New Member RX-7 Technical Post your first technical questions here, in an easy flame free environment, before jumping into the main technical sections.

2nd injectors issue i think

Thread Tools
 
Search this Thread
 
Old 06-30-12, 07:01 PM
  #1  
Junior Member
Thread Starter
 
azhonkie's Avatar
 
Join Date: Jun 2012
Location: Superstition Mountains
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
2nd injectors issue i think

Ok,i have downloaded the FSM from a link here on the forum,and i have my dad helping me as he is a mechanic,but never worked on a wankel.

Next,it was sitting for 2 years,but i bought a new fuel pump,screen,and now it runs.
Here is the problem:
cold starts fine.
Runs great up to 3500-4000-driving
will go to 7000 in neutral.
Will not go over 4000 in gear.

We just checked the secondary injector resistance,and it was 2.5 ohms.
Now the manual says they should be 11-16.
Is the manual right,or is there a misprint,and they should read 1.1-1.6?
Also,if they are bad,because of the low ohms,do you know why 2 injectors would go bad,and be at the exact same ohms?
I am going to look at the fsm manual, and the Haynes manual and make sure this motor is to be at 11-16 ohms,and not something else close to what i am getting.

We are getting fuel to the rail. I have to listen to the injectors next,and also buy the testor to check the boost sensor.

While i am at the boost sensor,when i pulled the vacuum hose off the boost sensor,and tried to blow through it,it had some resistance to it.
So i pushed a wire through it,and a small plastic piece came out.

This plastic piece was about as big as a grain of rice,and had a hole about the size of a toothpick on one end,and a very small,unnoticeable hole at the other.
So i am assuming this is designed to reduce the suction pressure on the boost sensor.
Now that i wrote all that,is this pressure reducer have to be in there?
Since i dropped it and cant find it now.
With out it,it will get full intake vacuum.

Thanks for any help,and i am just plugging along on this.
Old 07-01-12, 10:26 AM
  #2  
Engine, Not Motor

iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,789
Likes: 0
Received 108 Likes on 91 Posts
You have low impedance injectors. 2 Ohms is fine.

Yes, you need the little pill in the line. It smooths out the pulses from the engine.

Have you had all your injectors professionally cleaned and flow tested? After sitting, it is very common to have bad injectors.

Definitely test the pressure sensor according to the FSM. A bad pressure sensor will cause this.
Old 07-01-12, 11:14 AM
  #3  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
When driving can you ever so slowly creep above 4000 rpm (not talking about gunning it)? You can check to see if the injector plugs are secured properly by checking for battery voltage w/key to on at the ECU via pins 3F (Light Green/Red wire) and 3H (Light Green/Wire). Both pins are in the smallest ECU plug.
Old 07-01-12, 07:50 PM
  #4  
Junior Member
Thread Starter
 
azhonkie's Avatar
 
Join Date: Jun 2012
Location: Superstition Mountains
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
Thanks for the reply's.
I read a thread later on about the low impedance injectors.
I have also cleaned up both grounds on the drivers side strut tunnel,and then the one behind the trailing coils,then the one from firewall to rear of block.
No way to get to the one for the ecu under the intake manifold.

So,i am going to reground at the boost sensor.
But from Aarons page,and here in this forum,it said a black and brown wire.
Here is what mine has:
Black,with a white stripe
Brown with white strip
Brown with red stripe
Brown with black stripe
Now all the brown wires have a dark dot on them,
and the black wire has brown dots on it.
The Black and white wire is also a little bigger than the brown ones.
Is the Black wire,with the white stripe,the ground wire?

Next,the 5th and 6th ports open at around 3500 i understand.From reading my Haynes,and here at the forum.
I also downloaded the FSM and have been reading it.
This is my,and my dads first wankel. He is a mechanic with a degree in diesal,and heavy equipment,but also works on cars.
If the car is in neutral,and running,can i increase the throttle and see if they are opening,or would the car have to be in gear and driving so the vacuum is up high to open them.

I had a little wrong with my first post until my dad came over.He has been helping me.
After it is warmed up,if i slowly accelerate,or just push the throttle down slowly,it will go to 5000 rpms,and then sputter,or die off about a couple hundred rpm.

It cold starts fine,starts fine after warmed up. I can drive it all over twon no problem. I have had it out on the highway at 65. But as soon as i try and climb a hill, i cant do over 25 mph.

It is a 87,FC, 13b, NA.
I will check the battery voltage,and see if i can hear them clicking.
No testing done on the injectors other than my dad showing me how to check resistance.

