Ok, truck running ok. Built new motor due to thrust out. Fairly stock build on a 92 bronco 5.0. Put gt40p heads on and an E303 cam in. It has a low rpm surge (200 to 5-600) if it will stay running. Tried finding vacuum leaks with no find, clean iac and reset ecu. Replaced iac and reset ecu. Will run better with a vacuum leak. Surge will go away if timing is retarded below 0. But no power or throttle response. I'm at my last bit of hair on my head. Oh n I've been through a lot of other threads with surge problems n trying that stuff, but it seems all of them have a higher rpm surge. Thanks for any input.

 

A surging idle is what you're gonna get with that cam and the SD EFI system

 

So it's a MAP vacuum problem caused by cam ?

 

And if so, then what does the ecu need besides the tips signal for the trans to shift?

 

Yeah that cam doesn't produce the amount of vacuum or as stable a vacuum signal at idle as the PCM is expecting. Trans shifting isn't directly related to that but yes TPS and vehicle speed are necessary for correct trans shifting along with a few other things like the T-case range switch and the trans MLPS as well.

 

Well, I think I've made the choice to put a carb on, is why I asked. I know there's stand alone ecu's out there, but I'm kinda tapped out for now. I know my light will be on for some sensors not being plugged in. I can get a Tps for my carb. I have a roller cam distributer for a carb motor or do think it will be ok to run the stock one. Only thing that won't be hooked up is the fuel injectors and egr. Either way sounds ok to me, just don't want to go get an aod and build it to put in right now. Like I said, funds are low. Oh or would putting a mass air meter in help? I have some fox body harness, ecu and other stuff.

 

Or would retarding the cam 2/3 degrees help?

 

Ok, got my hands on a way1 ecu out of a 95 bronco and I pulled a complete harness from a 95 f150. Looks good to ecu, but may have to move some terminals/wires in connectors to trans and maybe in c202 and c295 to inside cab. I have aldata at work. Showed me those connectors on a 95 f150 but could not find the connector view for the 92 bronco. Anyone have access to that? Or if know any changes need to be made.