Secondary Injector Issues
 

Long story short I have an 87 TII with 96K on the clock. She sprung a massive water leak from the LIM, so while I was in there I ported the waste gate, added a 3 inch down pipe with no cat, Rtek 1.7 ECU with corresponding 720cc secondary injectors (brand new) and brand new 550cc primaries as the car had a tendency to flood, and K&N Cone filter. I have a good boost gauge and Koso digital AFR gauge.

The car runs fine, except when it hits the 3500 RPM transition there is a big lean bog, and if I hold any kind of boost I get stoich readings in the mid 13's to low 14's range...which is much to lean and wayyyyy worse than stock. This leads me to believe the secondary injectors are not working. I have the UIM pulled off again and cannot find anything wrong. Any suggestions? car ran perfect before the ECU was sent away.

Sounds like a grounding issue.

Any main grounds to check? I have both the factory and Hayes service manual. Shitty part is the first time the car was torn down I was not present so I am a newbie at pulling the LIM.

Proper RX-7 Grounding Procedures

bam. No need to take off the LIM for the factory grounds.

LIM comes off easier with turbo out. not really sure if its even possible with it still installed... but yeah no need to remove for grounds.

Are you sure you installed the correct impedance injectors?

Yes all are low impedance.

All grounds are in order
Checked the crank angle sensor
Checked EGI Relay
Checked resistor pack

The only thing that did not check out is the ground for the crank angle sensor wire lead. According the the haynes manual one of the terminals (terrible picture, hard to see) should should be a ground, and I am getting an ohm reading for all 4 terminals.

How did you check the grounds? Was it a visual only check.

I still have the UIM off so I cleaned the main ECU ground.

I went through and cleaned all the grounds in that right up also.

I am going to call Rtek tomorrow and see if they have had any issues like this. The car ran fine except for some occasional flooding before I installed their chip. It has really got me at a loss

Which fuel pump are you running? I ran a similar setup except mine is a large streetport. Once the engine was built I put it in with an rtek 1.7, 720cc secondaries, and an fd fuel pump. After the break in, I realized I was having the same problem. I went through so much headache to try and isolate the problem and never could. I just ended up going standalone and I am now running an adaptronic ecu. No more hesitation, of course. I did speak with Digital Tuning about it, they told me it was my porting that is causing it. I could understand that, but have seen numerous setups this way that did not have issues.

I forgot to add I am running an approximately 1 year old FD fuel pump.

Tomorrow I am going to put the car all back together and use an LED test light to see if the ECU is throwing anything at the secondaries.

I spoke with them when I first suspected I was having an issue and he told me to check grounds etc. I'll see what they have to say tomorrow.

With key to on, the ground wires at the ECU should register 0 volts. You could also have a loose connection at the secondary injector(s). The car detects load via the boost sensor, AFM and TPS so they might be playing a roll in your problem.

After reassembling the car and taking it for a ride, everything works....Must have been a grounding issue. 6K RPM, 9lbs of boost, 3rd gear it is showing 12.2-12.5 on the AFR