Last edited by azhonkie; 07-01-12 at 07:53 PM. Reason: Forgot some info
Old 07-01-12, 08:07 PM
  #5  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
You won't hear the secondary injectors when checking for voltage w/key to on at the ECU as this test just tells you if the injector plugs are connected to the injectors properly. If you had 0 volts when testing then the injectors will not work. And this means either the plugs are loose on the injector(s) or one of the wires in the plug is pulled back and not making proper contact or the plugs are cracked.

You cannot test the secondary injectors when free reving in the driveway unless you disconnect the TPS and unplug the vacuum hose to the Pressure Sensor as this puts load on the engine which is required for the secondary injectors to work, plus the rpm needs to be above 3800 rpm.

Of the four wires at the Pressure Sensor, three of them will have some voltage w/key to on. The Black/White wire will have 12 volts (so this is "not" the ground wire), one of the Brown wires will have 5 volts and another Brown wire will have a couple of volts or so. The wire that has zero voltage is the ground wire for the Sensor. If you ground this wire it is recommended by Mazda to ground it to the engine block and not the body frame.

If you had problematic 5th and 6th ports it would cause a loss of high end power, but it would not prevent the car from red lining.
Old 07-01-12, 09:00 PM
  #6  
Junior Member
Thread Starter
 
azhonkie's Avatar
 
Join Date: Jun 2012
Location: Superstition Mountains
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
Ok,i will check for voltage.
I will also check the wires to reground the boost sensor.

I just revved it up in my driveway in neutral,and it goes to 5000 rpms,
and them fluctuates from 4800-5000 surging. But remaining a steady surging.
The 5th and 6th port actuator rods did not move at all,ever,through the whole range of revving up or down.
I will do the testing then come back tomorrow.

Oh,forgot to mention,when it does the surging at 4800-5000 it smells like old gas is trying to burn.
Now, i did put in a new pump,flushed the tank,ect, and installed new filters.
I wonder if this smell is what is left in the injectors (the secondarys) from it sitting for so long.
it sat for at least 2 years before i bought it.

Last edited by azhonkie; 07-01-12 at 09:07 PM. Reason: forgot some info.
Old 07-01-12, 09:09 PM
  #7  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
The actuators are like the secondary injectors as the engine needs to be under load for them to work. If you don't pull the vacuum hose off of the Pressure Sensor in addition to disconnecting the plug to the TPS then neither will try to activate when they should. Is this the test you just tried or not? Meaning did you do the above to place the engine under load?

And to test the Pressure Sensor the voltage on the Brown/Red wire has 3.5 to 4 volts w/key to on and the vacuum hose disconnected. And the electrical plug needs to be connected to the sensor as the voltage is read by backprobing the wire.
Old 07-01-12, 09:34 PM
  #8  
Junior Member
Thread Starter
 
azhonkie's Avatar
 
Join Date: Jun 2012
Location: Superstition Mountains
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
No,i had the connector removed from the boost sensor.
This way i had 12 vts to black and white
5 volts to brown and black
And 2 volts to the other 2
I will redo my tests as how you just explained it.
Then i will re post tomorrow.
But,since i had the boost sensor disconnected,i revved it up and it did the same exact thing,no difference.
Old 07-01-12, 10:10 PM
  #9  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
You're not supposed to disconnect the plug to that sensor but disconnect the "vacuum hose". These are two different things. And the TPS is to be unplugged to create load on the engine. Doing otherwise will not work.

One of the Brown wires at the Pressure Sensor is an "output" signal which is read by the ECU. If the plug was disconnected then the sensor cannot send a signal on this B/R wire so you will not get an accurate voltage reading on this wire. It would be like someone trying to talk to you with their mouth taped and gagged as you would not be able to understand what they are saying.
Old 07-01-12, 11:05 PM
  #10  
Junior Member
Thread Starter
 
azhonkie's Avatar
 
Join Date: Jun 2012
Location: Superstition Mountains
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
Thanks satch,
I will go check or test everything as you suggested and then post back.
Monday evening,or afternoon.
Old 07-02-12, 06:53 PM
  #11  
Junior Member
Thread Starter
 
azhonkie's Avatar
 
Join Date: Jun 2012
Location: Superstition Mountains
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
I have to pull the mat and things to get to the ecu,but i did some of the tests by the fsm and this what i got.
TPS---disconected
Boost sensor vacum disconnected.
Revved up over half throttle and could hear the secondary injectors click on and start chattering,both of them with a long screw driver.

Then i revved it up again,and the 5th and 6th ports did not move,open,or the rods did not even move at all.

