Dropping or Draining the fuel tank

[bigshrimpin]

My comanche started running like crap last week. At first I though it was spark plugs . . . because I hadn't done cap, wires, plugs in about 2 years. So I swapped out the cap, rotor, and plugs and it still ran horrilby.

 

So today I change the fuel filter. There was so much dirt in the fuel it looked like chocolate milk. I had just changed the fuel filter a few weeks earlier when I changed the air filter, so I have no idea where/when

in the last few weeks . . . I picked up all the garbage in the tank.

 

There's at least 18 gallons of fuel in the tank now . . . what's the easiest way to drain the tank. I don't know if it's important, but it's a 1992 2wd 4.0L.

and it's missing badly . . . is it worth going though the injectors too?

[Wildman]

http://www.harborfreight.com/cpi/ctaf/d ... mber=93290

 

OR

 

http://www.harborfreight.com/cpi/ctaf/d ... umber=3878

 

I would siphon out as much gas that you can before dropping the tank, that much gas is a lot of weight.

 

There's a good chance your pump strainer (in the bottom of the tank) is all plug up too, causing your truck to mis-fire, run rough.

 

There was so much dirt in the fuel it looked like chocolate milk.

 

Normally you shouldn't pick up that much dirt in the fuel tank unless it's getting in thru the filler neck/hose??? Check to see if the tube or vent hose are connected or rotted out and your getting 'splash up' from the left rear wheel.

[FxRacing282]

what i did was i filled up a 5 gallon gas can and tied it in my bed and then when i ran out of gas i put the 5 gallons in, drove home and dropped the tank with my buddy ricky and problem solved.

[layback209]

Well if your fuel filter was clogged with debree it wouldn't be a bad idea to clean out the injectors too. They arn't that difficult to remove, just have to pull the fuel rail and a the c clip on the connector.

 

I would trace all the fittings on your fuel system if you have the time. Check for loose conections. Also have a peek at the plastic vents (plus lines) at the top of the gas tank, if one of them is cracked there is a realy good chance that you debree is getting drawn in through those.

 

Like the above post said, if your dropping the tank might as well clean her out and replace the fuel pumps pick up filter, or if you can't find one clean all the stuck garbage off.

 

Good luck.

[bigshrimpin]

Doh!! I drained and dropped the tank . . . Fuel was clean!!! Tank was spotless inside. The mesh bag like filter on the end of the pump was split open. Otherwise it all looks clean as can be inside the tank. I guess that it must be the injectors or some sensor that I'm over looking.

[deziped]

You said you changed your filter a few weeks back and then two weeks later it was filled with crap & muddy, but now after running your tank dry and then dumping in 5 gallons its clean and shiny. Sounds to me like your buying somebodys dirty gas somewhere. I'd change my choice of service stations or shine a light (don't use a match like an idot in this county did a couple weeks back) into any tank I was gonna put my siphon hose in. ;)

[bigshrimpin]

I'm almost 100% sure I know which station I got the bad fuel from . . . Anyways . . . I still have to figure out this mess. I think the prime suspect is the injectors. I've never taken them out . . . . should I just visit the bone yard and pull a set out of a 92 or newer jeep . . . or can you disassemble and clean these things. I saw the deal on the Design II rebuilt ford injectors . . . maybe I should just plan on replacing them???

[layback209]

Buying new injectors is pretty expensive. Like 70$/injector. I would spend a few hours pulling and cleaning them, and retry them. You use a pin "kinda like how you clean out a plugged oxy-acetalene tip" to clear them out. Also check you fuel pressure in the rail to see if its to spec.

 

I'm not sure what the recomended range is off the top of my head, but if you have 20$ lying around, pick up the hayes mechanic manuel. Every thing you need is in there.

 

Good luck

[mvusse]

The place from the thread in the clasifieds section sells remanufactured Ford/Bosch II injectors for the 4.0 litre for $114.95 for a matched set of 6. Use the "Jeep" discount code and get 10% off that price.

 

That is a lot cheaper than $70x6=$420...

[bigshrimpin]

It's all back together now with the new mesh bag filter. I have a factory manual and looked at the Hynes manual in the store. I didn't see anything in there specifically about cleaning an injector. I'm probably making too much of a deal out out of a simple task. The engine starts and idles better. I pulled the o2 sensor today and cleaned the throttle body. It was really gunked up. I started the motor with the o2 sensor out and it idled pretty well for about 1 minute and then seemed to start missing again. No vacuum or fuel leaks anywhere that I can see.

