Car is a 87 rx7 turbo, s5 block with all 87 parts on it. Emissions blocked off, fmic, no o2 sensor. stock injectors in primary 1st gen 680cc in secondary.

3k rpm and under, on light throttle acts like its getting loaded up/hesitating. no o2 sensor bung on the downpipe and there is a leak at the flange. Also believe the guy removed the o2 plug cause i cant find it in the engine bay.

Tried checking the tps, DMM from harbor frieght set to 2k ohm... hooked up to A+B read about 1500ohm, adjusted it down to 1019ohm open up the throttle to see what wot ohm will be at and after 2k ohm the sensor wont read. If I set the dmm to 20k ohm idle is 6.03 middle is 5. 44 wot 6.33 so since its not readin what its suppose to I guess this needs to get replaced?

Jim at jpr said there is a screw on the afm that adjust the air mixture to about 3-4k I turned it out about 4 turns the hesitation def got reduced but when I push in the clutch and go to stop idle keeps going up and down.

So I turned the afm screw in till the idle was even.

The car backfires like crazy and def smells super rich.

Pretty close to taking to a delear cause I have done everything I can and dont know what to do next.

I dont want to spend 300 on a tps sensor and still have the same problem, I rather buy a haltech and get it tuned and have a great running car

 

you should NEVER adjust the screw on the AFM. So... the problems, Wrong engine for car, wrong intake setup for car *no clue what was removed / changed from what ECU wants*, wrong injectors for car, possible dead TPS, no way to check AFR and no clue what has been done to your car to make it run like this.
now the questions.
is it running the stock turbo? why is there a FMIC? Is there any kind of standalone or piggyback fuel control? how long have you had the car and has it had this problem from the start or did it just start? do you have any of the parts that should be on the car? do you have a wideband or at least a AFR gauge? what pins are you using as A,B and C on the TPS?

 

Yea I gave up the afm screw idea. I got the car how it is now, not positive if the block is a s5... papers say 88-91 engine the engine has 41k on it. Looks to be the stock turbo since the manifold is stock. The FMIC was already on the car when I bought it, no stand alone or piggy back just the factory ecu. had the car for 3 days now just put it on the road today. I am going to order a afr kit since this will help evaluate the problem.

I followed fc3spro.com looking at the back of the plug red prong top and black prong bottom left.

 

There is really nothing else I can do besides go to the nearest rotarys shop, I did the timing cleaned the trailing plugs and replaced the leading plugs, the wires look to be in good shape.

I just dont get why its running perfect mid-wot but light throttle is total crap and its seriously driving me crazy because I have done everything I can do for now.

 

The 680cc injectors should have nothing to do with this since the problem is only present from idle to 3k rpm

 

ok. sounds like its a dead TPS and maybe some other problems from them trying to make it run right with the over sized injectors. Any exhaust place like Midas and such can put a O2 bung in the down pipe and will probably charge less if you take JUST the down pipe to them, if you are just getting a basic AFR gauge *wide band is much better* you only need a generic 02 sensor should be about $20 from autozone, advanced, whatever. The oem wire to the ECU is under the intake near the back of the engine it is a single wire in a green plug and will do nothing for how the engine runs at idle or WOT.
I only use the DMM way to see if the TPS is good, Get the FSM and use its method for it using two 12v leds tie the positives together with a spade on the end and the neg of each gets its own spade. After getting a known good tps set. Install a jumper in the initial set plug *two pin connector near the battery and coil pack, Set the idle speed, timing and idle mixture as per the FSM. Every time you change one of the three the other two can change so after making a change to one recheck the others and do the mixture last *you need the initial set jumper set for them to be done right
you may also need to change out the MAF as it will no longer read airflow properly.
after all this report back


but the car will run like *** after the secondarys kick on unless they do somthing to change how fuel is handled also changing how it runs befor they kick on.

 

There is only one problem, I do not have the green plug with the 3 prongs to set the tps with the led lights.

I will probably go up to the nearest rotary shop tomorrow and get a tps from him and do it there.

 

Never have I ever adjusted the AFM. I read about adjusting it once and also read never to adjust it hence why it is sealed with a metal plug. There is the A/F screw on the pass strut tower but that only adjusts for idle. What ECU is in there? Should be a N332 or N333? Check the timing and re check the TPS. Also, (some people swear you don't have to do this) Always jump the initial set coupler next to the leading coil before you change things like timing and idle and A/F and TPS. Here's how I check my TPS. I set the idle on my TII's at 850 (ported engines hence +100rpms) adjust the A/F screw to smoothest idle, then take a multimeter and plug the + into the middle wire coming off of the TPS ( I can't remember the color code a the moment) and then put the - to a ground. A correctly setup TPS will read almost exactly 1.0 volts at idle. If its not there, set it there. The after its set blip the throttle a few times and then recheck, then shut the engine off so you can make WOT checks from the TPS. there shouldn't be any dead spots in the sweap.

