Problems after H\C install...
Problems after H\C install... Ok Just did a heads and cam swap had REALLY bad probs at first but the MAF was on backwards 
I have custom tuning with the James with the Predator. When I start it, it idles fine but if I give it any gas the rpms shoot up to like 3K for 10 seconds or so then it plumments spits and backfires and wants to die. I can keep it running and sometimes it will idle sometimes it will jump back up to 3K. (I'm giving it gas at first to get it to idle.)
Also when driving down the street (all I've done) it will go up in rpms during a shift not down. So I put the clutch in to shift and the rpms jump up not drop.
Does this sound like a tuning issue or something mechanical???
I have custom tuning with the James with the Predator. When I start it, it idles fine but if I give it any gas the rpms shoot up to like 3K for 10 seconds or so then it plumments spits and backfires and wants to die. I can keep it running and sometimes it will idle sometimes it will jump back up to 3K. (I'm giving it gas at first to get it to idle.)
Also when driving down the street (all I've done) it will go up in rpms during a shift not down. So I put the clutch in to shift and the rpms jump up not drop.
Does this sound like a tuning issue or something mechanical???
Custom tune should not produce those problems. It has to be something in the install that is not right. I would find out if having the MAF on backwards (even for a short time) would hurt the MAF. Can you 'borrow' a stock MAF from a fellow fbody owner/friend and try it again?
I would first reset the PCM and reload the tune, then try again.
If it is backfiring out the exhaust, it means that the cam timing is off. (Hopefully not retarded by one tooth of the cam gear during the install)
I'm really guessing cuz I've been out of the game too long. Hopefully others will chime in and can re-educate me as well.
I would first reset the PCM and reload the tune, then try again.
If it is backfiring out the exhaust, it means that the cam timing is off. (Hopefully not retarded by one tooth of the cam gear during the install)
I'm really guessing cuz I've been out of the game too long. Hopefully others will chime in and can re-educate me as well.
Last edited by Proud2bSS; Apr 6, 2004 at 06:33 PM.
Oh not taken as a flame at all. Its possible although the MAF was put on by a VERY knowledgable person Late into the install 
Mistakes happen.
The wierd thing is the custom tune will move it up and down where it does it..I've had 3 now..
Will the MAF from my 98 fit on my 01 I could alway try it?
Mistakes happen. The wierd thing is the custom tune will move it up and down where it does it..I've had 3 now..
Will the MAF from my 98 fit on my 01 I could alway try it?
Sorry, I keep editing my prior post...it's different again.
Not sure about the inter-changability of different year MAFs, but I doubt it.
Do you still have the Predator 'box' tune? You could try loading that. The car should still work with that tune. It would be real rough, but it should not be that bad that it would surge and back fire. I have read where the TR224 cams are driavable, but a custom tune brings them to life a bit more. A 232/230 is not that much more....
Not sure about the inter-changability of different year MAFs, but I doubt it.
Do you still have the Predator 'box' tune? You could try loading that. The car should still work with that tune. It would be real rough, but it should not be that bad that it would surge and back fire. I have read where the TR224 cams are driavable, but a custom tune brings them to life a bit more. A 232/230 is not that much more....
Give it a good 30 min to an hour. There are also PCM/ECM reset instructions that I have used before:
Instructions on How to Reset the LS1 ECM
Submitted by: Scott Harroff
This is intended to reset that aggravating 'Service Engine Soon' light so many of us seem to see. The light is normally set due to a loose gas cap or a high frequency error on the mass air flow sensor in front of the intake manifold. If the light persists, you may want to have you car checked by a GM dealer. It may be a good idea to remove your K&N air filter, and replace it with the stock filter or equivalent before your visit to the dealer. Dealers, in the past, have been known to blame the MAS error on excessive oil in the K&N leaking onto the MAS. If the fuses aren't removed in this procedure, the codes will be stored in the ECM until the fuses are removed, or the dealer clears them with a scan tool. Rumors have it that stored codes retard timing and spark ignition which will hender the performance of you LS1.
