running rough( more at idle)
 

ok so i just fixed my fuel pressure issue by finding electrical tape in the primary fuel rail!!! anyways the car is running alot better now on both rotors, question is i am still experiencing the sound of a port mainly at idle. when free revving it sounds great no miss or anything. if slowly giving it gas it misses? any ideas or common problems?? new plugs,gas and wires already in. and no the hose is not disconnected off the map sensor :nod:

Could be a lot of things. A bad clutch switch will cause rough idle.

so where would you start? i know there are not any vaccum leaks. could any of the solenoids cause this? i have all the solenoids plugged in just no vaccum lines running to them as the rat nest has been removed

Do you have anymore details about your setup? For example, do you have an aftermarket ECU, sequential or non-sequential twins, etc?

Stock ecu, full exhaust, supra fuel pump, rat nest removed with solenoids still connected. Bought the vehicle as it is. Looks to be non sequential as the flap is welded. It does have a bad exhaust leak which j am going to fix probably next.

any other ideas guys?

What's your idle rpm?

About 1200

that idle seems high for not having a vacume leak check the 3 check valves by the throttle body in the uim and see if any of them are bad ,

and adjust the main screw maybe its opened up tomuch

also coils may be going , what is your alternator voltage . when my alt was going i would get miss fires at idle when it was charging only 11V , new alt and it doesnt miss anymore

ill check that tonight, i just bought a house so free time is hard to find lol. which three check valve are you referring to as all the factory "rat nest" has been removed. still has soleniods plugged in just no vaccum lines going to any besides the one for the fuel pressure

Get yourself a Power FC. The stock ECU can not support the current mods. Full exhaust and emmisions removed will cause the ECU to alter the fuel map too much causing your issues.

Once you have the PFC installed you will be able to go into the idle cells and remove 10% fuel, turn the O2 sensor off and your car will start to run much better (as long as the engine is healthy and there are not a bunch of other issues)

ok ill look into that, as of now i drove the car yesterday around the block and it did fine. didnt get into any boost just drove normal

update** went to adjust the tps sensor and found the tps faulty only showing .33 volts all the time no matter what, you can turn it and the voltage stays the same

That'll cause some issues ^^^

i got another one so ill put that on and adjust that and see where i sit

ok update with car.... i drove it today but still with kind of the same issue. im having trouble with the tps adjustment. on the narrowrange it is just at .65v...even if turning the tps left or right the voltage does not change. also if revving the car to full throttle the voltage does not change. any advise?

Start by validating you have the TPS installed properly:

https://www.rx7club.com/3rd-generati...1/#post7073722

ok i found out i did in fact have the tps installed wrong causing the voltage to stay at .65v...
i reinstalled the tps and adjusted it to the correct readings. narrow range closed is at 1.21 v
wide open at 4.99v driving home last night the car was wayyyyyy better on cruising, no more bucking and missing. although the first inital throttle response is horrible. it acts as if it chokes out for a second then catches? the car went into limp mode last night on the drive home as well probably because the omp has been deleted and some of the solenoids are throwing codes. can i just run resistors to get rid of these codes and keep from going into limp mode???? thanks so much guys im making alot of progress!!

You have to atleast plug an OMP in to get out of limp mode, you dont have to fully install it but you need to plug it in and hang it out of the way up by the oil filler neck.

You will need resistors for all 8 of the colorful rats nest connectors.

ok ill check that because it is plugged in just hanging to the side but the previous owner extended the wires so im sure some wiring is wrong. any idea on the throttle choking out?

Reset all your idle adjustment screws.

ok ill check back in later with updates! thanks for the quick replys

have you checked the CEL yet? you can put a jumper wire in your diagnostic port and it should flash to let you know what code it's throwing. Like your TPS issue... that would have shown up in the codes. If you have a JDM/UK cluster there's still a way to check your codes with a resistor and an LED in the Diagnostic port as well. I would also check that to make sure none of the other sensors are screwy...

thats the funny thing the tps wasnt throwing a code....but yet it was bad. i just made some 330ohm 1/2 watt resistors to put in place of the solenoids on the rat nest to clear those codes. after i install those i will se what if any codes return which im sure the omp code will (therefore causing the limp to kick in). just need to spend some more diag time hard to do while fighting a cold and its in the 20's at night!

gonna post up tonight but i went to take the car to work today and had to stop lol it is running horrible! under light throttle it is breaking up,sputtering and popping....under heavy throttle its happy and goes..

i second the motion for a PFC, too many things omitted for it to run correctly now on the stock ECU. it sounds like it is dumping about 50% too much fuel at idle which can be due to a number of issues. the PFC will give you troubleshooting as well as control over everything.

normally with this issue i find that the coolant thermosensor is either unplugged or swapped with the fuel thermosensor on the fuel rail. a map sensor issue will also give similar symptoms. the PFC will give you the data that the ECU is seeing.

what's funny about your issue.. it seems very similar to mine... even in your video with it running it's doing the same damn thing. Also have you tried to bleed air bubbles out of your coolant system? I discovered a LOT of bubbles in mine today... only for it to develop a leak... ugh. I replaced 4 of my solenoids for the "simplified sequential" to try it, and it helped out A LOT. Although for it still runs rich. really strange. I adjusted my TPS and it helped a lot. The screw on the throttle body that you can get to from the top that changes your throttle position as well just a FYI on that one. There's a lot of people that are saying to adjust that for idle speed, but it's really "readjusting" the TPS as well as holding the butterflys open. haha I'm at a loss currently!

