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firstalltrac
04-26-2008, 05:04 AM
I know a guy that has a 90ish celica alltrac that I have been thinking really hard about buying. He put a full JDM motor in it, a 3 inch downpipe and a BOV (not sure the brand). The battery has also been relocated to the rear. The problem is that since he installed the downpipe and BOV the car runs really rich. Fouls the plugs and blows black smoke. Does anyone here have any ideas of what would be causing this?

Also could you tell me what the difference is between the JDM motors and the stock ones?

Thanks

Shadowlife25
04-26-2008, 05:39 AM
The problem you are experiencing is common with the ST185 when an open atmosphere BOV is used.

Our cars use a flapper style AFM (air flow meter)

The AFM sends it's signal to the ECU, then the ECU takes into account the correct amount of fuel for the volume of air present. When you use an open atmosphere BOV, the air that the ECU "sees" is no longer present, but the fuel necessary for it IS. Hence the overly-rich condition.

The good news is that the fix for this is simple: instead of blowing the air out to open atmosphere, you recirculate it back into the intake (after the AFM ;) )

If you have any other questions, feel free, and welcome to C-Tech! :D

firstalltrac
04-26-2008, 05:21 PM
Do you think that a BOV is really needed on these cars? I also forgot to mention that it has a cold air intake on it also. He had to have the pipe modified to fit the BOV. I would have to assume that I would have to do the same thing to get the air back into it.
Do you have any certain areas on the intake that you think would be the best for this?

Also, I was wondering what the difference between the JDM complete motors and the stock ones are?

91 Celica GT-S
04-26-2008, 08:04 PM
i think ppl get blow off valves just for the sound

firstalltrac
04-27-2008, 12:33 AM
I do too. I personally do not like the sound they make. I prefer it to be silent as much as possible. That is why I am thinking that i will probably just take it off if there is really no reason to keep it on there.

We tried to start the car today...It has been sitting for awhile...but it would not start. seems like it is not getting any fuel to the motor. I know that some cars you can hear the fuel pump kick on when you first turn on the key. I tried it but i could not hear anything. The pumps are in the tanks, right? It is a 91 model year. Should I be able to hear it? Also, do these cars have a relief valve on the fuel rail somewhere to check for fuel pressure?

Uncrck2
04-27-2008, 01:06 AM
how do u make the bov recirculate i dont get wat u mean?

Shadowlife25
04-27-2008, 10:05 AM
Some BOV's have a smaller opening that you can use some vacuum line on to re-circulate back into the intake. Others you need to purchase a kit from the manufacturer (like Greddy)

A BPV (bypass valve) already works by re-circulating the air back into the intake.

The advantage of a BPV or BOV is that it helps to reduce spool time and helps prevent compressor surge. That's it.

Shadowlife25
04-27-2008, 10:09 AM
I do too. I personally do not like the sound they make. I prefer it to be silent as much as possible. That is why I am thinking that i will probably just take it off if there is really no reason to keep it on there.

We tried to start the car today...It has been sitting for awhile...but it would not start. seems like it is not getting any fuel to the motor. I know that some cars you can hear the fuel pump kick on when you first turn on the key. I tried it but i could not hear anything. The pumps are in the tanks, right? It is a 91 model year. Should I be able to hear it? Also, do these cars have a relief valve on the fuel rail somewhere to check for fuel pressure?


You'll find the diagnostic port by the firewall on the drivers side. Use a small paper clip to jumper ports FP and B+. your fuel pump should kick on.

For testing questions, you should be able to find everything you'll need in the BGB (Big Green Book) You can access it on the home page here since you are a member ;)

Uncrck2
04-27-2008, 11:09 PM
does a bpv make the bov sound cuz i know sounds gay but i like the sound and i wanna have that and if not u know of any bov that i can make recirculate and will it still make the sound?

Nitro_Alltrac
04-28-2008, 02:54 AM
If you recirculate the BOV, you're not really going to get any sound. The sound comes from the air rushing out of the BOV into the open atmosphere.

Main difference between JDM and North American 3SGTE engine is the JDM unit has no EGR valve and should have a ceramic turbine blade. USDM will have an EGR and a steel blade. There maybe some other differences, but these are the main ones. I have a JDM engine in mine and haven't had any issue with anything. Up till recently, it was running on the USDM ECU without problem. I have put a JDM ECU in there now (thought I was having an issue with the original one, but was wrong), no problems now either.

firstalltrac
05-01-2008, 09:55 PM
I am going to try the paperclip on the two ports this weekend. Would it be safe to assume that if the pump does not come on when I do that it is a sign of a bad pump?

Nitro_Alltrac
05-02-2008, 10:07 PM
Probably a pretty good chance. Doing this bypasses the fuel pump relay and puts power straight to the pump. If it's good, it should power up.

Shadowlife25
05-02-2008, 11:04 PM
Probably a pretty good chance. Doing this bypasses the fuel pump relay and puts power straight to the pump. If it's good, it should power up.

Exactly. No sound of pump running = Bad pump

Please be sure to post back with your findings :)

firstalltrac
05-06-2008, 10:59 PM
Well, we tried the paperclip on the ports and still could not hear the pump. The car has been driven since the motor was put into the car, but it has been just sitting for awhile now. He does not remember when the last time he drove it. Do you think that the fuel pump would just go bad from sitting? Also, could you tell me where the fuel filter is? Part of the troubleshooting says to remove the line and check for fuel.

Thank you for all of your help.

Shadowlife25
05-07-2008, 12:11 AM
The fuel filter is located towards the firewall. It is UNDER the charcoal canister and cruise-control actuator.