What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Engine missing after x-pipe install"?

Y

Yo

1/2 ton status
Joined
Nov 28, 2009
Posts
123
Reaction score
0
Location
Dallas
Hey all,

Weird little situation I have here. I did some work to my truck yesterday, including installing an H pipe into my dual setup. I also found another ignition power lead for my electric choke, so I finally got that working right.

After I did the work on the truck, it was missing under load, like I had a plug wire arcing out. I have had issue with plug wires arcing before, but resolved it by installing a different design header w high temp wrap, and moving to all 90* boots; since then my truck has been perfect.

I noticed my 12v. choke lead wasn't working. I have a 91 truck running a carbed 350, so I walked around looking for 12v switched ignition wires and realized the injectors have switched ignition leads running to them. Since all my EFI stuff is disconnected and set aside, I spliced into one of these leads to use for my choke. Could this be an issue? Volt meter gave me 11.4 v when I measured it.

Otherwise, would I need to make any A/F adjustments on the carb after adding an H-pipe?

Thanks for any suggestions.
 
The H-pipe only evens out exhaust pressures between the banks, so I would see no cause of a mis-fire with that installed.

It says you are running a carbed 350? Then you mention injectors. Kind of confused what you mean here.
 
Yes, carbed motor swapped in, so there's still wiring harnesses for EFI etc.

I used the 12v switched lead to one of the wires on the unused injector harness to wire up the electric choke. I was wondering if that could cause some sort of weird electrical scenario that could contribute to my problem.
 
I wouldn't think, unless you are hooked up to a wire that isn't hot all the time and then your choke slowly closes after the engine is warmed up. Maybe something like the EGR or IAC. Plus most of those components don't have full 12v, they are usually only 5v, which would also cause your choke to not open

Try running the choke wire to a switched ignition wire. When the key turns on the wire will get power and stay on till the key is off.
 
The injector harness is a switched 12v, that's why I used it. Engine is a ZZ4 so there's no EGR on there. The wire I used had a steady 11.4V when the ignition was switched on, zero when off, so it's not a constant.

I think I'll just give the wires a once over to see if there's any arcing I may be missing. I get on the throttle and it pops and goes silent for a split second. Really sounds like something is arcing under the hood.
 
I have an 86 with the 305 4bbl. What did you have to do to hook the headers up? I have them in, but when I went to install the cats, it looks like the cross member for the transfer case is in the way. Will a lift fix this problem? I will be putting a 12 inch lift on ot later, but this header thing is driving me nuts.
 
If the choke is not opening all the way the engine will pop and lose all power under a load. Make sure your choke is opening fully.
 
I'm np whiz on fuel injection,but I think the injectors are not "on" all the time,they are triggered by the crank sensor or module ,so they flash on and off in proper sequence to fire each cylinder...yes,you now no longer have a crank sensor or a module that triggers the injectors,(assuming your older carbed engine has HEI)--but hooking one of the injector wires to the choke is grounding that wire,and it could screw up the ignition if you still have an ECM installed and hooked up to run the other stuff on the engine..I would find a spot in the fuse box with 12V only in the "ON" position and run a new wire to the choke and then see if it still skips...
 
I'm not really paying attention to this thread cuz it brings the "wtf, back from the dead" thing, but injectors are ground fired... but it still would be much easier to just new wire it like Bob mentioned.... I'd be concerned about amp draw on an injector wire if it's now being run to a choke.. talking 18 g for injector wires iirc, and probably 14 for a proper choke wire..
 
wouldnt it be simple to see if it is your problem and just UNHOOK the wire you hooked up:dunno: It worked fine before you said so unhook it and see what it does.. I had a 350 carbed do the exact same under load missing. ended up being the switched lead going to the coil was tapped into to run the electric fuel pump the PO put in. Robbed power from each other when under load
 
I read this as you lost an entire engine after installing an exhaust... I need to quit drinking...carry on.
 
You must log in or register to reply here.

Latest Posts

Top Bottom