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-   -   Put LT1 up on jacks, now won't start (https://ls1tech.com/forums/lt1-lt4-modifications/1723247-put-lt1-up-jacks-now-wont-start.html)

Dadic 78 May 1, 2014 08:12 PM

Put LT1 up on jacks, now won't start
 
1994 Firebird LT1. Had the engine running in the garage, started lifting the car with my jack (passnger's side first) about 15". The engine stalled out when I had the right side in the air, and I didn't think much about it, figured it was starved of fuel or something... Proceeded to lift the other side, and left it alone for a couple weeks... Today I go to start it (no tires on, still in the air) and it'll turn over all day but it won't fire... Any ideas why???

I should mention that after it stalled out I didn't touch it for about a week. Today I completed an oil change on it, but nothing went sideways, no wet opti, etc... So I'm pretty sure lifting it one side at a time affected something.

1fastrock May 1, 2014 09:13 PM

Check for crushed fuel lines?

SS RRR May 2, 2014 06:54 AM


Originally Posted by 1fastrock (Post 18184717)
Check for crushed fuel lines?

First thing I thought of...

93M6Formula May 2, 2014 07:27 AM

You either crushed some fuel lines or you were low on oil and the low oil sensor got triggered and shut the car off (I believe that's how it works?) Are you that low on gas?

Shownomercy May 2, 2014 08:55 AM


Originally Posted by 93M6Formula (Post 18185327)
You either crushed some fuel lines or you were low on oil and the low oil sensor got triggered and shut the car off (I believe that's how it works?) Are you that low on gas?

Low oil sensor is an idiot light only. PCM does not care how much or how little oil you have.

Dadic 78 May 2, 2014 09:34 AM

There's almost a full tank of fuel. I'll double check the fuel lines.

93M6Formula May 2, 2014 01:19 PM


Originally Posted by Shownomercy (Post 18185453)
Low oil sensor is an idiot light only. PCM does not care how much or how little oil you have.

I was just curious because it also does not let you start your car when it doesn't sense oil. I was distracted one day when I changed my oil and forgot to put oil in and it wouldn't turn over, filled with oil after I realized I about fucked over my engine and it fired up then.

guppymech May 2, 2014 01:24 PM

Is the fuel pump running? I had a '88 mustang that had a 'roll over' switch that would turn off the fuel pump.

SS RRR May 2, 2014 01:51 PM


Originally Posted by 93M6Formula (Post 18185911)
I was just curious because it also does not let you start your car when it doesn't sense oil. I was distracted one day when I changed my oil and forgot to put oil in and it wouldn't turn over, filled with oil after I realized I about fucked over my engine and it fired up then.

Makes no sense after all the "my car is running with no oil pressure" threads that have popped up over the years. I do not believe the oil sensor is connected to the PCM in any way.

93M6Formula May 3, 2014 10:41 PM


Originally Posted by SS RRR (Post 18185962)
Makes no sense after all the "my car is running with no oil pressure" threads that have popped up over the years. I do not believe the oil sensor is connected to the PCM in any way.

Then my car is a freak because it wouldn't send power to the starter until I added oil.....

ditchdrift May 4, 2014 10:56 AM


Originally Posted by 93M6Formula (Post 18188374)
Then my car is a freak because it wouldn't send power to the starter until I added oil.....

then it would never crank to build up the oil pressure

mab6680 May 4, 2014 11:15 AM

when my oil pump drive gear broke my car didn't shut down or prevent me from staring it

WCT13 May 4, 2014 03:51 PM


Originally Posted by mab6680 (Post 18188900)
when my oil pump drive gear broke my car didn't shut down or prevent me from staring it

Mine didn't shut down, but when we towed it home, it wouldn't start back up.

Dadic 78 May 5, 2014 02:52 PM


Originally Posted by guppymech (Post 18185922)
Is the fuel pump running? I had a '88 mustang that had a 'roll over' switch that would turn off the fuel pump.

When I turn the key to "on" I'm pretty sure I can hear the fuel pump fire up. I still haven't had a chance to get back to check it out for crushed fuel lines, etc...

I thought as well that it may be a rollover type switch. How did you get your mustang pumping fuel again?

guppymech May 5, 2014 04:34 PM


Originally Posted by Dadic 78 (Post 18191340)
When I turn the key to "on" I'm pretty sure I can hear the fuel pump fire up. I still haven't had a chance to get back to check it out for crushed fuel lines, etc...

I thought as well that it may be a rollover type switch. How did you get your mustang pumping fuel again?

I never actually had the switch trip, IIRC there was a push button to reset it.

BALLSS May 5, 2014 06:19 PM

OP

confirm you have fuel "pressure"

Shownomercy May 5, 2014 06:33 PM

Have you checked the yaw sensors?

The angle could be extreme enough to make them fuzzy and cut out spark to the opti which means your starter wouldn't engage.

Dadic 78 May 5, 2014 08:08 PM


Originally Posted by BALLSS (Post 18191698)
OP

confirm you have fuel "pressure"

What's the best way for me to do that? (Sorry, haven't done ANY fuel line work in my past!)


Originally Posted by Shownomercy (Post 18191718)
Have you checked the yaw sensors?

The angle could be extreme enough to make them fuzzy and cut out spark to the opti which means your starter wouldn't engage.

Well the starter does engage, it will turn over no problem. Just never fires up, that's all.

BALLSS May 5, 2014 10:46 PM


Originally Posted by Dadic 78 (Post 18191927)
What's the best way for me to do that? (Sorry, haven't done ANY fuel line work in my past!).

with a fuel pressure gauge like this:

http://www.jegs.com/i/Hypertech/533/...FY6RfgodzbcAug

the hose screws onto the Schrader valve on your fuel line rear of motor. It will have a cap on it that looks like a large tire valve cap.

some auto part stores may have them as a "loan-s-tool" deal. A good tool to have in your toolbox.

Dadic 78 May 11, 2014 06:53 PM

Well I've just spent the afternoon in the garage. Inspected for crushed fuel lines, and found none. All seem to be in good shape. Interestingly, the fuel lines run along the left side of the car, and the engine stalled out when I lifted the right. I still haven't had a chance to get a fuel pressure guage, that's probably going to be my next step.

Can anyone confirm if there's any sort of rollover sensor in this vehicle? Or something of the sort that may be causing a no spark condition? And if there is one, how to reset it?


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