rx7 FC TII

iTrader: (3)

and yes ive searched but none of the threads i could find have the same symptoms as i do.

first its an 88 TII with about 5K miles on a rebuild/streetport. its got FMIC,catback exhaust walboro 255,no emissions, and i think thats about it.

this hesitation happens whether the engine is cold or hot and at any rpm. the harder i get on it the harder it hesitates. theres no smoke or sound coming from it.

could this be the AFM because ive checked all the grounds. and im kinda stumped on this.

RotaryRocket88

iTrader: (7)

What's the boost level looking like when it happens? I assume you've got something other than the stock boost gauge.

Force Fed

Bad plug wires.

Boost or Bust

iTrader: (1)

I agree. It definitely sounds like a problem with the spark. When you rev does it feel rough?

rx7 FC TII

iTrader: (3)

reving is fine and goes through the numbers. boost is normal when it happens as well. the spark plugs are recently new about 500 miles ago. the wires are a bit old but they should still be alright.

SpeedOfLife

iTrader: (16)

At least test the wires. When you have parts that are suspect due to the symptoms you get, never assume they're good just because they're new or worked fine a week ago.

rx7 FC TII

iTrader: (3)

ok i plan on testing the wires when it isnt completely shitty outside. and im also going to check the AFM when i get a chance.

arghx

iTrader: (3)

The FSM has the proper specs for plug wire resistance.

rx7 FC TII

iTrader: (3)

ok i decided to just go ahead and replace the wires. i havent replaced them since ive had the car and its prolly a good idea to get new ones anyway.

ill put them in today and report back and let you know if that was the problem

rx7 FC TII

iTrader: (3)

ok the plug wires did get the car to run a little bit smoother but still have the hesitation.

i guess the AFM is next.

Mankdrake 2661

iTrader: (8)

How's your timing look?
I'm having a similar problem too. Does it ever clear up? Like, can you rev past it if you keep on the throttle? Any particular RPM it happens?

backroad-junkie

iTrader: (3)

i had a similar problem and after i researched it a little, people who had symptoms similar to mine said it was the TPS or the fuel pump resistor relay. I havent gotten the chance to troubleshoot my own as I have my car apart for overhaul though, sorry. I replaced my injectors, got new injector connectors and new spark plugs and it would start and idle ok and i could granny it a little and feel nothing but when i put my foot down it would start bucking, jerking and missing.

SpeedOfLife

iTrader: (16)

Yeah your TPS could be misadjusted or broken, it's a very common failure point.
You should check your timing as well. And if you were thinking you wouldn't have to use a timing light, you do. Oh, but before you do, make sure you can see your timing marks on the front pulley. There should be two notches not far apart on the front main pulley closest to the block. They were painted from the factory, but many or most have faded/worn off, however the notches are still there. Has the car been doing this ever since the motor was built? I just rebuilt my motor and I used the pulleys from the motor that was originally in my car and the front hub from the core I rebuilt. Turned out to be a bad idea because the two hubs, despite both coming off of '87 TII motors, were different, and thus threw the timing marks way off.

rx7 FC TII

iTrader: (3)

the motor just started doing this about a week ago.

the timing should be fine given i havent ever touched it.

the more i get on the throttle the harder it will hesitate. if i just granny it up and slowly then it will hesitate less but if i get on it then it hesitates hard and keeps happening

it happens at any rpm but gets harder as it gets in the upper rpms.

thats why im thinking it could be the AFM going bad.

and the TPS should be fine. its somewhat new

backroad-junkie

iTrader: (3)

i was hearing clicking coming from the passenger headlight area while the car was idling or key in acc, i cant remember which, probably while in acc since i had a blown dp gasket.

Van Sema

iTrader: (1)

I'm having the exact same problem on my 87 t2. Basically can baby it up the rpm band but as soon as I press the throttle more than 1/4, it will cut off. If I let off the gas it will "catch" and start running back up the rpms slowly. It's like whenever I press the gas, it blows the fire out. Like the secondary injectors are not working at all.

It will also not idle on it's own ... thinking these problems are related.v I've found most the vacuum leaks it had and replaced the hoses. Cleaned the BAC valve, Air control valve, changed spark plugs, fixed several wiring concerns.

Kinda run out of ideas ... will replace the spark plug wires, test the BAC and ACV valves, and check the tps (after i find it -heh-) tomorrow.

Any Ideas??

This is my first turbo II, I'm used to FD's personally ... and recently FB's.

backroad-junkie

iTrader: (3)

definitely post up what you find b/c it sounds all too familiar

russianmob

iTrader: (3)

I think you guys are having problems with fuel, not spark.

rx7 FC TII

iTrader: (3)

im really hoping its not the fuel.

this seems to be a pretty large problem among this forum.

This thursday i will be pulling the UIM and inspecting the injectors because the more i think about it and drive it, its starting to make me think its the secondary injectors not firing correctly.

keep posting up your ideas and ill start working on mine 2morrow.

i do have a rtek 1.7 sitting at home and im thinking the hesitation fix may help. i just need to find some 720cc secondarys and wire in a resistor.

ill keep updating this as i do more work.

backroad-junkie

iTrader: (3)

any progress anybody?

Mankdrake 2661

iTrader: (8)

I found a couple vacuum caps cracked an fixing those helped alittle. I'm checking the fuel pump resistor pack in a few minutes. After that, new fuel filter, and after that....don't know.

well uhhh

this does sound all too familiar, i had the same problem. Cleaned injectors, replaced injector connectors, grommets, cleaned grounds, replaced all gaskets, fuel lines, vac lines, removed emissions. when i had the LIM off, i had a busted o-ring allowing coolant into the intake runners. I can't say that the oring was the problem but it was fixed after all this and i really think this was the problem. oh yea, also replaced fuel pump and filter and tps. hope it helps. I know its a pain but i would suggest pulling the UIM and LIM, just freshen it up a little, check o rings and gaskets.

Mankdrake 2661

iTrader: (8)

At idle(875-900rpm) my fuel pump connector at the pump is reading 8.8v. Cruising at around 3500rpm voltage is 9.0-9.1v. Now the strange/bad thing, When I get into boost the voltage drops to 7.5ish and comes up to 10ish. So looks like I'm rewiring my pump. Hope that helps. Hope that fixes my problem.

well uhhh

^ yea do that, thats scary low voltage. I did this at the same time as the rest of the work too...maybe that was it.

SpeedOfLife

iTrader: (16)

WOO, yeah, rewire your pump.