Injectors not firing?
#1
Senior Member
Thread Starter
iTrader: (3)
Join Date: May 2007
Location: San Diego
Posts: 316
Likes: 0
Received 0 Likes
on
0 Posts
Injectors not firing?
installing the rebuilt engine into my S5 T2. Everything is stock. Got spark, fuel pump is working, filled up a jar with gas in about two seconds at the inlet to pipe that goes to the pulsation dampner. Engin cranks, but no start. Killed a battery cranking it, charged it and killed it again. Sprayed starter fluid in the filter box and it acts like it's going to start until I take the key off crank. Di the part wher you jumper the connector to fill the fuel system back up. Nothing...zip. Should I at least smell fuel from an overly crank car with know start? No Check engine lights. Even if I crossed connectors on the primary and secondary injector, one of the sets ought to pumping fuel into the engine. I got nothing. Checked connectors on the ECU and they are fine. Can't find any disconnected wires of vacuum lines. Any ideas?
#3
Senior Member
Join Date: May 2010
Location: vancouver, bc
Posts: 535
Likes: 0
Received 0 Likes
on
0 Posts
have you pulled the plugs to check for fuel on them?
if bone dry, back probe the injector circuits at the ecm. check for battery voltage KOEO at the primary pins
if bone dry, back probe the injector circuits at the ecm. check for battery voltage KOEO at the primary pins
#4
Senior Member
Join Date: May 2010
Location: vancouver, bc
Posts: 535
Likes: 0
Received 0 Likes
on
0 Posts
if no voltage, the most common cause is backed out pins at the injector connector(s). those connectors get very brittle given their location, and if disturbed, can easilly break the locking tang(s)
#5
Sharp Claws
iTrader: (30)
the S5s don't have such a bad problem with the injector connectors as the S4, those are horrible.
with the pump connector jumpered it will only turn on the pump with the key on.
check the ground under the upper intake manifold to the rear rotor housing, without that you get nothing for injectors.
if all that checks out simply disconnect the AFM and try to start it, if it chugs or starts and stalls then try finding a known good afm to test the car with. if that fails try disconnecting the TPS and try again, also keep in mind the injectors won't kick if you apply more than 30% throttle with it connected.
with the pump connector jumpered it will only turn on the pump with the key on.
check the ground under the upper intake manifold to the rear rotor housing, without that you get nothing for injectors.
if all that checks out simply disconnect the AFM and try to start it, if it chugs or starts and stalls then try finding a known good afm to test the car with. if that fails try disconnecting the TPS and try again, also keep in mind the injectors won't kick if you apply more than 30% throttle with it connected.
#6
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,826
Received 2,592 Likes
on
1,841 Posts
generally if the ecu has power, and sees an rpm signal it will fire the injectors, so default tends to be flooding.
however if you have spark, that means the ecu has rpm and power. if there is no fuel, you should be able to squirt some flammable liquid into the engine, and get some kind of fire.
the next step depends. easiest is probably to plug in a CAS and spin it with the key on, you should hear the injectors clicking. if not then next you check them for power, ecu is easiest i think. if there is power but they don't work, you need to manually give the injector power and ground, sometimes they stick.
if the injectors work, i'd look at the pump. the FSM has tests for volume and a dead head pressure
however if you have spark, that means the ecu has rpm and power. if there is no fuel, you should be able to squirt some flammable liquid into the engine, and get some kind of fire.
the next step depends. easiest is probably to plug in a CAS and spin it with the key on, you should hear the injectors clicking. if not then next you check them for power, ecu is easiest i think. if there is power but they don't work, you need to manually give the injector power and ground, sometimes they stick.
if the injectors work, i'd look at the pump. the FSM has tests for volume and a dead head pressure
#7
Senior Member
Join Date: May 2010
Location: vancouver, bc
Posts: 535
Likes: 0
Received 0 Likes
on
0 Posts
and agreed; s4 clips are horrible.
i would still pull the plugs first. start from the top and easiest. and if dry (that's the key here to not going on a wild goose chase), next easiest is to backprobe at the ecm, since you've already confirmed adequate fuel supply. that ground under uim supplies other components as well. it would be fairly easy to see how good that ground is, testing at the ecm, without resorting to removing the uim. i dunno. personally, i like to leave as much intact as possible and not immobilize things until i know i have to
Last edited by welfare; 06-30-15 at 12:53 AM.
Trending Topics
Thread
Thread Starter
Forum
Replies
Last Post
HalifaxFD
Canadian Forum
126
05-09-16 07:06 PM
Adaptronic 1280s Hot Start 3 Rotor 20b RX7
Monsterbox
Adaptronic Engine Mgmt - AUS
5
09-11-15 03:29 PM
windom
Adaptronic Engine Mgmt - AUS
4
09-11-15 04:48 AM