Author Topic: 79 deville efi sending unit question  (Read 707 times)

Offline bcroe

  • Posts: 2062
    • CLC Member
      CLC Member #14630
79 deville efi sending unit question
« Reply #20 on: July 31, 2016, 09:16:50 PM »
Quote from: 79caddy
Tank pump working now and have pressure to fuel rail now (7.0L) bUT injectors not firing. Also pulled frame pump and  bench tested it. Seems to function well. Car has not run in 13 years but will fires up briefly and sounds great if I pour gas in top.I will check fuel pressure tomorrow. What pressure should I have at release valve?  Are there other obvious reasons that injectors are not pulsing?

There are 2 ways your injectors are fired.  Try turning on the ign and slowly opening
the throttle.  The injectors should click up to 21 times.  Otherwise its likely an ECU
problem.  Cranking there should be ign pulses triggered by the speed sensors.  If not,
most likely the ECU has a bad IC or bad MAP sensor.  ICs are still available, and I
have designed a replacement MAP for the unavailable original.  I can test your ECU
for free if you pay postage, email the results.  What is its #?  Bruce Roe  CLC # 14630

Offline 79caddy

  • Posts: 16
  • Name: Phil Landes
Re: 79 deville efi sending unit question
« Reply #21 on: July 31, 2016, 09:34:41 PM »
Thanks Bruce! So I guess low pressure may not be the culprit. I have not heard any clicks. I will check the numbers and likely send you the unit for testing.

Offline 79caddy

  • Posts: 16
  • Name: Phil Landes
Re: 79 deville efi sending unit question
« Reply #22 on: August 02, 2016, 06:28:39 PM »
FIXED! She is running. Got a noid light and saw they were firing. New fuel filter and finishing ingnitor seals (few still leaking) and pressure must be high enough to spray.
NOW IF I COULD JUST FIGURE OUT HOW TO REPLACE THE SPARK PLUG IN CYLINDER 7!

Offline BLUE79DEVILLE

  • Posts: 3
  • Name: Cameron
Re: 79 deville efi sending unit question
« Reply #23 on: November 29, 2017, 01:19:32 AM »
what did you do to make her run? having same symptoms

Offline bcroe

  • Posts: 2062
    • CLC Member
      CLC Member #14630
79 deville efi sending unit question
« Reply #24 on: November 29, 2017, 08:09:28 AM »
What symptoms are those? 

By the way I did get my 190 high pressure pump installed in the
(403 powered) 79 Eldo tank, rewired it and replaced all that stuff
in the frame with a simple in line filter.  I have a fuel pressure
gauge, it seems to be working OK. 
Bruce Roe  CLC # 14630

Offline BLUE79DEVILLE

  • Posts: 3
  • Name: Cameron
Re: 79 deville efi sending unit question
« Reply #25 on: November 29, 2017, 03:22:05 PM »
79 deville not firing up, only start when I pour fuel inside TB. Fuel pumps working. I donít hear the 21 click trick. But reading ohms through wiring for injectors are good. What can cause a cold no start. Next Iím purchasing the air and coolant sensor

Offline bcroe

  • Posts: 2062
    • CLC Member
      CLC Member #14630
79 Deville efi no start
« Reply #26 on: November 29, 2017, 06:09:22 PM »
Quote from: BLUE79DEVILLE
79 Deville not firing up, only start when I pour fuel inside TB. Fuel pumps
working. I donít hear the 21 click trick. But reading ohms through wiring
for injectors are good. What can cause a cold no start. Next Iím purchasing
the air and coolant sensor   

Check for 39 psi fuel pressure when the ign is turned on.  It should for
some seconds after the pumps shut off.  Put a noid light on the injectors
(each of 2 banks) to see if the ECU is driving them; otherwise the ECU
might be bad.  Just turn on the ign and slowly open the throttle to see
if you get up to 21 injector clicks; if not the ECU is probably bad. 

Unplug the EFI 2 wire temp sensors with an ohmmeter.  They should
measure around 1000 ohms cold, more hot.  They interchange; if you
only have one good one make sure its the one in the coolant which
has much more effect.  Bruce Roe

 

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