Burning ECM with bigger injectors?
Thread Starter
Corvette ***** OG
Joined: Oct 2003
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From: Charlotte NC
St. Jude Donor '05
CI VI Veteran
Burning ECM with bigger injectors?
After rebuilding the LT1, I added GM's almost .600 lift Hotcam, bigger throttle body, headers, ported and polished heads. (2600 converter)
Point is I haven't sent the computer out to get reburned for the necc. settings because I'm waiting until I know what gear ratio I'm going to change to so I can get it done all at once.
Though I was thinking that perhaps the opti was giving me problems, I got to thinking that the car acts like it wants to load up a little while sitting at a light. While idling, it tends to load up a bit and you can watch the tach surge a bit. When you give it gas, it doesn't bog but it seems you have to hit the gas and then it all of a sudden takes off. After idling, there is not ease off from the light... it'll feel like it's going to stall.
Like I said, it only does this when I've been at a long light.
Since the ECM hasn't been reprogrammed, do you think that the 30lb injectors are too much? I'm assuming that once it gets reprogrammed, everything will be set for the correct changes.
Opinions?
Mark
Point is I haven't sent the computer out to get reburned for the necc. settings because I'm waiting until I know what gear ratio I'm going to change to so I can get it done all at once.
Though I was thinking that perhaps the opti was giving me problems, I got to thinking that the car acts like it wants to load up a little while sitting at a light. While idling, it tends to load up a bit and you can watch the tach surge a bit. When you give it gas, it doesn't bog but it seems you have to hit the gas and then it all of a sudden takes off. After idling, there is not ease off from the light... it'll feel like it's going to stall.
Like I said, it only does this when I've been at a long light.
Since the ECM hasn't been reprogrammed, do you think that the 30lb injectors are too much? I'm assuming that once it gets reprogrammed, everything will be set for the correct changes.
Opinions?
Mark
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Joined: Sep 2000
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Re: Burning ECM with bigger injectors? (C4 Newbie)
I would put the stock injectors back in until the PCM gets reprogrammed.
Usually just a HotCam install alone needs some programming. The longer duration cam usually wants more closed throttle timing advance. The throttle blades usually need to be closed to allow more IAC air to even out the BLM's.
If you have an adjustable fuel pressure regulator, you could lower it some.
Best of luck,
Gordon
Usually just a HotCam install alone needs some programming. The longer duration cam usually wants more closed throttle timing advance. The throttle blades usually need to be closed to allow more IAC air to even out the BLM's.
If you have an adjustable fuel pressure regulator, you could lower it some.
Best of luck,
Gordon
Le Mans Master
Joined: Jan 2003
Posts: 8,596
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From: Portland Oregon
Re: Burning ECM with bigger injectors? (C4 Newbie)
Use the stock injectors, using 30lb injectors is going to make the engine run very rich. As for your throttle body, which one did you use? The reason I am asking is that it may need to be modified. Most aftermarket TBs needs to have the Idle air circuit modified to fix the split BLM problem that is caused by them.
If you take the throttle body off, and take a look at the front of the intake TB mounting surface. You will see the two large inlet holes, then below them and in the middle you will see a small hole about 9/16" in diameter. This is the idle air port. From this port there are separate passages to each and every port for each cylinder. If your TB does not isolate this passage and if your TB gasket does not isolate this passage, then the idle air from the IAC will go into the main plenum instead of flowing through this port as GM intended. This can lead to idle instabilty and split BLMs.
Check it out, email me off list and I will email you a fix.
If you take the throttle body off, and take a look at the front of the intake TB mounting surface. You will see the two large inlet holes, then below them and in the middle you will see a small hole about 9/16" in diameter. This is the idle air port. From this port there are separate passages to each and every port for each cylinder. If your TB does not isolate this passage and if your TB gasket does not isolate this passage, then the idle air from the IAC will go into the main plenum instead of flowing through this port as GM intended. This can lead to idle instabilty and split BLMs.
Check it out, email me off list and I will email you a fix.
Team Owner
Joined: Dec 2000
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From: SE NY
Cruise-In II Veteran
Re: Burning ECM with bigger injectors? (C4 Newbie)
I believe your '95 LT1 uses 24lb/hr injectors, which can spray enough fuel for close to 400chp.
Install an AFPR along with the stock injectors and then bump fuel pressure for best HP. Then use a scan tool to record the BLM values (you have OBD 1?), which can then be used to cut a new chip.
Install an AFPR along with the stock injectors and then bump fuel pressure for best HP. Then use a scan tool to record the BLM values (you have OBD 1?), which can then be used to cut a new chip.
Thread Starter
Corvette ***** OG
Joined: Oct 2003
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From: Charlotte NC
St. Jude Donor '05
CI VI Veteran
Re: Burning ECM with bigger injectors? (65Z01)
Guys, thanks for the suggestions. Several things. The throttle body is a BBK 58mm body. The injectors are Ford SVO 30 lb. injectors, the cam is a .586 lift with 1.6 ratio rockers with ported and polished heads.
With this same setup without the injectors and throttle body, it was producing 426 HP in my S10. I'm assuming that with these add'l items, it may be a few HP more...
I will check the throttle body but it seems to me that it looks like I'm simply going to have to get the ECM reburned (which was my original intention, I was just waiting for gears)
Thanks for everyone's input.
Mark
With this same setup without the injectors and throttle body, it was producing 426 HP in my S10. I'm assuming that with these add'l items, it may be a few HP more...
I will check the throttle body but it seems to me that it looks like I'm simply going to have to get the ECM reburned (which was my original intention, I was just waiting for gears)
Thanks for everyone's input.
Mark
