1jz Plugs gapped to .20 and still blowing out spark?

[Supracentral]

I can make it to 14psi but theirs no power when get their. Then the wide-band starts showing lean.

Honestly sounds like more of a fuel system problem.

Give us an overview of your car: Turbo, injectors, fuel system, base fuel pressure, pump, lines, etc.

I tried adding more fuel and still breaking up, wish their was a dyno that was near that i could hop on and see wassup with the fuel pressre when i get into boost. IJ you said the TT fuel pumps have a 60psi relief valve?

Adding fuel isn't going to help if the fuel isn't there to be delivered. You could be deadheading the pump.

Read this post (it's not 100% specific to your issue but that post and the rest of the thread talk about problems like the ones you are experiencing):

http://www.supramania.com/forums/sh...but-a-boosted-car-problem&p=179880#post179880

 

[kamikazemkiii]

Stinger EMS
61mm turbo
Aeromotive afpr
550 mkIV injectors
40ish base fuel pressure
TT fuel pump
Stock fuel lines


Could the relief valve on the fuel pump be weaker than 60psi? the car has been running on a walbro but since the fuel pump swap it seems like ive got my problem. I had a collapsed fuel line but thats fixed. The car breaks up when going into boost and leans out so i get out of it, i uploaded another tune and still the same thing but it drives like normal under vacuum.


My buddy and I also checked the resistance of the coils and they were all pretty good
new they are .08 and mine were .08- .09

 

[Supracentral]

You could try getting the pump flow tested, or replacing it with a known good unit. Since your problems appear to have started when you swapped the pump, I'd suspect wiring or the pump itself as the culprit.

A set of six 550's theoretically flow about 200 lph @ at 100% injector duty cycle. If your base fuel pressure is 40 psi and you're running 14psi of boost, your pump needs to be able to flow 200 lph @ 54 psi. Testing has shown a factory MKIV pump will flow 220 lph @ 58 psi @ 12 V - this should be ample fuel for your application.

I'd start with checking electrical to ensure you're getting a minimum of 12.0 V at the pump. In reality under load with a good alternator/battery you should be able to put 13.5 V to it. Beyond that you may have a bad fuel pump or an obstruction in the feed side of the fuel system.

 

[kamikazemkiii]

Its been running off the original wiring without the 12v mod. Does the TT pump require at least 12v?

 

[Supracentral]

Its been running off the original wiring without the 12v mod. Does the TT pump require at least 12v?

Fuel pumps are very voltage dependent. The MKIV pump runs acceptably at 12v, runs very well at 13.5v.

I generally run a large gauge home run directly to the positive terminal of the battery (with a fuse on the battery end) and feed the pumps off of that via a relay. The only thing I use the factory wiring for is the trigger for the relay. Fuel is too critical on a turbo motor to trust it to 30 +/- year old wiring designed for a lighter pump, IMO. Pistons and rings always cost more than wiring.

 

[kamikazemkiii]

Im going to try the 12v mod, but since the walbro ran fine i would think the wiring is okay. But the TT pump is bigger so i guess it would require more. Do you think that the stock wiring isnt delivering enough juice to the pump and thats whats going wrong and why im going lean?

 

[Supracentral]

Do you think that the stock wiring isnt delivering enough juice to the pump and thats whats going wrong and why im going lean?

It's one possibility. And it's one of the easiest to test and/or eliminate.

Read JetJock's voltage drop testing walk through here, it will help a lot:

http://www.supramania.com/forums/sh...hly-technical)&p=771496&viewfull=1#post771496

 

[kamikazemkiii]

Ive done some checking and the ecu is getting its power straight from the battery, In boost its only receiving 9.8 volts i believe. Could this cause it? haha

 

[IJ.]

Ive done some checking and the ecu is getting its power straight from the battery, In boost its only receiving 9.8 volts i believe. Could this cause it? haha

Ya think..... :nono:

 

[kamikazemkiii]

Ya think..... :nono:

Yes, i think. What should i be looking into? maybe an alternator, or wiring

 

[Supracentral]

Ive done some checking and the ecu is getting its power straight from the battery, In boost its only receiving 9.8 volts i believe. Could this cause it? haha

Ya think..... :nono:

Yes, i think. What should i be looking into? maybe an alternator, or wiring

Start the car, test the voltage at the battery. If it's not 9.8, you can discount the battery/alternator.

In all seriousness this is the source of ALL of your problems. It's one of the reasons why I suggest a home run from the battery to the fuel pump. Going lean is the most devastating thing that can happen on a turbo motor.

 

[kamikazemkiii]

When i start the car its in the 11's or high 10's. Ive noticed at idle the car runs richer than usual too

For what its worth i had to jump the battery before it would crank earlier this afternoon, but the interior lights were on all day yesterday.

 

[IJ.]

Yes, i think. What should i be looking into? maybe an alternator, or wiring

That's a HUGE drop there's something seriously wrong....

at idle are the lights dim?

As Mike pointed out engine failure is a real possibility if you continue to push it into boost while this condition exists.

 

[oldsking]

fuel system upgrade and wiring Marcus will fix MOST of your problems. I looked at the car with ya and told you it was a hack job so now it's time to clean up their mess and do it right Just like Supracentral mentioned, running new wires to your pump and checking the factory wires is what needs to be done. I have alllll the same plans in mine for my car and set up

 

[kamikazemkiii]

fuel system upgrade and wiring Marcus will fix MOST of your problems. I looked at the car with ya and told you it was a hack job so now it's time to clean up their mess and do it right Just like Supracentral mentioned, running new wires to your pump and checking the factory wires is what needs to be done. I have alllll the same plans in mine for my car and set up

I am getting things set up for that now, ill probably pull the alternator and take it by autozone and see if they can check it out, same with the battery, run new power and ground wires the ecu and fuel pump along with the 12V mod. HOPEFULLY this cures it.

That's a HUGE drop there's something seriously wrong....

at idle are the lights dim?

As Mike pointed out engine failure is a real possibility if you continue to push it into boost while this condition exists.

Ill check the lights out tonight. Should be safe to drive out of boost right?

 

[Supracentral]

Should be safe to drive out of boost right?

Provided you stay out of boost, it will likely run like crap but will probably be ok. You do risk fouling your 02 sensor and destroying your cat if you have one.

 

[kamikazemkiii]

Thanks for the notice, i might just remove them. Runs fine out of boost

 

[kamikazemkiii]

I datalogged a run and at idle their are 11.7 volts, the biggest drop is to 10.5 at 13psi. Can i eliminate the map sensor as the problem since pressure showed up on the datalog?

 

[IJ.]

Should be at least 13.8v under power there's something wrong with your alternator.

 

[kamikazemkiii]

For sure the alternator?