Grey_Ej

Hello there H-T,

I have a 1998 Honda Civic ex that I have just swapped a Sir-II b16a into. I live in California so I'm going to have to take it to the referee to get a bar label. I have visited them once already and my car failed due to visual tampering and all of the computers test had not run. The only thing wrong with it is that I had not installed a purge joint before the evap purge solenoid. Also my computer ha not run the evap system test. The computer finally ran this test and now I am getting a CEL for codes p0451 (fuel tank pressure sensor range/performance) and p0453 (fuel tank pressure sensor high input).

Before doing this swap I had no trouble with my FTP sensor and I have also tried approximately 3 other sensors. Any input would be really appreciated, thank you.

Grey_Ej

anyone, have an idea what to do?

Grey_Ej

bump, anyone?

Grey_Ej

Still in need of some help.

Grey_Ej

bump. When I test the FTP voltage at the computer after resetting the ecu and with the gas cap off (the way the book tells me to diagnose it) I come up with around 2.7v which then the diagnostic tells me is a faulty sensor and to replace it. Since I have done this with no success, could it be that my computer is bad?

HondaPartsHero

What ecu are you using?

dueyx99

the high input is almost as if the connector is unplugged, but obviously its not, since you have already replaced the sensor a few times, id say check for 5V at the at tank with the sensor unplugged, also check for decent continuity on the signal wire to ecu

dueyx99

also, what purge joint are you missing?

Grey_Ej

@HPH I'm running a usdm P2T.

@Dueyx, I'm going to test that in morning and I'll post what happens.

Thank you for the input on this, I appreciate it

Edit: I was missing the purge joint near the Evap purge solenoid, I have it installed now though

HondaPartsHero

Try this
http://technet.ff-squad.com/code91.htm

doctorake

Fooling the ECU will not allow you to pass, isn't a P2T obd2B and your chasis is OBD2A?

You could always grab a P30 from a del sol, that won't look for the FTP sensor.

Grey_Ej

@HPH I've looked at that page a couple times but like doctorake said, fooling it might not work and I'd like to solve this problem where it is.

@doctorake Yes, my chasis is OBD2A, which I have repinned to be plug n play with my OBD2B computer. The repinning was pretty easy, expect I couldn't find where SHO2SG went, so I have it grounded to the frame. I don't think this is has an affect on my FTP sensor though, and my secondary 02 throws no code.

Also, I don't think I can pass california emissions (BAR) with a P30 because I have to use everything from a 99-00 Civic Si.

doctorake

I think the repinning is your problem, I have never seen anyone do one correctly on this forum.

Grey_Ej

@doctorake If so, which wires should I double check at the ECU? The only one I know coming straight from the FTP is a light green one on connect A, pin 29.

Grey_Ej

bump. I checked the wires at the ECU for the FTP sensor and they are all in their right spot.

Grey_Ej

So I just went and unplugged the fuel tank pressure near the tank and took some voltage readings. I used my multimeter to teset the wires on the harness and not the sensor itself. It looks like I am getting the normal 5v reference, but when I check voltage between the FTP signal wire and the ground, it reads 4.59v. Correct me if I'm wrong, but shouldn't it read 0v? I thought the sensor sent the singal, so why would i have the 4.59v coming from the computer?

sive

you can use a p30. Im not from ca but what ive gathered is when using a b16 you need it to be complete. It doesnt matter if its a 97 del sol or a 99 si. there both b16 us computers and you just need everything that goes along with that engine... obd2 p30 evap consists of a purge sol and char can. period. no ftps.

5v with key on, engine off should be your power. If you used that power source to test ground and you got 5v then the ground is good. If you get 0 it means there is no ground. after reading everything id say you have a pressure issue not a wire/sensor issue. when you turn the key to on do you hear any air escaping. if not maybe a hole in tubing, gas cap off/not tight/bad...

Grey_Ej

Thanks for the reply Sive. I'm going to go pick up new hoses and see if that's it although I don't hear or see signs of a leak. Hopefully that's the problem, because I'd really like to get my car registered so I can finally drive around. As for the ecu, I was under the impression that you can only pass the ref with an engine from the same model and newer. Since the p30 is only in the del-sol, wouldn't that mean I can't use it? Even though it is still a b16a2.

Grey_Ej

So I replaced all the evap tubing on the tank side and I'm still getting a CEL. Should I try replacing the gas cap next? I wish I could try another known good computer, but I don't know anyone with a P2T.

doctorake

Are you still using an OBD2B harness in an OBD2A car? As far as I have seen no one has ever done this without switching out the cabin harness also.

Grey_Ej

No, I'm using the Obd2a harness that came out of the car (98 ex). All I did was repin the pig tails using diagrams from ff-squad, and had to ground the secondary heated o2 sensor ground to the chasis. Everything electronically works fine, the car runs great, but whenever I reset the ecu it takes the car until the next morning for the CEL to come on. I'm really baffled, and need to be able to drive this car when school starts up in a couple weeks. I'm not sure what else to do though.

HondaPartsHero

Interesting as I just glanced at the Civic FSM and the 96-98 Civics with the code P0453 show a 3 pin connector for this sensor and the 99-00 Show a 6 pin connector (5 wires used). That may be part of your issue there but I'll try to post pics later.

Grey_Ej

That's interesting, I'd really appreciate more info on that. Thanks HPH

dueyx99

a quick glance at the pinouts for obd2a vs obd2b, you can see that the signal for the FTP is located on connector D pin 15 for obd2a, but its located on connector A pin 29 for obd2b, easy enough to switch around

Grey_Ej

That is correct, but that is also how I already have it placed.