No VTEC - Narrowed To Mechanical
05-06-2013, 06:44 AM
#1
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No VTEC - Narrowed To Mechanical
I've recently been trying to diagnose a series of issues with my engine. I think most have been fixed, but now I've got one final hurdle: no VTEC.
We've had the car on the dyno and everything looks good up until the VTEC engagement point. Then it actually loses power, as the ECU attempts to go into VTEC and starts dumping fuel into the car. It continues to run on the lower cam profiles though, starving it of air and running it rich, which drops the power even from the non-VTEC levels.
All the signals are good (obviously, since the ECU thinks it's in VTEC) and we've swapped the solenoid/spool valve with a known working one. This makes me think there is a mechanical issue with VTEC inside the head. As part of the engine work, I had the cams out and the head off. Could I have forgotten to put something back in during reassembly? Would a missing pin cause this sort of issue (i.e. would the oil dump out from that rocker and flood the head instead of pressurizing the system or would just that set of cam followers fail to engage while the rest did...not exactly sure how this works)?
I've got another head siting around with a bent valve so I should have some spare parts to work with, I just need to know what I'm looking for! Thanks!
We've had the car on the dyno and everything looks good up until the VTEC engagement point. Then it actually loses power, as the ECU attempts to go into VTEC and starts dumping fuel into the car. It continues to run on the lower cam profiles though, starving it of air and running it rich, which drops the power even from the non-VTEC levels.
All the signals are good (obviously, since the ECU thinks it's in VTEC) and we've swapped the solenoid/spool valve with a known working one. This makes me think there is a mechanical issue with VTEC inside the head. As part of the engine work, I had the cams out and the head off. Could I have forgotten to put something back in during reassembly? Would a missing pin cause this sort of issue (i.e. would the oil dump out from that rocker and flood the head instead of pressurizing the system or would just that set of cam followers fail to engage while the rest did...not exactly sure how this works)?
I've got another head siting around with a bent valve so I should have some spare parts to work with, I just need to know what I'm looking for! Thanks!
05-06-2013, 07:42 AM
#3
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That's sort of the direction I'm leaning. I thought I had them all in, but I guess there's an outer pin and an inner pin or something like that? I'm not sure I was keeping track of multiple pins per set.
What would the symptoms/result of a missing pin be?
What would the symptoms/result of a missing pin be?
05-06-2013, 11:36 AM
#6
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Also, I didn't mean for it to be a leading question. Are there other components that could either fail or be left out that would cause a similar problem?
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