Ok folks,

I'm getting really close to pulling the EFI and converting to carb. I've been having an intermitentent problem for the last few weeks and can't seem to figure it out. First off, I have a 86 F150 4x4 with the EFI 302. It will take spells where if cuts out, runs really rough, sputters and bangs and will usually stall. When I pull the codes, it comes up with code 18 which is SPOUT circuit grounded. It only seems to do it when the truck is good and warmed up. It's almost clock work where it starts to act up after 12-15 minutes of running. Here's what I've done so far. Fuel pressure is good, I've checked it while it is acting up and the pressure remains constant. The timing is set to 10 degrees and the SPOUT connector has been reconnected. The PIP sensor and ICM was replaced which didn't make any difference. I later questioned if the rotor in the distributor could be the culprit so I put in a remanufactured distributor with another new PIP sensor and ICM. Since it only acts up after 10-15 minutes of running I thought maybe the ICM was acting up after getting hot, but the second new one didn't make any difference. I've unraveled the PIP SPOUT wiring leading to the ECM and didn't find any broken insulation or anything. I went ahead and replaced the pigtails on the distributor and the ignition coil which didn't help. Oh, the coil has been replaced twice as well. I've replaced a resistor in the coil wiring as well as a diode and no difference. I was leaning to a faulty ECM at this point, but I just pulled one from a local pick-n-pull junk yard and it still does the exact same thing. The part numbers weren't an exact match, but the problem is still the same. The TPS has been replaced and is is adjusted to 1.0V at idle. It is just under 5V at full open throttle. The throttle body has been removed and cleaned. The fuel injectors have been replaced so that shouldn't be a problem either. Any suggestions or guidance would be greatly appreciated. I've been searching the forums and have done almost everything everyone else has been doing. I am considering rewiring everything from the distributor the the ECM, but the more I think about it the more I'm thinking about a carb. The biggest draw back is the linkage to connect the aod TV cable to the carb. Help!!!

kc

 

I have to warn you, what I am about to say is just based on my personal experience and opinion (but mostly opinion)... Your truck is an 85, which was a very early year for EFI. The engineers that designed it (that EFI system) might very well be pushing up daisies right now... I have a carb'd 302 which runs great when it's tuned properly (see my current posts - 84 F150, 2bbl 4x4). If you are not afraid to tinker with your engine (and it seems that no one here is) then I would recomend going to a carb. Again, this is just my opinion. My experience with EFI has been limited to late model jet skis and boats, and they run like a top 98% of the time. But they are not a quarter-century old. The most memorable problems I have run into with EFI were extremely tricky to troubleshoot, and it always ended up being some simple electrical problem in the end (double check ALL of your ground wires). In my experience, the less electronics you can involve with a mechanical process, the better. Part of the reason car companies like ECM's is that, in cases like yours, people like us are forced to go back to a dealership in the end, and we don't like that, otherwise we would not be posting here. Only opinion though, someone else will probably come along with a better response.

 

Don't go down rabbit trails. The computer is telling you what's wrong, it's losing the signal from the dist. You said you looked at the wiring. I was reading a automotive tech magazine a while back, and they said some Fords had trouble with the shield getting against some of the dist wiring, shorting it out. Some of the wires going to the dist are shielded correct? Check to make sure the shield is not rubbing any bare wires.

You can also put the computer in "wiggle test" mode. It will sit there and monitor all the circuits, and you can start playing with the dist wiring. If it detects a fault, then it will immediately send out a code. You could also play with a hair dryer on a component if you thought it was heat related.

 

Run some dedicated gas line dryer before replacing parts, 2 of heet and 2 of iso heet
and call me in the morning. Pull apart the connectors on the drivers side fender well
they are big connectors and can get corroded.
http://www3.telus.net/cbradley/Engin...fications.html This may change your
mind why go backwards? It really is not that hard to work on do the wiggle test like he said and see what the gas line dryer does.

 

All,

Thanks for the replies. I'm in the military and my work schedule doesn't allow much time during the week to work on the truck. I really don't want to go to a carb and I can definately see the loss in horsepower and would imagine reduction in fuel economy as well. I have never heard of the "wiggle mode" for the ECM, but I will do a search of the forum for the procedures. I know it is probably something simple as I think I've ruled out about everything else aside from a wiring short somewhere.

kc

 

Did you ever resolve this. I am having the exact same problem with the exact same engine ('85 302 efi).

 

Bump

I too am pulling this code along with PIP Circuit Failure. Any insight into this problem would be helpful.

Thanks Brad

 

If you get the code 18 during the KOER test, that means it's a constant fault. First thing is to check the spout connector and make sure it's in place. This is the connector that is pulled to check the timing.

You can try replacing the ignition module. Also carefully check the wiring at the distributor, and at the computer. Unplugging and plugging back in the computer plug may help if there happens to be a bad connection at the computer.

 

same thing
died mid-flight and was dead before it hit the floor. crank no start, no spark. code 18...

replaced tfi module with a spare, no change.

i too, contemplate the carb swap every time this thing decides to act up. never had this many problems with my old '71. (it ran better too)