Celica Swapped 1JZ - In need of Fuel Pressure Regulator?

[SupraFreak13]

I'm trying to get my 1JZ celica running right. When driving, the motor sputters/cuts out if I get on the throttle heavy, and when the boost gets at or near positive PSI. I have been searching SM since Jan and I've tried lots of things that I found here, but haven't solved the problem. It has;

-Walbro 255 external pump, new braided steel fuel feed, using the OEM celica feed line as the return.
-JDM 440cc injectors
-3" turbo back exhaust
-2.5"/3" intercooler pipes with decent sized front mount
-NGK BKR7E plugs .032 gap that they came with.
-HKS SSQV

The most recent progress I had is when I hooked up a fuel pressure guage. It is 30-35psi at idle. Just yesterday I took it out and when I get on the gas and the motor is about to boost, it cuts out, and the Fuel pressure drops to around 20psi...From that I would think it's the Regulator. I have not checked the voltage at the pump, is it more likely the regulator or the pump voltage?

If anybody has an OEM 1JZ regulator that you know is good I'm trying to buy one to see if that is the problem. I was thinking about getting an Aeromotive, but I don't want to spend the cash if I'm not positive that's the problem.

any help would be greatly appreciated, and if someone has a 1JZ regulator please let me know!

 

[OneJSupra]

I have stock 1jz fuel regulator. pm sent.

 

[pnutcar]

First thing I'd say is that ur plugs are gapped wrong. Stock is .028, and I run .0255 on mine. You might also want to look into some ngk 6097s. I know my stock fpr is good, Ill look for it when I get home and shoot you a good deal.

-Todd

 

[suprastanger507mgte]

Sounds more like your TPS needs re-adjustment. Running your plug gap at .032 is fine and within specs. People run lower gapping to cure higher rev spark blowout.

You should also check to makse sure the vacum is plugged at the map sensor.

 

[SupraFreak13]

Sounds more like your TPS needs re-adjustment. Running your plug gap at .032 is fine and within specs. People run lower gapping to cure higher rev spark blowout.

You should also check to makse sure the vacum is plugged at the map sensor.

I don't think the plug gap would be doing this either, I'm not trying to increase boost, just get it to run. I was suspicious of the TPS since I had taken it off, but after calibrating it to specs I found here it was still the same.

What do you mean check to make sure the vacuum is plugged at the MAP? Make sure it's tight and not leaking at the MAP sensor?

 

[suprastanger507mgte]

I don't think the plug gap would be doing this either, I'm not trying to increase boost, just get it to run. I was suspicious of the TPS since I had taken it off, but after calibrating it to specs I found here it was still the same.

What do you mean check to make sure the vacuum is plugged at the MAP? Make sure it's tight and not leaking at the MAP sensor?

Yeah make sure the vacum is from the intake manifold and not leaking or kinked. If in doubt, change the hose altogether.
Check to make sure all the coil plugs are inserted properly and fully contacting. Sometimes bad coil plugs can back out from vibration.
what procedure are you using to calibrate the TPS?

 

[pnutcar]

PM'd about fpr.

 

[SupraFreak13]

Yeah make sure the vacum is from the intake manifold and not leaking or kinked. If in doubt, change the hose altogether.
Check to make sure all the coil plugs are inserted properly and fully contacting. Sometimes bad coil plugs can back out from vibration.
what procedure are you using to calibrate the TPS?

The vacuum line is new and good, I'll put a zip tie on the MAP side. My coils are bolted down, though one is cracked I don't think it would cause the problem I've having.

I used this procedure for my TPS. I'll admit it ran better after that, especially the tip-in, but it still has the same breaking up problem at heavy throttle/boost. I have a good OEM regulator on the way thanks to pnutcar, so hopefully that will be what it is.

To adjust it, stick a continuity meter across E2 and IDL (I think those are the pins), stick a 0.4mm (not a 0.6mm like the 2JZ) spacer between the throttle adjustment screw, and the stop on the throttle, then adjust the TPS so it JUST reaches continuity. Then double check that <0.4mm has continuity, and >0.4mm doesn't. It's VERY tricky to get right, and may take you a couple tries.

 

[Turbo Drifter]

I had a MAP sensor go bad over night, swapped in a spare and was all good. It did the same thing right as it was coming into boost it would cut out.

 

[S.A. supra]

any pics?

