Cylinder 1

[ninety1two40]

I'm still having issues with cylinder 1 not working. You can read my last topic for the last issue I had: zerothread/336607

So this is what is happening:Car starts up kinda rough, have to give it some gas for a couple seconds for it to stabilize. The engine runs rough and I found out that cylinder 1 isn't firing. I unplugged the cyl 1 coil and no change to the engine. If I unplug any other coil the engine stumbles. I swapped coil, no change. I pulled the coil out and connected a spark plug and grounded it and it does spark when turning the engine over. So then I looked at the injector, I put a screwdriver to the injector cap when running and it sounds like it doesn't click as loud as the other injectors. So I pulled the injector plug off and measured 12V on one wire and the other wire showed the voltage dropping down to 300mV the longer I left the multimeter on it. The coil resistance is about 11 Ohms (same as other injectors). I also swapped injectors with another cylinder and the same results. The injectors click when I connect ground and 12V to them. My fuel pressure is around 45 PSI (IIRC). Umm I ran continuity checks for all my injectors and ignitor wires to the ECU and everything was good. I connected an o-scope to my ground trigger on the cyl 1 coil and it was the same as the other coils. I also recently relocated my batter to the trunk, could it be a ground issue? All the other cylinders seem to run fine. The car is sluggish though and my power-fc shows the timing to be around 25*. A timing light shows around 17*, I can't bring the timing down lower because I can't get the idle down lower than 1100RPM, I also set my TPS to 0.5V but I had to set it lower to 0.35V so that click when you rev the engine isn't on when idling. I also have the same problems with the stock ECU.

Any ideas?

I had another ignitor around somewhere that I was going to try out but I can't find it. Anybody want to sell me one?

[WhatsADSM]

Sounds to me like the coil and igniter were working fine since you pulled it out and it was sparking.

You sort of ruled out a bad injector since you swapped injectors and that didn't change anything.

So here are my 2 suggestions:1) Run a compression check on that cylinder. Even if you have spark and fuel if the cylinder is mechanically damaged then it wont do anything.2) If you have good compression, get your o-scope back out and check the signal at the non +12v side of the injector. Just because you have good continuity between the injector and the ECU, it still doesn't mean the ECU has a good injector driver in it.

[lilskyline240]

i doubt its the ecu because hes using a PFC and has tried using the stock ecu. that kinda rules out a bad injector driver. I wonder if your CAS is bad and not sending the correct signal to the ecu of when to fire cylinder 1

[WhatsADSM]

i doubt its the ecu because hes using a PFC and has tried using the stock ecu. that kinda rules out a bad injector driver. I wonder if your CAS is bad and not sending the correct signal to the ecu of when to fire cylinder 1

Didn't notice the part about the stock ECU. Then yea likely its not an injector driver in the ECU.

Get that compression check done... Really sounds like it's something mechanical.

BTW the entire firing runs off the CAS so if there was no signal nothing would work.

[ninety1two40]

Forgot to mention that I also did a compression test - 160PSI on Cyl 1.

What about the ignitor chip... maybe it is somehow sending the wrong signal? What if I swap cylinder 1 and 2 at the input and output of the ignitor? It would be like switching over to another "channel"... I think I'll try that tonight.

Thanks for the ideas.

[WhatsADSM]

You said you checked the output of the ignitor with a scope right? ("the ground input at coil1")

Or you checked the input?

[WhatsADSM]

Also this is a long shot but check the fuel rail and the injector boss in the head to make sure nothing is clogged.

[ninety1two40]

Ok here the update:

Pulled the fuel rail with the injectors, turned the car on, pulled the CAS out and give it a spin, all the injectors except #1 sprayed fuel (during the "cold start" and when spinning the injectors continuously). But I get all the proper voltages at the connector and harness??? So I exposed the power and signal wires while still connected to the stock ECU, and gave a ground signal to the white signal wire... the #1 injector pissed nicely! So I did the same at the ECU...and the injector worked. I even plugged the #1 injector connector into another injector and that injector won't work. So it seems even though the ECU gave all the right signals and it made the injector click but very quietly it never sprayed fuel on it's own, so it basically isn't supplying enough current. This probably was related to a frayed wire I found a while ago in the injector harness (wasn't #1 though...) that might of been getting grounded, it's all fixed now.

But this didn't work with the PFC when I tried it before... So I checked my grounds since my battery was recently relocated to the trunk and I had a really good ground in the trunk but my front ground (for the engine block wire) was kinda poor looking, so I welded a nut to the car to get a nice connection. Replaced my Q45 TB with another one since my old one leaked and cranked the engine over......

Perfect... It idled so smooth and at a nice 650RPM! I went through the 30minute PFC idle learn procedure since I just got the PFC and all the sensors and battery voltage and timing and everything was perfect! I let the car run for about an hour+ total and gave it a few revs after the idle learn procedure and it has wicked fast idle response, faster than the car ever had. I'm soo happy, now I can finish my Silvia conversion and get this car on the road again!

Thanks Guys!

[ninety1two40]

You said you checked the output of the ignitor with a scope right? ("the ground input at coil1")

Or you checked the input?

Yeah I checked the output of the ignitor with the scope and checked the input wires for continuity to the ECU. But I was thinking maybe the ignitor chip was having some weird signal cross-talk and sending signals at the wrong time interval... it was a long shot. But that turned out not to be the problem after all

[WhatsADSM]

Yea without a solid ground almost anything can happen.

Great to hear you got it all worked out!