mattsdajam

I'm New to the rotary world, very enthusiastic about finding my car for 1500$ its got a lot of modifications which might make the process of getting things smooth a problem
at this point i have tried everything to the best of my ability to fix my cars idle. the car runs fine, it will take a couple turns of the key to engage the starter, and then the car turns over. the idle will fluctuate when the motor is cold but when it settles it will stay at a little under 1000 rpm, i can run it at that idle for 10-20 mins then it dies. when trying to turn the motor over it won't start for about 30-40 mins. I have rebuilt the throttle body, checked my vacuum lines, constructed a modified schrader valve on the fuel rail to check the fuel pressure but i havent gotten around to it. I need some oppinions from a reliable source on what the problem could be, I live in a small town that does not have any kind of rotary performance shop or diagnostic tools. I took it to a local shop, the owner had an rx7 two rotar in the past, he thinks its the ECU. Im not sure what to think of his oppinion so i wanted a second before i try to get my hands on a custom wiring harness and ECU. I dont have a lot of money to blow at this point and getting it running smooth is my main priority. any suggestions ?

Thanks, Matt

RotaryRocket88

iTrader: (7)

Has the car been driven with the timing advanced? If so, compression test first. A lot of advance can easily blow an engine.

http://www.banzai-racing.com/compression_test.htm

To correct the timing problem, you need to restab the CAS. A Haynes manual should cover this procedure, and there are numerous threads in the 2nd gen section. Just search titles for "CAS".

Also, when checking timing, the idle must be under 1000 RPM. Above that point, the ECU will advance timing. Under that point, it will be -5* leading and -20* trailing.

mattsdajam

thank you i will see if this helps !

mattsdajam

Thanks for that it sounds like its running a lot better. But its still dying out but i think i figured out why, NO SPARK from my trailing coils. I thought i checked it before but i guess i was wrong. is there a way to check if its the coil or an electrical issue somewhere else? im at a halt. any info would be appreciated !

Thanks, Matt

Lmill86

iTrader: (10)

What state are you in?

mattsdajam

Im in Arizona

mattsdajam

i know this could be a lot of diffrent things but any suggestion on what to try from here would be phenominal im at my witts End

mattsdajam

Bump

Still need some advice

satch

iTrader: (1)

You might want to check the Water Thermosensor as it helps the ECU define how much fuel to use based on the engine temp. A cold engine requires more fuel than a warm one. If the sensor or its wiring is poor then it might be giving the ECU a cold reading when in fact it should be warm. So pin 2I of the ECU has a Green/White wire and its voltage w/key to on on a cold engine should be 2 to 3 volts and it drops to .4 volts when warmed.

Gothpanda

Not a bad find, I've had no luck finding any sort of turbo RX7 down here.

mattsdajam

I got it to idle normally now, the problem im facing now is that the engine will randomly shut off now, it doesent sputter, its an immidiate stop, then it will turn and turn but wont catch, I replaced the starter and coil assembly(including the igniter). sometimes when you turn the key it clicks and does not turn at all. Im wondering if the problem is related or something seperate all together. Also when i redid the crank cngle sensor there are four marks on the excentric shaft about a half inch apart i started on the one on the far right. they are white not yellow, But ther are two marks on the very front that are panted on yellow and one red mark. Im not sure if its something the previous owner painted on there or the factory. so i may not have the idle just right. but if i use a timing light im not sure what mark to compare it to.




on a seprate note. Are there any performance shops in Arizona that work on an FC?

satch

iTrader: (1)

The pulley should have two notches grooved into the pulley so you shouldn't have to rely on paint marks.

mattsdajam

i will try to post a picture tomorrow, There are only 4 white marks very close together

satch

iTrader: (1)

Are you sure there are no notches cut into the pulley? Your fingernail should be your guide here.

Post #2 in the following link:

https://www.rx7club.com/new-member-rx-7-technical-256/trailing-2-timing-way-off-1000733/

RXSpeed16

iTrader: (41)

Does it look like this one? http://www.racingbeat.com/RX7-1986-1...tem/11469.html

mattsdajam

Yes it has the notches just like that !

RXSpeed16

iTrader: (41)

As posted in the description, it has marks at 20 Before TDC, 10 Before TDC, 0, 10 After TDC. Adjust the leading ignition to 5 deg after TDC with the idle under 1000.

mattsdajam

this is going to sound like a stupid couple of cousetions but, According to instructions how would i know its five degrees is that a little after the 0 and before the ten ? and also im a little confused as to how i tell if the idle is under 1k rpm, my tach is not working. am I adjusting the CAS with the engine on ??

mattsdajam

also where would i be pulling this reading ? the ECU or the thermosensor?

mattsdajam

UPDATE

I made an ECU tester as described in the FAQ. Im throwing a Code for my TPS sensor
Is there a way to salvage this part ? or does anyone have on they would like to sell me ?
Also who makes a good Aftermarket throttle body? While i was working on the car i noticed a row of four connectors on the coil side of the Block does anyone have any idea what these could be? One of the housings is cracked on female side, and im not sure if its integrity is comprimised. Thanks again for all your help gentlemen

satch

iTrader: (1)

Pin 2G of the ECU is for the TPS. If you take the reading from the ECU like you would at the TPS you'll be able to tell if the wiring/connection is the problem or not.

mattsdajam

I took the reading from the Diagnostic terminal. Im not sure if thats the same.

satch

iTrader: (1)

You pulled codes from the diagnostic connector. The ECU receives input from the TPS. If the ECU detects a fault in the wiring connecting the ECU to the TPS then it will show a code. The TPS has a Green/Red wire that should have 1 volt w/the key to on and the engine as warmed up as possible. This wire connects to the TPS as stated thus the reading at the ECU Green/Red wire at pin 2G should be the same as at the TPS. If it is different then there is a wiring/connection issue that needs to be addressed. Do it.

mattsdajam

AH-HA! that makes more sense now thank you! i found a wire backed out of the connector to my coil pack its brown or black with a yellow stripe I couldnt tell, is this possibly the reason im not getting spark from the trailing coil?

satch

iTrader: (1)

Black/Yellow provides voltage to the coil.