Bronco 5.0 EFI will not run unless way advanced. FIGURED IT OUT!!!

[sp71eb]

Hello, I was wondering if anyone else has had this problem. I did some google searching and founds lots of suggestions from people but no actual solid solutions. My rig runs but if you try to take any timing out of it under 20 adv it wants to die. It smells pretty rich also. I was in a hurry to get home after work today so I didn't dig into it too much. I did check for vacuum leaks and didn't find any obvious ones. And yes I did have the spout connector out. It seemed to run best around 25 to 30 adv. Some online answers were. Incorrect firing order (the engine has a b303 cam so I'm pretty sure its 351 firing order). Some said too much flow from pcv that is acting like a vacuum leak. Some said bad dizzy. Any help would be greatly appreciated.

 

[73azbronco]

go back to basics, make sure you really have TDC, then verify dizzy is stabbed to cyl 1. Vacuum leaks would make it lean. If this is a new build, check to make sure the TDC on the cyl matches TDC on the balancer and timing pointer is correct for front dress.
Smoke? Black, blue? Rough idle, popping when running, double check firing order?
Could be a bad dizzy as a last resort, did it work before or is it an unknown? Might want to swap it with another.

 

[sp71eb]

Yeah tomorrow I will verify tdc. Its not a new motor and has been ran with the cam in it by the previous owner. Not much smoke but what is there is rich gassy and light black. Idle is smooth and then you hear a sucking sound at the intake and she rough idles. I couldn't hear any pinging. I will dig into it and hopefully figure it out tomorrow.

 

[Broncobowsher]

Don't trust timing marks either. Mixmatch of damper markings and pointers can make them worthless. As will a spun damper ring.

Has this engine as it sits now ever ran right? That is did this problem suddenly happen? or is this the first time it has ran since putting it all together? I am trying to determin if we are chasing down something that was good and went bad or if we are chasing down a problem from putting parts in wrong?

Have you tried running with the MAF unplugged? That will put in limp home values into the MAF and if it is giving bad signals it will now bypass them and run without it. Old trick for diagnosing a bad MAF. MAF is also direction sensitive, you can't install them backwards. Double check the flow arrow on it.

 

[sp71eb]

I bought it from a guy with the efi harness/ computer. This is the first run for me. No check engine light on while running. I am going start diag tomorrow. I had thought about unplugging the maf but it is running pretty rough and seems to warm up quick so I haven't had lots of run time to figure things out. I will try as much as I have time for tomorrow. Hopefully it is something stupid that I overlooked.

 

[Sporto]

I agree with previous post. The dissy sounds like it is not stabbed correctly. Maybe a tooth off. I had this problem with my EFI conversion, and the system is so eager to get the engine started that it goes to great lengths to get it up and running (even poorly).

Do the old rag in the #1 cylinder method to determine true TDC, check your marks and re-stab your dissy making sure that the rotor is directly beneath #1 wire. This should get you close enough to start and then set to 10 degrees advanced with the SPOUT jumper out. The computer should take over from there.

I am running an HO setup with an old firing order engine, and I have never had any issues whatsoever with that. It starts and runs fine every time, but it did take me a few tries to get the distributor alignment right. I attached a picture of what my distributor alignment looked like when it was at TDC. The rotor points to the middle of the upper plenum between the two bolts. Also note the location of the TFI module in lower part of the photo, it should be somewhat aligned as shown too.

Good luck.

Rich

 

[ransil]

Pull codes

 

[Sporto]

Pull codes

Ya do that too! ;D

Ransil is known for his verbose and long winded posts. LOL! He is right though...

 

[baddad457]

Check the balancer to make sure the outer ring hasn't spun.

 

[KyleQ]

You have the wrong wire hooked up to crank - there is a wire that retards timing on crank, you probably have it hooked up to 12v constant.

I had the same problem for awhile too - do your manifolds glow as well?

 

[jw0747]

your distributor is a few teeth off #1. if you feel your timing marks are correct line up TDC and restab dist. make certain rotor is pointing at #1 at full bottom stab and not when gear teeth start to mesh.

 

[sp71eb]

Yep, Lug Nut Fixed it!

Well figured it out and she runs like a dream now. Some jack wagon(this guy) installed the plugs all one spot to the right. Moved them all over and now she purrs like a kitten....well a rumbley kitten. Thanks for all of the help and suggestions guys!

 

[Ourobos]

Sweet...

 

[KyleQ]

Good deal - always start with the easy stuff first!