Vortec 454 Help Needed

1320-camaro-383 · January 23, 2009

Hopefully someone can help,I am at a loss.I have a 97 3500 with the vortec 454.I was towing up a hill and it started running real rough,like it was missing a cylinder.I replaced the complete ignition system,plugs,wires.cap rotor coil module distributor.I changed the fuel filter,the injectors are only 6 months onld but I removed them and cleaned them,cranked the engine over to make sure each one is spraying and all looks fine there.The fuel pressure is almost 50 psi,the back pressure is 1.5 psi at 2k rpm,I did a compression test all cylinders have 135 psi except one has 125 and one has 140.I removed the new plugs,all look perfectlly clean except a little heat discoloration but one was slightlly black,not bad but not as clean as the others.I swappped that one with another cylinder to try to isolate a posible problem,I wont know until I drive it again.There were 2 codews,one for a o2 sensor and one for bank 1 rich.I cleared them and drove it for around 10-15 miles and they have not come back on yet.The cam retard was off,it was at 7-8 but when I replaced the distributor today I rest it back to 0.I plan to remove the valve covers to look for maybe a broken valve spring but other than that Im at a dead end.I just dont know what else to test or check.It idles ok and if Im not on the gas going down the highway is seems ok but when I give it gas especially when taking off from a dead stop the truck shakes and has no power.Any ideas?Please help.

grampadirt · January 23, 2009

I wonder if the ignition module is going bad,might be something to check..how 'bout the EGR valve?

1320-camaro-383 · January 23, 2009

Hey,Thank you for your help.The ignition module is brand new,the egr seems to be ok.Its not throwing any codes.I will have tot ry to find the values it should be at and compare them on my scanner.

L29er · January 23, 2009

50 psi is to low for fuel pressure, try replacing the regulator, if that doesn`t fix it get a new pump. should be 55-60 psi running and flow at least 1 pint in 60 seconds. your back pressure is getting a bit high too.

66nova · January 23, 2009

I can't be of much help, because you have replaced most of what I would think of with out seeing/hearing the truck, but for all of my engine stuff I usually post over on Speed Talk. Some of the worlds top engine builders frequent that site.

Speed talk and GM-Trucks are the only two websites I really use because of the amount of great info and great guys.

SpeedTalk.com

Good luck and lets see some pics of your truck and that Camaro.

MarkD · January 23, 2009

Vacuum leak? have you tried covering the intake and revving to listen for whistle? (something my mentor used to do first on any rough condition)

1320-camaro-383 · January 24, 2009

Thanks for all the advice guys.I can not find any vacume leaks.I thought 50 psi was good on this engine.I thought anything over 45 was good.The fuel pump is only 3 months old but I will explore that as a possibility.I wish my fuel pressure gauge had a longer hose so I could see what it is driving.It holds stedy when I rev it up but that doesnt really simulate the amount of fuel it dumps under acceleration.Another thing is if it had low fuel pressure I think it would run lean and the scanner is showing it at 14.7 and toggling back and forth rich/lean.I thought 8 mpg was bad which is what I was getting,Im closer to 5 right now which sucks because this truck is my money maker.

Hey 66 nova,thats a nice car what does it run?I tryed to put in a couple pics of my truck and camaro but Im not sure if I did it right.The camaro is a 91 with a 383,edelbrock rpm cam,heads,intake etc,Hyperutectic pistons.1.6 roller rockers,150 shot of nitrous,10.5 to 1 compression bg 750,brand new 9" moser rearend,pro built 700r4 with 3000 stall,6 point cage,sphon drag sway bars,frame connectors etc etc etc.Now I just have to get it to the track.

dietz4ibanez · January 24, 2009

You mentioned something about the distributor and just to clarify you pulled it and replaced it back in its corretion position.. Or did buy a new one to replace the old??

My 99 was having the same problem... I called my uncle who was a head mechanic at a chevy dealer in Ohio...

He said that the first thing that he would check is the gear on the bottom of the distrubutor shaft...

When I took it to my mechanic, I told him that and he said that it was the plenum... And while they fixed that they replaced the fuel injectors....

The problem still persisted... They checked the gear like I told them too and some of the teeth on that gear were worn down to the width of a razor blade.... They replaced it...

And that did the trick...

1320-camaro-383 · January 24, 2009

I tryed to put a couple pics of the camaro for you but it keeps saying failed due to file size too big.Im not that computer savvy.

dietz4ibanez · January 24, 2009

I tryed to put a couple pics of the camaro for you but it keeps saying failed due to file size too big.Im not that computer savvy.

Go to www.photobucket.com ... Register an account there and you can upload the picture on there and post the link on the site!

66nova · January 24, 2009

Thanks for all the advice guys.I can not find any vacume leaks.I thought 50 psi was good on this engine.I thought anything over 45 was good.The fuel pump is only 3 months old but I will explore that as a possibility.I wish my fuel pressure gauge had a longer hose so I could see what it is driving.It holds stedy when I rev it up but that doesnt really simulate the amount of fuel it dumps under acceleration.Another thing is if it had low fuel pressure I think it would run lean and the scanner is showing it at 14.7 and toggling back and forth rich/lean.I thought 8 mpg was bad which is what I was getting,Im closer to 5 right now which sucks because this truck is my money maker.
Hey 66 nova,thats a nice car what does it run?I tryed to put in a couple pics of my truck and camaro but Im not sure if I did it right.The camaro is a 91 with a 383,edelbrock rpm cam,heads,intake etc,Hyperutectic pistons.1.6 roller rockers,150 shot of nitrous,10.5 to 1 compression bg 750,brand new 9" moser rearend,pro built 700r4 with 3000 stall,6 point cage,sphon drag sway bars,frame connectors etc etc etc.Now I just have to get it to the track.