It wouldn't hurt to check over the FMIC tubing to make sure there isn't a leak. Building a pressure tester is the best route for checking this. What did the PO di with things like the BAC? and all those other extra stuff that I take out too? The O2 sensor is a narrow band and only reads up to 1 volt. It, in a perfect working state, will hardly change the fuel map. I didn't notice any difference in my AFR when I unplugged mine and my Rtek can prove it since I made one run with it plugged in and logging and another run without it.

You might wanna study a FSM on how to set the AFM back to stock settings since I've never touched mine and I don't think many other people have either.

Good luck and post back with results

 

I just did everything over again I started the car waited till the e fan turned on then I used a piece of wire and put it in both ends on the 2 wire green plug connecter next to the coil, then connected my dmm set it as close to 1.0k ohm as possible(1018) then moved onto timing. idle is ok, took out the wire in the green plug, shut off the car and restarted it. took a short drive, cruising at 50mph in 5th gear it starts to load up then clears out and repeats unless i accelerate or lift my foot off of the gas. My DMM wont read the tps sensor at wide open throttle, it will read till almost 1800 1900 then it stops reading if I open the throttle further.

The plug for the screw was already off the AFM so I guess the PO messed with it.

I will have to check what ecu it is.

 

and i wonder why no one believes i get 17/29 mpg

good info, you built off my post so now im going to do the same :P

with the initial set, you need it due to
A/F pot = will make no change in ecu with out it set.
Idle speed = if you change the amount of idle bypass air with a working IAC, BAC the ecu will fight you when setting the speed.
timing = again tells the ECU that you are trying to make a change so it will stop the IAC, BAC and 0 engine load. If you do not set the jumper when setting timing the ECU may think there is up to a 15º difference than what there is.

as for the FSM and setting the MAF this is a direct quote.

"Precaution
the air bypass adjust screw is pre-set and sealed at the factory and must not be tampered with."

so.... at this point there is not much you can do.

 

bigger problem now... car wont start, changed the plugs and no go still. tried disconnecting the fuel pump cranking it then pop in the plugs crank it then connect the fuel pump still no go.

Really sucks when i have been trying to put this car in a shop for the past few days.

 

Wow! You need to download the FSM for both series as you have both series parts in your car. But really it sounds like you are in over your head so just have it towed to a local shop and let them do the work.

 

I doubt its a s5 block, only thing s5 i see on it is the altenator.

The injector transistor was clicking and the ground wire was gettin damn hot, wanted to start but was gettin no spark.

Its getting towed to a rotary shop not to far away. I know the motor is good so hopefully just needs a few simple things.

 

said it might be ready monday, i know its going to end up being something super retarded!

 

like a bad engine ground

 

I am just glad it will get sorted out now, the exterior and interior are in excellent shape, also has brand new tires. After I get it back I am going to install some speakers and a simple head unit. Should order a wideband and maybe look into a rtek.

This car will be my daily driver, my 1st rx7 10ae ran so beautiful and i really loved and miss that car and I know after this gets finished it will feel the same way.

 

I can work on these cars, I did all the work on my fd but I would of never thought that something like this would have me so stumped after going through everything in the FSM.

Had no choice but to have it taken to a shop since they have all the parts to test on it and the only fc parts I have is a fcd, but got plenty of fd parts

and I must say if you own a FC a DMM or voltmeter is a must have tool since these cars are so old and have been through a lot.

 

Sorry man, I read a couple into the thread and then went straight to writing a reply. Guess we both had the same answers. Aside from the car not starting now which is most likely something simple like flooded and you'll probably figure out since nothing changed under the hood to make it not start, the TPS should have no gaps from idle to WOT. possible bad tps maybe... then again 5 thousand RPMs would be a constant reading and should not load the engine up more... I'm stumped at the moment. stay tuned

 

Yes exactly, I will update this post when I get the phone call cause I am sure it will be something simple.

I really appreciate all the help this forum has given me and all the information on here is extremely valuable to anyone with a RX7.

Without this forum I don't think I would of been able to do a motor swap and really learn how to work on my own vehicle so I am very glad this site has been here for all of us to share our knowledge,support, and great advice.

 

Ok so I got the call, he found 1 last vacuum leak.

said he switched the tps, the car responded much better

said there is a real real slight hesitation, went over everything and can't find anything else wrong

said the injectors probably need cleaning. So I can either get the car tomorrow and get em cleaned or wait till he comes back from vacation which is the 17th

 

I'm going to wait till he gets back from vacation so he can send em out to get cleaned and they will be done by the time he gets back, just would like this thing in perfect running condition before it leaves the shop. Hes also going to fix my idiot lights since they are not coming on at all.

Then I just need to detail it and install a cd player and the car will be perfect.

whole reason why I wanted another t2 was because I really loved my 10ae, got good gas mileage, smooth power, was a blast to drive, and was super clean.

This one is damn clean just like my 10ae I had so after I get it back that void of missing my 10ae will be filled.

I know how to work on these cars also which makes it easier on me.

So I guess I was spot on with the tps being bad. There's 112k on the body and I am going to guess the injectors havent been cleaned so if they have never been cleaned then that may be it right there.