secondary injectors??
#1
Full Member
![](https://www.rx7club.com/images/misc/05_year_icon.png)
Thread Starter
Join Date: Feb 2003
Location: nepa
Posts: 156
Likes: 0
Received 0 Likes
on
0 Posts
secondary injectors??
my secondary injectors are not firing, need help on why they are not?
i've checked:
crank angle sensor
injector resistance
they all seem to be ok. its a s5 turbo in a 90 n/a, I believe they did work when firt installed. any help would be great! thank you
i've checked:
crank angle sensor
injector resistance
they all seem to be ok. its a s5 turbo in a 90 n/a, I believe they did work when firt installed. any help would be great! thank you
#4
Full Member
![](https://www.rx7club.com/images/misc/05_year_icon.png)
Thread Starter
Join Date: Feb 2003
Location: nepa
Posts: 156
Likes: 0
Received 0 Likes
on
0 Posts
took out the 720s and put the stock 550s back. now my question is: the haynes manual says to listen for clicking above 3800 rpms. would it be a clicking or more of a buzzing at that high an rpm?
Trending Topics
#11
HAILERS
![](https://www.rx7club.com/images/misc/10_year_icon.png)
Join Date: May 2001
Location: FORT WORTH, TEXAS,USA
Posts: 20,563
Likes: 0
Received 22 Likes
on
20 Posts
The manual does have a valid test where you disconnect the vacuum line off the boost/pressure sensor , plug the vac line and listen for clicking above 3500 rpm.
It sounds like they are working but have some type problem when they come online.
The cheapest first thing you might do is make sure the orfice is in the boost sensor line. The part number is on this site somewhere. You can make your own by using the descriptions given on this forum SOMEWHERE. You might do a search for PILL or ORIFICE. It is called a orifice in the parts manual though. It's just a piece of plastic with a very small hole in it to dampen surges to the boost sensor.
If you had a meter and wanted to check the secondarys, you could back probe the secondary injector wire at the back of the small ECU plug, and watch for a voltage drop at 3500 rpm. The voltage would be approx battery/alt voltage until then and once 3500 is reached under load, the voltage will drop dramatically to say, 8 vdc or so. I forget. It depends on load. With the vac line off it will happen each and every time you hit 3500, load or no load.
It sounds like they are working but have some type problem when they come online.
The cheapest first thing you might do is make sure the orfice is in the boost sensor line. The part number is on this site somewhere. You can make your own by using the descriptions given on this forum SOMEWHERE. You might do a search for PILL or ORIFICE. It is called a orifice in the parts manual though. It's just a piece of plastic with a very small hole in it to dampen surges to the boost sensor.
If you had a meter and wanted to check the secondarys, you could back probe the secondary injector wire at the back of the small ECU plug, and watch for a voltage drop at 3500 rpm. The voltage would be approx battery/alt voltage until then and once 3500 is reached under load, the voltage will drop dramatically to say, 8 vdc or so. I forget. It depends on load. With the vac line off it will happen each and every time you hit 3500, load or no load.
#12
HAILERS
![](https://www.rx7club.com/images/misc/10_year_icon.png)
Join Date: May 2001
Location: FORT WORTH, TEXAS,USA
Posts: 20,563
Likes: 0
Received 22 Likes
on
20 Posts
I forgot. If they are low impedence (the 720), you NEED to put a 10ohm resistor in line to them or after them. The drivers in the ECU need to see this 10-12ohms approx or they will get too much current and kablooi. No more worky. Chances are they are not blown. It takes some time for that to happen, hopefully.
Another way to hear the injectors click would be to pull the ECU plug off and put a ground on the injector wire your interested in. The ground would be put on the PLUG not the ECU'S jack. And just for a second or two, just to hear the thing go click each time a ground is put on it. Clicks once each time the ground is put on the wire. You'd do that with the engine not running of course. Just key ON
Another way to hear the injectors click would be to pull the ECU plug off and put a ground on the injector wire your interested in. The ground would be put on the PLUG not the ECU'S jack. And just for a second or two, just to hear the thing go click each time a ground is put on it. Clicks once each time the ground is put on the wire. You'd do that with the engine not running of course. Just key ON
#13
Full Member
![](https://www.rx7club.com/images/misc/05_year_icon.png)
Join Date: Mar 2003
Location: The Colony Tx.
Posts: 179
Likes: 0
Received 0 Likes
on
0 Posts
unplug the boost sensor and use a test light hooked up to the + on the bat. and stick the probe in the black wire in the injector clip and run the rpm's up to 3800 if it flashes plug it in
and plug the boost sensor in check it agian if no flash the boost sensor took a ****
and plug the boost sensor in check it agian if no flash the boost sensor took a ****
#14
HAILERS
![](https://www.rx7club.com/images/misc/10_year_icon.png)
Join Date: May 2001
Location: FORT WORTH, TEXAS,USA
Posts: 20,563
Likes: 0
Received 22 Likes
on
20 Posts
Originally Posted by silverFC
unplug the boost sensor and use a test light hooked up to the + on the bat. and stick the probe in the black wire in the injector clip and run the rpm's up to 3800 if it flashes plug it in
and plug the boost sensor in check it agian if no flash the boost sensor took a ****
and plug the boost sensor in check it agian if no flash the boost sensor took a ****
Have fun doing that with a TURBOII. You can't access the injector plug on a turboii.
In the driveway, the secondarys only operate IF you disconnect the vacuum line FROM the boost sensor. If the secondaries come online WITH the vacuum line connected, THEN the boost sensor is kaput. PUlling the vacuum line OFF simulates LOAD.
#15
Full Member
![](https://www.rx7club.com/images/misc/05_year_icon.png)
Thread Starter
Join Date: Feb 2003
Location: nepa
Posts: 156
Likes: 0
Received 0 Likes
on
0 Posts
thanks for the info hailers. i have the orfice in the line, but it wasnt in when this problem started! i guess i will try to check the injectors at the ecu. i have a feeling its going to be something with the ecu. this car seems to like my money!
Thread
Thread Starter
Forum
Replies
Last Post
HalifaxFD
Canadian Forum
126
05-09-16 07:06 PM