KitsuneRacer

iTrader: (-1)

Ok so, I've always had this problem in my car where if you go WOT for too long (ie, running 1st, 2nd, and into third at WOT, or going up a long hill) the car will hit a wall, lean out, and not have anymore power. It will start bucking and won't be able to accelerate for a few seconds and then its back to normal.

At first I thought I needed to rebuild the carb. So I did that. I now have GOBS more power, but I still hit that wall. I changed the fuel filter, same thing. I changed the fuel pump, same thing. I've adjusted everything, even the float levels, and it still does the same thing.

What could possibly be going on? I'm getting sick of this

Let me know if you need anymore information.

its an 84GS

Siraniko

iTrader: (13)

It buckles then it moves...Common sign for empty bowl. Which pump are you running? PSI? FPR set at?

KitsuneRacer

iTrader: (-1)

It had the stock pump before that was a little weak at ~1.5psi I changed it for a Puretell(?) and its doing 2.5psi. I had the same pump on my last RX7 and had absolutely NO problems... I don't think its that.

Siraniko

iTrader: (13)

You really believe it is something else?
For stock motor/set-up I say maybe. but if this is on a ported motor with an aftermarket carb, 100% your fuel pump is not good enough.

KitsuneRacer

iTrader: (-1)

stock motor and stock carb

Siraniko

iTrader: (13)

and this problem only happens when going up hill right? not enough fuel pressure to fill up the fuel bowl period.

KitsuneRacer

iTrader: (-1)

either up hill, or when at WOT throttle running through gears... it only makes it into third and runs out of fuel.

Could the fuel lines be clogged possibly?

vipernicus42

iTrader: (4)

My guess : Accelerator pump adjustment problem or Vacuum Secondary diaphragm

If your carb is stock and still has vacuum-actuated secondaries, then if you slam your foot to the floor when you take off, only your primaries are open until enough vacuum builds up to open the secondaries.

So you pull nice and hard through the primaries, then your secondaries open up and either they open too fast, or you don't have that corresponding squirt of fuel from the accelerator pump. So when you transition from primaries to secondaries you get too much air, not enough fuel, and bog until the vacuum generated by the engine is enough to pull the fuel.

That's my guess anyway. When you rebuilt the carb, did you replace the accel pump diaphragm? Did you do any adjusting to the spring or nut by the accel pump ?

Edit: I started writing this like an hour ago before all these replies. Fuel starvation definitely sounds like it. Replace the fuel filter for sure, and if that doesn't do it, invest in a good quality pump, regulator and gauge.

Jon

Kentetsu

Lack of fuel. You've just described the exact symptoms of a clogged fuel filter. The fact that you have changed yours now makes it look like a weak pump. Maybe the pickup in the fuel tank is partially clogged too.

One of the best upgrades you can make is the Carter fuel pump/Holley regulator install. The stock pump is barely adequate, even when brand new. Same goes for the dinky fuel filter. I ended up running two filters in parallel, so each one only has to perform 50% of the duty.

Here's info on the pump upgrade: https://www.rx7club.com//showthread.php?t=529605

KitsuneRacer

iTrader: (-1)

hmm ok, I guess I'll check out the pump upgrade... I just never have had this problem before and my old car had a holley 4??cfm carb and it would run through red line in all the gears... it had the same fuel pump that I just put on my new one... That just doesn't make sense to me at all.

danielson

did you clean/ replace the small filters where the carb and fuel and return feed lines connect. my brothers car did the same thing, we rebuilt it and ran fine for a little bit but started bucking and cutting out, up hills too. it only happened in fourth and fifth. we never checked those two small filters when we rebuilt the carb, after cleaning them the car ran great.

Siraniko

iTrader: (13)

unfortunately, **** happens

KitsuneRacer

iTrader: (-1)

Yeah, I understand..

Actually, my dad was thinking that might be the problem... there was a problem with one of them and dad thought he fixed it... maybe we'll just get new ones and try that.

Thanks for the suggestion! I had forgotten about that!

RW-7

iTrader: (56)

If you are still having problems PM Chris "BLWFLY" (on the forum) He lives in Springfeild and is an expert with these stock carbs. Just tell him Robert refered you. Infact he might have a few rebuilt nikki's with mechanical secondaries just laying around.