Hard start 94 LT1
Thread Starter
Intermediate
Joined: Mar 2012
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Hard start 94 LT1
Car starts hard have to step on gas peddle when turning motor over. It has no codes, fuel pressure good doesn't drop any. Changed all sensors. Two different mechanic at dealership who specialize in vettes say coil windings. Currently have fuel rail & injectors at injector performance place getting checked for flow rates. Last summer same place did a sonic clean & flow rates checked on them any body have this problem before and are after market injector any good such as ACCELL
Race Director
Joined: May 2001
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Car starts hard have to step on gas peddle when turning motor over. It has no codes, fuel pressure good doesn't drop any. Changed all sensors. Two different mechanic at dealership who specialize in vettes say coil windings. Currently have fuel rail & injectors at injector performance place getting checked for flow rates. Last summer same place did a sonic clean & flow rates checked on them any body have this problem before and are after market injector any good such as ACCELL
If your injectors are the problem contacr FIC, they will fix you right up. I'm betting though that it is not injectors.
Thread Starter
Intermediate
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Seems like when i had injector sonic cleaned & flow checked they would have found bad injectors but one injector did have different flow & they matched flow for all injector. Couple other people have said ECM needs to be flashed.at this just want to know what wrong and take care of it very frustrating.
Race Director
Joined: May 2001
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It is most certainly best to have the proper size injector that the computer is expecting. The computer can compensate for small variances while the engine is running but during cranking it has no feedback. It can only assume that the injectors are correct.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
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From: Orlando FL
Check the vacuum line of the fuel pressure regulator. See if it wet or dripping. If it is leaking back and filling the manifold with fuel, it will cause hard starting by being too rich.
You can have good fuel pressure and will run fine but the FPR can still be bad. Holding the pedel down on starting kills the injector pulses while cranking. So it may tend to start easier doing that.
You can have good fuel pressure and will run fine but the FPR can still be bad. Holding the pedel down on starting kills the injector pulses while cranking. So it may tend to start easier doing that.
Thread Starter
Intermediate
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Yes fpr vacuum was checked for fuel no fuel there. Kind of grasping for straws. Don't want to change injectors & that not be the problem. If I'm going to start replacing parts makes more sense to me to start looking at ECM first. right or am I wrong. Still waiting to get fuel rail & injectors back from shop. I'm kind of hoping there something wrong with with them, so I can fix problem. Kind of embarrassing have nice vette that starts like old Chrysler
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Safety Car
Joined: Sep 2010
Posts: 3,752
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From: Indiana PA
How much are you stepping on the throttle pedal to get it to start?
1/4, 1/2, WOT?
What are the IAC counts while it has trouble starting up? Idle Air Control
On a electronically fuel injected car the IAC controls air at start up and idle. If it is sticking shut or close to shut, you could not be getting enough air into the engine to start it.
1/4, 1/2, WOT?
What are the IAC counts while it has trouble starting up? Idle Air Control
On a electronically fuel injected car the IAC controls air at start up and idle. If it is sticking shut or close to shut, you could not be getting enough air into the engine to start it.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Get a little technical. Connect a noid light on one of the injectors. Have a plug wire taken off (or get a in line spark tester) a with a screwdriver inserted, hold it near ground to test for spark. Have someone watch the noid light and for spark while the other person cranks the engine.
You might find a required input is missing at initial cranking.
You might find a required input is missing at initial cranking.
Thread Starter
Intermediate
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Have bad news and goods new on hard starting 94LT1. Injector where flow tested at injector shop bad news all injectors drip. Good new I know what's wrong and now I can fix it. I will be calling fic. Thanks you Nathan plemons for info. Do you think that when they where sonic cleaned last year it did something to them?
Race Director
Joined: May 2001
Posts: 14,165
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Have bad news and goods new on hard starting 94LT1. Injector where flow tested at injector shop bad news all injectors drip. Good new I know what's wrong and now I can fix it. I will be calling fic. Thanks you Nathan plemons for info. Do you think that when they where sonic cleaned last year it did something to them?
Thread Starter
Intermediate
Joined: Mar 2012
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Yeah I don't know what to think. Thought I was doing right thing having injector cleaned and flow matched when I had motor out. Motor did have little miss before I had injectors cleaned. O well more $ and it will be better dealership wants like $900 to $1000 I can get new injectors from FIC for $300 & something. Feel bad for people that can't do there own work.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
That’s pretty strange having all the injectors leaking at the same time. If a couple leaked it probably would not affect the starting but all sure would. Engine was definitely loaded up on the start.
What kind of injectors were they?
Glad you found it.
Who would have guessed.
What kind of injectors were they?
Glad you found it.
Who would have guessed.
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
If that long, my goodness. Yup, leaking injectors that will cause a hard start. Fuel pressure gauge should have revealed this.
Thread Starter
Intermediate
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Yeah u would think so but it didn't it was describe to me as drip from injector shop. Must of been very slight drip. When I had motor out I was thinking about replacing injectors but when your repairing and replacing multiple things $ adds up fast. Thought cleaning and flow matching was just as good. So any body doing same thing save themselves $200 and replace injectors you can get Bosch type III for $320 Owell it only $ sometimes you learn the hard way