1998 ranger problem child

[nick_d_4.0]

I have a 1998 ranger xlt 4.0l 5 speed 4wd truck with cranked torsion bars and 33s and it has three problems. This is going to be an essay but most of these threads are just asking questions the publisher should put out there to begin with. Check engine light reads lean banks. Shit gas mileage like 13mpg highway (bigger tires/lift make it that bad). What I have done/What is new:

new exhaust from headers back, new plugs, coil pack, IAC valve, egr valve, cleaned throttle body, MAF sensor, air filter (aftermarket K&n), new battery, new TPS sensor, all vacuum lines have been looked over and replaced if needed (that I can see), more and more I'll probably think of

1. Weak start up: on cold starts especially it cranks right at the key turn, sputters at less than 500 rpm, surges on its own to over 1500 rpm for about 30 seconds, falls down to 1000, then after driving for a while and stopping at red lights and such, I can see it idles at around 750. During start up it shakes, tries to die, has no throttle response until shes ready to go meaning after the surge and at 1k rpm idle. My truck runs the show here and I want to be in control. Some days she wont even start or itll take several cranks and fluttering the gas to get her going. Also going uphill is a struggle, thinking problem is related. Decelerates from 70mph to around 55mph over a bridge I take (big tires?). Lean mixture is problem...but where I've sprayed the engine bay with cleaner while running trying to get rpms down and find vacuum leak but no luck.

2. Hot air blows out of foot vents all the time, all air is always hot from AC vents: Part of the gas mileage problem could be I always have windows down even at 60+mph.. beside the point. This hot air blows through foot vents when the AC is off and it cooks the whole truck, radio buttons become hot, things in glove box, ect. The Ac will change intensity settings and all the directional air paths work when switched. It is just always blazing hot and blows from foot vents after driving for about 15 minutes. I live in FL... going to need new seats after this fix as these have been soaking up sweat for a while now... I've gotten down a looked behind the dash but never taken it off, changing the direction of air settings will move the vacuum pumps under the dash that i can see and direct air. I had hoped a vacuum leak would solve AC and start up problem... life ain't that easy.

3. GEM relay bad? Wiper blades, dome light, 4wd, power windows don't work all at same time, when dome light works they all work, it flicks on here and there. Could all this heat behind the dash be frying my electrics?

Any help at any of these problems, please. Been driving my dad and I crazy for months.

 

[Mickey Bitsko]

Wow.... lota crap goin on there, You changed out a lot of things , never mentioned gas filter ? As far as the heat behind the dash, if there is a problem it seems there should be burning or foul hot electric smell. Maybe a voltmeter to check your voltage at dome light, window switches etc ? Not sure I'd drive it till I found the " hot spot ", wouldn't want to have a fire while driving..

good luck

 

[nick_d_4.0]

Never thought to smell the air coming out... ill try it. The truck ran for 12 hours straight from MD to FL and no fires so I don't think it is that scorching but windows/wiper/lights worked the whole time it seems after I let it sit for a night the next day those aspects didn't work. The air really flows from foot vents when moving so its hard to get down and feel/look for a location.

Really do not want to pull the dash... yeah lotta crap you're telling me, wont get into what we already fixed prior to this

 

[enjr44]

For problem #1 it sounds to me like your fuel pump assembly is on its way south. On my 02, with just about the same symptoms the fuel pressure was dropping with the engine off (it should hold 40/50 pounds for just about forever). When you first turn the key to run, the fuel pump can raise the pressure 10/15 pounds before the computer shuts it off and waits to see 400/500 rpm (engine running) before turning it back on. So you may have just enough pressure to get it started; but, not enough the get the rpm the computer (wide open IAC) is calling for (it jumps to the 1500 or so after the pump has been running long enough to deliver the needed fuel pressure). It holds this high idle until sensors start coming online. The sensors will call for about 1100 rpm until the engine is warm. So once you get fuel pressure it runs normal (mine did until it quit completely).

Number 2 is the temp control control or the blend door. Google, the tech section here and youtube are your friends with this mess. I mean it is total BS, what with vacuum motors, cables with gears and electrics. And, you cannot find a complete diagram on how this system works. So good luck!!!


