back fireing and runs real ruff
Thread Starter
Teching In
Joined: Dec 2008
Posts: 16
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back fireing and runs real ruff Can't seem to figure out what is going on with my car. I installed a new cam, valve springs and roller rockers. The car wouldn't idle but ran fine and then progressively started to run worse until it wouldn't start unless at about half throtle. I had the computer scanned and it was throwing codes for the opti so i bought a new one from jegs and put it on. Now it runs but back fires a lot and it won't rev up if i stab it but it will go up slowly at like 1/4 throtle. I replaced the ICM and the coil and have the same thing. what else could it be? It"s not the plug wires i have checked them probably 10 times and there right.
TECH Regular
Joined: Apr 2007
Posts: 420
Likes: 0
From: Kempner, TX
Whenever a problem like this arises, it's best to check the easiest things first. One thing that far too many do is assume that something's "okay", then move on to something else. As a practical matter, checking involves checking everything, without assuming.
There are a number of different things that could be causing your problem, but I recommend that before tearing into the engine again, first check everything else.
Here's an example, a recent poster was having a similar problem and after tearing out his hair for days, finally found that he'd routed one of his plug wires too close to the ignition control module. Voltage from the plug wire was being picked up by the module and just moving the plug wire solved the problem. This is the kind of LITTLE THING that can cause such a problem.
Lifter preload set too tightly is a possible cause; with a valve being held open. Could be a sensor, so a scanner would be needed to see if one of them is operating out of range.
Unfortunately, none of us is able to pin-point exactly what's causing your problem, wish we could. Best we can do is give suggestions and recommendations and leave it in your hands to do the heavy lifting.
I'll try to help as best I can but I need you to post the details and specifics of what's going on. Remember the "Devil's in the details".
Jake
West Point ROCKS!
There are a number of different things that could be causing your problem, but I recommend that before tearing into the engine again, first check everything else.
Here's an example, a recent poster was having a similar problem and after tearing out his hair for days, finally found that he'd routed one of his plug wires too close to the ignition control module. Voltage from the plug wire was being picked up by the module and just moving the plug wire solved the problem. This is the kind of LITTLE THING that can cause such a problem.
Lifter preload set too tightly is a possible cause; with a valve being held open. Could be a sensor, so a scanner would be needed to see if one of them is operating out of range.
Unfortunately, none of us is able to pin-point exactly what's causing your problem, wish we could. Best we can do is give suggestions and recommendations and leave it in your hands to do the heavy lifting.
I'll try to help as best I can but I need you to post the details and specifics of what's going on. Remember the "Devil's in the details".
Jake
West Point ROCKS!
Are you 100% positive that you installed your cam dot-to-dot?
Did you adjust your rockers correctly?
Check your plug wire routing.
Check your fuel pressure.
The JEGS opti is a POS! Ask me how I know... Return it and get a AC Delco/Delphi opti.
When I installed my cam and rockers. Car would fire right up and idle was smooth, but as soon as I got on it, the car stumbled and back fired like crazy. Found a couple vacuum leaks, but no dice. I finally readjusted my rr's with the engine running and it was smooth sailing from then on.
Keep trouble shooting, you'll get it figured out.
Did you adjust your rockers correctly?
Check your plug wire routing.
Check your fuel pressure.
The JEGS opti is a POS! Ask me how I know... Return it and get a AC Delco/Delphi opti.
When I installed my cam and rockers. Car would fire right up and idle was smooth, but as soon as I got on it, the car stumbled and back fired like crazy. Found a couple vacuum leaks, but no dice. I finally readjusted my rr's with the engine running and it was smooth sailing from then on.
Keep trouble shooting, you'll get it figured out.
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Verdad Gallardo Thread Starter
Teching In
Joined: Dec 2008
Posts: 16
Likes: 0
Changed the fuel pump tonight and that didn't make a difference. Checked to make sure the injectors weren't leaking and they weren't. After these two things it seemed to run better less back firing. Then the battery started to finally die so I gave up for the night.
I'm 100% sure that the cam is in right. I remember when lining it up I went dot to dot and went one tooth each way to make sure I had it right. The push rods are 7.2 I checked them when got them with a calipers.
Thanks for the help guys.
I'm 100% sure that the cam is in right. I remember when lining it up I went dot to dot and went one tooth each way to make sure I had it right. The push rods are 7.2 I checked them when got them with a calipers.
Thanks for the help guys.
