much for the stock bottom end to handle. *shrugs*
I'll find out soon if it was rod bolt failure, but it honestly doesn't look like that is the case. Nor should it have been because I neither make much torque nor rev past 7600 rpm.
edit: There are my modifications:
CBRD BB-X turbo, ported exhaust manifold & turbine housing, Invidia DP/TP/N1 catback, Cobb Intake + Inlet hose
Custom UICP, Snow Performance CH3OH/H2O injection, AMS inline fuel pump, 1000 cc/min DW injectors, Cossy fuel rail (doesn't matter, but just illustrating the adequacy of my fuel system), replaced OEM fuel relay w/ green one
Last edited by UT_EvoX; Jan 15, 2010 at 06:05 PM.
Jan 14, 2010, 02:39 PM
#3
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1.) 17000 miles @ failure
2.) Hole through side of block, at least 1 broken rod. Led to an oil fire which destroyed 1/3 of my engine bay. No symptoms up until catastrophic failure.
3.) Stock rod was either defective or they simply cannot handle 32+ psi on a CBRD BB-X turbo. From what I can see currently, the rod split clean in half and the big end is still in tact.
Moral of the story, the stock rods are weak as hell. I honestly spiked to about 36-38 psi 3 times on 3 partial pulls when I had some mapping issues with EcuFlash. That probably produced a torque spike of ~500 lb-ft which weakened one of the rods.
Oddly, the failure happened in 5th gear under 1/2 throttle while passing somebody going under the speed limit on I-29. I would convert back to stock and make the dealer fix it, but I honestly don't want another stock block that is incapable of handling a decent 450-500 WHP.
No tuning issues. 2-3 counts of knock max. 11.6 AFR with a large shot of methanol/water. Very conservative timing. 30-32 psi straight across from 3500 to 7500 rpm.
Must have just been too much for the stock bottom end to handle. *shrugs*
I'll find out soon if it was rod bolt failure, but it honestly doesn't look like that is the case. Nor should it have been because I neither make much torque nor rev past 7600 rpm.
2.) Hole through side of block, at least 1 broken rod. Led to an oil fire which destroyed 1/3 of my engine bay. No symptoms up until catastrophic failure.
3.) Stock rod was either defective or they simply cannot handle 32+ psi on a CBRD BB-X turbo. From what I can see currently, the rod split clean in half and the big end is still in tact.
Moral of the story, the stock rods are weak as hell. I honestly spiked to about 36-38 psi 3 times on 3 partial pulls when I had some mapping issues with EcuFlash. That probably produced a torque spike of ~500 lb-ft which weakened one of the rods.
Oddly, the failure happened in 5th gear under 1/2 throttle while passing somebody going under the speed limit on I-29. I would convert back to stock and make the dealer fix it, but I honestly don't want another stock block that is incapable of handling a decent 450-500 WHP.
No tuning issues. 2-3 counts of knock max. 11.6 AFR with a large shot of methanol/water. Very conservative timing. 30-32 psi straight across from 3500 to 7500 rpm.
Must have just been too much for the stock bottom end to handle. *shrugs*
I'll find out soon if it was rod bolt failure, but it honestly doesn't look like that is the case. Nor should it have been because I neither make much torque nor rev past 7600 rpm.
- Bryan
Jan 14, 2010, 04:24 PM
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Jan 14, 2010, 06:07 PM
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Detonation will melt a piston and render that cylinder compressionless before it snaps a rod. Especially at 3400 rpm on the highway. Didn't I mention that's when/how my engine failed? Wasn't detonation, I guarantee every plug is in perfect condition except for a single one which is now smashed in by a loose piston.
In fact, I'll go pull them right now once I chisel off the fire-melted coils...
I've experienced every other kind of engine failure. EVERY other kind. But never a snapped rod and vented block. Learn more about the 4B11 before you spout off detonation to somebody who has a bit of engine-building and tuning experience under their belt...
edit: anyway, I pulled the plugs and 3 are heavily fouled, 1 is not so much. Probably the last cylinder that actually was firing before my wiring harness melted. All 4 show NO signs of ground strap erosion/damage, porcelain damage, or electrode erosion of any kind. None of the gaps are closed at all, the plugs are fine. These didn't come from an engine that was experiencing enough detonation to snap a rod and vent its block.
In fact, I'll go pull them right now once I chisel off the fire-melted coils...
