2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.
Sponsored by:

Looking for help No rpm signal for cranking after engine gets hot

Thread Tools
 
Search this Thread
 
Old 06-24-17, 11:46 PM
  #1  
Junior Member
Thread Starter
 
Radorix's Avatar
 
Join Date: Dec 2016
Location: Md
Posts: 10
Likes: 0
Received 0 Likes on 0 Posts
Looking for help No rpm signal for cranking after engine gets hot

So let me preface with I have switched to a Haltech ECU but it had been starting just fine on it since mid March til up about 2-3 weeks ago. I started having a no start situation after driving the car around in the summer heat. If i wait like 5-20 minutes the computer and the tach show rpm signal again and the car will start it acts like a bad CAS but until I stop the car everything seems just fine. The haltech basically sees it like this 0,0,0,50,0,0,0,0,0,0,250,0,0,0,50etc so it won't send the priming pulse. And if I use my rotary compression tool when hot all rotor faces when normalized to 250rpm see 88-92 psi but it doesn't matter as it like I said doesn't try to prime as the computer is still essentially seeing zero

Short story once car is driven the cas signal doesn't get to computer only on startup.

What should I check I'm abit stumped thought maybe was a battery so I swapped the optima out of my other car in no change and most of the bad CAS threads end with it not being the issue but no real checks or solutions posted.
Old 06-24-17, 11:59 PM
  #2  
rotorhole
 
insightful's Avatar
 
Join Date: May 2017
Location: retired rotorist
Posts: 680
Received 70 Likes on 66 Posts
open the CAS cap and loosen the HES mount screws and close the gaps with the engine warm until they just do not touch the vanes, tighten screws and retry.

if that doesn't do it, there is 2 CAS connectors in the engine bay that need to be cleaned with electric cleaner, the other that people forget about is underneath the brake master cylinder.... brake fluid anyone?
Old 06-25-17, 06:08 AM
  #3  
Junior Member
Thread Starter
 
Radorix's Avatar
 
Join Date: Dec 2016
Location: Md
Posts: 10
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by insightful
open the CAS cap and loosen the HES mount screws and close the gaps with the engine warm until they just do not touch the vanes, tighten screws and retry.

if that doesn't do it, there is 2 CAS connectors in the engine bay that need to be cleaned with electric cleaner, the other that people forget about is underneath the brake master cylinder.... brake fluid anyone?

Ty I will try this hopefully this afternoon
Old 06-25-17, 10:54 AM
  #4  
Rotary Enthusiast

iTrader: (9)
 
R-X-R's Avatar
 
Join Date: Jun 2011
Location: Syracuse,NY
Posts: 805
Received 4 Likes on 4 Posts
I have the same exact issue!!! And it sucks.
Old 06-25-17, 11:58 AM
  #5  
Moderator

iTrader: (3)
 
j9fd3s's Avatar
 
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,856
Received 2,619 Likes on 1,856 Posts
if you take an extra CAS and plug it in an spin it by hand does it see RPM? or is it only when cranking? which haltech is it? the E8/11's will turn off if voltage drops under about 10v, which can be a problem.
Old 06-25-17, 04:08 PM
  #6  
Junior Member
Thread Starter
 
Radorix's Avatar
 
Join Date: Dec 2016
Location: Md
Posts: 10
Likes: 0
Received 0 Likes on 0 Posts
Hey insightful thanks that seems to have done the trick now to take care of the light burns from all th hot bits in that area haha.

as to the other question I purchased a sport 1000 when they had then discounted that and the factory ECU wasn't giving the car enough full when I bought it
Old 06-26-17, 12:04 AM
  #7  
rotorhole
 
insightful's Avatar
 
Join Date: May 2017
Location: retired rotorist
Posts: 680
Received 70 Likes on 66 Posts
no problem
Old 07-04-17, 07:46 AM
  #8  
Full Member

 
PatrickT's Avatar
 
Join Date: Nov 2006
Location: Germany Southwest
Posts: 158
Received 41 Likes on 22 Posts
Had the exact same issue with haltech.
cost me half a trackday.

It can be easily fixed by lowering the threshold voltage for the CAS at cranking Speed in the Setup.

After this lost an other trackday due to ECU shutting off after 10min.
Polyfuse in the ECU was the problem, fixed it by bypassing it with an ordinary melting fuse, cheers!

-Patrick




All times are GMT -5. The time now is 08:05 PM.