1979-1993 & 94 Conv [Subscribe to Daily Digest] |
[Profile/Gallery]
, Tue, 4 Mar 2014 07:44:17
Members do not see ads below this line. - Help Keep This Site Online - Signup
Hey CMyles (or anyone willing to read this),
Lot's of info below. Sorry! For those who haven't read other parts of this thread. The car died while driving. I checked spark by by holding a plug against the engine and I do have spark.
------
I checked the grounds they looked good. I checked the one by the lift lug with an ohm meter by probing each wire to ground and they had good connection. The power block looked clean and tight. Maybe that wasn't the best way.. but more tests below regarding ground wires.
I removed the bolster and did a ton of tests on the ECU harness and the main relay and fuel pump relay by following Bentley.
The main relay tested good with multiple tests and I could hear it clicking. I also swapped it with the fuel pump relay and hot wired the fuel pump and still no start.
The tests:
Ground present at pin 17 --result OK, 0.0 ohms
I jumped pin 21 to ground and checked for voltage at pin 9 with ignition on. Questionable result -- voltage was present at pin 9 with key on (that's good) AND OFF (weird?). Not sure if that means anything. The second part of the test was checking for voltage at pin 5 of the AMM--- result OK, voltage was present.
Checked voltage at system relay (main relay above ECU) terminals 30 and 86 --- result OK, battery voltage present at both 30 and 86.
(Control unit power switched) Grounded pin 35 and checked for voltage with ignition on. ---result OK, 11.42 volts present
(Control unit power constant) Grounded pin 4 -- result OK, 12.15 volts present
(Control unit grounds) checked voltage between pins 4 and 5; and pin 4 and 17 -- result OK, voltage present for both tests, 12.1, 12.2
(System Relay) Jumped terminals 17 and 21 -- all results OK except output to injectors was a much lower voltage (is that normal?), main relay clicked, 12.5 v present at pin 9, 12.14v at pin 5 of AMM, 0.40 volts to red/blue fuel injectors wire. Was the voltage to the fuel injectors supposed to be higher that 0.4 volts?
(Fuel Pump) Jumped 5 and 20; 17 and 21. Fuel pump ran. I could hear it humming away.
I finally ended up checking the fuel injectors and got a more conclusive (hopefully) result.
I unplugged an injector and hooked up a digital voltmeter across the connector. I reconnected the ECU and made sure all relays were plugged in. Cranked the engine. NO voltage. I could not even get a little blip with the voltmeter turned up to higher sensitivity.
Next step per Bentley: I checked for voltage on one side of the connector and it was present. 11.4 volts at the connector.
If I understand how it works, the ECU pulses a ground signal to the injectors allowing the voltage move through the circuit and open the injectors.
I tested the ground signal wire circuit (pin 18) to the injector connector (the to-ground side) and got a good connection, 0.0 ohms.
The final thing I did was hook up a spare LH 2.4.2 ECU I removed from a known working 91 (blown transmission). Even with the different ECU, still no dice. No start.
So I think I've narrowed it down (maybe) to the injectors not receiving ground signal from the ECU.
Any ideas on where to go from here? Sorry for the overwhelming info I crammed into this post.
Thanks again for any help!
For some moral support a guy in a new sweet black Saab convertible (aero maybe?) was picking up his daughter from school and stopped to offer assistance. He looked over the car, complete with clear coat falling off, and said, "That's a beautiful car!"
posted by 98.204.7...
, Tue, 4 Mar 2014 07:44:17, Fri, 7 Mar 2014 13:04:32, Fri, 7 Mar 2014 18:29:55, Tue, 4 Mar 2014 08:08:04, Wed, 5 Mar 2014 17:08:42, Wed, 5 Mar 2014 17:56:11, Thu, 6 Mar 2014 09:22:39
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
