Top end swap done....rough idle and other problems

[The AntiRice]

i just got done putting the top half of my motor together yesterday and now ive got a rough idle and when i stab the gas pedel it bogs down to about 600 rpms and then comes back up. it also likes to bog and die when i start out from a stop forward or reverse unless i rev it up a bit first.

heres a list of whats been done:

track heat upper and lower intake manifolds
24# injectors
75mm maf matched to the 24# injectors
bbk fpr
bbk equal length ceramic headers
msd drop in billet dizzy
bbk 70mm tb
egr, smog pump, and purge can delete(these were done with the ron morris motorsports delete kits)
tfs tw track heat heads

the following mods were already on the car when it was running fine before the above parts went on:

bbk fenderwell intake
2.5in off road h pipe
msd wires
msd coil
bbk underdrive pulleys

edit: also not getting any codes. other thoughts are that i might have a vacuum leak somewhere but that would have to be one hell of a vacuum leak right?

 

[jrichker]

Beg, borrow or rent a vacuum gauge. At 1000-1200 RPM you should see 18"-21" of vacuum.

 

[The AntiRice]

yeah i was thinkin i should do that. if its not a vac leak any other ideas?

 

[ls1beater4eva]

ok does it feel like its missing when u rev it? If so doubel check your valve lash and make sure you dont have any to tight or to loose

 

[jrichker]

yeah i was thinkin i should do that. if its not a vac leak any other ideas?

Only the obivous...

See "Surging Idle Checklist for help with all your idle problems. The first two posts contain all the updates to the fixes. I continue to update it as more people post fixes or ask questions.

 

[SPEEDYLIFSAVR]

Check your plug wires , wrong plug , arcing on header etc .

When I did my top end I had a similiar problem , ended up being my CAI , it was an underhhod style and MAF was getting fan wash from radiatior and alternator . Changed to fenderwell and problem solved , you can also try "clocking" your MAF .

 

[cenok is family]

ok does it feel like its missing when u rev it? If so doubel check your valve lash and make sure you dont have any to tight or to loose

i'm having this problem too....how do i check my valve lash?

 

[1992mustangLX]

I am doing a top end swap as well and was told it was neccasary to get a bigger fuel pump when doing these modifications, with the bigger injectors etc.. just a thought. Good luck.

 

[93lxdm78]

Welcome to the club brother

Good old track heat top ends

http://forums.stangnet.com/showthread.php?p=6952543&posted=1#post6952543

 

[jtfairlane]

What is your fuel pressure set to? You have a BBK AFPR, what did you adjust the pressure to? If it is way out of range, which it most assuredly will be if you did not adjust it, your car will run like crap.

 

[ShortThrow50]

set base idle, set tps. Set ur base idle a little hiher to about 800 rpm. Other than that, its not gonna idle 100 percent till u get a tune.

 

[93lxdm78]

Also trick flow doesn't give great instructions but don't reuse your old plugs you need to use auto lite's with the 3/4 inch reach I forgot the part number I think they are like 3924's but I would double check with trick flow.

I learned that lesson the hard way