Then,since everything was disconnected,i took the readings from the boost sensor by leaving the plug in,and back probing.
This is what i read:
Blk and Wh stripe- 12.37---volts
Brwn and Wh stripe---5.01-- volts
Brwn and Red stripe------3.4 volts
Brwn and Blk stripe-----.03 volts

I can not check the boost sensor as per the FSM because i have to buy or borrow the hand vacuum pump to put the proper load on it to read the voltage.
Unless i can hook it back up,and check it while running.
Maybe i will just do it and see what happens.

I took it for another drive,and i can go 60mph and higher on level ground.
But when i hit a hill, it bogs down.
Now when i went to my dads house,i have to go from 1500msl to 3000msl.
So,the climb up the hill,even though the climb is at least 2 miles long,and with 2 turns,i had to do it in second gear,at 25mph.

Cold starts fine,hot starts fine,and still revs up to 5000, and then just sits there and fluctuates. Acts just like a piston engine,when the valves float at high rpms.
Anyway,i guess i will pull the mat,and check the terminals like satch suggested,or is it necessary since i can hear the injectors(secondary's),at least kicking on.
Or just pull the seconday's,and do a fluid,and volume test.
Old 07-02-12, 07:02 PM
  #12  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
That the Brown/Red wire indicates 3.4 volts is good, and thusly the Brown/Black wire is your ground wire.

You can drive the car w/the TPS disconnected and the Pressure Sensor vacuum line disconnected/unplugged to see if there is a noticeable change. And w/these items disconnected/unplugged could you come close to red lining or not?

If you can hear the secondary injectors click then you don't need to check the two pins at the ECU for the clicking would tell you that their plugs are connected.

And near the ECU is the Atmospheric Pressure Sensor. It's located just above the passenger kick panel and has a plug w/four wires. The sensor is rectangular and the Green/Yellow wire is the output wire to the ECU and w/key to on it reads 3.50 to 4.50 volts at sea level and the voltage decreases w/elevation such that at 6,500 ft above sea level the voltage drops to a range of 2.5 to 3.5 volts. And the connector needs to be plugged in and voltage is read by backprobing once again
Old 07-02-12, 08:48 PM
  #13  
Junior Member
Thread Starter
 
azhonkie's Avatar
 
Join Date: Jun 2012
Location: Superstition Mountains
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
Willl take it for a test drive and see what happens,and will check the APS sensor.

Did i test the boost sensor as best as i could,by my explanation.I dont have the hand vacum,so i did it as described.
Why would there be .03 volts at a ground?
Could the boost sensor be bad?
That is why the very low voltage on a ground.
Is it searching for a ground maybe.
Anyway,i will reground the brw, and blk wire to the engine as described in aarons site,and here. But to the engine.
Old 07-02-12, 08:58 PM
  #14  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
.03 is rather insignificant in the scheme of things. Mathematically it is three one hundreths from zilch.

And Aaron mentions a method of aplying grease to the actuator rod to verify whether they are working.
Old 07-02-12, 09:41 PM
  #15  
Junior Member
Thread Starter
 
azhonkie's Avatar
 
Join Date: Jun 2012
Location: Superstition Mountains
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
Yes, i read the part at Aarons on the grease.
But when i had the tps, and boost unplugged,i stood at the side of the car,and looked at the actuator rods,after listening to the injectors,and did not see them move.
But i will take it for a test drive,with grease,and see what happens.

I will also reground the way Aaron explained.
And do the APS.
Old 07-03-12, 09:49 PM
  #16  
Junior Member
Thread Starter
 
azhonkie's Avatar
 
Join Date: Jun 2012
Location: Superstition Mountains
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
Ok,checked the atmospheric pressure switch,and it calls for 3.5-4.5 volts at sea level.
It calls for 2.5-3.5 at 6500 msl.
I am at 3000msl and it reads 4.99vots, ign on,back probing.
So that is fine.

Now,when i stand on the pass side of the fender,and do the 5th and 6th port actuator test.as per the fsm, fuel and emission control section,and blow a little air into the actuator tube,here is what happens.
Looking down on them.

The one on the right,looks like it is halfway open.When air is applied,it moves maybe a 1/4 inch.But,it is in the same position,stuck half open. According to the length of the rod,it is not against the stop.

The one on the left,is right at the closed position,and is against the stop. When air pressure is applied,it moves 1/4 inch. So it is basically stuck closed.

So,i will try and free these up. I will read some more,but would this scenario cause not being able to redline, only does to 5000rpms,and just sits there and surges.

Also,no power when trying to climb a hill.
There is also a K@N cold air screen,filter on the front of the MAF sensor.
So,should the lean mixture be set at lean,or rich,or should i just try moving it around and see what happens.