I've experienced every other kind of engine failure. EVERY other kind. But never a snapped rod and vented block. Learn more about the 4B11 before you spout off detonation to somebody who has a bit of engine-building and tuning experience under their belt...
edit: anyway, I pulled the plugs and 3 are heavily fouled, 1 is not so much. Probably the last cylinder that actually was firing before my wiring harness melted. All 4 show NO signs of ground strap erosion/damage, porcelain damage, or electrode erosion of any kind. None of the gaps are closed at all, the plugs are fine. These didn't come from an engine that was experiencing enough detonation to snap a rod and vent its block.
Last edited by UT_EvoX; Jan 14, 2010 at 06:30 PM.
Jan 14, 2010, 07:13 PM
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Tuning an Evo X is quite easy to do.
If the motor tanks from the relay the car WILL be covered under warranty.
the failures that we have seen occur can only come from an EXTREMELY lean (like16:1 afr) condition
you cannot tune a car that lean without intentionally trying to blow up said car.
When the fuel pump relay fails, the fuel pump does not get full voltage and there fore not full flow
when that happens the car goes EXTREMELY lean and the mixture in the cyl as it compresses,
heats up and can ignite the very lean mixture very easily before the spark event and that is what shoves the piston down and breaks the rod.
If the motor tanks from the relay the car WILL be covered under warranty.
the failures that we have seen occur can only come from an EXTREMELY lean (like16:1 afr) condition
you cannot tune a car that lean without intentionally trying to blow up said car.
When the fuel pump relay fails, the fuel pump does not get full voltage and there fore not full flow
when that happens the car goes EXTREMELY lean and the mixture in the cyl as it compresses,
heats up and can ignite the very lean mixture very easily before the spark event and that is what shoves the piston down and breaks the rod.
Jan 14, 2010, 07:18 PM
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Tuning an Evo X is quite easy to do.
If the motor tanks from the relay the car WILL be covered under warranty.
the failures that we have seen occur can only come from an EXTREMELY lean (like16:1 afr) condition
you cannot tune a car that lean without intentionally trying to blow up said car.
When the fuel pump relay fails, the fuel pump does not get full voltage and there fore not full flow
when that happens the car goes EXTREMELY lean and the mixture in the cyl as it compresses,
heats up and can ignite the very lean mixture very easily before the spark event and that is what shoves the piston down and breaks the rod.
If the motor tanks from the relay the car WILL be covered under warranty.
the failures that we have seen occur can only come from an EXTREMELY lean (like16:1 afr) condition
you cannot tune a car that lean without intentionally trying to blow up said car.
When the fuel pump relay fails, the fuel pump does not get full voltage and there fore not full flow
when that happens the car goes EXTREMELY lean and the mixture in the cyl as it compresses,
heats up and can ignite the very lean mixture very easily before the spark event and that is what shoves the piston down and breaks the rod.
AMS in-line fuel pump, Cossy fuel rail, DW 1000's, replaced OEM pump relay. I also check at every fill up to make sure I can hear the inline pump running. It had still been running.
A defective fuel pump relay didn't kill my engine. The rod was likely compromised when I boost spiked due to a glitch in the EcuFlash mappings (I actually created a warning thread about it). I saw over 400 load (400 is the max EvoScan logs in my case) twice that day, and roughly the next day the engine failed at relatively low, 5th gear passing load. The few boost spikes up to God knows how much boost pressure probably did my engine in with WAYYYY too much torque.
Not really complaining, I wanted to build a lower-end anyway, just not right this moment.
Last edited by UT_EvoX; Jan 14, 2010 at 07:20 PM.
Jan 14, 2010, 07:20 PM
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EDIT: Nevermind found your thread: https://www.evolutionm.net/forums/ev...ward-wgdc.html
You said spikes of over 40 in that thread. That will do it.
- Bryan
Jan 14, 2010, 07:24 PM
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This one: https://www.evolutionm.net/forums/ev...ward-wgdc.html
When it happened, I honestly thought I had a bad flash. I made a good guess on the side of the road after the spikes, and flashed back with the -64 value, and all was good. Honestly I shouldn't have messed with the downward compensation value, but I figured I would to minimize the severity of a potential full boost cut, considering I only have a single solenoid now.
Thanks for the input.
When it happened, I honestly thought I had a bad flash. I made a good guess on the side of the road after the spikes, and flashed back with the -64 value, and all was good. Honestly I shouldn't have messed with the downward compensation value, but I figured I would to minimize the severity of a potential full boost cut, considering I only have a single solenoid now.
Thanks for the input.