On 3, the GEM can have a mind of its own and I have not found anyone that understands it. Mine was doing all sorts of weird crap (locking and unlocking the doors, turning the wipers on and off, etc.) and I found all sorts of explanations as to why it was going to cost $500 to fix it. However, my battery was really old, 11 plus years old, the one that came with the truck, and I decided to change it because the overnight voltage was down to around 11.5. Since the old one lasted so long I wanted to replace it with an OEM battery just like it. Anyway battery was out of the truck for a couple of hours, resetting the computer and for some weird reason, that fixed the problems with the GEM. That was at least two years ago. I have been told that the really low voltage when starting the truck was causing the GEM's processor the do the weird stuff.

 

[nick_d_4.0]

For problem #1 it sounds to me like your fuel pump assembly is on its way south. On my 02, with just about the same symptoms the fuel pressure was dropping with the engine off (it should hold 40/50 pounds for just about forever). When you first turn the key to run, the fuel pump can raise the pressure 10/15 pounds before the computer shuts it off and waits to see 400/500 rpm (engine running) before turning it back on. So you may have just enough pressure to get it started; but, not enough the get the rpm the computer (wide open IAC) is calling for (it jumps to the 1500 or so after the pump has been running long enough to deliver the needed fuel pressure). It holds this high idle until sensors start coming online. The sensors will call for about 1100 rpm until the engine is warm. So once you get fuel pressure it runs normal (mine did until it quit completely).

Number 2 is the temp control control or the blend door. Google, the tech section here and youtube are your friends with this mess. I mean it is total BS, what with vacuum motors, cables with gears and electrics. And, you cannot find a complete diagram on how this system works. So good luck!!!


On 3, the GEM can have a mind of its own and I have not found anyone that understands it. Mine was doing all sorts of weird crap (locking and unlocking the doors, turning the wipers on and off, etc.) and I found all sorts of explanations as to why it was going to cost $500 to fix it. However, my battery was really old, 11 plus years old, the one that came with the truck, and I decided to change it because the overnight voltage was down to around 11.5. Since the old one lasted so long I wanted to replace it with an OEM battery just like it. Anyway battery was out of the truck for a couple of hours, resetting the computer and for some weird reason, that fixed the problems with the GEM. That was at least two years ago. I have been told that the really low voltage when starting the truck was causing the GEM's processor the do the weird stuff.

Thank you for your time and info, I appreciate it all.

1. I dreaded the fuel pump probability... but actually don't know if it will be that bad on a truck, only done a car super low to the ground. Ill get a pressure gauge from auto zone and test that some time next week.

2. Ive replaced the control controller behind the knob, and checked the blend door for functionality and it works. There is some foot vent that is stuck open somewhere behind the dash mess, and the hot air does get less hot when turned to cool, but it is still hot.

3. Mind of its own... that's what I have been saying and people think I am crazy... I say the truck is having a bad day when she does not work right and a good day when she decides to work.. so weird. I'll try the battery disconnect idea next week as well

Got a fun weekend planned going off road so I hope she holds up for now, and I'll fuss with it when I get back. Don't want to make matters worse just yet.

 

[Big Jim M]

Check the blend door again! That is your problem.
Big Jim

 

[nick_d_4.0]

Check the blend door again! That is your problem.
Big Jim

Well I popped the blend door out left it plugged in, turned key to on and changed the temp from hot to cold, and the pin moved. That means good right? That's what I thought anyway

 

[Big Jim M]

Does the door move from full open to full closed? Small things can enter the defrost vent and wind up in the blend door! I once pulled three .22 shells out of a door that wasn't working as built.
Big Jim

 

[nick_d_4.0]

well its been a while.

Not sure its a fuel pump because once it is warm, it starts 10 times better but not perfect. Wouldn't a fuel pump have the issue no matter what on start up?

Blend door does look like full range of motion, if it is cheap ill just buy one.

My relay issue... the lights/wipers/windows have not had an issue since that first day it occurred. BUT the 4wd has constant issues after that first day. It used to have one click going in and one click going back to 2wd, now you switch to 4wd and it clicks 5-7 times then after a 10 second delay the 4wd light comes on but half the time it is still in 2wd. When this occurs, both the 4wd high and low lights do a flash 6 times every couple minutes. When it actually locks in, it all works and this weekend it got the job done lol

My main concerns are the hot air in vents when AC is off, and the lean codes/bad start up