 

Is it normal for the o2 sensor to get hot . . . when removed from the exhaust mainfold? when I ran the car . . . it got pretty hot just dangling down by itself

[mvusse]

O2 sensors need to be 600 degrees or hotter before they start working. To reach that temperature faster, some have a heater built in. Those have 3 wires. 2 wire O2 sensors do not have a heater and rely on exhaust heat only.

 

Yours have 3 wires?

[bigshrimpin]

I think it has 4 wires . . . it's a bosch 15704

 

BTW - Thank you everyone for your help!!

[bigshrimpin]

I let the truck sit for 20 minutes started it again. Almost 1 minute idle (without any misses) and then it started to miss again and idle rough.

 

Could this be the o2 sensor? or something else? I'm stumped . . . haven't touched the injectors yet.

[mvusse]

Pure speculation here, but it seems it idles fine when in open loop (running rich) and starts to mess up when it leans out the mixture in closed loop.

 

Could be the O2 sensor, or could also be an air leak between the throttle body and intake manifold (gasket?)

 

That's my take, but then, I build furniture for a living. Engines are just a hobby, and I'm more at home with a Chevy 350. Have only had my Jeep 4.0 for a month and a bit now. so I'm not necessarily qualified for this.

[bigshrimpin]

Doh - not the o2 sensor. Just bought one and still have the same issue. Time to throw some more money at this one.

[bigshrimpin]

Just read how to get the codes . . . I'm getting code 14 . .

 

Code 14-MAP voltage too high or too low

 

Any ideas on how to fix?

[Mitch]

i don't know but when you fix it let me know, I am almost positive that I have the same problem and don't want to throw money at it :)

[Wildman]

Try here, about the 3rd article down- For the MAP sensor-

 

http://www.lunghd.com/Tech_Articles/Eng ... ostics.htm

[bigshrimpin]

Thanks for that reply. Here's my confusion . . . cause the voltage checks out according to my multimeter but it still throws error code 14 right away (after I reset the battery). Hmmmmm . . .

 

********************************************************

What does it do? Compares ambient barometric pressure during start-up (cranking) to engine load while engine is running. The ECU computes that information and adjusts the air-fuel mixture accordingly.

*********************************************************

 

would engine load would be coolant temp sensor data???

what feeds the ecu barametric pressure?

[maddzz1]

Try checking if the vacuum line is clogged from the map sensor. If it is idling ruff you can also check the fitting where the ccv tube off the back of the valve cover connects to the intake, sometimes that fitting can get clogged.

[bigshrimpin]

Doh - I'm an idiot :) Turns out that I accidentally dropped two of the spark plugs before I put them back in for the last time. I didn't notice . . . but it must have landed arse end down . . . there was no gap at all on plug #1. regapped the plug back to .35 . . . no more code 14????? The truck purrs like a kitten!!! with the new design III ford injectors, cap, rotor, o2 sensor, and total fuel system douche.

 

I step on the gas and I can light up the tires . . . wohoooo!!

 

Thanks everyone for all your help . . . I learned a ton working through this "problem".

****************************************************

Mitch - I had multiple problems going on with the truck.

 

Dirty Throttle body, Vacuum Leaks everywhere, Dirty Injectors, Torn filter bag (in fuel tank), old cap and rotor, old plugs.

[Mitch]

great! :cry:

 

Looks like I get to spend the money that I was hoping to save. I just did a tune up - plugs included, and I know mine are all gapped fine.

 

I am however very glad that you got your truck running tip top!

 

:cheers:

[bigshrimpin]

Mitch - start with the free stuff . . . Cleaning the throttle body, check vacuum lines, read the codes, etc. I think the real problem besides the dirty fuel was the injectors and the vacuum leaks. Honestly they were simple to swap out . . . and I paid $50 for 8 rebuilt ones.

[Mitch]

ya, i did those, cleaned the TB with spray cleaner, then I sprayed all the vacuume lines and connections with the same cleaner while the engine ran trying to get it to stall. and I don't think I see or hear any codes. Maybe shes just old. It runs and drives good, just has a slightly rough idle.