LT1 Problem
Thread Starter
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Joined: May 2007
Posts: 76
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From: Johnson City TN
LT1 Problem
Have a 94 LT1 in my street rod (my other ride is a C3) and having a fuel problem. Getting a code 55 which says lean fuel problem. Fuel regulator test out fine, according to the manual the fuel pump is putting out enough pressure (45 lb @ initial key turn on, then drops to about 39 to 40 @ idle). Car will run fine for about 15 minutes then when you hit the throttle the engine won't build RPM, starts to miss and will even backfire. If you keep the throttle down the check engine light will come on and throws the code noted above. I don't know where else to look for the problem and since I've had good luck with help on the forum for C3's I thought I'd check with you folk for help. Is there a sensor that monitors the fuel mixture? Almost forgot, the computer was reprogrammed to eliminate the anti theft and smog stuff which we eliminated on the engine swap. Also have the
4L60E trans. Thanks in advance for any help.
4L60E trans. Thanks in advance for any help.
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
O2 sensors monitor the mixture in closed loop.
Have you checked to see if all the injectors are getting signal to fire as well as ohm testing them to make sure the coils in them are all ok?
Have you checked to see if all the injectors are getting signal to fire as well as ohm testing them to make sure the coils in them are all ok?
Thread Starter
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Joined: May 2007
Posts: 76
Likes: 0
From: Johnson City TN
The O2 sensors are new but I can look at that. The injectors were cleaned/checked when we had the engine rebuilt, but that was about 2 years ago. I can check the voltage to the injectors this weekend. Could a voltage drop from the alternator cause this type of problem? I'm running an electric fan that pulls heavy amps, running through a relay, but I've noticed the meter drops down to around 12.5 or so when the fan comes on. Thanks for the leads on getting this thing straightened out. I'm really new to this whole FI thing, but I do like it when it's running right.
