88 turbo w/no emissions or ACV
Rtek 1.7
780 secondaries, 550 primaries

When I'm accelerating I can't floor it once I'm past about 5000ish without it backfiring, bucking, whatever.

Any help would be appreciated
--John

 

maybe your running way to rich...do u have a wideband gauge?if not i would get one its one of the best investments u can get

 

Yeah that was my guess.
I'm in the process of getting a S-AFC and air/fuel meter.

 

I can't get rid of it.
I don't think it's a backfire crackle.
I feels like a fuel cut(I think) but I have the Rtek 1.7 chip.

It doesn't happen in 1st or 2nd. From third on If I try to accelerate full throttle to the redline it cuts our at about 4500-5000 on up.
I can go to the redline at like 3/4 throttle but anything more than that, it cuts out.

(Just so noone asks, in neutral it revs fine.)

 

bump

 

Could it be clogged secondaries?

 

i'm thinking that, cuz as you accelerate, your secondaries are suppose to open up and release more fuel, thats a reason for bad gas mileage i've noticed. But yeah get your secondaries checked out, clean or replace, it seems best

 

This may sound a bit crazy, but I had a similar problem when my O2 sensor went. Give that a shot....worse thing that happens is it doesn't work, you've spent 20 bucks and you have an O2 sensor.

 

The Rtek website says the 1.7 will handle up to 720cc injectors, so if it thinks you have 720cc injectors when you actually have 780cc injectors you could be running rich.

NM, i just reread it and it says minimum 720cc injectors. Get a wideband or Air/Fuel gauge.

 

Spitting flames is cool...

 

Definitely wouldn't be your O2 sensor, also if you were running lean from bad secondary injectors you probably would've blown your motor. You *could* be running rich depending on how much boost you're running, but I don't think the sympoms would be as extreme as you're describing.

Have you checked/set your timing recently? Spark-plugs, wires and coils all good?

 

Went to school for piston, but all i wison operate same. Back firing is caused by a rich condition, injectors are to be checked 1st. if injectors are k, lines are k (duh). Only other ave is the ecu. o2 sensor confuses and bewilders everything. If change, o2 sen's., ecu is to be blame. What was that about 720cc and 780cc (take heed).

 

if your still running stock fuel pump it probly cant keep up at high rpm and your running out of fuel for the huge injectors to inject, hook up a fuel pressure guage and watch it at full throttle in 3rd, i bet your fuel pressure starts falling.

 

Are you sure its not ignition related?

 

start with your injectors...switch em out for some 720s.....

 

ignition would be in every gear, rpm related. your problem seems to be happening in 3rd where you will have a couple more seconds at high rpm load, meaning you will use more fuel for a longer period of time, i think its fuel. what part of your fuel system is the question IMO

 

I have the same problem.
My car is a FC3S completely stock and the car has the same behaviour almost every time that i am at WOT.It does it even with the low gears (1st while i am doing doughnuts,2nd while i floor it...)

My motor has over 130.000km and i think that i am running rich.
I think too that its a problem related to fuel.
I will check my injectors and fuel pump asap.

 

How much boost are you running?
What FP do you have?
Have you checked for boost leaks?

 

In 4th gear I hit just over 10psi at about 6500RPM.

The break up starts at about 7-8 PSI but, it stays smooth all the way up.

I don't have a fuel pressure gauge so I don't know about that yet.

I checked all my hose clamps and plugs and can't find any leaks.

How can I check if it's ignition(i.e. spark breaking up, weak spark...)?

thanks John

 

Well? Anybody?

 

My 2 cents.
Rx7's run rich. From the factory. Without Cats or ACV/etc u will backfire etc. Now with that said,
1: Have you pulled error codes?
2: Have you checked the condition of your wires on the Boost sensor (you have the right one right?)
3: Have you checked all of your vacuum lines for leaks?
4: TID , is that cracked or leaking?
5: Any leaks from your IC hoses? U can make a boost checker with some end caps from home depot, (plastic) and a shraeder valve. Drill a hole in some 2 inch caps from home depot, add some air pressure from a bike pump. U can use a motorcycle valvestem that screws into the hole or have a press in schraeder/valve stem from a tire shop. I used this to find leaks in my Intercooler.
6: Grounding problems?
7: fuel leaks at the rail. Some injectors have to be modified and even so you should replace all of the rubber injector seals, grommets, and the air diffuser orings (the all come in a kit u can get from your Autozone called injector seal kit). My diffuser orings were hard like plastic.
8: Injector pigtails : My pigtails on my secondaries were gone, causing them to respond inttermittently.
9: Sticking injectors/swapping secondaries with primary (location), bad TPS, bad Coolant sensor (pull codes ..)

Hope I helped you at least get moving in the right direction.

 

OK, I'm an idiot, ignore this. I responded to the wrong thread.

 

To eliminate overboost fuel-cut, unplug the boost sensor at the electrical plug.
Drive around.
If it doesn't solve the problem, it's not the fuel-cut.


-Ted

 

Dcrasta and RETed u help a lot....thanx...i ll check what u mentioned.
I know that my stock TID plastic S tube has a small crack that i fixed myself...and i am sure that i didnt fixe it properly....