But,i will have to get the ports actuating first.
Have not tried to drive yet with the TPS,and Boost sensor disconnected.
Have been working to free up the actuators,and now is getting dark.
So im quitting for the night.
Old 07-03-12, 10:05 PM
  #17  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
Might you explain what 3000msl means?
Old 07-03-12, 11:42 PM
  #18  
Junior Member
Thread Starter
 
azhonkie's Avatar
 
Join Date: Jun 2012
Location: Superstition Mountains
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
Sorry,
mean sea level.
My elevation. Is 3,000 feet,(msl).

Last edited by azhonkie; 07-03-12 at 11:55 PM. Reason: Forgot something
Old 07-03-12, 11:51 PM
  #19  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
So you're at 3000 ft above sea level? If that's the case then I don't think your sensor is giving you a reading within spec. If it's supposed to read less than 4.5 volts at sea level and decreases w/height then a 5 volt reading doesn't make much sense. That sensor has a Brown/White wire that supplies the sensor w/5 volts w/key to on. Are you certain you read the correct wire and if so it appears this voltage is being passed on to the G/Y wire. You can either make a code checker and see if it indicates an error for this sensor or perhaps disconnect the plug to the sensor which I think will put the ECU into a default mode regarding this sensor which is sea level.
Old 07-04-12, 12:06 AM
  #20  
Junior Member
Thread Starter
 
azhonkie's Avatar
 
Join Date: Jun 2012
Location: Superstition Mountains
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
I will look at the plug again.
According to the fsm,it is suppose to be socket D,or the lower left corner,when looking at it with the top,being the clip,at the top,or at the North position on a compass.

This is what i thought i probed.
I will check again,but yes it was a brown,with a white stripe.
Tulsa is 700 msl,or 700 feet above sea level.
Old 07-04-12, 12:13 AM
  #21  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
Originally Posted by azhonkie
I will look at the plug again.
According to the fsm,it is suppose to be socket D,or the lower left corner,when looking at it with the top,being the clip,at the top,or at the North position on a compass.

This is what i thought i probed.
I will check again,but yes it was a brown,with a white stripe.
Tulsa is 700 msl,or 700 feet above sea level.
Well that's the wrong wire. Just focus on the color of the wire rather than its position in the plug. You want to check the Green/Yellow wire.
Old 07-04-12, 12:45 AM
  #22  
Junior Member
Thread Starter
 
azhonkie's Avatar
 
Join Date: Jun 2012
Location: Superstition Mountains
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
Ok,i will check the other wire.
Would the 5th and 6th ports not working be my problem(s).
I would think so.
How about the Lean or Rich mixture?
I pobably should take care of the ports first though.
Old 07-04-12, 01:05 AM
  #23  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
From what I understand you should still be able to redline while driving w/o the ports working properly but there will be a loss of power/oomph but not the inability to reach a high rpm or failure to climb a long length of upward sloping road.

The Variable Resistor is supposed to affect just the mixture at idle. The secondary injectors come online at 3800 rpm. Perhaps they are clogged but there are other factors which could cause your problem.
Old 07-04-12, 01:09 AM
  #24  
Junior Member
Thread Starter
 
azhonkie's Avatar
 
Join Date: Jun 2012
Location: Superstition Mountains
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
I will go through the trouble shooting section of the fsm again.
And see what other symptoms there are.
I might just take the secondary fuel rail off,tie wire the injectors to the rail as the fsm instructs.
And then do a fluid,and volume test just to see what is happening.

I mean me and my dad,i am still learning.
Thanks for all your help,and have a great 4th.
Old 07-04-12, 07:34 PM
  #25  
Junior Member
Thread Starter
 
azhonkie's Avatar
 
Join Date: Jun 2012
Location: Superstition Mountains
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
G/Y wire checked out at 3.8 volts.
Have 80lbs of fuel pressure through out the system,with the checker jumped,and key on.
Checked after pump,after secondary filter at fire wall,and on return line by the secondary filter so it was going completely through the cycle,back to tank.
I will start seeing what i can do to the ports.

On Aarons page he said there are probably quite a few people running around with there ports shut because they dont go over 7000 rpms,and just drive around normally.

He said,and the fsm said,under the trouble shooting,that if they are always open,it will degrade low end performance,and i have 1 stuck closed,and 1 stuck open.

So i will pull the actuators off,and see if i can free up the arm.
I might check the secondary injectors for fuel flow and volume also.

Last edited by azhonkie; 07-04-12 at 07:36 PM. Reason: forgot some info


Quick Reply: 2nd injectors issue i think



All times are GMT -5. The time now is 01:13 PM.