Fuel cut = check engine light? 1jz break up at 4500 rpm

[scottiedawg66]

i am still having the trouble, tried new coilpacks and soldered in new connectors and they did not help. I am going to look into the ignitor and alternator next. the grounds look good, but I am going to run a huge cable straight to the block and kinda over to it just to rule that out.

this is driving me CRAZY!!!

 

[525gte]

Look at the wires going into the water temp sensor.. I had this problem close to yours not to long ago. Turned out to be half broken wires to water temp sensor. Replaced them and all was fixed

 

[scottiedawg66]

crazy! was it the single wire with the grey connector, or the dual wire with the green connector?

 

[mk3tattoos]

Duel wire with green connector.

Did you get it figured out yet or have any updates?

 

[scottiedawg66]

i have not had time to work on the car. but I am hoping to spend some time with it over the weekend. I'll be sure to post up as I try things out.

 

[scottiedawg66]

Yesterday I connected a 12 gauge ground wire from the battery - directly to the intake manifold, confirmed my TPS calibration was correct, and confirmed that my timing is at 10 degrees when jumpered. The timing increases to about 13 degress when not jumpered. I also sprayed soapy water all around my exhaust system to try and see if I had an exhaust leak. I found no bubbles, which makes sense since I used new gaskets and studs when I went single.

The damn car still breaks up at ~4800 rpm.

I still have MUCH different fuel settings than other users with 550s. I have the MKIV fuel pump, and stock regulator. I am suspicious of the fuel at this point due to what other people have shared with their settings.

My thoughts for today are:
Investigate voltage at the fuel pump, double check my resistor pack wiring for the 550s, swap out the map sensor again, and hopefully swap in a new ignitor.

any other ideas?

 

[te72]

Scottie, has anyone suggested different coils to you? Breakup is often an ignition issue on our cars once they start being pushed a bit.

 

[scottiedawg66]

I tried known good coil packs last weekend with no luck.

In my work today I found some issues with the resistor pack. The yellow wire broke right at the plug. I am going to pull the entire harness tomorrow and solder in some new connectors double check everything and hopefully put a rebuilt fresh harness back in next weekend.

At the Fp pin in the diagnostic box I had 12 volts at idle, and the voltage would rise with the revs. So I think I am good there???

 

[525gte]

just a long shot but have you looked over all the fuel lines for a crimp in it. and how is your fuel filter? and what about the screen onthe pump in tank, is sounds like your starving for fuel.. also can you take out the resitor pack and run the stock injectors to see if this help out the issue?