1. Turn key on but don't start car.
2. Pull PCM BAT and PCM IGN fuses in engine compartment.
3. Wait a few minutes.
4. Turn ignition off.
5. Replace fuses.
It will take the car a while to relearn the fuel and timing curves so don't worry about a temporary performance loss.
Disconnecting the battery will erase the tables for the prior LTFT's, etc and resort back to the base mapping.
Instructions on How to Reset the LS1 ECM
Submitted by: Scott Harroff
This is intended to reset that aggravating 'Service Engine Soon' light so many of us seem to see. The light is normally set due to a loose gas cap or a high frequency error on the mass air flow sensor in front of the intake manifold. If the light persists, you may want to have you car checked by a GM dealer. It may be a good idea to remove your K&N air filter, and replace it with the stock filter or equivalent before your visit to the dealer. Dealers, in the past, have been known to blame the MAS error on excessive oil in the K&N leaking onto the MAS. If the fuses aren't removed in this procedure, the codes will be stored in the ECM until the fuses are removed, or the dealer clears them with a scan tool. Rumors have it that stored codes retard timing and spark ignition which will hender the performance of you LS1.
1. Turn key on but don't start car.
2. Pull PCM BAT and PCM IGN fuses in engine compartment.
3. Wait a few minutes.
4. Turn ignition off.
5. Replace fuses.
It will take the car a while to relearn the fuel and timing curves so don't worry about a temporary performance loss.
Disconnecting the battery will erase the tables for the prior LTFT's, etc and resort back to the base mapping.
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LOL I was like "what why does it keep changing "
I think I got the problem reading the predator it the Map pressure didn't move from 13.3. Looked at the connector and one of the wires is out. Off comes the intake manifold. I think after this though I'll have it licked! Opps probably shouldn't have said that....
"I think I got the problem reading the predator it the Map pressure didn't move from 13.3. Looked at the connector and one of the wires is out. Off comes the intake manifold. I think after this though I'll have it licked! Opps probably shouldn't have said that....
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Verdad Gallardo Yeah. I was typing, saving, then saying to myself "Is that going to **** him off?", then editing. pretty much a long day already......
Good thinking to watch the real time data on the Predator. Sometimes those little 'birds' (you know...that voice that says "hey, try this") know what they are talking about. And don't lick that loose wire while the motor's running! LOL
Let us (maybe me, since I'm the only one posting in here) if that takes care of it. It always pays to check everything backwards to catch any 'oopses'.
Good thinking to watch the real time data on the Predator. Sometimes those little 'birds' (you know...that voice that says "hey, try this") know what they are talking about. And don't lick that loose wire while the motor's running! LOL
Let us (maybe me, since I'm the only one posting in here) if that takes care of it. It always pays to check everything backwards to catch any 'oopses'.
LOL I know what you mean on the pissing off thing but with me you never have to worry about it I KNOW I'm a clueless dumbass so someone telling me doesn't offend at all 
I CAN'T believe how bad it ran because of this I was SERIOUSLY worried about P\V clearance and Valvetrain geometry!!! It really seemed like a vavles were not closeing (you have to read my post in internal tech on the first problem)
Good news the heads don't have to come off and the problem is relatively easy to fix. Unfortunately GM doesn't sell pigtails I can splice in so I'm going to have to fix this connector.. Oh well I'll get good at taking off the intake manifold
Thanks!! I'll update all my frantic posts when this is all resolved. I hate searching posts and you KNOW they fixed it but it doesn't say how!
I KNOW I'm a clueless dumbass so someone telling me doesn't offend at all I CAN'T believe how bad it ran because of this I was SERIOUSLY worried about P\V clearance and Valvetrain geometry!!! It really seemed like a vavles were not closeing (you have to read my post in internal tech on the first problem)
Good news the heads don't have to come off and the problem is relatively easy to fix. Unfortunately GM doesn't sell pigtails I can splice in so I'm going to have to fix this connector.. Oh well I'll get good at taking off the intake manifold
Thanks!! I'll update all my frantic posts when this is all resolved. I hate searching posts and you KNOW they fixed it but it doesn't say how!