loosing sleep over my 1998 454 -compcams timing issue

[camminchevy]

98 chevy 7.4L compcams towing cam part#01-412-8(37) timing at 1200 rpm is 25* sapose to be 0*-2* to be in spec DTC p1345 cam/crank correlation can pcm re programing help my timing ive tried distributor a tooth over both directions towing cam but no low end power.2000+rpm power comes on like a light switch any one with an educated guess please help-CamminChevy

[schwoch1]

Can you post a log to your cal for us to look at???? If you are throwing a P1345, you have to get the distributor back where it needs to be to get the cam/crank relationship back in line. Just turning the distributor in hopes of adding spark advance don't work anymore :) A Few of the 454 cals I have seen are super conservative on ignition timing all over the board. Get us a cal to look at and maybe someone can make a suggestion!!!

Mike

[schwoch1]

Plus, if someone could get this into the forum that it really should be in that would probably help.......
Really has nothing to do with shipping....

Mike

[joecar]

Plus, if someone could get this into the forum that it really should be in that would probably help.......
Really has nothing to do with shipping....

MikeMike,

I'm sorry that flew over my head, I lost context, what are you saying (if I can, how may I help...?)...?

[schwoch1]

Mike,

I'm sorry that flew over my head, I lost context, what are you saying (if I can, how may I help...?)...?

I think that if we could move this thread into the vortec forum, he may get more help than in the SHipping and purchasing forum....

Mike

[joecar]

Ah, of course, I really didn't wake up out of deep sleep today, did I... :doh2::doh2::doh2::doh2:

[pullincrazy88]

The high timing your seeing at low rpm is normal for how these motors are set up, is this at WOT or just cruising? Mine runs quite a bit of timing under light throttle and at idle. I really don't think you would want to put that little of timing into the motor especially when your trying to add a cam. Got to remember these truck are pretty heavy to its gonna take a little bit to get them rolling if your running a stock converter. I have a comp cam extreme energy cam shaft in my vortec 454 and it seems to like more timing crusing then little to none, and am getting 28 degrees at WOT as soon as I punch it but im also running a 93 octane tune. What are you running for over all timing in higher rpms under WOT.

[camminchevy]

The high timing your seeing at low rpm is normal for how these motors are set up, is this at WOT or just cruising? Mine runs quite a bit of timing under light throttle and at idle. I really don't think you would want to put that little of timing into the motor especially when your trying to add a cam. Got to remember these truck are pretty heavy to its gonna take a little bit to get them rolling if your running a stock converter. I have a comp cam extreme energy cam shaft in my vortec 454 and it seems to like more timing crusing then little to none, and am getting 28 degrees at WOT as soon as I punch it but im also running a 93 octane tune. What are you running for over all timing in higher rpms under WOT.

What did you do about your check eng light and does your 454 seem to run rich with your timing I think we have the same compcams towing cam part #01-412-8(37)? I have a low stall torq converter aswell mine truck starts pulling as soon as you let off the brake. My timings around 28° wether im idleing or driving it varies from around 19°-28° timing. I rebuilt my 7.4 just about every thangs new except distributor. I ordered a new billet distributor since the one I currently have in it has play when you wiggle the rotor other than Smelling rich the check engine light bugs and I have no cats.......any ways are you having a dtc p1345 an can it be eliminated by efilive reprograming

[pullincrazy88]

As someone else stated above the code is being set by your distributor being a tooth or to off from the correct instilation, you need to find the correct position for the dizzy to get it to turn off. It will run and start fine still because the computer will correct it. But as for running rich at idle that isn't a timing issue that's going to be all to do with commanded AFR and your fuel trims. Is there any modifications that have been made to the tune file yet? And I'm not sure if it's the same cam grind I'd have to look back through my truck info.

[pullincrazy88]

And yes you can get a quality aluminum bodied distributor actually off eBay for around 69-80 bucks instead of the 200 or what ever it is through summit or Jegs. That's what I am running in mine

[L31Sleeper]

Keep in mind on these engines the distributor position has NOTHING to do with engine timing.
It's sometimes difficult for people to get their head around that.

[schwoch1]

Keep in mind on these engines the distributor position has NOTHING to do with engine timing.
It's sometimes difficult for people to get their head around that.

Yep.... some people still are thinking back in the stone ages. "Back when I was a kid in the old days, when you turned the distributor, it changed the timing!!!"
This system just looks at the cam and crank sensor, and figures out where the spark needs to be, within reasonable mechanical and electronic limits!!! All timing on this engine/ computer system is computer controlled, all the distributor does is route the spark where it needs to go!!!


any ways are you having a dtc p1345 an can it be eliminated by efilive reprograming
yah, use the scanner and moniter the pid for cam/crank error and turn the distributor (while above 1100RPM) until the error is 0 degrees (+or - 2 degrees). Just don't go and shut the code off, that will get you nowhere!!!

Hope this helps
Mike

[L31Sleeper]

As far as Comp Cams is concerned it's just another big block roller cam, but I'm starting to think
that the cam gear needs to be indexed. A friend of mine has the exact same engine and could
not get the offset correct, after about 10 stabs of the distributor he gave up. It was a situation
where one tooth in either direction is too much.