Injectors Not Functioning
09-22-17, 05:28 AM
#1
Injectors Not Functioning
I finished putting my 88 SE together last night and went to start it and got a crank no start issue. Spark plugs are bone dry. I confirmed that I have fuel to the engine and that the fuel pump is working properly. The engine started right up and ran fine on starting fluid. Since I put this car together from boxes of parts and got it as a rolling shell I was wondering if it had an injector driver pack originally like my 88 TII did. Didn't see one listed in the FSM but figured I' ask. Just trying to narrow down where I should go with this. I did check grounds, especially the ground under the UIM. I haven't pulled the connectors from the injectors and applied a noid light to each injector but I can if need be.
09-22-17, 05:32 PM
#6
i had a similar problem on my 88 gxl when i swapped it to turbo.. what i found was that there was a large vacuum leak. large enough to not be able to pull the flapper door on the MAF open via vacuum, so the fuel pump wouldnt kick on. try getting a helper to hold the flap open and try starting it
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09-22-17, 09:01 PM
#8
If you have red top injectors you do not need the fuel resistor box
Since your at your injectors, bring the motor to TDC according to the front pulley, take out the CAS, and with your test light, hook up the clip to the positive, and the light to the ground part of the injector and give the CAS a spin, the light should flicker as the CAS sends a ground signal to the injectors
Since your at your injectors, bring the motor to TDC according to the front pulley, take out the CAS, and with your test light, hook up the clip to the positive, and the light to the ground part of the injector and give the CAS a spin, the light should flicker as the CAS sends a ground signal to the injectors
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mazdaverx713b (09-23-17)
09-23-17, 06:43 AM
#10
If you have red top injectors you do not need the fuel resistor box
Since your at your injectors, bring the motor to TDC according to the front pulley, take out the CAS, and with your test light, hook up the clip to the positive, and the light to the ground part of the injector and give the CAS a spin, the light should flicker as the CAS sends a ground signal to the injectors
Since your at your injectors, bring the motor to TDC according to the front pulley, take out the CAS, and with your test light, hook up the clip to the positive, and the light to the ground part of the injector and give the CAS a spin, the light should flicker as the CAS sends a ground signal to the injectors
09-23-17, 06:47 AM
#11
I have checked the grounds but I feel like I'm missing something. I had a GSL-SE about 15 years ago do the same thing and it ended up being the way ground on the top of the engine. I checked with a flashlight and my ecu ground is secure and is grounded to the bolt holding the mounting bracket for the dynamic chamber towards the left side of the engine. I wonder if this ground is not sufficient and that it needs direct contact with the engine. I'm willing to pull the uim and secure the ground elsewhere.
09-23-17, 08:06 AM
#13
I'm going to pull the intake this morning anyway. I'll test them at that point with the noid light and see what happens. I want to recheck the ecu ground that's under there anyways. I do have a spare CAS that I can hook up and spin by hand to check for injector clicking with the key in the on position. It has to either be a faulty ground, ecu or bad injectors. That's where my mind is going.
09-23-17, 09:53 AM
#14
Sucker for Punishment
Check the ground on the firewall to housing. You should be able to reach it without removing intake. You can listen for the injectors with ignition on and turning your engine by hand.
09-24-17, 07:15 AM
#18
rotorhole
disconnect the ECU connector and measure the resistance on the injectors that way. if there's infinite or a very large amount then your injector clips may be bad. if it's fine(~14ohms), apply 12v in quick bursts to see if the injectors make an audible click, if not, they are probably seized from sitting in your box and need to be serviced.
09-24-17, 07:57 AM
#19
That's a great idea. The injectors could very well be seized. I hadn't considered that option thoroughly honestly, figuring that they should still be good. But who knows with electronic parts that have been sitting for some time.
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mazdaverx713b (09-24-17)
09-25-17, 04:55 AM
#21
Ended up pulling the upper intake manifold again and tested the injector pulse with a noid light. There was pulse when cranking. I took a longer look at the injectors and after pulling them and testing them, I found that while the secondary injectors were functioning properly, the primary injectors were stuck. After about an hour of working on the injectors, I got them freed up and measured their resistance and it was within spec per the FSM. I put the intake manifold back on and the engine fired right to life. It was such a struggle because everything tested good the entire time, but the injector wasn't pulsing. Wish I had considered it as an option sooner. Thank you all for your help!
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mazdaverx713b (09-25-17)
09-26-17, 11:49 AM
#24
i had a similar problem on my 88 gxl when i swapped it to turbo.. what i found was that there was a large vacuum leak. large enough to not be able to pull the flapper door on the MAF open via vacuum, so the fuel pump wouldnt kick on. try getting a helper to hold the flap open and try starting it
https://www.rx7club.com/2nd-generati...erence-671004/
post #3, pic #5
edit: never mind. will read whole thread next time. SMH
Last edited by pfsantos; 09-26-17 at 11:55 AM.
09-27-17, 05:36 AM
#25
You're good pfsantos! I actually learned a lot undertaking this crank no start issue. All I've ever had were TII's and first gens. I've never had an NA FC and this was a really good learning experience. I'm happy to take any advice so that I can quickly diagnose and repair issues that present themselves.