C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

LT1 start/idle problem

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Old 02-01-2006, 03:46 PM
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aminnich
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Default LT1 opti spark change out

I have hi miles 95 vette, auto, LT1. New plugs, wires, optispark and coil. Now new problem has just started. It is hard to start, seems like it is flooding out.

OK, got scanner, even ohm'ed the wiring, and it is definitely opti-spark.
New one was defective (and no, I don't wash my engine and water pump not leaking, just a bad buy on wonderfull E-bay, stupid me).
Got everything pulled apart in little less than 2hours, EXCEPT pulling the crank pulley/balancer forward. Got puller hooked up, moved it forward about 1/4" and it won't budge any further. Anybody else seen this? Help, it's got me worn out and frazzled.

Thanks

Last edited by aminnich; 02-03-2006 at 07:15 PM.
Old 02-01-2006, 04:04 PM
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SupaVette
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Maybe a leaking injector? have you checked fuel pressure to see if it holds any?
Old 02-01-2006, 04:09 PM
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Redeasysport
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St. Jude Donor '05-'06
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Originally Posted by SupaVette
Maybe a leaking injector? have you checked fuel pressure to see if it holds any?

The easiest thing to check is pull the vacuum line from the FPR and check for gas.That would make it a bad FPR.Other than that you will need the gauge and start doing the leakdown test by clamping lines after enegizing the FP.Do a search on bad fuel pump to learn about it.
Old 02-01-2006, 04:20 PM
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REDC4CORVETTE
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Sounds like the regulator ,do you have the stock regulator on the car?
Old 02-01-2006, 04:26 PM
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aminnich
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Originally Posted by REDC4CORVETTE
Sounds like the regulator ,do you have the stock regulator on the car?
Car is supposed to be all stock, I have had it 3 months. What does the regulator look like and where is it mounted? You can tell by that question I am limited in lt1 knowledge. But trying to learn with help from forum members, which is greatly appreciated.
Old 02-01-2006, 04:29 PM
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Redeasysport
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St. Jude Donor '05-'06
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It is on the pass side the regulator is on the rear of the fuel rails and you will see the vacuum line going to the middle of the intake.If you do not have a manual go to www.helminc.com and oder one it is the best money you can spend on your car.
Old 02-01-2006, 04:37 PM
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aminnich
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Originally Posted by Redeasysport
It is on the pass side the regulator is on the rear of the fuel rails and you will see the vacuum line going to the middle of the intake.If you do not have a manual go to www.helminc.com and oder one it is the best money you can spend on your car.
Thanks. I got a GM manual right after I got the vette, but it is mostly useless. Looked at the Helms site, pricey, but if I am going to keep the Vette it might be worth it. Now I need to go check the FRP and vacuum hose, at least visual check and for gas odor. Is a gauge for on the motor dealer item only, or something a NAPA or such sells?
Old 02-01-2006, 04:47 PM
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Redeasysport
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St. Jude Donor '05-'06
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Got my Gauge at advance.The money you will save with the FSM from helm will pay for itself in no time.It is complete 3000 pages of everthing the dealer knows about your car including diagnosis and code info.The only manual worth having.
Old 02-01-2006, 06:14 PM
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aminnich
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Originally Posted by Redeasysport
Got my Gauge at advance.The money you will save with the FSM from helm will pay for itself in no time.It is complete 3000 pages of everthing the dealer knows about your car including diagnosis and code info.The only manual worth having.
Pulled the fuel rail covers off and looks like the regulator is probably original, or at least been there awhile. Took vacuum line off the regulator and no gas smell, neither sitting nor running. Whren idling and it starts to quit if i give it gas to keep it from stalling it shudders, coughs, rattles, etc and then brief bit of smoke out the air cleaner and it quits. Guess I will be working on it again in the morning. Again, Thanks for the Help.
Old 02-01-2006, 06:18 PM
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St. Jude Donor '05-'06
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Next thing I would do is a good TB cleaning.The IAC may be plugged.It is cheap and easy to do.There is a tech tip on it.Then do the leakdown tests.You might try a can of Techron in the gas it is a good cleaner.


I hesitate to mention this as you need to do the tests first but hard start, rough idle and backfiring in the intake are two different things.The first can be caused by lots of things but backfiring is ignition related and points to the OPTI.Keep working to elminate everything else before looking there.Air ,Fuel ,Spark when they are all correct it will run great.If your fuel checks out ignition seems to be the next place to look.

Last edited by Redeasysport; 02-01-2006 at 06:25 PM.
Old 02-01-2006, 08:07 PM
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aminnich
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Originally Posted by Redeasysport
Next thing I would do is a good TB cleaning.The IAC may be plugged.It is cheap and easy to do.There is a tech tip on it.Then do the leakdown tests.You might try a can of Techron in the gas it is a good cleaner.


I hesitate to mention this as you need to do the tests first but hard start, rough idle and backfiring in the intake are two different things.The first can be caused by lots of things but backfiring is ignition related and points to the OPTI.Keep working to elminate everything else before looking there.Air ,Fuel ,Spark when they are all correct it will run great.If your fuel checks out ignition seems to be the next place to look.
Hate to say it, but looks llike the OPTI. On the good side means YOU are good in on-line diagnostics Friend came over with scanner. It is clearly throwing codes 16 and 51. Need to OHM out the wires tomorrow evening to be sure, but looks like the new Opti we put in just month ago is bad. That really sucks! I am pretty disgusted right now.
Old 02-01-2006, 08:15 PM
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ittlfly
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Did you get the opti wet..wash the engine? Antifreeze will take it out too.
Old 02-01-2006, 08:27 PM
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St. Jude Donor '05-'06
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Code 16 is the low res side which explains why it will still start.36 is high res and if you get that you are done tow it home.Sorry but it looks like more work.Make sure the hoses to it are all good and clear.Sometimes the Opti can run like yours with no faults.That is when the cap and rotor needs replaced.
Old 02-01-2006, 08:30 PM
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aminnich
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Originally Posted by ittlfly
Did you get the opti wet..wash the engine? Antifreeze will take it out too.
NO, I know better than that and no water pump leak. My mistake, assuming it is the opti at this point, was that I bought it on e-bay, and not ac/delco made. I don't look forward to having to change the (&*&%%^$ thing again. and all the other unhappy smiley faces too. But thanks for thinking of me.
Old 02-01-2006, 08:57 PM
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St. Jude Donor '05-'06
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The only upside is it will take you half as long to do it.All the bolts will come out easier.Plus you "Have Been Experienced" as Hendrix would say.
Old 02-01-2006, 10:38 PM
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aminnich
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Originally Posted by Redeasysport
The only upside is it will take you half as long to do it.All the bolts will come out easier.Plus you "Have Been Experienced" as Hendrix would say.
Yes, I have been experienced. I manage a truck repair shop, but have some techs that are also excellent auto technicians. One of the master techs and I did it last time and took about 8hrs, including the plug wires.
Figure this time, even by myself it should be 4-6hrs, but probably will be longer. Didn't replace hoses last time, will this time though, might do the water pump while I am at it just because I don't want to have to get into front of motor again anytime soon.

Notice you are in NE Ohio. We lived in Medina County for 15yrs before we moved south (job transfer). Still Browns and Indians fans. Someday, someday Browns will get to superbowl.

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