What did you do with the venting of the fuel tank?

 

I'd study up at Fixing 1970s and 1980s Fuel Evaporation Control Systems | Allpar Forums .

No, I haven't converted to a carb - I like myself too much to inflict that kind of damage on my psyche.

RwP

 

Good suggestion Ralph! But you dont have to be so mean about it, especially on Thanksgiving!!

Best I can tell, this thing has 3 solenoid valves and 2 canisters... Going to read up some more on it, but it was controlled by the computer, which is unique on dakota's (one year only)

From what I understand with older vehicles, ported vacuum was used to purge. Basically a line to ported vacuum, one to the pvc line, and one to the tank.

 

My 87 works a bit different than the Allpar link. It has the vacuum solenoid in the tank vent line between the tank and canister. Tank is not vented when its not running. I would guess when you start the engine it opens the tank vent line, the line that went to the carb base plate which you would tee into the pcv had an electronic valve to purge the canister above idle. I bought a new 2 port canister as mine had 2 canisters and alot of lines. For you to mimic that you would need a new canister and 2 vacuum operated solenoids. I'm going to have to decide if I want to purge at idle as I do not have a ported vacuum source.

If you have any tuning issues when you get it running I can help. I ran a 98 5.2 with the rpm intake and holley carb. The stock cam at least in the 5.2 made a lot of vacuum at idle so it was a tuning challenge to tune out lean tip in. I put the comp xr265 cam in it after about a month of driving it and it really woke up. I will likely never have another carb after learning efi. Carbs do one thing really well and thats make hp at full throttle.

 

I did carbs WWWAAAYYY too long when I was younger. I'll take EFI any day nowadays; even TBI beats carbs.

Now if I could only tune my ECU, I'd be one super happy camper. (Lack is some files for the hardware and software I currently have.)

RwP

 

Quote:

Originally Posted by Glen440

My 87 works a bit different than the Allpar link. It has the vacuum solenoid in the tank vent line between the tank and canister. Tank is not vented when its not running. I would guess when you start the engine it opens the tank vent line, the line that went to the carb base plate which you would tee into the pcv had an electronic valve to purge the canister above idle. I bought a new 2 port canister as mine had 2 canisters and alot of lines. For you to mimic that you would need a new canister and 2 vacuum operated solenoids. I'm going to have to decide if I want to purge at idle as I do not have a ported vacuum source.

If you have any tuning issues when you get it running I can help. I ran a 98 5.2 with the rpm intake and holley carb. The stock cam at least in the 5.2 made a lot of vacuum at idle so it was a tuning challenge to tune out lean tip in. I put the comp xr265 cam in it after about a month of driving it and it really woke up. I will likely never have another carb after learning efi. Carbs do one thing really well and thats make hp at full throttle.

Glen, first off, thanks for your input on the canister setup. Second thanks for the offer on tuning! In time, I will probably be hitting you up on that.
Looking at the 87 FSM, I believe the tank has 1 line going to the evap. system. It comes from the (Fuel tank rollover and liquid vapor separator valve)
My thoughts are, could I simply run that to a 2 port canister, then run to the ported side of the carb.?
Im trying to understand, if I need a solenoid and if so, how to trigger it off idle. Really hate to add a switch to the throttle linkage.......
If I ran it direct to the ported vacuum side of the carb, would it cause any problems with the dist. advance tied in to the same line?
Thanks for your input.

 

Quote:

Originally Posted by RalphP

I did carbs WWWAAAYYY too long when I was younger. I'll take EFI any day nowadays; even TBI beats carbs.

Now if I could only tune my ECU, I'd be one super happy camper. (Lack is some files for the hardware and software I currently have.)

RwP

Ralph,
The truck only gets driven 3 to 4 thousand miles a year.....
While I agree, in theory, fuel injection is better....
But when considering its a vehicle that came with a carb, considering how little aftermarket support is out there for mopar, (esp. magnum engines) for me, going with a carb seemed best.
In time, I would like to go with one of the self tuning EFI systems,
But before that, I will probably try to get headers to fit with a decent 2.5 in dual exhaust, and then a cam and spring change out.
but to be honest, I dont believe I would ever go with a magnum, OEM, EFI of any year..... JMO

 

You will see the vacuum solenoid right at the evap canister, these do not cause a vacuum leak, I had my vacuum tester on one to see how it worked. I'm thinking the one in the tank line gets full time vacuum and the one in the purge line gets the ported vacuum. The tank vent has to be open whenever its running incase you try to idle it a long time. You need to T the vacuum advance line. You would need to buy 1 more vacuum solenoid and a 2 port canister. I got one from summit, its a chevy one I think. It looks like the Allpar one.

I have a harder time setting up evap than you do. I can use my efi to trigger the purge but it will need 1 of my 4 outputs and they are all spoken for. I would either have to run 1 fan control instead of 2, or change my IAC setup away from the ford pwm. I could make a block like I did for the ford. I didn't have a 1 inch thick piece of aluminum so I took 4- 1/4" pieces and welded them together.

 

on my son's 89 Ramcharger, we did swap to a carb. That TBI system is hands down, the WORST OEM FI system they could have chosen..... but we just left the vent open, ran a extension (rubber hose) up high, just as the rear end vents are on most 4ws....

 

duh wrong post