Fuel problem - Help
Thread Starter
Intermediate
Joined: Apr 2010
Posts: 49
Likes: 0
Fuel problem - Help
Hi Just checking to see if someone knows what this problem may be and if its pricey.
Just bought my first vette a 1987 in great condition. The only issues that it has is that the cluster seems to indicate the fuel is full and only noticed it after driving it 100 miles and and the meter never lowered.....so its stuck on full.
The next issue is that the car seems to have a hard time starting after shutting it off after the first start of the day. It cranks for about 3-5 secs before it finally starts.......is this normal on this car ? Do i need to pump the gas before starting it ?
thanks for any help anyone can provide on any of this.
Just bought my first vette a 1987 in great condition. The only issues that it has is that the cluster seems to indicate the fuel is full and only noticed it after driving it 100 miles and and the meter never lowered.....so its stuck on full.
The next issue is that the car seems to have a hard time starting after shutting it off after the first start of the day. It cranks for about 3-5 secs before it finally starts.......is this normal on this car ? Do i need to pump the gas before starting it ?
thanks for any help anyone can provide on any of this.
Race Director
Joined: Dec 2000
Posts: 17,551
Likes: 26
From: El Paso Texas
Issue #1. Fuel gauge. See my tech article on this
http://forums.corvetteforum.com/c4-t...h-article.html
....remove the sending unit and clean the contact and windings. This solves about 90% of all fuel gauge issues. I did it on my 84 back around 2001 and the gauge is still working fine. Takes less than an hour to do the procedure.
Issue #2. Long cranking times are usually due to a bad fuel pump relay. When the relay fails, the system relies on a backup....the oil pressure switch. If the relay is dead, cranking the engine builds oil pressure...when it reaches about 4 PSI, it closes the fuel pump circuit via a secondary path and energizes the pump. NOTE: They are wired in parallel, not series. If the relay is functioning, the engine will start and run with zero oil pressure. The OP switch is NOT a failsafe to prevent engine failure if oil pressure suddenly drops.
Pumping the gas pedal will have zero effect on anything on an EFI equipped car. In the old carbureted days, this activated the accelerator pump in the carb....which sent an ultra rich mixture into the engine. Not so on EFI. The ECM decides what the fuel ratio will be based on input from the sensors in closed loop, and from (some) presets in open loop.
Clean your sending unit, replace your fuel pump relay, enjoy your car.
http://forums.corvetteforum.com/c4-t...h-article.html
....remove the sending unit and clean the contact and windings. This solves about 90% of all fuel gauge issues. I did it on my 84 back around 2001 and the gauge is still working fine. Takes less than an hour to do the procedure.
Issue #2. Long cranking times are usually due to a bad fuel pump relay. When the relay fails, the system relies on a backup....the oil pressure switch. If the relay is dead, cranking the engine builds oil pressure...when it reaches about 4 PSI, it closes the fuel pump circuit via a secondary path and energizes the pump. NOTE: They are wired in parallel, not series. If the relay is functioning, the engine will start and run with zero oil pressure. The OP switch is NOT a failsafe to prevent engine failure if oil pressure suddenly drops.
Pumping the gas pedal will have zero effect on anything on an EFI equipped car. In the old carbureted days, this activated the accelerator pump in the carb....which sent an ultra rich mixture into the engine. Not so on EFI. The ECM decides what the fuel ratio will be based on input from the sensors in closed loop, and from (some) presets in open loop.
Clean your sending unit, replace your fuel pump relay, enjoy your car.
Racer
Joined: Jan 2007
Posts: 322
Likes: 0
From: Chapin South Carolina
Learn to do things yourself and you will be happy. The fuel sender unit is very easy. It is cheap if it can be cleaned but if someone screwed it up then you will need to purchase anew one and that is about $300 on ebay. I have not done a relay so I do not know the cost.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
I agree with everything Frizlefrak posted. I will add one other thing.
Your 87 is equipped with a cold start injector (9th injector).
Read the thread below for lots of info on it.
http://forums.corvetteforum.com/c4-t...old-start.html
Your 87 is equipped with a cold start injector (9th injector).
Read the thread below for lots of info on it.
http://forums.corvetteforum.com/c4-t...old-start.html
