painlesswriter

First off I guess the problem with the car ( 88 fc n/a). I had a really bad clogged primary injector so I had removed the Dynamic chamber and had the injectors cleaned ( secondaries as well) ordered new manifold gasket and vacuum lines and injector O-rings and grommets. Once everything was replaced and reinstalled I let the car warm up and took it for a light drive........

Everything was fine and so I decided a more spirited drive, again no problems and ran better than ever. Next day however I was driving like normal when the car started acting like it was struggling again to get up to speed.after I let the car warm up and while I haven't done anything yet it will rev fine and redline at any throttle, full or half or quarter, Then once I try to drive the car its fine..... once I go over 25% throttle it will then cut out till it returns to 1k rpm and will continue to do so till I shut it off then restart.

I have set the TPS and rechecked it a few hundred times just bc I know that it can be a culprit to the 3800rpm thing , however mine does not simply do it at a specific rpm only at certain throttle opening.

Also in regard to throttle and TPS, My sensor registors full throttle while only 25% throttle is applied, well I mean the plunger is fully out on TPS but by that time the TB is only open about a quarter ( will keep going but by the end of the sensor its a quarter) Is this normal? I can try to get a Pic to show exactly whats going on in this regard if needed. I just don't remember if that's how it was prior to removal. Other than that the TPS has full range no dead spots.

The other issue.... While trying to readjust idle and everything ( which by the way idle is fine still) I noticed that the variable resistor made no change leaning or rich and that it just spins forever doesn't stop one way or the other. Yes the initial set coupler was jumped. I tried looking too so if anyone knows where to get one of these variable resistor sensors PLZ let me know WTB PLZ.

I also noticed that I may have a leak problem with one of the check valves under the TB that goes to the Thermowax , To check I capped both sides and it made no difference, not sure if this is ok to cap or not but I did it anyway to see if the car would just go bonkers or not.


The only things I have came up with prob wise after checking everything over a few times is Maybe The intake manifold gasket didn't seat right ? and is causing a vacuum leak? can this even cause these probs?

Are the TB butterflies suppose to be barely open by the time the TPS is getting WOT signal? This one is the most curious considering I didn't remove anything from the TB. Tho this may be normal Im not sure and the fsm doesn't mention TB vs TPS distance = signal.

Any help in any area would be awesome, sorry for being so long winded just had a lot of questions after a couple of days of testing and trying diff things to make a diff and getting no where kinda makes me crazy.

satch

iTrader: (1)

If the middle spot between lean and rich on the Variable resistor was 12:00 O'clock then the range it should turn from left to right ought to be about from 9:00 to 3:00 if that much so apparently the resistor is broken.

The piston rod on the TPS should be fully extended at about 1/3 or so of full throttle.

Using brake cleaner you can spray at the areas you may thing have a vacuum leak while the engine is idling and if there is a sudden change in the way the engine sounds then you have found a leak.

The TPS is not really associated w/the 3800 rpm hesitation as it is linked to the secondaries not activating which is usually tied to a grounding problem. The Pressure Sensor is also used to tell the ECU that there is load on the engine which is required as well to get the secondaries to activate. Did you replace the vacuum hose to this sensor? This hose has a restrictor pill inside it which is necessary.

Also, the engine only uses the primary injectors to rev the engine while in neutral as the secondaries are not used at all. If you can rev as stated then that points to the secondaries as being somewhat problematic. You can trick the ECU into seeing load by unplugging the TPS and disconnecting the vacuum hose to the Pressure Sensor and capping the hose. Then reving the engine above 3800 rpm while in neutral will activate the secondaries.

painlesswriter

I will check the above again, did not do a vacuum leak test bc the car was warm all day and ill be spraying in proxy to the manifold. Now if I try to trick the ecu would work underload and driving? bc it already will 90% of the time go past 3800 rpm in neutral sitting, in fact doesn't feel like a cut at any specific rpm just over 25% throttle even if I get it to 6k rpm and then try to give more throttle it will cut and return to 1k rpm.
Also do you know where I can buy a new variable resistor ? cant seem to find anywhere. or is it a junk yard part? which would suck bc there are absolutely no rx7's in junk yards much less driving anywhere around here ( mine seems to be the only on in my town other than one older guy who has a cherry vert gtu but im sure hes not parting with anything).

satch

iTrader: (1)

Remember, in neutral, the secondaries do not work, so if you really don't have a problem reving in neutral then that doesn't point to a primary injector problem.

Tricking the ECU allows you to activate the secondaries while in neutral or even driving. If you don't trick the ECU then the only time the secondaries come online is if the engine is under load and the rpm exceeds 3800 rpm.

You also can try driving under a normal condition where the only thing you adjust is unplugging the TPS to see if it changes anything.

You can source a used Variable Resistor from the parts forum on this web site. You can call your local dealer to price a new one if they are still inventoried by Mazda, but they'll likely be costly.

And if you replaced the vacuum hose to the Pressure Sensor then make sure the hose has the restrictor pill in it. And also make sure you have the hose running to the proper vacuum nipple on the manifold and didn't accidentally switch places w/the nipple dedicated to a solenoid only.

painlesswriter

Yeah I checked the pressure sensor hose again I did not replace that one bc it seemed like ii read about a pill in that one so I left it alone since it wasn't bad anyway.

But I did plug the injectors ( secondaries) up to an injector cleaner thing my neighbor had that had a pig tail to apply power to the injectors in bursts and we noticed no sound from them at all there was current just no operation sound, which they did have when I checked them when they came back from cleaning and they sounded fine. So im thinking maybe they got clogged again? I replaced everything fuel delivery wise except the metal fuel house routings under the dynamic chamber, if they were clogged I don't believe they would operate right considering there is no actuall pressure being applied. Maybe the FPR ? tho it was fine yesterday when I checked the pressure per the fsm.

