brobradh77 Posted October 4, 2007 Report Share Posted October 4, 2007 As most of you know I put a radix, GT2-3 cam with 2.5* advance, Lt's, No cats, 3.2" pulley. The problem is I'm making no power and at WOT the exhaust starts popping and I knnow have an emission code for my 02's that were deleted so they shouldnt be showing up. I put it on a dyno the other day and it was only making around 275 RWHP with all the popping so i'm losing a ton of HP somewhere. The truck falls on its face. I have ran a scan at WOT and here are the results Timing 12.8 Air/Intake temp 126 MAF 10775 hz, 360 gm/sec Air/fuel stays about 11.9 on my wideband and on the dyno sheet at WOT Fuel pressure is at 64 Boost is staying 5-6 where it should be. all seems to be where they are supposed to be. Any ideas? Thanks in advance. Quote Link to comment Share on other sites More sharing options...
rivierakid55 Posted October 4, 2007 Report Share Posted October 4, 2007 thats a bummer brad. hope you get everything worked out real soon and get some good numbers down! Quote Link to comment Share on other sites More sharing options...
Black2003SS Posted October 4, 2007 Report Share Posted October 4, 2007 Brad, what plugs are you running and what are the gaps? Your timing is severly retarded which screams spark knock. I am running between 16-19 degrees of advance at WOT with 0-2* KR. That is a starting point for you. Have you scanned for KR and seen how much KR you have? You need someone with HPT or LS1edit to get inside that truck and see whats going on. Also, your IAT's are slightly higher, but you are in Texas compared to where I am. Quote Link to comment Share on other sites More sharing options...
Black2003SS Posted October 4, 2007 Report Share Posted October 4, 2007 One more thing, did this problem originate since install or did it just appear? If its been since install, it was an installation error. Quote Link to comment Share on other sites More sharing options...
brobradh77 Posted October 4, 2007 Author Report Share Posted October 4, 2007 One more thing, did this problem originate since install or did it just appear? If its been since install, it was an installation error. I just got off the phone with magna charger and they think its a cam installation issue. maybe it wasnt lined up cpmpltetely when they it was installed. It originated since install. Quote Link to comment Share on other sites More sharing options...
Black2003SS Posted October 4, 2007 Report Share Posted October 4, 2007 Its the cam more than likely. Why was it not installed TDC? Quote Link to comment Share on other sites More sharing options...
sprayed99 Posted October 4, 2007 Report Share Posted October 4, 2007 The cam was i installed at TDC. Quote Link to comment Share on other sites More sharing options...
Black2003SS Posted October 4, 2007 Report Share Posted October 4, 2007 I guess you did the install sprayed99? I know you guys changed the springs and everything on the heads right? If the cam was installed TDC, does it have a 2.5* advance on the grind? Is that the way the cam comes from lingenfelter? Good luck guys, this one is going to be hard to diagnos without seeing the truck. I would go over all of the vaccuum lines and clamps just to be sure one more time that everything is ok. Quote Link to comment Share on other sites More sharing options...
.justin. Posted October 4, 2007 Report Share Posted October 4, 2007 I just got off the phone with magna charger and they think its a cam installation issue. maybe it wasnt lined up cpmpltetely when they it was installed. It originated since install. Something to that effect is what I was thinking. Quite simpler than that, did you perform a crank relearn (perhaps using Steve's EFILive) when you installed the tuned PCM? Could accidentally over-torqued rockers be an issue? Would be very easy for you to re-check them... 22 ft-lbs is all they need Quote Link to comment Share on other sites More sharing options...
sprayed99 Posted October 4, 2007 Report Share Posted October 4, 2007 The problem I think is the stock plugs. We need the install the TR6 plugs and see it changes anything. Quote Link to comment Share on other sites More sharing options...
misterp Posted October 4, 2007 Report Share Posted October 4, 2007 (edited) I highly doubt the problem is a camming issue; I could be wrong but I seriously doubt it. I might have some outside help for you Brad - do you have logs of the truck on the dyno? Since you said earlier the PCM is pulling a lot of timing, a suggestion - I noticed that your passenger header is very close to the frame rail, take a look at the front tube where the unused/capped air injection tube is, there is like less than 1/8" clearance; I would take a big-assed wrench or prybar and gently pursuade it over until you have 1/2" clearance there. If the AFR is rock-steady at 11.9 the whole time then that is perfect for the load (boost) you are running; I would experiment by swapping your original PCM in and making a run to about 3000-3300 RPM and see if it is backfiring. I am not bothered with making low power, because your timing is way low; what has me stumped/worried is the popping/backfiring. What was your fuel mileage like on the drive back home? stock? better? worse? Need more clues... Mr. P. ahh I see Justin chimed-in. Edited October 4, 2007 by Mr. P. (see edit history) Quote Link to comment Share on other sites More sharing options...
SSThunder Posted October 4, 2007 Report Share Posted October 4, 2007 I thought stock plugs with a SC is a Quote Link to comment Share on other sites More sharing options...
.justin. Posted October 4, 2007 Report Share Posted October 4, 2007 (edited) 12.8* of timing isn't the cause of the lack of power though. When I dyno tuned my truck, the power pulls I made at the end of the day were with 150* IATs, 230* ECTs, 11-13* of timing and power was still over 400hp with the stock cam. Fuel is good, spark isn't horrible (assuming it's correct), there is something else going on. I thought stock plugs with a SC is a Not a big deal as long as they're gapped around .035" with the stock coil dwell times. With longer dwells, can increase that a bit. Edited October 4, 2007 by .justin. (see edit history) Quote Link to comment Share on other sites More sharing options...
sprayed99 Posted October 4, 2007 Report Share Posted October 4, 2007 The problem I think is the stock plugs. We need the install the TR6 plugs and see it changes anything. Quote Link to comment Share on other sites More sharing options...
misterp Posted October 4, 2007 Report Share Posted October 4, 2007 BRAD - If you want to verify a camming/valvetrain issue, do it the old-fashioned way: use your new-fangled vacuum guage. On a healthy motor at idle the vacuum needle should be rock steady, if it is wavering at all you have a valve not closing. What is the vacuum behavior like at idle, what does the guage read and is it steady? I don't think there is a valvetrain issue, that engine idled way too smooth IMO. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.