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91 LS no start, no power to fuel pump relay!UPDATE TO MY 91 LS400 no start!

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Old 05-07-14, 06:28 PM   #16
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wow...quite involved
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Old 05-07-14, 07:43 PM   #17
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zGagnon1 - An OBD1 reader is called a paper clip. Readily found in quantity at your local Staples.
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Old 05-12-14, 04:55 PM   #18
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Click the image to open in full size.

only issue I'm having is the open circuit relay on the LS is a 6 pin.. and they aren't numbered or anything so these instructions confuse me a tiny bit.

but so far fuel pump relay checks out fine, resistor checks out fine, EFI relay checks out fine.
So I'm hoping this circuit opening relay is the issue once i can figure out how to test it
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Old 05-12-14, 08:08 PM   #19
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found this finally

http://workshop-manuals.com/lexus/ls...opening_relay/

and tested it.. seems fine. NOW IM MAD AND STUMPED ALL OVER AGAIN.
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Old 05-12-14, 09:08 PM   #20
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Quote:
Originally Posted by ZGagnon View Post
NOW IM MAD AND STUMPED ALL OVER AGAIN.
It looked me that you have been running in a same circle for a week. You definitely need to find out the root cause why the circuit opening relay stops the +B supply, as I mentioned you last week.

Touching only to the relay does not give you any more progress. Bypassing +B and FP is only for the short time test and too long may harm your engine since +B supply is stopped by the relay which is controlled by the ECU. The ECU detects something serious that needs to prevent the engine to run and the relay keeps the contacts open. There are different items that the ECU judges so. For an example, the continuous opening of fuel injectors is one of them. To read the code is the fastest way to find out the root cause quickly.
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Old 05-12-14, 11:05 PM   #21
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Yeah, the fact that the car didn't start when he did the bypass is a red flag. He had fuel and no start. There's two coils in the circuit opening relay, one that operates only when you start the car and the other is energized by the ECU when it detects that the car is running. You need to run down the cause of the no start.
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Old 05-13-14, 09:12 AM   #22
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yes was sick the last week and got no work done on the car..

also car did end up start with the bypass in, ran just fine, little smoke from sitting, removed the bypass and car still ran until giving it some higher revs and it cut out and died.

And engine light was never on when the issue first started, only when doing the bypass. So working on getting the car scanned.
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Old 05-13-14, 01:29 PM   #23
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also I've tried the paper clip and the jumped wire from E1 to Te1.. follow all the steps and my engine light aight flashing or giving me codes. so F that idea
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Old 05-13-14, 04:09 PM   #24
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p.s… engine light would just continuously flash. no breaks, just non stop flashing.
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Old 05-13-14, 05:32 PM   #25
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Constant flashing usually means multiple misfires.
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Old 05-14-14, 06:59 AM   #26
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Quote:
Originally Posted by python View Post
did u spray a small amount of starting fluid into the fresh air intake hose..then try to start it
exactly why i asked this question
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Old 05-14-14, 09:49 PM   #27
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when i did the jumper wire and got the car started it ran just fine and that was the only time the engine light came on, possibly because i was jumping a ton or fuses and relays.

I am not messing around with spraying anything anywhere to try and start it. Ive gotten it started with the jumper, just gonna try and bribe my mechanic to make a house call
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Old 05-15-14, 06:12 AM   #28
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Ok so you got it all worked out then. Let us know what your mechanic says is the root cause. Spraying started fluid in the intake is a pretty common mechanic trick to see if the problem is related to any part of the fuel system. If it starts you would begin to suspect a fuel issue. If It does't start then you start looking at the car not getting spark. Just a test to isolate the issue more. If you knew all this already then I digress.
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Old 05-23-14, 12:35 PM   #29
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UPDATE!

gave up trying to figure it out, got it towed to a shop.

At first he was thinking the timing belt jumped and through timing off bla bla bla….

ended up finding that the crank sensor was covered in "gunk", cleaned it up got the car running but was not running good at all, so a tune up was recommended and since the car was already there i just say F it, do it. The plugs, wires, distributors is what i was hoping it was in the first place because i could have done that in my driveway but the no power to the fuel pump and thinking it was electrical through me off, but apparently the issue with the crank sensor is what cause that problem.. fun stuff.

$900 later… she's runs like new and is up for sale :P I have two cars so ill just use the 4 cylinder gas sipper and slowly find something new i wanna modify, may go back to the SC world, found a CHEAP 95 black on black.
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Old 05-23-14, 01:15 PM   #30
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Glad you got it fixed and thank you for coming back and sharing what you found out. May help others later...
Good luck on the sale and the new build...
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Old 05-23-14, 01:15 PM
 
 
 
 
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75, 91, 94, crank, fuel, fusable, fuse, lexus, link, location, ls, ls400, pump, relay, st

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