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Ls1 was running great now won’t start ????

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Old 01-23-2019, 05:47 PM
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Default Ls1 was running great now won’t start ????

Have fuel pressure 53-58 psi
have tons of spark on no 1
have 12 v to ea injector on ea wire
I don’t get it. Was running fine day before. Fuel was low
bought 5 gal. Still won’t start.
Custom ecu and harness from street and performance now out of business. Now what ?? Help. Thanks.

Last edited by indydrt; 01-23-2019 at 07:20 PM. Reason: Add photo
Old 01-23-2019, 07:16 PM
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When were you seeing 53psi? When it was still running? If so that's too low, especially if that was under no load. Should be 58-60psi under full load. So if you were seeing dips to 53, then there is a restriction or the pump is getting weak, etc.
Old 01-23-2019, 08:09 PM
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Originally Posted by RPM WS6
When were you seeing 53psi? When it was still running? If so that's too low, especially if that was under no load. Should be 58-60psi under full load. So if you were seeing dips to 53, then there is a restriction or the pump is getting weak, etc.
could have been higher. When turn ignition on it went probablybto 60 and dropped back to 55 etc my buddy was watching gauge as I was in car. It won’t start . I did not notice a drop in any gas pressure while I was driving the car other day. Ran fine actually. Did couple burnouts on video try to post one here now. So I can here it. Can’t upload video I tried. If I had a email for you I can send direct if u like thanks for your help. Don
Old 01-23-2019, 09:48 PM
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Did you only check spark on #1 ? Give it a quick squirt of ether and see if it runs. If it does , you know it is not getting fuel
Old 01-24-2019, 07:06 AM
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Default Won’t start

ok will try dig up a bottle to squirt some fuel in it’s a cable driven throttle not drive by wire also. Don’t matter I guess.
Thanks. Jetech
Old 01-24-2019, 07:11 AM
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Default Won’t start

yes we only checked for spark on no 1
Old 01-24-2019, 07:57 AM
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Originally Posted by indydrt
ok will try dig up a bottle to squirt some fuel in it’s a cable driven throttle not drive by wire also. Don’t matter I guess.
Thanks. Jetech
Good , drive by cable is easier to work with.
Old 01-24-2019, 09:47 AM
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Default Starts now.

Hey thanks jetech. Used water bottle started but was rough. And then. We also had the mass airflow meter off and when we put it back on it ran rougher. Also spark plug in one was rich yesterday. So. Is there a mass air flow cleaner Spray or do you think might need to replace it ? Ughh well at least it runs yea!! Thanks man. How much are these part number
Delco part number 25168491
Old 01-24-2019, 10:34 AM
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Default Starts now mass airflow going bad we think

my buddy gets one wholesale brand new no rebuilt 165 .00
advamved auto has a spectre. Aftermarket. Didn’t want to chance that. Even though most reviews look ok.
So was 110 $ for a rebuilt delco but had to give a core also. So decided to go new. It seems like engine ran a lot better when it was off the car the mass airflow. When we put it on it ran like crap. So there ya go. It’s clean inside also. So thanks all !!
so now the plug didn’t matchup even with the adapter. Thankgod he can return the mass airflow. He’s on way back with the original mass airflow to match it up and find out exactly what year my motor is. No vin number avail to see. Ughh so iam totally not used to these modern engines. Thought I had a 97-98 Vette ls1 because of the permiter bolted valve covers. Well turns out I was looking at the bolts on the coil brackets. Not the valve cover actually. Duhhh. So after matching. Upnthe one I had it matches exactly to a 2001 Vette Ls1. Uhhh. Is that a good year for a ls1. How much hp should it be ? Thanks all

Last edited by indydrt; 01-24-2019 at 12:37 PM. Reason: Wrong year motor not 97-98 it’s A 2001 just found out
Old 01-24-2019, 02:34 PM
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Originally Posted by indydrt
So after matching. Upnthe one I had it matches exactly to a 2001 Vette Ls1. Uhhh. Is that a good year for a ls1. How much hp should it be ? Thanks all
The 2001+ LS1s only make about 5-10hp more than the earlier models, so it's not a big power difference in stock form. Ratings for the Corvette were 345hp (2000 and earlier) and 350hp (2001 and later). The biggest advantage is the LS6 intake, which isn't worth a ton on a completely stock engine but is a significant upgrade once other modifications are done (such as heads, cam, etc.)
Old 01-24-2019, 03:03 PM
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IAT sensor?
Old 01-24-2019, 06:55 PM
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Default It’s running finally !!!

thanks jet tech and all others. So replaced the mass air . With the right 2001 specific for the 2001 only ls1 . Then took off throttle body and cleaned it inside and out then the motor would not start. I couldn’t believe it ... ugh. We loosened up the mass air took it off and then motor started. I don’t get it .
After the motor warmed up it would start up no problem when the mass was back on. So now Gona wait till mourning when cooled off completely and try it again with mass air on. So we’re not totally out of the woods and I need to clean my spark plugs also. Or replace but will clean for now .
Old 01-24-2019, 06:57 PM
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Default Uat sensor ???

Originally Posted by cam
IAT sensor?
what is a IAT sensor ?
Old 01-24-2019, 07:02 PM
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Default Check again the fuel psi

Originally Posted by indydrt


could have been higher. When turn ignition on it went probablybto 60 and dropped back to 55 etc my buddy was watching gauge as I was in car. It won’t start . I did not notice a drop in any gas pressure while I was driving the car other day. Ran fine actually. Did couple burnouts on video try to post one here now. So I can here it. Can’t upload video I tried. If I had a email for you I can send direct if u like thanks for your help. Don
Today we check fuel p again it was 60 psi. When started motor and when turned motor off it stayed at about 45 for like 30 min or so or less. Then it slowly leaked down etc
Old 01-25-2019, 10:58 AM
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IAT, intake air temperature sensor. On the older systems this is not part of the maf. Its a small black bulb plug that fits in the intake tract somewhere in front of the MAF and TB. Sounds like the MAF though it goes into limp mode with it unplugged so you can try cleaning it, more than likely need to replace it though. If your planning on upgrades and whatnot an LS7 MAF card is worth the step up. Anyways try cleaning first, spray with MAF cleaner available at most parts suppliers and see if it wakes up
Old 01-25-2019, 02:01 PM
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Originally Posted by indydrt

Today we check fuel p again it was 60 psi. When started motor and when turned motor off it stayed at about 45 for like 30 min or so or less. Then it slowly leaked down etc
That sounds perfectly normal, so I don't think your current issue is related to fuel pressure then.
Old 01-25-2019, 09:18 PM
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Ok thanks ,,,I replaced the iac sensor today and spark plugs big difference. Started better but idle was way high when cold. Hardly wanted to come down ,,,like it was stuck at 1500 rpm , so when it warmed up it went down to 1200. Still to high Etc.. Then I used the Torx tool to lower the idle ...seemed better but then the idle was starting to hunt Lil higher rpm then little lower at 800. It likes 800 but did not stay there until reached 190 degrees then the fan sensor finally turned the #1 fan on yeaaaa! That was installed this outing also separate temp thermal static on/off switch .




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