I am having a problem with the front bank vtec kicking out due to low oil pressure and getting a CEL 22 code (Front Vtec Oil Press Switch).
First some history on the car. The car is basically stock. I purchased the car this past Feb with 54k miles on it. From 2001 to June 2014 the car had only been driven maybe 6-7k miles and spent most of it's time in storage container until it was sold in June 2014 to the guy I purchased it from. When I bought the car it was still on the original timing belt so I had immediately put the car into the shop for extensive maintenance. After I got the car back I still had to replace the exhaust system and radiator and do some suspension work so the car was only occasionally driven. During a dyno run I did prior to installing the new headers and exhaust we found that the car was not putting out the HP it should have been putting out. After doing a lot of investigating we found that the new timing belt had jumped a tooth. At this point I decided to pull the motor to retime it and replace the LMA's. During the process is when I found that one front intake cam journal was wiped out. This then led to installing a new front head/cams/rockers. In the process Cometic head gaskets and all new seals and orings were installed. The oil was also changed from what had been 10/40 syn blend that the previous owner had been using to 10/30 Penzoil Utra Syn. The reason for why the journal wiped out is up for debate, but not part of this discussion. Prior to this I was not having any issues with the Vtec that I knew of, but the car was also not driven hard between the time I purchased it and when I found the bad bearing.
I've already eliminated the pressure switch as being the problem, so I now needed to test the system by a process of elimination. First was to do a high rpm test run while keeping a close eye on oil pressure. As RPMS increased into Vtec range I could hear and feel the Vtec come on, but as it did oil pressure dropped from 4.5-5 down to less than 1. Simultaneously the CEL light came (later determined to be a code 22). When this happened I immediately backed off of the throttle, and watched the oil pressure come back up to above 4. I then repeated the run and watched the same thing happen again. This is the first time I've seen this happen, but it's also the first time that I paid close attention to the oil pressure gauge while in vtec rpm range. On this car oil pressure runs anywhere from 1-2 at an idle and 4-4.5 at 3000-4500 rpms, which is normal. Since I just replaced the front cylinder head I was thinking that the oring seal on the vtec oil passage way fell out of position during reassembly and the oil for the vtec is just dumping without any restriction into top of the head, hence the low oil pressure after the valve is opened. To eliminate this possibility I first disconnected both Vtec solenoids and then did another high rpm run. This time pressure actually climbed to above 6 as rpm climbed, which was to be expected with no vtec operating to bleed down the pressure. Next I reconnected only the rear bank solenoid and repeated the run. This time oil pressure remained stable at about 4-4.5 throughout the rpm range including into vtec. I then disconnected the rear solenoid and reconnected the front, and repeated the run again. Again oil pressure remained stable, as it did with the rear bank, with oil pressure remaining at approximately 4.5. There was no severe oil pressure drop like I had with both vtecs engaged simultaneously.
It would appear that the oil pump can't keep up with the demand of both front and rear vtecs running simultaneously, and when the valves open pressure drops dramatically causing the ECM to sense low vtec oil pressure. What doesn't make sense is why am I getting only a code 22 for the front bank and not a 52 for the rear bank. I would think that if one cuts out due to low oil pressure (as indicated on the instrument panel gauge) the other should.
I've put close to 1000 miles on it since the head change and it doesn't appear that I have burned any oil, and there is no indication in the exhaust that I'm burning oil.
One thing to note is that when I purchased the car in Feb the previous owner was using 10/40 syn blend oil and I changed it to 10/30 following the head replacement. There is a remote possibility that the 40 wt oil he was using was masking an oil pressure issue and may have been raising pressure just enough to keep the Vtec engaged. It also may have contributed to the cam bearing failure.
First some history on the car. The car is basically stock. I purchased the car this past Feb with 54k miles on it. From 2001 to June 2014 the car had only been driven maybe 6-7k miles and spent most of it's time in storage container until it was sold in June 2014 to the guy I purchased it from. When I bought the car it was still on the original timing belt so I had immediately put the car into the shop for extensive maintenance. After I got the car back I still had to replace the exhaust system and radiator and do some suspension work so the car was only occasionally driven. During a dyno run I did prior to installing the new headers and exhaust we found that the car was not putting out the HP it should have been putting out. After doing a lot of investigating we found that the new timing belt had jumped a tooth. At this point I decided to pull the motor to retime it and replace the LMA's. During the process is when I found that one front intake cam journal was wiped out. This then led to installing a new front head/cams/rockers. In the process Cometic head gaskets and all new seals and orings were installed. The oil was also changed from what had been 10/40 syn blend that the previous owner had been using to 10/30 Penzoil Utra Syn. The reason for why the journal wiped out is up for debate, but not part of this discussion. Prior to this I was not having any issues with the Vtec that I knew of, but the car was also not driven hard between the time I purchased it and when I found the bad bearing.
I've already eliminated the pressure switch as being the problem, so I now needed to test the system by a process of elimination. First was to do a high rpm test run while keeping a close eye on oil pressure. As RPMS increased into Vtec range I could hear and feel the Vtec come on, but as it did oil pressure dropped from 4.5-5 down to less than 1. Simultaneously the CEL light came (later determined to be a code 22). When this happened I immediately backed off of the throttle, and watched the oil pressure come back up to above 4. I then repeated the run and watched the same thing happen again. This is the first time I've seen this happen, but it's also the first time that I paid close attention to the oil pressure gauge while in vtec rpm range. On this car oil pressure runs anywhere from 1-2 at an idle and 4-4.5 at 3000-4500 rpms, which is normal. Since I just replaced the front cylinder head I was thinking that the oring seal on the vtec oil passage way fell out of position during reassembly and the oil for the vtec is just dumping without any restriction into top of the head, hence the low oil pressure after the valve is opened. To eliminate this possibility I first disconnected both Vtec solenoids and then did another high rpm run. This time pressure actually climbed to above 6 as rpm climbed, which was to be expected with no vtec operating to bleed down the pressure. Next I reconnected only the rear bank solenoid and repeated the run. This time oil pressure remained stable at about 4-4.5 throughout the rpm range including into vtec. I then disconnected the rear solenoid and reconnected the front, and repeated the run again. Again oil pressure remained stable, as it did with the rear bank, with oil pressure remaining at approximately 4.5. There was no severe oil pressure drop like I had with both vtecs engaged simultaneously.
It would appear that the oil pump can't keep up with the demand of both front and rear vtecs running simultaneously, and when the valves open pressure drops dramatically causing the ECM to sense low vtec oil pressure. What doesn't make sense is why am I getting only a code 22 for the front bank and not a 52 for the rear bank. I would think that if one cuts out due to low oil pressure (as indicated on the instrument panel gauge) the other should.
I've put close to 1000 miles on it since the head change and it doesn't appear that I have burned any oil, and there is no indication in the exhaust that I'm burning oil.
One thing to note is that when I purchased the car in Feb the previous owner was using 10/40 syn blend oil and I changed it to 10/30 following the head replacement. There is a remote possibility that the 40 wt oil he was using was masking an oil pressure issue and may have been raising pressure just enough to keep the Vtec engaged. It also may have contributed to the cam bearing failure.
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