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Sorting out no-start problem
#1
Posted 19 November 2003 - 10:46 AM
The ecu I have has four connectors, each a different size. The ecu that came with the engine, and was not used, has three connectors.
I NEED a positive ID on the ecu I have. It is SUPPOSED to be the one I need.
#2
Posted 19 November 2003 - 10:49 AM
#3
Posted 19 November 2003 - 11:43 AM
I've mentioned this page before, but people seem to forget
http://www.main.expe...cans/FSM_Scans/
it has all the pinout info you want. ECU & TCU.....was taken from the 1990 FSM's.
I'm also assuming you've seen this pic, which shows the physical location of each....the ECU & TCU
http://www.main.expe...ges/ecuhide.jpg
#4
Posted 19 November 2003 - 11:44 AM
#5
Posted 19 November 2003 - 06:35 PM
I put it in check mode today, and it cycled the fuel pump. The check engine light wire was hooked to my voltmeter, but it doesn't react quickly enough to determine the number of blinks. Does that light need to be a LED?
I also checked the resistance on the ignition coil. It appears to have the continuity of a brick.
If the coil is dead, does the computer keep the fuel pump off so fuel isn't unnecessarily injected into the engine? That's my new theory.
I didn't even think about the fact that the automatic car has a TCU. Now I feel dumb.
#6
Posted 19 November 2003 - 11:02 PM
The fuel pump definately is not running while cranking. It comes on with the key momentarily. Test modes on the computer work, it cycles the fuel pump, and it tries to spit out codes, which I can't read for the lack of a CEL.
Checking for ignition output at the computer yeilded some odd results. With the ignitor plugged in, the FSM says to backprobe it and look for voltage pulsations which is the computer telling the ignition coil to fire. With the ignition on, I get around 5 volts. Cranking, it drops to zero. Is this the fault of the ignitor, or ecu? I didn't think to check it with the ignitor unplugged to try to isolate it, cuz the FSM never mentioned that. It said after that check, if abnormal results are found, to replace the ignitor. But that still doesn't explain the fuel pump not coming on while cranking, unless the computer is looking for the correct ignition signal. I don't know. Anyone got a used ecu sitting around they wanna sell?
#7
Posted 20 November 2003 - 10:44 AM
flow chart
Crank angle sensor => ECU => Fuel Pump Relay => Fuel Pump
If that's the case, then the ignitor shouldn't affect the fuel pump....
#8
Posted 20 November 2003 - 10:48 AM
#9
Posted 20 November 2003 - 12:17 PM
just a guess
#10
Posted 20 November 2003 - 01:30 PM
#11
Posted 20 November 2003 - 01:32 PM
If that was the case, it isn't anymore. I disassembled the entire harness and streamlined it to include only things to make the engine run.
#12
Posted 20 November 2003 - 06:34 PM
#13
Posted 20 November 2003 - 07:17 PM
I might have a few problems, but this afternoon I came to the conclusion there is no spark because of the ignitor.
#14
Posted 20 November 2003 - 10:37 PM
#15
Posted 20 November 2003 - 11:11 PM
good luck - I bet you're close.
#16
Posted 21 November 2003 - 07:49 AM
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