hesitation and bog under throttle

[Brunoboy]

I have a new knock sensor, I put in a new maf, and the hesitation has gotten a LOT better. but still knocks from time to time, I have either and exhaust leak now, or intake manifold gasket leak. I hear it under boost. 0_o.

 

[dsm10o0]

Basically we have the same identical problem. haha My car knocks once in awhile and hesitates alot less than before.

 

[Brunoboy]

lol hopefully someone at the meet knows

 

[Brunoboy]

resolved, the last 4k miles i have been driving with one intake valve not opening due to a fallen rocker. Tre3zy and Ryuto fixed my problem tonight thinking i had to retorque the head and I saw the rocker. replaced and good to go.
-Shane

 

[citymunky]

I'm have the same problem with my car, right at 4K or just before 4k my car starts to bog and shutter. The funny thing is if I start boosting after 4.5K I don't have the shutter. After reading this thread I have a lot of stuff to check. I hope I can fix my problem asap

 

[citymunky]

So I checked a few things far.

-Open the Valve cover and looked at the rockers, they all looked fine to me.
-Spark Plugs (NGK; BR7ES). -> They look good, running a little on the rich side, but the gaps were at 0.035". I re-gapped them to 0.028"
-Fuel Pressure is at 40 PSI at idle
-Op Temps for my car: Oi l= 210 deg and above, Water = 180 deg and above

Quoting mitsuturbo:
When i bought 555 it ran like this. Turned out a couple valves were slightly bent.

Check compression. If it's not great, do a leakdown. If everything checks out, make sure your timing is good, your plugs/wires are good, and you're getting proper fuel pressure.



What should the Timing be set at? I checked yesterday and it was over 10 deg BTDC.

I read 5 deg BTDC is a good place to start.
click

 

[Brunoboy]

5* BTDC is right

 

[citymunky]

I just adjusted my timing to 5 deg BTDC. The bog at 4K RPMs is still there, but it's got a little better. /ubbthreads/images/graemlins/frown.gif

 

[Brunoboy]

plugs, wires, coil pack, fuel pump, boost leak,

 

[496of2000]

Did you try another set of plug wires? i had a set of magnacores that had a pinhole in it where it arched.

 

[citymunky]

Quoting brunoboy:
plugs, wires, coil pack, fuel pump, boost leak,



Plugs: Are Ok, gap set at 0.027"
Wires: I have 7mm NGK installed now. The last owner give me 2 sets of used wires, I can try those out.
Coil pack: I will do a Ohms test

Fuel Pump: Is a stock Supra TT 260Lph fuel pump. I got to find out if how to test it, if that's even possible.
Boost Leak: That's a whole can of worms I don't want to even think about.

 

[Brunoboy]

honestly boost leak is your best bet first off. im sure you must have a couple leaks somewhere.

 

[citymunky]

The first thing I did was do the Ohms test on the coil pack. Everything was with in limits.

Quoting 496of2000:
Did you try another set of plug wires? i had a set of magnacores that had a pinhole in it where it arched.



Next I poped my NGK plugs wires out, number 4 was good. Number 3, 2 and 1 had cracks along the whole shafts. Problem solved. /ubbthreads/images/graemlins/grin.gif

 

[Brunoboy]

good to hear