I need help, I just finished my 3400 swap, problem iam having is when starting the car it sputters than surges to 3000 rpm and stays there, the specs on my cam are lift intake 268, exhuast 268, lobe seperation 113, duration at .050 intake and exhuast are both 212, I am really stumped and dont what else to check, I already repulled the timing chain cover off and doubled checked the timing, crank dot is at 12 oclock and camshaft mark is also at 12 oclock with the cam dowel pointing towards 9 oclock also made sure lifter preload is ok since i had to use custom pushrods, also the this cam was reccommeded by compcams when i told them what is was doing and what is was in, it is a custom grind, but iam starting to wonder if the cam is my problem, I also have double checked and rechecked vaccum lines, pulled lower intake to see if it is leaking, butterfly valve on throttlebody is closed, my plugs are fouled, completely black, also performed compression check and everything seemed to be in spec, got readings from 155 to 170 psi, car ran perfect before swap, iam am currently running TG chip and jeff m crossover, any suggestions and help would be greatlly appreciated to you guys who have done this swap, Iam ready to get a stick of dynamite, :icon_twisted: should have stuck to the 260 h gm cam,
Have you pulled the lifter covers to make sure they are moving properly?
Can you send me a log to see what all is going on? Sounds like to me it is running pig rich. Did you change fuel injectors or the fueling system in any way?
running stock injectors right now and i did pull covers, everything looks ok, have laptop ,havnt baught cable to data log yet, this probably would be a good time to do so
Wow 3k on a new cam, hope you haven't already ruined the cam. :icon_sad: If you have the v covers I would mark the last 6 pushrods so when you do get it fixed you can make sure the lifter/pushrods are rotating.
Sounds like you have a massive air leak like a gasket out of place some where in the intake system. Spray break cleaner around everything and listen for a difference of rpm's. Include the entire TB.
Is this a top end swap?
Jud
yes complete 3400 swap, as soon as i started it up the first time it was sputtering at about 1500 rpm and then shot up to 3000 and stayed there, I was thinking the same thing about it sucking air from somewhere to but haven't got to check with spray yet, how else would it be able to jump to 3000 + rpm with the throttlebody butterfly completey shut,just cant wait to get it running to see perfomance gains i get, i also spoke to comp cams to get some input form them and they said that it was the computer that needed to be tuned to get it running right but from what I have read on this sight that is cannot be true, any input is greatly appreciated
sorry for not being clearer, just a 3400 top end swap :icon_lol:
Yea I got it. Top end 3400 with a flat tappet cam.
Did you do it with the motor in or out?
Check the ears on the ends of the UIM they break real easy. Lousy design. I know if you don't leave the front brace of the fuel rails the wire bundles are pretty tight in there.
Jud
Ya I will double check for cracks tommorrow, as far as the wires holding the intake up i made sure that they were not holding up the upper intake by removing some of the loom that the wires go in and taping them up nice, really helped alot, i did this after i found the out about the idle problem thinking that might be it, i even test fit it afterwards to make sure that it sat flush on the lower intake, judd do you think this cam is ok to run with the setup with no problems, thanks for your input, its really appreciated :icon_biggrin:
:icon_biggrin:Sorry forgot to mention that I did it in the car, cut hole in wheel well :icon_biggrin:
Glad to see somebody else is using the hole in the fender well trick. Where did you learn that? :icon_wink:
Did you clay the valves for piston clearence?
Did you use Cranes cam break in oil?
With that cam I am guessing Advertised duration is in the 260's. That OK. You may want to put a heated 02 on it if your eyes start burning on cold mornings. Leans it out pretty quick. The 113 overlap should give you a good idle. You may notice a very slight lope, if any at all. It's a moderate cam and should work well.
Couple more things to look at. I don't know what your using for TPS and IAC. Take the TPS off and just let it hang by the wires.
Use your old IAC and MAP seeing how it ran good before.
Jud with one d.
Sorry about the extra d, trying to type to fast, I did reuse old IAC and map, of course you cant use the TPS, but i did already try unplugging the tps to see what would happen and got no change, the duration is 265 on both intake and exhuast at .006 like you said and here are all the other specs, valve timing intake OPEN: 3 BTDC, EXHUAST OPEN 43 BBDC, INTAKE CLOSED 35 ABDC. EXHUAST CLOSED 11ATDC, cneterline is 109, I am thinking it has to be a leak somewhere, just wish I could find it, are the specs on your cam similiar to these, just curious, I talked to compcams after finding my problems and they said the cam should be fine and that the computer just needed to be tuned, :laugh:, if these specs for the cam look funny let me know, thanks for the info
Brandon
finally figured out my problem, egr valve gasket not sealed and sucking major air, just have some finishing touchs to do, seems to run good
Like I said a vacuum leak...oh wait that was Jud! :laugh:
No Kenny I said a massive leak. Had to be a gasket missing or out of place to make it rev that high. Wasen't just a line unless like the pvc valve hoses. Just went through it, Was trying to run 12 psi and blue the pvc hose off. :icon_redface: It would not idle under 2200 rpm. Embaressing when you come to a signal with lots of cars around.
Bigger the hole the higher the idle. Sucked a TB gasket in once and got a 3300 Idle couple years ago. Right aginst the rev limiter. Needless to say I ruined the cam with that screw up. Had just put it in. Ah life is a b itch when playing with thes cars. Live and lern. I have lived enough learning.
From now on I'll just repalce the whole damn motor. :icon_lol: :icon_lol:
Jud