Thanks man! I have a lot of fun with it and drive it all over the place. Currently, it runs 10.80's @ 124.XX. That is on all motor. I built the car for NOS and it is really not set up to run motor (wrong cam, gear, convertor, etc). It will have a 150-200 shot on it in the near future. I really need to do some suspension work to it first, I have to be at a good track for it to hook as it is. My goal is to get it into the mid 9's.

Your camaro should be a fun ride. With that 700R4 it should leave pretty hard without having to have too much gear. I will keep my fingers crossed for you that it holds up. I haven't seen too many of them live with NOS and traction, but every now and then they suprise me.

Like stated above. Get a photobucket account and its really easy to upload photos and its free.

I look forward to seeing pics and hearing some times once you get them.

1320-camaro-383 · January 24, 2009

http://s658.photobucket.com/albums/uu301/1...ttonight009.jpg

http://s658.photobucket.com/albums/uu301/1...ttonight008.jpg

http://s658.photobucket.com/albums/uu301/1...ttonight007.jpg

http://s658.photobucket.com/albums/uu301/1...ttonight006.jpg

http://s658.photobucket.com/albums/uu301/1...ttonight004.jpg

http://s658.photobucket.com/albums/uu301/1...ttonight002.jpg

http://s658.photobucket.com/albums/uu301/1...ttonight001.jpg

Ok tell me if I did that right.That is a bad ass ride you have.With my hp (650 with the 150 shot) weight gearing etc I expect to run right about where you are.I know what your saying on the 700r4,I was running a 5 speed and after 3 trannys and 3 center force duel friction clutches later I decided to go auto.It held fine until I hit the fun button.I was goiung to go with a th350 but I have a detroit tru-trac system with 4:11 gears and it is a street car so I wanted the overdrive.I bought the tranny from a company in C.A called bow tie overdrives,they guarentt it to a 10 second quarter mile so time will tell.Two years ago I put that in alnog with the rear end and other toys and have only drivin it around 150 miles since,I work so much I just havent had the time to break it in before I bring it to the track.

Geez · January 24, 2009

Is the distributor cap itself contacting the upper plenum? What instrument or software did you use to set camshaft retard offset?

________________________________

Thanks for all the advice guys.I can not find any vacume leaks.I thought 50 psi was good on this engine.I thought anything over 45 was good.The fuel pump is only 3 months old but I will explore that as a possibility.I wish my fuel pressure gauge had a longer hose so I could see what it is driving.It holds stedy when I rev it up but that doesnt really simulate the amount of fuel it dumps under acceleration.Another thing is if it had low fuel pressure I think it would run lean and the scanner is showing it at 14.7 and toggling back and forth rich/lean.I thought 8 mpg was bad which is what I was getting,Im closer to 5 right now which sucks because this truck is my money maker.
Hey 66 nova,thats a nice car what does it run?I tryed to put in a couple pics of my truck and camaro but Im not sure if I did it right.The camaro is a 91 with a 383,edelbrock rpm cam,heads,intake etc,Hyperutectic pistons.1.6 roller rockers,150 shot of nitrous,10.5 to 1 compression bg 750,brand new 9" moser rearend,pro built 700r4 with 3000 stall,6 point cage,sphon drag sway bars,frame connectors etc etc etc.Now I just have to get it to the track.

Thanks man! I have a lot of fun with it and drive it all over the place. Currently, it runs 10.80's @ 124.XX. That is on all motor. I built the car for NOS and it is really not set up to run motor (wrong cam, gear, convertor, etc). It will have a 150-200 shot on it in the near future. I really need to do some suspension work to it first, I have to be at a good track for it to hook as it is. My goal is to get it into the mid 9's.

Your camaro should be a fun ride. With that 700R4 it should leave pretty hard without having to have too much gear. I will keep my fingers crossed for you that it holds up. I haven't seen too many of them live with NOS and traction, but every now and then they suprise me.

Like stated above. Get a photobucket account and its really easy to upload photos and its free.

I look forward to seeing pics and hearing some times once you get them.

1320-camaro-383 · January 24, 2009

Hey,its funny you should ask that.When I replaced the distributor to get the cam retard to 0 yes the front distributor terminal on the passenger side is touching the upper plenum.I used my dinosaur scanner to set the cam retard,its a otc/mac pathfinder enhanced.Before I replaced the distributor the cam retard was at 7-8 degrees.Once I replaced it and set it to 0 I thought I solved the problem because it idled much smoother and does seem to run better but far from where it should be.I think the cam retard being off was probably already like that,it never ran great since I bought it 8 months ago and I bought the truck from jack the hack.So please let me know why did you ask about the cap terminal?Do you have a idea whats wrong?Thanks