Bogging, pulling back under hard acceleration

[nismo24T]

I installed a turbo and intercooler....the pipings dont seem to leak...i also have stock fuel pump, stock injectors, and no rrfpr...the car pulls back and boggings under hard acc....??? any ideas...already searched but none seem resemble my setup...

[GEO]

Umm.... PSI? Also, you should be running a fuel pump my friend. Depending on the PSI, the stock injectors would need some upgrading. Your timing set correctly?

[nismo24T]

PSI?...i dunno....the gauge is reading -10 to -9 at idle and hits -4 to 0 while accelerating...I was thinking the reason why it does pull back because it wasnt getting enough fuel?...i dunno...as for timing....i'm gonna check it tonight

[nismo24T]

oh...and i dunno anything about timing...what shud it be set on...and i also have a btm from msd....eheheh....how do i use this thing

[nissanfanatic]

Your vacuum is high. It should be at like 21 in HG. Check for leaks in the vacuum system. You should check for boost leaks too. Make sure you are getting a good spark. What are your spark plugs gapped at? If it is above .035", try gapping them down to like .030". Shouldn't have to go lower than that. I had problems with the MSD BTM. If I were you, I would just take it out. I had problems the entire time that thing was in and as soon as I took it out, the car ran and boosted like it was supposed to. IF you do want to keep it, try setting the boost retard knob to 0 and the start retard screw to 0. If you get knock, turn the boost retard knob a little. I got it to make like 3psi with that but it still bogged and backfired. I would just get rid of it http://www.240sx.org can explain the timing thing. Make sure your idle is at 700rpm when you adjust the distributor. He meant how much boost are you attempting to run. Sounds like an ignition problem. As for your fuel system, at least get a 300zx fuel filter and a Walbro. A FMU would be a good idea. An aftermarket coil also helps. Good luck.

[GEO]

Yeh wait intill tonight when the more EXP'd high HP KA guys get online, they will be able to give you some hints.

[Structure240sx]

so are you saying you are not hitting boost?

if you msd is hooke dup u might be retarding too much timing with it. also anything over 5psi is totally out of the question on stock injectors. the car wouldnt be moving at all after a couple boost runs over 5psi ont he stock fuel system. running a turbo with a setup like that shows you dont really know what you are doing. no offense but its the honest truth

[nismo24T]

Yeah...don't know wut I'm doing at all...I'm learning with each step...I pay homage to your mastership....I will take all advices ...... Don't know how far the gap is on plugs....I'm definitely gonna get a walbro and new injectors and a rrfpr....I lessened the knock to almost nothing...only once and a while...btm is set at one...I'm gonna play around wotht the plugs also...oh yeah...I'm getting a lot of boost...I'm also gonna check for leaks a again...thanks guys...any more possibilities???

[nissanfanatic]

Are you getting knock under hard acceleration or just cruising? Your answers don't make a lot of sense. How much boost is a lot of boost? You just said before that you were only getting the vacuum down to 4in/Hg. Boost is on the other side of the 0 line. For a start, try doing this:http://ka-t.org/tech/

That should get you in the ballpark of correct timing. I still don't know how much boost you are running so I can't really advise a degree of retard. Considering you have the BTM, you should be able to just play around with the retard control and get it running somewhat correct. Good luck.

[C-Kwik]

Im thinking he is blowing the spark out. If you didn't set your plugs to a lower gap, you are likely running the stock gap. Turbo motors have a denser mixture of air and fuel between the sparf electrodes. This means there is more resistance. You either have to increase spark energy, decrease the gap or both to remedy the problem. If this is what is happening, it will feel like you hit a rev-limiter.

And fuel isn't the likely cause. If you keep leaning out and getting detonation, you'll likely find pieces of the motor in your oil pan quite quickly. A motor will still run during detonation. In fact it will run strong. That is until something breaks.

[nismo24T]

nice...i have s msd blaster coil installed...im gonna try the plug gaps...thanks

[nismo24T]

also...i'm running an automatic...is their a rev limiter?....i dont think I've hit it at all so i dunno....if so...is there an easy way to get rid of it...I know I can by a chip...or disconnect wires from the transmission...or the yellow and green wire on the ecu...?

[RMiller]

This is scary. Don't blow it up.

[DRIFTEADOR]

sounds like a leak in your intake manifold or any vacumm lines going to it. as mentioned earlier, vacumm at at idle should be closer to 20-22in/hg. the btm setting shouldnt be a problem since youre not seeing positive pressure....same with spark plugs.

[nismo24T]

fixed the boggin while accelerating....gapped the spark plugs .03 .... then installed walbro fuel pump....fixed the problem...i think it just need more fuel per boost

[klattr1]

if your vacuum was 10inHg at idle then you definitely have a vacuum leak.glad u fixed the misfire now, any small boost leak will cause it to hesitate in WOT.make sure and upgrade your injectors at least. your motor wont last long with stock injectors, especially if you are overboosting. definitely pull out at least 5-6 degrees base timing.i hope you havent detonated hardcore already. quite possibly have.