Help me diagnose 408 problem
05-13-2007, 04:49 PM
#1
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Help me diagnose 408 problem
Alright. I got my 408 running last week. I am having random multiple misfiring. Its not just a code, the truck is shaking a bit more than it should at low RPM idle, but fine when I hold it at like 2000rpm+
My suspicion here is that the injectors I bought a while back are stuck or clogged... My possible solution: Buy new 42lbers and hope it fixes this!
Truck dies when put into any drive gear unless I hold it above 1000 RPM.
I have no idea why.
Other people's suspicion: Need to have my 3500rpm converter put in to solve problem.. I dont know much about converters, but this is what a couple guys have told me now.
I welcome all advice and suggestions!
I am holding off on ordering any parts until I know for sure the issues at hand.
I plan on just not driving for a few more weeks(summer break) then getting a new transmission installed and the fuddle converter I have on my shelf installed along with it.
Let me know what yall think it may be, and how I might solve this problem!
-Lurius
My suspicion here is that the injectors I bought a while back are stuck or clogged... My possible solution: Buy new 42lbers and hope it fixes this!
Truck dies when put into any drive gear unless I hold it above 1000 RPM.
I have no idea why.
Other people's suspicion: Need to have my 3500rpm converter put in to solve problem.. I dont know much about converters, but this is what a couple guys have told me now.
I welcome all advice and suggestions!
I am holding off on ordering any parts until I know for sure the issues at hand.
I plan on just not driving for a few more weeks(summer break) then getting a new transmission installed and the fuddle converter I have on my shelf installed along with it.
Let me know what yall think it may be, and how I might solve this problem!
-Lurius
05-13-2007, 05:07 PM
#2
could it be a spark issue. Coil packs? Plugs? wires?
if it were a fueling issue wouldnt the problem get worse under load?
have you checked your fuel pressure?
whats your idle set at, it may be too low for your cam!
i think its just a simple tuning issue.
if it were a fueling issue wouldnt the problem get worse under load?
have you checked your fuel pressure?
whats your idle set at, it may be too low for your cam!
i think its just a simple tuning issue.
05-13-2007, 05:12 PM
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I need a data logger damnit lol. I dont want to spend the 500$ on tuning software right now, i was hoping to wait until I got the truck driving to do that.
-Lurius
-Lurius
05-13-2007, 05:22 PM
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check all your coil and injector plug ins,make sure there in and in the right spot also make sure your plug wires are clicked in, if your injectors sat around for awhile they my well be pluggged it happens alot.Its probly somethig simple man.
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05-13-2007, 07:12 PM
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Its an ms3 cam from TSP, around .600" lift and 239ish/242ish durations.
Charlie tuned it, but being that im like 400 miles away we couldent do an in person tune just yet(or until I can drive her). I wanted to check any other possibilities beyond tune before bugging him with a retune that would possibly do very little, being that he has no data to read and adjust based on. So im kind of trying to check everything I can now, then if I must, buy the software so I can send him some logs.
-Lurius
Charlie tuned it, but being that im like 400 miles away we couldent do an in person tune just yet(or until I can drive her). I wanted to check any other possibilities beyond tune before bugging him with a retune that would possibly do very little, being that he has no data to read and adjust based on. So im kind of trying to check everything I can now, then if I must, buy the software so I can send him some logs.
-Lurius
05-13-2007, 07:22 PM
#9
Are you actually getting the misfire signal (rapidly flashing SES light) or is it just chugging?
A big cam (depending on the overlap) like that can throw that code a lot. I have my sensitivity turned waaaay down. It may be a combination of the cam + injectors being slightly out of tune. Since it goes away with a little pedal, that's where I'm leaning (needs idle tuning).
Thing is, getting it smoothed out will probably take some logging. Idle can be a bitch with a cam like that and a new displacement. You also probably want to clear all your learned stuff (if it wasn't already).
A big cam (depending on the overlap) like that can throw that code a lot. I have my sensitivity turned waaaay down. It may be a combination of the cam + injectors being slightly out of tune. Since it goes away with a little pedal, that's where I'm leaning (needs idle tuning).
Thing is, getting it smoothed out will probably take some logging. Idle can be a bitch with a cam like that and a new displacement. You also probably want to clear all your learned stuff (if it wasn't already).
05-13-2007, 07:27 PM
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The misfire code I am getting is a p0300, random multiple misfire. I am also getting lean on both banks, but I imagine that is because of the injectors needing some tuning.
-Lurius
-Lurius