351W Carb/Timing Issues
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351W Carb/Timing Issues
I have an '83 F-150 with the 351W engine (Duraspark III, EEC III setup from what I can tell). The variable venturi carb on that damn thing finally ate through the last diaphragm I'm going to feed it. I sent it in to a shop to have it converted from the feedback venturi setup to a standard 2bbl or 4bbl carb. They found a standard Motorcraft/Holley (not sure on the PN), installed it, and tuned it so that the engine runs really good on idle. However, they had to disconnect the TPS and whatever the other sensor is that was attached to the venturi, so under acceleration I'm getting hesitation and pinging. I've been scouring the Internet but I can't seem to find an answer for this. Can I spoof the EEC into thinking it is getting a TPS signal so the timing can resolve itself? Or should I just fall back to a Duraspark II setup (and wondering if anything else was involved other than a new distributor and ICM?). Anyone else have to convert one of these or did you just stick with the venturi setup?
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From: Where they take the census by counting the appliances on the front porch and multiplying by five
351W Carb/Timing Issues
Hey kc5zom and welcome to FTE!
I have an '83 F-150 that had all of that on it as well. Before I converted over to a 351 I tried to make the 302 work. Turns out the engine was worn out. But what I did was change the carb to the standard 2 bbl. and then changed the dist. to the electronic version. Even though it was worn out it ran 100% better and got better mileage to boot. Plus, I eliminated a maze of vacuum plumbing.
I do not recommend this if you have emissions testing in your area.
Maybe someone else can help with your question.
Again, welcome aboard!
Chuck
I have an '83 F-150 that had all of that on it as well. Before I converted over to a 351 I tried to make the 302 work. Turns out the engine was worn out. But what I did was change the carb to the standard 2 bbl. and then changed the dist. to the electronic version. Even though it was worn out it ran 100% better and got better mileage to boot. Plus, I eliminated a maze of vacuum plumbing.
I do not recommend this if you have emissions testing in your area.
Maybe someone else can help with your question.
Again, welcome aboard!
Chuck
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351W Carb/Timing Issues
When you say electronic are you referring to the one without vacuum advance? The distributor I have has no lines or wires running to it except for the ignition module to distributor wire. I'm not sure if its a mechanical advance model or not, I'll try and get the ford part no's later today, but there is no way to adjust the timing on it and no vacuum lines either. That is why I was wondering if a Duraspark II based system might not be a better choice?
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From: Virginia
351W Carb/Timing Issues
Your computer system has complete control over the timing. As you eliminate the information it receives( such as the TPS sensor) it will start making bad decisions on what the timing should be. Your EECIII dist has no way to advance the timing. You do need to convert to a duraspark II or an aftermarket dist. There have been some guys on here who have been concerned about the distributor shaft length being different from the Dura III to the Dura II dist, but from all the research so far, they should interchange. I haven't heard back from them yet on what they finally came up with.
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351W Carb/Timing Issues
Well, who makes a decent stand-alone ignition system? I've been looking through the aftermarket ones but I did not find one that would work without the older ignition still installed. They all seem to want to trigger off of the original ignition system.
I'm going to go junkyard browsing this weekend I guess and see if I can find the parts necessary to go to a DuraSpark II system.
I'm going to go junkyard browsing this weekend I guess and see if I can find the parts necessary to go to a DuraSpark II system.
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From: Quaker Hill ,CT U.S.A.
351W Carb/Timing Issues
http://www.performancedistributors.com/forddui.htm try this site ..they are a standalone system but at quite pricy though
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From: SW Maryland
351W Carb/Timing Issues
hrmmm... My 83 351w doesn't have feedback on the throttle / venturi, and the distributor has a vac advance and a wire or two that runs to the EEC (i'm guessing that's the box mounted on the drivers side wheel well guard). Looks like several others were sniped. Other than the engine needed to be rebuilt, it ran very well.
I can take a picture of the current state of the EEC (showing wires that are cut and not cut) if it would be helpful to you. I know one of those wires from the distributor to the EEC was for the tach,but that's about it. Wish I could provide more information, but i'm not the owner that cut the wires and ripped that crap out in the first place...
I can take a picture of the current state of the EEC (showing wires that are cut and not cut) if it would be helpful to you. I know one of those wires from the distributor to the EEC was for the tach,but that's about it. Wish I could provide more information, but i'm not the owner that cut the wires and ripped that crap out in the first place...
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351W Carb/Timing Issues
You are lucky. You have a Duraspark II setup. Some of the trucks in the early eighties got the variable venturis with feedback. But it is nice to know that you have the system I need on the same model year. That is what I will probably do, unless it is more than getting a stand alone (that place listed above is over $350 for one).
The EEC is under the dash somewhere. I haven't looked for it yet, the module on the wheel well is the Duraspark ICM. On my engine it feeds back to the EEC under the dash and the EEC controls the spark timing from there (I'm actually starting to find some good information on this thing).
There should be 3 to the distributor, 2 to the key switch, and 1 to the coil on your module (unless the connector on the module is a color other than blue).
The EEC is under the dash somewhere. I haven't looked for it yet, the module on the wheel well is the Duraspark ICM. On my engine it feeds back to the EEC under the dash and the EEC controls the spark timing from there (I'm actually starting to find some good information on this thing).
There should be 3 to the distributor, 2 to the key switch, and 1 to the coil on your module (unless the connector on the module is a color other than blue).
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From: Drayton, ND
351W Carb/Timing Issues
Need to be educated!! Replaced a 302 with a 351w, tried the old autolite carb, but ran horrible. Would love to try a different intake and carb, but have been told that my auto overdrive tranny poses a problem with going to an edelbrock or holley, because of the kickdown rod. Also need to find headers to fit this f-150 2wd. Any and all abuse would be appreciated. Thanks
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351W Carb/Timing Issues
It was deceptively easy to find the Duraspark II modules today. I found 5 or 6 and bought two. Couldn't find a distributor though. Ended up buying one from the parts store ($50 /w lifetime warranty). I'm going to try wiring it up tomorrow. Wish me luck.