S13 SR20DET CAS issue - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Quiche2192 · 06-22-2022, 10:12 PM

I'm having trouble idling and accelerating. Idling is very inconsistent and the engine will eventually stop if I don't rev it up. Revving it up sounds really bad. Breaks up badly. Once up there, it'll run ok, but getting up there sounds bad.

Running stock ECU. I checked the diagnostic LED and got code 11, which is the CAS code. Checked CAS wiring. 12V feed is good. Ground is good. 180 Deg signal to ECU is good. 1 Deg signal to ECU is good.

Thought it was the CAS itself so I pulled the CAS and found that both the 180 Deg and the 1 Deg signals were sending square waves with voltages ranging from 0.3 to 5.2 volts, which seems good.

Timing was set correctly.

So I am at a loss as far as what might be going on. I think it's unlikely, but I suspect:
- Grounding issue
- Bad MAF and ECU is just getting confused and throwing the 11 code
- Bad O2 sensor and ECU is also getting confused

Appreciate any input

jr_ss · 06-23-2022, 05:34 AM

I’d find a local with a known good MAF and try that. Sure you have fuel/ignition on all cylinders?

Quiche2192 · 06-23-2022, 09:11 PM

Looked into it today and found that... my alternator was unplugged. I haven't been able to start the car yet though cause I gotta put the CAS back in, but haven't had the time.

Kingtal0n · 06-23-2022, 09:42 PM

boost leak test, pressure test, OEM maf plumbing, rule out the maf

Rev the engine without maf connected -> Revs fine = problem is maf (only revs to 2500 or something but its clean)

06-22-2022, 10:12 PM	#1
Quiche2192 Join Date: Oct 2018 Location: FL Age: 33 Posts: 49 Trader Rating: (0) Feedback Score: 0 reviews	S13 SR20DET CAS issue I'm having trouble idling and accelerating. Idling is very inconsistent and the engine will eventually stop if I don't rev it up. Revving it up sounds really bad. Breaks up badly. Once up there, it'll run ok, but getting up there sounds bad. Running stock ECU. I checked the diagnostic LED and got code 11, which is the CAS code. Checked CAS wiring. 12V feed is good. Ground is good. 180 Deg signal to ECU is good. 1 Deg signal to ECU is good. Thought it was the CAS itself so I pulled the CAS and found that both the 180 Deg and the 1 Deg signals were sending square waves with voltages ranging from 0.3 to 5.2 volts, which seems good. Timing was set correctly. So I am at a loss as far as what might be going on. I think it's unlikely, but I suspect: - Grounding issue - Bad MAF and ECU is just getting confused and throwing the 11 code - Bad O2 sensor and ECU is also getting confused Appreciate any input

06-23-2022, 05:34 AM	#2
jr_ss Post Whore! Join Date: Dec 2005 Location: Pa Posts: 6,415 Trader Rating: (35) Feedback Score: 35 reviews	I’d find a local with a known good MAF and try that. Sure you have fuel/ignition on all cylinders? __________________ My SR20VET Does your VTC gear rattle in your S14/15 SR? PM me.

Thread Tools
Show Printable Version Email this Page
Display Modes
Switch to Linear Mode Hybrid Mode Switch to Threaded Mode

06-23-2022, 09:11 PM	#3
Quiche2192 Join Date: Oct 2018 Location: FL Age: 33 Posts: 49 Trader Rating: (0) Feedback Score: 0 reviews	Looked into it today and found that... my alternator was unplugged. I haven't been able to start the car yet though cause I gotta put the CAS back in, but haven't had the time.

06-23-2022, 09:42 PM	#4
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 42 Posts: 4,829 Trader Rating: (17) Feedback Score: 17 reviews	boost leak test, pressure test, OEM maf plumbing, rule out the maf Rev the engine without maf connected -> Revs fine = problem is maf (only revs to 2500 or something but its clean)