Why wont my Miata start? - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


General Miata Chat A place to talk about anything Miata

Reply
 
 
 
LinkBack Thread Tools
Old 09-27-2016, 11:37 PM   #1
Newb
Thread Starter
 
Join Date: Sep 2016
Posts: 4
Total Cats: 0
Default Why wont my Miata start?

I have a 91 NA6 that I just completed an engine swap with another 1.6. The new engine is stock and has 160k miles; the only thing brand new is the clutch and flywheel. It ran before it was pulled. I ended up tucking the engine bay, which led to extending lots of wires that Iíve triple checked that they go to the intended harnesses. I was having a grounding issue, the (+) on the starter was touching the block which was grounding out the car and fried a pair of jumper cables. Needless to say, Iíve fixed that issue.

My main issue right now is it cranks strong but will run for no longer than 2 seconds and will not rev up higher than 1000 rpm (usually around 200-500 if I donít give it throttle). It was throwing 4 codes: 1- No igf signal; 2- No Ne signal; 26- Evap canister purge; 34- ISC valve. Iíve replaced the CAS, coil pack, and fuel pump relay with known working parts from the old engine. No change. I have no vacuum leaks, I have fuel pressure at the rail (the fuel pump kicks on while jumping F/P and GND), the injectors have been cleaned while the engine was out, and spark plugs were replaced. While checking for spark by pulling a spark plug wire (which are new within the past year) and connecting a spark plug on the end to visually record arc, the driver side coil is firing, but the passenger side is not, hence the reason I replaced the coil pack. Even after I replaced it, no spark was observed on the passenger side coil, which led me to a bad CAS (not sending a signal to ECU when to send spark to cylinder), but still the same issue occurred. The voltages on the harness of the CAS were in spec (12 5 5 0 volts) as was on the harness for the coil pack. After replacing the Ignition control module the engine still would not start but codes 1 and 2 went away.

Finally, I was getting somewhere and I moved my attention to the other two codes, the evap canister and the ISC valve. Iím not surprised the 26 code was thrown because of air in the fuel lines during the swap. But after further investigation, the previous owner removed the evap canister in the engine bay and the open hard line goes back to a smaller canister in front of the rear passenger wheel. And Iíve cranked the engine many times over the course of 2 weeks that the air shouldíve worked its way out of the lines or at least be negligible. So I donít know why that code is being thrown still because it was not throwing it before I removed the engine.

So onto the next code (34- Idle Speed Control Valve). The voltage on the harness is in spec (12 0 volts) and the resistance of the valve itself is also in spec (13 ohms) I cleaned it the best I could with it still attached with TB cleaner. While cranking the car to try and diagnose this issue, I noticed code 1 popped back up, great! Now Iím completely lost.

Where Iím at now: I know the ECU is working because it is throwing codes, the CAS and coil pack are not broken because they have been replaced with working parts, the timing belt is not broken as I have checked with valve cover off, no fuses are blown, Iíve triple checked my engine grounds, both the main relay and circuit opening relay are working and click when they should. The only thing I have not checked is spark in the passenger side coil as I installed the ICM yesterday and didnít have time to check. Iíve got to the extent of my knowledge and have done everything I know to try and diagnose the reason it will not stay running.

Any ideas??? Any help will be greatly appreciated.
dfully is offline   Reply With Quote
Old 09-28-2016, 02:30 AM   #2
Junior Member
 
Join Date: May 2007
Location: Atlanta
Posts: 318
Total Cats: 27
Default

Fuel. Air. Spark. Compression.

Check your wires end to end for continuity, especially your CAS and AMF wires. There's a idle air screw adjustment on the throttle plate, crack it wide open (lefty loosy) so it'll idle (high, but idle) without needing the valve.
gooflophaze is offline   Reply With Quote
Old 09-28-2016, 07:51 AM   #3
Boost Czar
iTrader: (60)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 71,532
Total Cats: 1,565
Default

live by the wire tuck, die by the wire tuck.
Braineack is offline   Reply With Quote
Old 09-28-2016, 07:57 AM   #4
mkturbo.com
iTrader: (24)
 
shuiend's Avatar
 
Join Date: May 2006
Location: Charleston SC
Posts: 13,066
Total Cats: 912
Default

Is your AFM hooked up?
shuiend is offline   Reply With Quote
Old 09-28-2016, 07:59 AM   #5
Junior Member
 
Join Date: Jan 2010
Location: Anderson, SC
Posts: 141
Total Cats: 6
Default

Are you still running the old flapper style air meter? You description sounds like it could possibly be something to do with that.

EDIT: Beat me to it
sharkythesharkdogg is offline   Reply With Quote
Old 09-30-2016, 09:21 PM   #6
Newb
Thread Starter
 
Join Date: Sep 2016
Posts: 4
Total Cats: 0
Default

So I cracked open the idle screw, followed and double checked the CAS wiring and its good, and after starting it, there was no difference. The MAF was plugged up originally, but tonight I unplugged it to see if it would make a difference, to try and diagnose it, and what do you know, no change. So the connection to the MAF or the MAF itself is bad. I did not extend or touch the wires on the driver side (which includes the MAF wiring) while doing the swap, so they haven't been tampered with. I researched the voltage, resistance and wiring diagram of the MAF and to be honest I don't really know what I'm looking for when I test it, I did test the two pins that turn on the fuel pump for continuity and there is none when the flap is closed and there is continuity when it is open, so that part is not broken. On the harness the two grounds had continuity and the (+) had 5 volts (which is spec), and the other two pins I'm not sure what they should read.

So how do I diagnose between a bad MAF and bad wiring?
dfully is offline   Reply With Quote
Old 10-01-2016, 01:20 AM   #7
Junior Member
 
Join Date: May 2007
Location: Atlanta
Posts: 318
Total Cats: 27
Default

Which is more likely - that your MAF broke while you were tucking your wires, or that you put a wire back in the wrong place?

Flapper wiring:
A - B - Ground
B - LG - FP relay
C - B/LG - Ground, tee's to TPS and 2D 2C
D - LG/R - ECM 2K
E - B/LG - Ground, tee's to Coolant Sensor and 2D, 2C
F - R - ECM 2O
G - R/G - ECM 2P

Yes, both pins C and E are also in the passenger side harness. You need to continuity test each pin end to end.
gooflophaze is offline   Reply With Quote
Old 10-01-2016, 02:47 PM   #8
Newb
Thread Starter
 
Join Date: Sep 2016
Posts: 4
Total Cats: 0
Default

what do you mean by 2D 2C?
there is continuity in the b/lg wires between the MAF and CAS, MAF and TPS, and MAF and coolant sensor.
dfully is offline   Reply With Quote
Old 10-01-2016, 11:09 PM   #9
Junior Member
 
Join Date: May 2007
Location: Atlanta
Posts: 318
Total Cats: 27
Default

Pins on the ECM.
gooflophaze is offline   Reply With Quote
Old 10-02-2016, 04:26 PM   #10
Newb
Thread Starter
 
Join Date: Sep 2016
Posts: 4
Total Cats: 0
Default

Ohhhh ok! I gotcha I'll be checking that today
dfully is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Fix the car for the boys in green... retrothis Meet and Greet 17 02-07-2017 06:02 AM
Cranking but no spark on MS2 Jordan MEGAsquirt 17 08-22-2016 08:35 AM
Fuel Issues after Testing EJNite General Miata Chat 2 08-15-2016 04:50 PM
second engine build, started last night Darbymx5 DIY Turbo Discussion 1 08-15-2016 04:37 PM
Ignition Switch Issue miataki General Miata Chat 4 08-15-2016 11:28 AM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 06:12 PM.