I havent read through the complete thread, but you mentioned that as car warms up, it hesitates and get worst.

My first thought was, O2 sensor. I'd personally check your O2 sensor to see if it switches correctly.

Report back after you test our your O2 sensor.

Also, use a rubber mallet after the car has been sitting over night and cold. Knock on the car to see if it is clogged? Car free revs ok, but lacking power and hesitates. I'd look into those two matters to eliminate any potential fault.

-AzEKnightz

 

My car is doing the same thing, but its running really rich, the A/F will drop to 9.8 at times. I highly recommend you put a o2 gauge on this car to see whats going on inside. I'd hate to think you're running lean which could kill your engine. With how finicky this engine is the first thing I put on my FD was a o2 gauge to make sure I'm not running lean and endangering my engine.

 

Thanks for the help guys! My daily driver was off the road for a bit so ive been putting the rx7 off. Damn jdms!! anyways I disconnected the exhaust from the down pipe and it still drove the same. Ive bought a fuel pump and it should be here within a week or so. also looking into an o2 sensor now. Ill be back to post my results and probably have more questions too haha.

 

new supra fuel pump
Fuel pump rewired
new fuel filter
new alternator
new tps (correctly adjusted)
new o2 sensor
new spark plugs
Converted to non sequential (all vaccuum lines check out)
Exhaust isn't clogged

The car runs nearly flawless while its cold, it accelerates great (although i havent gone even close to wot). But shortly after the stock temp guage gets to operating temp, the car starts bucking. It gets worse and worse till the car pretty much wont accelerate. Also, the car starts to die and even stall while idling after its warmed up.

Im stumped.

 

Anyone? Could it be an ecu? injectors? plug wires? ignitor? The car doesnt sputter like its misfiring. But I dont get why the hesitation would get worse as it warms up, if its a fuel issue.

 

Check map sensor? Maybe manifold gaskets.

 

Wide band is the best way to determine your issue.

 

Ill replace map sensor next. I sprayed a bunch of brake cleaner around the lower intake manifold etc and the idle didn't noticeably change. I think the wide band is probably a good idea lol. Ill invest in one before i do anymore pulls.

 

With all those dash lights on, you have earth/alternator issues.

Check the earths in the engine bay, make sure your alternator is supplying full voltage.

 

Dash lights are all fixed now. just having the hesitation/idle issues.

 

Ignition issues tend to get worse with more heat, so it could be ignition related. Have you checked all of your grounds? However, the bucking/hesitation at idle and under higher loads sure sounds like it could also be a vacuum/boost leak.

 

Ill go over grounds, havent done that yet. Ill also go over the intake and everything again with brake cleaner. Just to make sure, the car is supposed to rev up if theres a leak right? I haven't noticed any noticeable idle change.
It was odd, after my car sat for a few weeks, i changed the fuel pump. It started up great and idled a lot better than normal. I let it warm up for 5 10 minutes, took it for a drive and I was getting into boost and even higher rpms. Was probably half throttle at most. I got a couple really nice smooth pulls and then the hesitation started again.
I let it sit for a couple days and took out the o2 sensor, it idled worse (probably cause the o2 was unplugged) but i still got the same hesitation when I took it for a drive. A new o2 sensor is on the way regardless.
But ya like I said, Ill change the map sensor, check for vacuum leaks again, check grounds, get a wideband. Would an ignitor cause the issues ive been having?

 

Bringing this one back from the dead..

Have you had any luck? Im having a really similar issue

 

O2 sensor is a good guess. car runs on open loop when cold and rich, then switches to the O2 sensor when warmed up. could be a bad signal from the O2 sensor.

 

Wish i woulda checked this a few months ago. IT WAS AN o2 SENSOR! After 2 years of screwing around on and off. The o2 sensor behind the thermostat. That fixed the deceleration and acceleration issues. The non seq mod must have fixed some boost leaks cause it idled/revved alot better. And I think the fuel filter, fuel pump, and fuel pump rewire all helped with the revving and acceleration.

It is idling a little high still at 1000 rpm and the idle drops to 600 when a/c is turned on. Ill have to do a little research.

But other than that WOW. Its runnin like a top. Engine revs and sounds amazing. Accelerates and decelerates like a rebuilt engine. Just piecing the little things together now to make it road worthy for the trip to our new home on the west coast.

Thanks for all the help guys, it wouldnt be running without this forum.

 

Check the main ground that goes to the firewall from (i think) the UIM.
Also check the ground that's tucked in near the front upper spark plug.

 

there is no O2 sensor behind the thermostat ? LOL I think thats the water temp sensor and if it wasnt reading the correct water temp it was either giving tomuch fuel and flooding the car under boost more then likely

 

haha water temp thats the one! I changed the o2 sensor as well in the downpipe thats where i mixed up.

 

The water temp sensor under the alternator near the Fan Switch sensor?

green plug?

 

Ya like behind the alternator. I forget where exactly without looking at it. Fixed my issues for a bit. I was driving it around for about a month with no issues. Then the hesitating started again when driving under load. Also, power fc shows more knocking when this hesitation starts.
Feels and sounds like fuel cut. Also revd like crap.

Then I changed the water temp sensor again just to see if it was in fact the sensor. Didn't work. Went over the vac lines and tighten up the intercooler piping. also bought a power fc. Been extremely helpful at pinpointing my issue. Started revving better but still the damn hesitation. Gets worse the more I drive.

I'm pretty sure it might be my throttle position sensor at this point. The vta2 (wire 3g or narrow signal er whatever) won't come down from 4.8x closed throttle. This is my second tps so Idk maybe it's a fluke or the sensor thinks it at wot for some reason, don't remember if the old tps did the same thing.

Any ideas anyone?

 

Cleaned the tps and electrical connections. still nothing. took it off and unplugged it, everything read close to 5v. so im assuming the sensor has some kinda resistor that isnt working for the narrow range signal. That leads me to believe I have a second bad sensor and the harness and everything must be fine since its getting power. Gonna order the tps. Anyone have a better idea in the mean time?

 

Bump

Current issue:

Car hesitates when accelerating and gets worse the more i drive it. The more load the worse it gets also.

Things ive done:

-New TPS and recalibrated perfectly
-New supra tt fuel pump
-rewired fuel pump
-new fuel filter
-new alternator
-new spark plugs
-new o2 sensor

IDEAS ANYONE?

 

The purge solenoid, is it stuck open by chance? Ensure that operates as intended.

Matt

 

Im curious to know why you think its the purge control solenoid? Funny you said because i was gonna start checking some solenoids. But per the FSM (F-192), only the 5 turbo solenoids effect acceleration. Ill check anyways.

 

It's a hunch. I had a 240sx that had a horrible hesitation issue. It ended up being the purge solenoid being stuck open. I guess it was feeding way too much vapor from the tank.

Matt

Edit: also read through your whole thread. Map sensor was mentioned but let's throw this out there; there isn't a check valve where the map sensor filter should be right?