question about secondary injectors- searched and referenced
03-24-08, 01:01 AM
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question about secondary injectors- searched and referenced
post by hailers
https://www.rx7club.com/showthread.p...rys+come+on%3F
"Secondary injectors come online when there is a Load on the engine (seen by the pressure sensor) AND you've reached 3800 rpm. On a series four car, the primary injectors duty cycle is cut in half at the same time as the secondarys come online. Like the primary duty cycle was maybe 60* and now it's 30* along with the secondarys being 30*.
On early 86 and 87 cars Mazda noitced the hesitation and came out with a fix where they added a second ground wire to the pressure sensors already existing gnd wire. They terminated this new wire on the water pumps thermostat housing. They added this wire to the boost sensor gnd wire, not because the problem was boost sensor related, but because it was a afm related problem according to the bulletin. The reasoning behind this is, all the gnd wires on the sensors in the engine bay, are all spliced together inside the EM harness. Add a gnd at one point effects all those sensors gnds. All those gnds that are spliced together, end up at the ECU's middle plug. Pin 2A if memory serves, maybe 2C, I forget and I'm not going to look it up.
So the gnd enters the ECU at the middle plug. Well it's still looking for a gnd point. The ECU's internal gnds exit the ECU and end up on top of the rear rotor housing (series four).
Some people, and more than a few, have found that finding the ground wires for the ECU, where they Exit the ECU plugs, and then soldering another gnd wire to those existing wire, will fix the hesitation problem. I've done this on a 86 and grounded the new gnd wire to the bracket that holds the ECU in place.
This requires unwrapping a couple of inches of wrapping on the harness, and then finding where those gnd wires attach to the 02 sensors shielded cable. That's where you could add the *extra* gnd mentioned.
Common sense says to first, make sure the existing gnd wires for the car are clean and connected. Like the gnd wire from the batt neg terminal goes to the chassis below the left front strut tower, then goes on to attach to the long starter bolt or at least to one of the transmisson/engine bolts nearby.
Then again, you don't say much about the 3800rpm no go. I mean, if you left your foot in it, would it get over the hesitation and then keep going to 6-7000 rpm. Or did you mean it got to 3800 and just would not go any further no matter how long you held the pedal down? If that were the case, then the secondarys are just flat not coming online at all. Plugs off the secondarys."
okay well the question i had was about this post. hailers you said that the secondarys come on ONLY with a load on the engine. can they come on if my car is n neutral? or do i have to be driving? The reason i ask is because of this damn fuel problem i have (think its fuel). what is the best way to check to see if the secondarys are comming on? back plug the ecu at the pins and rev it? or drive it past the transition?
https://www.rx7club.com/showthread.p...rys+come+on%3F
"Secondary injectors come online when there is a Load on the engine (seen by the pressure sensor) AND you've reached 3800 rpm. On a series four car, the primary injectors duty cycle is cut in half at the same time as the secondarys come online. Like the primary duty cycle was maybe 60* and now it's 30* along with the secondarys being 30*.
On early 86 and 87 cars Mazda noitced the hesitation and came out with a fix where they added a second ground wire to the pressure sensors already existing gnd wire. They terminated this new wire on the water pumps thermostat housing. They added this wire to the boost sensor gnd wire, not because the problem was boost sensor related, but because it was a afm related problem according to the bulletin. The reasoning behind this is, all the gnd wires on the sensors in the engine bay, are all spliced together inside the EM harness. Add a gnd at one point effects all those sensors gnds. All those gnds that are spliced together, end up at the ECU's middle plug. Pin 2A if memory serves, maybe 2C, I forget and I'm not going to look it up.
So the gnd enters the ECU at the middle plug. Well it's still looking for a gnd point. The ECU's internal gnds exit the ECU and end up on top of the rear rotor housing (series four).
Some people, and more than a few, have found that finding the ground wires for the ECU, where they Exit the ECU plugs, and then soldering another gnd wire to those existing wire, will fix the hesitation problem. I've done this on a 86 and grounded the new gnd wire to the bracket that holds the ECU in place.
This requires unwrapping a couple of inches of wrapping on the harness, and then finding where those gnd wires attach to the 02 sensors shielded cable. That's where you could add the *extra* gnd mentioned.
Common sense says to first, make sure the existing gnd wires for the car are clean and connected. Like the gnd wire from the batt neg terminal goes to the chassis below the left front strut tower, then goes on to attach to the long starter bolt or at least to one of the transmisson/engine bolts nearby.
Then again, you don't say much about the 3800rpm no go. I mean, if you left your foot in it, would it get over the hesitation and then keep going to 6-7000 rpm. Or did you mean it got to 3800 and just would not go any further no matter how long you held the pedal down? If that were the case, then the secondarys are just flat not coming online at all. Plugs off the secondarys."
okay well the question i had was about this post. hailers you said that the secondarys come on ONLY with a load on the engine. can they come on if my car is n neutral? or do i have to be driving? The reason i ask is because of this damn fuel problem i have (think its fuel). what is the best way to check to see if the secondarys are comming on? back plug the ecu at the pins and rev it? or drive it past the transition?
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