Engine won't crank after upper intake replacement

[johndallara]

Recently got a set of BBBs and replaced my stock upper intake w/the new one. Same throttle body, the DIS and other stuff was new from the rebuilt intake. Also replaced the plugs and wires w/ stock items while intake was off.

After replacing the intake, I couldn't get the engine to crank. Checked all the connectors, and hadn't grounded the intake properly. Re-tried, this time got 511 (ouch), 116 and 636 codes. Had a spare PCM, so I replaced it and this time got different codes: 11, then 663/611/6?, then 11 followed by 512. Also tried zero-ing out the computer by 30sec brake pedal w/ battery off, and the second set of codes persists.

Any ideas? Fuel pump is coming on, engine is turning over and engaging, is running roughly w/ backfiring through the TB and quitting when foot off the gas.

JD

 

[Mr Anonymous]

First, you're probably not reading the codes right, since they should all be either 2-digit or 3-digit codes, not a combination.

Your description in the title says it's not cranking, but then in your post you say it is cranking, so I'm a little confused. Is it cranking but not starting, or not cranking at all?

Double-check the ground path from the DIS to the intake to the firewall again, especially the two bolts that secure the crossover tube to the surge tanks. Also check to make sure you didn't disconnect or damage the CPS connector which should be attached to the forwardmost DIS connector harness on the inner side of the crossover tube.

 

[shoteen95]

^agreed^ I learned just how important that ground was when I painted my intake manifold. Not just the strap, but the bolts/brackets and surfaces they mount to should be bare metal. If not, the ignition seems to get all wonky.

the DIS and other stuff was new from the rebuilt intake.

So you're using the DIS off of another intake you recently acquired? Perhaps this DIS has been damaged?

 

[johndallara]

OK, checked the grounding again (OK to the firewall), and put back the heavy metal bracket on to the grounding post connected to the intake -- still no luck.

DIS module was from new intake, not from my running vehicle.

Checked the codes -- my first time reading these-- looks like they are:

116, 636 KOEO and 511

These are with the replacement D4U1 computer (original stock).

Not much luck so far. Engine still cranking but misfiring, stalling out.

Also replaced plugs and wires, and used Autolite double PP, could it be that simple ? wrong plugs? I read on SHOtimes these are not optimal but should work.

JD

 

[cougarman]

Just a thought, but when you replaced the wires, did you go by the firing order in the shop manual? I found out from this forum, that the manual is wrong.

 

[RAYJAY]

also did you didn't paint where the dis mounts did you? and did you also use the heat sink grease on the back of the dis ????

Jeff

 

[johndallara]

good thoughts. the DIS module is the one of the new intake, has not been removed. also I noticed the odd coil arrangement and left the firing order as it was on the car, rather than changing it.

have some motorcraft plugs coming along w/ another set of wires, am still suspicious of the autolite plugs, maybe this is the problem.

also had replaced the vacuum hoses w/ a new set that did not feel as stiff, wondering if the hoses are collapsing w/ vacuum loss resulting in problems.

looking as if the next step is re-pull the upper intake, replace plugs and wires, and new vacuum hoses all around, then retry.

JD

 

[JATRAMMELL]

Why not try the old DIS that you know works?

 

[SASHO91]

Agreed^^

then RE-CHECK your firing order....

did you use new gaskets for the intake to head gaskets? or are you re-using them...

 

[johndallara]

OK, much better.

Main problem was the upper intake -to- lower intake gasket was not seated properly, giving a significant vacuum leak. It think one of my seating pins was not quite sitting right, but a little jiggling helped. Tightened the engine down, and the engine started right up w/ the new manifold in place. Always the simple stuff first.

Still running a little rough at idle, but smooth w/ opening throttle. Maybe still a small leak somewhere, did use new intake gaskets on the replacement job -- this is with the original IAPB valve.

Thanks for all the help. Definitely learned a few things about this engine in the process.

JD