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New project 94 C3500 350

Ok I took some videos but I can't get them to load off my phone.

Anyone willing to PM me their email and try to post them for me? There are 4-5 videos
 
Try unplugging the MAP sensor, and see if it will run in limp mode. Let me do some digging, but 94 MAY also have an intake air temp sensor. Cannot figure what would cause it to idle so low. By unplugging the timing plug, you're taking the ECM out of the equation as far as timing goes, and its common for them to idle rough in base timing mode at 0 degrees. Also you need to take the aire breather off, and shoot the timing light at the injectors to watch there spray pattern.
 
I'll check the spray pattern. It idles worse with the breather off, won't even run on its own long enough to get under the hood.

What should I see on the spray pattern? Is it a constant spray?

Another thing is a mouse did get under the hood at some point and it is covered in splices. Mainly around the intake.
 
You want to see a clean mist spray of fuel. No dribbles or solid streams spraying down. These things are really VERY simple, BUT with that simplicity also comes the problem that 1 little problem will take the whole system down. This could EASILY be as simple as a cracked vacuum line to the map sensor giving the wrong vacuum reading.
 
It does seem like a fueling problem, but Get that can of starting fluid you don't allow near your 6.5s and try searchng for a vacuum leak just to rule it out.

If you have a vacuum gauge throw it on there.
And video it at idle then reving up slowly without stoping. Then from idle with holding lvelsmevery 500 rpm. Ive posted pics of reading vacuum gauge before, cant find it at the moment- if youd rather search for it than post that video.
 
I'll give it a shot, gotta buy a vacuum gauge first.

I'll try messing with the map sensor. Is it on the firewall or throttle body?

Iirc the only vacuum line on this thing is on the back of the intake going toward the firewall. It's hard plastic
 
Heres a pic I found online with the map sensor circled. Another 5hing to check that I have seen on high milage 5bi 7nits is the rear portion of the throttle body where the iac goes gets gunked up over the years with oil sludge. If you notice the vent tube goes in at the rear of the throttle body, and the iac air passage is also back there. The vacuum port for the map sensor is also back there, and I've seen the sludge get so thick it blocks the passage off,
map.jpg
 
Did you put a heavy dose of injector cleaner in the tank and run the piss out of it? Just to give you the assurance that the lines are relatively cleared
 
Well I dumped 1 can of seafoam in it and have used a full tank of fuel in 100 miles (guessing 30ish gal rear tank).

I know the vent hose, I pulled the valve cover to confirm I was near tdc and not a turn off. I looked in the throttle body and it's pretty dang clean. Do I need to unplug ports or disassemble the throttle body and blast it with carb cleaner or try the map sensor first?
 
The part I seen get plugged up was underneath the iac port. This one was slightly ginked on the outside, but when I pulled it it was caked underneath.
 
Ok, so bout a month ago this truck broke down in town on a parts run for one of my tractors. I was able to limp it home but couldnt get it over 40mph and had to down shift into 2nd to climb hills.

Today I decided restart the project by working on some sketchy wiring. Cut it out and soldered in new wire and heat shrink over it all. A LOT better! The wires that were chewed up went to the injectors.

So now it kinda has power and will even chirp the duals if I dump the clutch in 1st at 1/2 throttle.

Now it's main power issue it about the last 500rpm before the rev limiter and still won't go over 75mph (Dash gauge) 80mph (by GPS). No cutting out at that speed just wont accelerate any further.

My only thought was 4.56 gears but the sticker is gone and the truck doesn't have a tach. But even with 4.56 gears I'd think I could still get over 75mph.

Other though, there is more splicing near the fuel pump I will be soldering in the AM but I'm not holding my breath on that one.
 
Need to know RPM's, but those 350 TBI engines are running out of air come 4000 RPM's, come 4500 they're pretty much done.
 
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