Need engine guru help!
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,133
Likes: 2
From: GEAUX TIGERS PSL FL.
Need engine guru help!
Hey guys.
New to the engine mods. So here goes. I purchased a 1980 L-82 which has some engine mods. So forgive me if I have that deer in the headlights look so to speak. The car currently has (list given to me by the previous owner) a Mallory distributer and ingnition, rhs heads pro action ,180 intake port 72cc combustion chamber, comp cam ex 262 exteme energy,462 intake lift 469 exhaust lift ,1.6 comp cam roller tip rocker arms transmission is from bow tie overdrive its a 200r4 stage 2, Hedman headers, Mass-flo EFI. Timing is set at 16 degrees.
The car starts right up no problem. Has a bit of a rough idle, surges up and down. Not a consistant idle. While driving the car, hesitates on pickup, then is smooth while picking up speed, but again is not smooth at consistant speed. At a stoplight it has quite the lobe to it.
I just need some thoughts as to what might be the cause of surge. Idle fluxuates between 900 and 1500 rpm.
I am thinking about going back to a carb. Not very impressed with the EFI
Thanks in advance
New to the engine mods. So here goes. I purchased a 1980 L-82 which has some engine mods. So forgive me if I have that deer in the headlights look so to speak. The car currently has (list given to me by the previous owner) a Mallory distributer and ingnition, rhs heads pro action ,180 intake port 72cc combustion chamber, comp cam ex 262 exteme energy,462 intake lift 469 exhaust lift ,1.6 comp cam roller tip rocker arms transmission is from bow tie overdrive its a 200r4 stage 2, Hedman headers, Mass-flo EFI. Timing is set at 16 degrees.
The car starts right up no problem. Has a bit of a rough idle, surges up and down. Not a consistant idle. While driving the car, hesitates on pickup, then is smooth while picking up speed, but again is not smooth at consistant speed. At a stoplight it has quite the lobe to it.
I just need some thoughts as to what might be the cause of surge. Idle fluxuates between 900 and 1500 rpm.
I am thinking about going back to a carb. Not very impressed with the EFI
Thanks in advance
Last edited by RushThruLife; Oct 29, 2009 at 09:23 AM.
Burning Brakes
Joined: May 2007
Posts: 945
Likes: 0
From: Ventura California
I would suggest that the fuel injection system is trying to do it job. The mods that have been done already changed the fuel / air mix, flow, etc... the injection is gonna have a programming set up for stock. It's trying like crazy to run stock and can't.
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,133
Likes: 2
From: GEAUX TIGERS PSL FL.
The car does smell like its running rich. According to the Mass-flo`s website it should be able to handle the mods. Think I`ll try setting the timing back to 12 degrees and see what happens.
Instructor
Joined: May 2009
Posts: 243
Likes: 0
From: salisbury missouri
i agree with wiemer20 sounds like the controll box or computer for the fuel injection are having problems reading the cam and fuel ratios.
i would say the bigger cam is throwing more fuel than the fuel injection is set for and the o2 censor and the air flow into the engine are having coflicting readings with the bigger fuel ratio from the bigger cam this is why the engine is running rich all the time.i would go to the fuel injection manufacture on the web and read about the guide lines for this fuel injection unit and try to set it up right.
just my thoughts on what to do
i would say the bigger cam is throwing more fuel than the fuel injection is set for and the o2 censor and the air flow into the engine are having coflicting readings with the bigger fuel ratio from the bigger cam this is why the engine is running rich all the time.i would go to the fuel injection manufacture on the web and read about the guide lines for this fuel injection unit and try to set it up right.
just my thoughts on what to do
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,133
Likes: 2
From: GEAUX TIGERS PSL FL.
i agree with wiemer20 sounds like the controll box or computer for the fuel injection are having problems reading the cam and fuel ratios.
i would say the bigger cam is throwing more fuel than the fuel injection is set for and the o2 censor and the air flow into the engine are having coflicting readings with the bigger fuel ratio from the bigger cam this is why the engine is running rich all the time.i would go to the fuel injection manufacture on the web and read about the guide lines for this fuel injection unit and try to set it up right.
just my thoughts on what to do
i would say the bigger cam is throwing more fuel than the fuel injection is set for and the o2 censor and the air flow into the engine are having coflicting readings with the bigger fuel ratio from the bigger cam this is why the engine is running rich all the time.i would go to the fuel injection manufacture on the web and read about the guide lines for this fuel injection unit and try to set it up right.
just my thoughts on what to do
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,133
Likes: 2
From: GEAUX TIGERS PSL FL.
Instructor
Joined: May 2009
Posts: 243
Likes: 0
From: salisbury missouri
i have always tested o2 sensors with my scanner,on my scanner o2 sensors osalate between rich and lean have seen them stuck in lean condition theirfor adding fuel when not needed and causing car to run very rich all the time.i have never manually tested one.
i think you can with an ohm meter.
o2 sensors send a rich, lean measurement to the computer to regulate fuel in conjuction with the mass air flow sensor which is reading air intake to match it with fuel air ratio.their are other sensors to but i will not get into that.
if o2 sensors go bad they stick in open or closed loop,meaning they will either send a signal of lean all the time or rich all the time.if your car is running rich all the time it could be bad.
i would call the manufacturer of the after market fuel injection system and talk to their tech line most of them have a free phone # to call with any problems.tell him the cam size and anything else he might want to know he will advise you.
i think you can with an ohm meter.
o2 sensors send a rich, lean measurement to the computer to regulate fuel in conjuction with the mass air flow sensor which is reading air intake to match it with fuel air ratio.their are other sensors to but i will not get into that.
if o2 sensors go bad they stick in open or closed loop,meaning they will either send a signal of lean all the time or rich all the time.if your car is running rich all the time it could be bad.
i would call the manufacturer of the after market fuel injection system and talk to their tech line most of them have a free phone # to call with any problems.tell him the cam size and anything else he might want to know he will advise you.
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Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,133
Likes: 2
From: GEAUX TIGERS PSL FL.
i have always tested o2 sensors with my scanner,on my scanner o2 sensors osalate between rich and lean have seen them stuck in lean condition theirfor adding fuel when not needed and causing car to run very rich all the time.i have never manually tested one.
i think you can with an ohm meter.
o2 sensors send a rich, lean measurement to the computer to regulate fuel in conjuction with the mass air flow sensor which is reading air intake to match it with fuel air ratio.their are other sensors to but i will not get into that.
if o2 sensors go bad they stick in open or closed loop,meaning they will either send a signal of lean all the time or rich all the time.if your car is running rich all the time it could be bad.
i would call the manufacturer of the after market fuel injection system and talk to their tech line most of them have a free phone # to call with any problems.tell him the cam size and anything else he might want to know he will advise you.
i think you can with an ohm meter.
o2 sensors send a rich, lean measurement to the computer to regulate fuel in conjuction with the mass air flow sensor which is reading air intake to match it with fuel air ratio.their are other sensors to but i will not get into that.
if o2 sensors go bad they stick in open or closed loop,meaning they will either send a signal of lean all the time or rich all the time.if your car is running rich all the time it could be bad.
i would call the manufacturer of the after market fuel injection system and talk to their tech line most of them have a free phone # to call with any problems.tell him the cam size and anything else he might want to know he will advise you.
I have contacted the tech.
