I am having some serious trouble with my Jeep and would love if someone could steer me in the right direction -
It is a 1987 Jeep Cherokee Pioneer, 4.0l V6, auto. So, it has been having a rather high idle for the past couple of weeks but nothing that seemed to be cause for alarm, just something I notice. On Thursday of last week I drove into work (a 35 mile commute) with no troubles at all. When I left my office for lunch, the car started up like a champ and off I went. I got about 1/4 mile down the road and she just sputtered out and died. Long story short, the car will start fine, idle fine, rev fine, everything fine, until I put it into gear and try to drive. When that happens it sputters, sort of half-ass backfires, bogs down, and stalls. If I take my foot off the gas and just leave it in drive it will roll along at idle speed (aka granny gear) just fine, but as soon as I give it gas the problems start.
I’m just looking for some advice mainly on what to do from here. I know exactly nothing about cars, but I am trying to learn. My ignorant theory is that it is an air problem, like it is not getting enough air. I cleaned the throttle body up as best I could, checked the air filter, check the vacuum lines, and nothing jumped out at me, however, like I said, I am car-stupid.
Very doubtful it’s not getting enough air, more likely it’s not getting enough gas. If you want to try fixing it yourself before taking it to a shop, replacing the fuel filter is a good place to start. Certainly not the only possibility, but a reasonable chance that’s it and it’s relatively inexpensive and easy to replace. If that doesn’t fix it, some testing will be necessary.
The high idle is not necessarily related to the inability to accelerate, but I’d address the acceleration problem first and not worry about the idle until that’s taken care of.
When was the last time you changed your transmission fluid or had it serviced? Your description sounds exactly like what happens when you shift your transmission to too high a gear from an idle. Your transmission might be putting you in 2nd or 3rd gear from a stop. Do a little research into 1987 Jeep transmissions and see if this is a common problem.
To be honest I have never changed it. I just bought the car a few months ago and I am trying to just trying to keep it running for a few months (maybe a year). Right now it has 297,000 miles so I don’t expect much.
My brother in law is a Jeep mechanic and he is coming by today to take a look at it, I just wanted some ideas that I could run by him so I seem like I half-way know what I am doing
Getting too little gas also means getting too much air. Check for vacuum leaks, and check your intake manifold gasket. You can do this by gently spraying carb cleaner or something similar around the edges while the engine is running. Why? If you spray some fuel (or similar) into an air leak, it makes its way right to the cylinder and gets burned. If the RPMs go up when you hit a certain point, there’s your leak, and you’ll need a new gasket. It’s easier than you may think, but still a bit of a chore if you haven’t done it before.
The only reason I say it may be an air issue is that when I disconnect the line that runs from the air filter to the throttle body and plug the hole up with my hand, it does the EXACT same thing as when I put it into gear.
sounds typical of a clogged fuel filter. Start there if it has not been changed real recently. It could be low fuel pressure because of a failing pump, but I vote for the filter. Certainly you always go for the cheapest and most likely item first. A quick change oil change establishment might change that filter for about $30. You could limp there and check this possibility out before going to a more expensive mechanic.
Autozone suggested that replacing the fuel filter without replacing the fuel pump was pointless. I thought they were just trying to change the purchace from a $15 filter to a $110 pump, but I may be wrong. Should I go ahead and replace everything or just start with the filter?
They claimed that if there was a problem with the fuel pump and gunk in the tank that I would ruin the new fuel filter right away and then it would have to be replaced again.
Really? EXACT? I question that because it sounds like you’re blocking the idle air supply, which would cause it to die (when idling), but would not cause it to do anything like a backfire.
It’s apples and oranges. At idle, only a small amount of air is going into the engine, and if it’s blocked off the engine will die. Pressing on the accelerator pedal, however, opens a big air passage to the engine. There needs to be a corresponding amount of fuel getting to the engine. I can think of several ways the fuel supply would be compromised (a restricted fuel filter being one). I can’t think of any realistic way the air supply would be compromised.
Note that it will rev up when standing still. That means it’s getting plenty of air, and enough gas to run when the engine isn’t really working. Moving the vehicle is a whole different ball game. When the engine is under load, as when accelerating, it requires a LOT more gas than when the car’s not moving.
My advice: don’t mention the “air issue” to your brother-in-law. I don’t think it will make you appear wise.
In all the years I have been in this business I can count the number of gas tanks I have seen with “gunk” in them on the fingers of one hand and have several fingers left over.
Not a very common problem.
I would buy just the filter. when you remove the old one, tip it so the fuel drain out of the inlet end. Is it clear? Dirty? Cloudy? Then tip it so the outlet end drains. Is the fuel clear? Remember this is the front end of the filter and you will be seeing all the crap the filter stopped over the last OG knows how many miles.
I dunno, blind faith?
Beyond that, over the years they’ve made a few suggestions that have helped me fix problems. I’m not saying they know any more then a random shade tree mechanic, but I’ve always gotten better answers from Autozone and Napa than Checker.
Of course, I’m not saying you’re wrong either. If, based on the problem you present them with, they know that all you need is new plugs, selling you plugs, wires, a rotor, a cap and points will also fix the problem.
If your car has Fuelinjection it could be that the Electronic has failed, I had an similar problem with my Opel/GM, the Shop plugged in a new Module and it was running fine again, that was pretty expensive, set me back a 1000.-SFr.
!
Another vote for fuel starvation…the engine is getting the barest amount of fuel to run and idle but if you try to go above that, it doesn’t get enough fuel and runs badly. I also say to try changing the fuel filter first. It’s fast and cheap. And if the problem’s not fixed, you can move on to try the more expensive options and know the filter is good already.
Well the voted for the fuel starvation are correct. After testing the fuel pressure, it is not holding near enough pressure. I will be replacing the fuel filter today and if that doesn’t solve it, the fuel pump tomorrow. Thanks for all the great advice