 

[annoyingrob]

Sounds like a map sensor. The fuel pressure dropping when you cut is likely a product of engine vacuum when it cuts, and your motor starts decelerating.

 

[SupraFreak13]

Sounds like a map sensor. The fuel pressure dropping when you cut is likely a product of engine vacuum when it cuts, and your motor starts decelerating.

Is there any easy way to test the MAP out of the car? I haven't figured out how to get some probes into the wires without cutting the sheath. Can I test it at the ECU? It doesn't help that there is only a few inches of the MAP harness coming out of the firewall, behind the intake manifold, so it's really hard for me to get any probes near the plug...I read the write up on comparing the 1JZ and 2JZ map sensors, and he used a USB cable for 5V power somehow, the hooked up a vacuum tester and checked the voltages that way...

any pics?

Do you want a specific picture? I have most of my pics of it in my album
http://www.supramania.com/forums/album.php?albumid=384

I'm going to try the Fuel Pressure Regulator that's on the way, and if that doesn't help I'll be looking for a MAP sensor.

 

[SupraFreak13]

Ok, the fuel pressure regulator came today and I installed it...only to find it running worse! Now it idles around 30-32ps, and when I pull the vacuum line off the needle bounces between around 36-42psi as fast as the needle will move.

Now,when parked, if I give it more than 1/4 throttle it usually won't rev and breaks up. If I just crack the throttle the RPMs will rise steadily, and the Fuel pressure drops until the motor starts breaking up and I have to let off.

Is the regulator I just got bad as well? It seems much worse than with my old regulator in....maybe I should just bite the bullet and get a new Aeromotive AFPR so I know it's good....

What could be causing this problem?
thanks for your advise..

 

[ForcedTorque]

Many car owners have gone very broke fixing problems like this. Research and questions work much better. This place is full of information, and good people.

 

[SupraFreak13]

Yes, it's very frustrating. It's been a few months now I've been trying to figure this problem out. I thought for sure the fuel pressure problem was regulator related, but for all I know the regulator I just put on is in worse condition than the one I pulled off.

One thing I wondered about while putting the *NEW* regulator on....the end of the regulator(which has the vacuum port) can easily spin separately from the regulator housing. Is that normal? Also, the nut was so seized onto the regulator I had to use channel locks on the regulator housing to get the nut free, which left small dents on both sides of the regulator body. Could that have ruined this one?

back to the drawing board......

 

[RockPaperSwoRD]

do you have a wideband? what are you using for tuning?

 

[SupraFreak13]

do you have a wideband? what are you using for tuning?

No wideband, no tuning. Stock ECU.

 

[aphxero]

Really easy way to rule out the regulator. Restrict the return line by pinching it. Get it to like 60 psi.

Go boost it a little.

As far as the map why not use a meter and watch the voltage? Or put a vacuum pump on it and take down the readings.

 

[RockPaperSwoRD]

your problem is your injectors. theyre too big and your not compensating for them thru tuning.
stock injectors on a 1jz are 370 and you put in 440s, so your running super rich, the ecu doesnt compensate for it because it doesnt know they are 440s.
so replace with stock injectors or get fuel control

 

[SupraFreak13]

Really easy way to rule out the regulator. Restrict the return line by pinching it. Get it to like 60 psi.

Go boost it a little.

As far as the map why not use a meter and watch the voltage? Or put a vacuum pump on it and take down the readings.

Well, on my first post I wrote that I installed the JDM 440s...when doing the initial testing(with the 370's in) someone mentioned what you said to do, so I started pinching the return line until I could hear my fuel pump slow down(before I ever hooked up the fuel pressure guage), and it idled much better and reved better...then the next day I was pinching the return line, and BAM, it started running like complete shit, and the injectors were ticking very loud. I think I raised the pressure too much and damaged my 370s...does that sound possible?

I was told by the shop I bought the 440's from that the ECU could compensate for such a small change by watching the O2 sensor at idle...maybe they just wanted to make a quick sale.

A few posts back I was asking how I could test the MAP with it out of the car, it's really hard to get to the plug/wires the way I have the harness run.

your problem is your injectors. theyre too big and your not compensating for them thru tuning.
stock injectors on a 1jz are 370 and you put in 440s, so your running super rich, the ecu doesnt compensate for it because it doesnt know they are 440s.
so replace with stock injectors or get fuel control

I think I ruled out the injectors when I switched them...it ran the exact same way with the 370s in(before I damaged them)