So codes are 23,28,30,38,39,40.....I currently found a loose ground and put all resistors I made it and it doesn't reallyseem to help. I did notice upon the very first start it runs perfect not missing a lick for about 20secs and then it starts.. please help as I'm running out of ideas

23 is the main one causing your issue (if you read the codes correctly). You likely have an issue with your wiring harness. If you put resistors in and the codes are still showing, then you have a ground wire issue. Likely, the wiring harness is old and crusty which means there is probably some continuity issues as most of the solenoids will share a common ground.

If you intend on keeping this car for a while, just fork out the money for a new emissions harness and enjoy.

So Yea wiring harness I think it is..I can grab the emissions harness and if I move it the car will spit and sputter..so the next step if a new harness. Why is the fuel thermosensor my main code causing issues?

It will throw the car into limp mode. The others are more emissions based codes which won't necessarily cause an issue other than throwing a code.

OK gotcha. I'll keep updating. I pulled the harness out tonight and found some of the wiring going to two of the solenoids on the ground side showing bare wire.

Forgot to motion this is a JDM harness which explains the fuel thermosensor as I've read

quick question.....is it possible to just soldier the 330ohm 1/2 watt resistors in place of the connectors while making them clean with heat shrink??? i feel this would look alot better!

Yes, but that's not going to address your problem. Get the car running properly, then make it "look better".

not that im disagreeing with you but wouldnt that in a way be better?? i mean im pretty good with wiring but def not expert. i redid my whole 88 10thae harness and it ran alot better and looked better. not that i am going for the "looks" right now but if im going to redo the harness i might as well make it look good ya know? basically what im saying if if i can make this harness ok and delete all the emmision connectors execpt for the fuel pressure one wouldnt that be better and "look" better on the eye and wallet in the long run? im planning on trying this out and if it doesnt work just get another harness and probably the rywire.

I'm suggesting to get the car running properly first before trying to make it "look better". If you do the latter right now, you won't know if your issues are because of your "beautification" work or your un-diagnosed current problem.

At the end of the day, it's your car. Do as you like. You asked for advice and you got it. It's up to you what you do with it.

thanks for all your advice really!! thats why i love this site awesome knowledge and people. i will continue to update this as im working on it every free chance i get

ok so still in the process of repairing the harness first. i do have a couple of questions as this is a jdm harness. 1st- it doesnt appear that there is a connector or wire that goes to the coolant temp sensor on the drivers side of the block. anyone know what color wire this should be? 2nd- does anyone have wiring schaematics for jdm harness? as far as colors? thanks!

ok so im thinking that the ecu may have gotten fried from the wiring grounding out. where i stand now is the injectors are not getting any ground. all have power from the bl/y wires but no ground signals which are supplied from the ecu itself. i have verified that the wires have no open or shorts in them .3 ohms of resistance. the ecu itself has all grounds and power as there is spark but just not sending signal to to the injectors??? any other thoughts???

Personally, I would replace the harness and buy a PFC. A fair amount of initial cost, but you will be thanking yourself later.

So update the fuel injectors are not getting the ground pulse signal therefore not firing. I put a know good ecu in and still the same issue. What is tied in to telling the ecu to send ground pulses to the ecu? Help

so now just research after research....looks like looking at the fsm the pcm gets its inputs for injector pulses from the tps and the cas? correct?
94F%20-%20Fuel%20and%20Emission%20Control%20Systems[1].pdf

sigh....so now more problems.....finally replaced the harness and i did get the car to start last night( sprayed a lil starter fluid in it and it fired up and kept running) went to work on it more tonight and could not get it to start at all!! i can get it to sputter on starter fluid but wont run. i verified spark and pulled the fuel rail up to verify that the injectors are spraying. what the hell else could it be??? as im sitting here thinking could it possible be the plugs??? i have had those in there while chasing all these issues.

bump please help anyone??? thi is driving me crazy

replaced plugs and that didnt seem to help, think i narrowed it down to a cold start issue. once i get it fire up and warm it starts with no problem at all. so tonight im going to check my connectors to the coolant temp sensor and air intake temp sensor. ill post up results

94 fd will not start cold
 

ok so i figured is start a new thread since my old thread is getting no input. The problem i am having is the car will not spit,sputter...nothing on a cold start. i have to spray a little brake cleaner in the intake and it will spit and start. it runs fine with no problems when running. the car starts fine on a warm or hot start with not problem at all.
- i have verified fuel ( pulled the fuel rail up and watched the injectors spray as i turned the ignition)
- i have verified spark by testing each wire with a spark plug tester ( both leading and trailing)
- i have verified compression by not being the best but 95psi on each face

tonight i plan on checking the fuel pressure and my connectors to be sure i have the coolant temp and air temps plugged up correct

little background i got the car and it was a wiring nightmare!! replaced the engine harness and fixed alot of mistakes. i have the rats nest removed and 330ohm resistors in the plugs.

can someone please help me out with this

The air temp sensor should be reading colder temps and then the ECU supplies more fuel for starting and running. Check the AIT sensor.

will check tonight and post results. im hoping its something simple