My E-150 was runnng great until Monday night. It developed a really rough idle and started "surging". I checked all vac. lines, manifold leaks, carb leaks etc. Finally bought a code reader. Codes I got with engine off are for Throttle Position Sensor voltage out of tolerance and Coolant Temp. Sensor voltage incorrect. With engine running it gives codes for O2 sensor(too lean), Throttle Position Sensor voltage, and MAP signal voltage. Now that I have some codes, where should I start. I'm thinking the carb (carter YFA) is the root of most of the problems but I need some more opinions. The Van has the 300 CID w/C6 trans, Carter YFA Feedback carb. Everything is stock. Have just finished replacing all gaskets (engine/carb/manifold etc.), vac. lines, rebuilt carb (it was running fine after rebuild), plugs, cap/rotor, all filters, PVC, oil breather. I've only had the Van for a month or so and hoped I was done fixing the neglect of previous owners but now I'm head-scratching.

 

My VERY biased opinion is to yank all that feed back stuff off and go with a new 4bbl carb, header, and ignition. Alot of passing power you shall recieve! But then again, it's my VERY biased opinion.

What model year is your van? I might be able to help.

 

I thought the throttle position sensors are for EFI and not carbuerated motors. Auto Zone has a little booklet that tells you how to check each one of the sensors with an ohmeter.

 

Here's an update on my Van problems. I ran the diagnostics on it again and got he following codes with key on engine off, hard code 23 Throttle Position sensor out of range and continuous memory code 22 MAP or BARO sensor out of range. Key on engine running it gives 21 cooling temperature sensor out of specified range or ECT out of range, code 23 (same as above), code 72 MAP, MAF, or BARO out of range during Dynamic Response Test, 73 Insufficient Throttle position change during Dynamic Response Test, and code 41 O2 sensor voltage low system lean. I disconnected the TPS to see if it would change anything and got the same codes with engines running. It still starts up fine, choke kicks down and it runs for a minute or two then starts to idle very rough. Exhaust tends to be white and very stinky (not like gas). I've replaced the MAP but it didn't change any codes so I'm thinking that I've got one thing screwed up that is causing several codes to flag. The only way I can get it to idle smoothly is to disconnect the float bowl vent line that runs down to the charcoal canister. If I put my finger over the vent outlet at the carb it goes back to a rough idle so I thought the vent line check valves and might be bad. Replaced them with no change. Vent line on, it runs like dog-droppings, vent line off it runs fine.....Help...I'm scratching my head and not getting any bright ideas. How much of the electronic BS can I disconnect and still get the EEC-III/IV? (I'm guessing because it's got the TFI module on distibutor but is carbureted.) to run correctly???

1987 Econoline 150
L6-300 (but of course, replaced 302 van originally came with)
Carter YFA-feedback carb, 1 barrel
Stock head, cam, manifolds, ignition. All Emission stuff still installed. 144,000 on van. Unknown mileage on engine.

 

First thing I would do is reset the codes unhook battery for a few minutes. Then warm up vechile. Then run key on engine off tests and see what you have. Thats way to many codes. Also check all the ground connections make sure everything is hooked up. Let us know what you come up with.

 

OK. I could make up a big story about how it got fixed, but...I made a map of all the vacuum lines. There is no sticker under the hood so I didn't have a good reference for any of the "spaghetti" mess of vacuum lines. When I got to the plumbing for the float bowl vent it occurred to me that if the check valve was on the wrong side of the vacuum line (canister purge) then it would be blocked all the time. I checked the handy Hanes and Chiltons. Lo and behold. I had put the purge valve and check valve in backwards when I was cleaning them and replacing the vac. lines!!! DOH! After replacing some more vac. lines and putting the canister purge components in correctly it works 4.0. Idles as smooth as a baby's...belly. At least it forced me to figure out where all the vac. lines and solenoids are. Lesson learned. All that time I was getting mad at my GLORIOUS L6-300 and it was me that screwed it up!!!