Yeah I do think your right tho I did notice the change only happens when the car is put into motion even just for a sec then the cut constantly happens till I shut the car off ( even in neutral)

it is also getting low on fuel now lol ill need to remedy that before that interfers.

painlesswriter

going to remove the rail and see if there clogged again. even while applying pressure to the rail we still cant hear them operate like before

satch

iTrader: (1)

And what do you mean you cannot hear them?

painlesswriter

the little clicks they make when they open, the fsm shows using basically a rod to listen to them. but the tool/machine my neighbor brought over listens for it itself and lets you know if theres an operation sound.

satch

iTrader: (1)

If you're referring to the secondaries when do the secondaries activate?

satch

iTrader: (1)

Pin 3H (Light Green/White wire) and pin 3F (Light Green/Red wire) at the ECU should both have 12 volts w/key to on. This basically verifies that the injector plugs are mated to the secondary injectors properly.

painlesswriter

we just plugged them into the machine, without them being plugged up to the cars harness and the injectors themselves aren't working so they wont work even if the ecu and plugs are fine. this test is not with the car running either the machine supplies the power and pulses as if they were on the car and running. My neighbor is a car restorer and its his machine so Im assuming hes testing them right, I mean were getting readings from the injectors and the injectors are just dead in the water themselves. So first I need working injectors right? but when he brings them back ill check the ecu pins

satch

iTrader: (1)

Just a note, but the machine should supply power to one terminal and a ground pulse to the other injector terminal to activate them.

painlesswriter

well when I got them back from cleaning he tested them then and they were working right, and the car ran great for a day with no problems at all even in spirited driving but the next day is when all the problems happened mid drive. Ill wait to see what he says. he restores all kinds of cars tho he did say he has never worked on a wankel before so don't ask him to rebuild it or nothing lol. but said he has plenty of expensive machines I can use.... well he can use for me lol.

painlesswriter

just got em back and there working fine now when he took them off the rail, they sprayed fine and had good volume, so is there a chance its the FPR? also I had replaced all of the lines in the car could a loose line at the tank cause the FPR to loose pressure and or not have enough ? bc there was a clip that seemed a tad to big for the return line... idk ill check it again anyway. But anything else that may be making me loose fuel pressure now other than the FPR?

Also just now noticed that the fuel pump is turning on ( not jumped atm) when I turn the key on, not cranking is this normal? I thought it was only suppose to turn on when it is cranking over in the on position.

satch

iTrader: (1)

The fuel pump should turn on only w/the engine cranking/running, but there are some caveats. It will turn on w/key to on w/the fuel check connector jumpered or if the AFM flapper door is opened.

Also, the injectors might be working outside of the car but when installed they might not. Again, the plugs need to be on securely and to prove that you can check at the ECU to validate this. Also, the Pressure Sensor needs to be working properly.

And as said previously on two occasions, if the TPS is unplugged and the vacuum hose to the Pressure Sensor is unplugged and capped you can get the secondaries to turn on while in neutral if you get the rpms above 3800.

And you should also try operating the car w/the TPS unplugged.

And lastly, there is a vacuum hose which runs to the FPR. (vacuum should be present on the hose after it has been idling for close to one minute) You can also check the fuel pressure after the FPR and compare the reading to those found in the service manual. While idling it should be around 28 to 35 psi.

painlesswriter

ok so I ran the car with the tps unplugged no diff other than surging idle, Fuel pump is running with no jumper and the afm flap is closed. not sure why this is happening, ill try tricking the ecu to turn on the secondaries tom. checked the vacuum to the FPR its working properly. so Ill also check the ecu pins tom since something is keeping them from turning on.

also if im driving the car will go all the way to redline as long as I don't give more than 25-30% throttle its not cutting at any given rpm at all weither driving or just sitting only when I give too much throttle. ive had it cut at 1500-2000rpm as well driving and sitting.

satch

iTrader: (1)

If the fuel pump is powered w/just key to on then the Circuit Opening Relay is stuck closed. The relay is located under the dash and just to the right of the steering column. It is Yellow and Black. The plug has two rows. Top row far right is a Blue wire. This wire powers the pump. W/just key to on the Blue wire should not have voltage to it.

Other things which might cause your problem is a troubled fuel pump, clogged fuel sock, clogged fuel filter, clogged catalytic converter, problemed Pressure Sensor, faulty grounds, and misplaced vacuum hoses. The Brown/Red wire of the Pressure Sensor should read 3.5 to 4 volts w/key to on and plug connected to the sensor.

And make sure you removed the Intial Set Coupler jumper.

satch

iTrader: (1)

Another possible cause for the pump to run w/key to on would be the fuel switch internal to the AFM being stuck closed. At the Circuit Opening Relay the bottom row far right wire is Brown. W/key to on the wire should have 12 volts to it. If ii thas close to 0 volts then the fuel switch is closed when it should not.

painlesswriter

alright only thing I really had time to check quickly was the FPR vacuum line, also wasn't sure if the car needed to be cold or not but I start it every day anyway, I shut the car off went back to look so the car was Norm op temp, but had just started it and checked the vacuum to the FPR and it was under vacuum already from the time to start the car and walk to the passenger side it was already showing vacuum so maybe 10secs tops. What could cause that ? or should I try again when the car is cold?

satch

iTrader: (1)

Hot starts create different results than cold starts.