94 corvette misfiring
Thread Starter
Intermediate
Joined: Nov 2022
Posts: 37
Likes: 0
94 corvette misfiring
I replaced the coil with an msd blaster. But when I try to starter I have to pump the gas. Fuel pump sounds ok. So is the fuel filter clogged up? It will die if ran for 15-20 mins
Burning Brakes
Joined: Apr 2014
Posts: 828
Likes: 189
Id start by checking fuel delivery conditions.
1. Check for failed fuel pressure regulator. After running the engine for a short time, turn it off and pull the vacuum line off the regulator. It should be dry inside the vacuum line. If its wet with gas, the regulator is bad.
2. Check the fuel pressure at the rail with vacuum line disconnected from the regulator, engine running. Should be in the high 40’s.
3. Leave the pressure gauge connected and turn the engine off. The pressure on the gauge should hold steady. If it drops off after a few minutes, you may have injectors that are stuck open.
1. Check for failed fuel pressure regulator. After running the engine for a short time, turn it off and pull the vacuum line off the regulator. It should be dry inside the vacuum line. If its wet with gas, the regulator is bad.
2. Check the fuel pressure at the rail with vacuum line disconnected from the regulator, engine running. Should be in the high 40’s.
3. Leave the pressure gauge connected and turn the engine off. The pressure on the gauge should hold steady. If it drops off after a few minutes, you may have injectors that are stuck open.
Thread Starter
Intermediate
Joined: Nov 2022
Posts: 37
Likes: 0
After some thought, backfiring has to be an ignition problem. Like the optispark is crapping out. And if I’m not getting enough fuel it would just die.. not backfire
QUOTE=John Dirks Jr;1605930958]Id start by checking fuel delivery conditions.
1. Check for failed fuel pressure regulator. After running the engine for a short time, turn it off and pull the vacuum line off the regulator. It should be dry inside the vacuum line. If its wet with gas, the regulator is bad.
2. Check the fuel pressure at the rail with vacuum line disconnected from the regulator, engine running. Should be in the high 40’s.
3. Leave the pressure gauge connected and turn the engine off. The pressure on the gauge should hold steady. If it drops off after a few minutes, you may have injectors that are stuck open.[/QUOTE]
QUOTE=John Dirks Jr;1605930958]Id start by checking fuel delivery conditions.
1. Check for failed fuel pressure regulator. After running the engine for a short time, turn it off and pull the vacuum line off the regulator. It should be dry inside the vacuum line. If its wet with gas, the regulator is bad.
2. Check the fuel pressure at the rail with vacuum line disconnected from the regulator, engine running. Should be in the high 40’s.
3. Leave the pressure gauge connected and turn the engine off. The pressure on the gauge should hold steady. If it drops off after a few minutes, you may have injectors that are stuck open.[/QUOTE]
Burning Brakes
Joined: Apr 2014
Posts: 828
Likes: 189
I was not suggesting lack of enough fuel. I was suggesting perhaps too much fuel. Unburnt raw fuel from leaking injectors can leak into the exhaust where it can ignite and cause backfiring.
Other than having a fuel pressure gauge, the tests i suggest would not cost you any money. Its worth the effort in my opinion to rule out things conducive to the symptoms you described.
Other than having a fuel pressure gauge, the tests i suggest would not cost you any money. Its worth the effort in my opinion to rule out things conducive to the symptoms you described.
Burning Brakes
Joined: Apr 2014
Posts: 828
Likes: 189
My thoughts are that you said you have to open the throttle to get it started. That sounds like it may be flooded with too much gas. Hence you need to open the throttle and let a bunch of air in to get it to start.
Having to open the throttle to get it started would not normally be related to an ignition problem
Having to open the throttle to get it started would not normally be related to an ignition problem
