Will only run when i put gas in the throttle body??????

[MadMrJake]

Hey guys I have a problem that I need help with; Fist I want to thank you for your time. I know its a wrangler but i still need help,I have looked though manuals and other threads before posting this. I want to start by giving you some history about this 1993 4 cylinder Jeep wrangler . I picked this jeep about 6 months ago, prior to that it has set for about 4 years.
We were not able to drop the tank and drain it when we picked it up but we did change the fuel filter. We changed the battery and add some fuel stabilizer and she turned over right away. We drove it out of the driveway and on to a trailer and away we went. I had to keep it at my buddies house for a few months. In that time we had to move it a few time drove it around the block (after drain the fuel and add new fuel). It started stalling and now it wont run on its own.
If I add fuel to the throttle body I can get it to run so I know I am getting spark, and it sounds good for a 4 cylinder. I have taken off the fuel rail and injectors and cleaned them. I don’t know if taking the injector out and clean them with a brush is the right way, but I have had improvements in the past doing this on my XJ. I have fuel pressure in the rail and can hear the pump working, I have not been able to verify exactly how much psi there is but I know I have pressure. My next thought was signal/power to the injectors. I was able to get a reading on my ohms meter it was about 1700 I believe.
I am kind of at a lost, I suspect it might be the ECM but scratching my head as I can get it to run by adding fuel into the TB. Any thoughts suggestions? I hate the Haynes manual as there trouble shooting sections sucks! Thanks

 

[5-90]

1) Welcome!

2) Got you filed properly - there are just enough differences between vehicles that putting non-XJ/MJ posts in "Other Tech" cues us to change hats (and thinking) and makes it a bit more likely for you to get a useful answer.

3) If we can't do anything for you here, there are some other sources you might want to look into - although I suggest searching extensively before posting if you go to Pirate...

With all that out of the way...

1993 YJ will be OBD-I ChryCo controls. Since it sat for a good long time, but will run with fuel dumped down the throttle opening, we can assume that you are getting spark - just no fuel.

Did you know that gasoline will eventually turn into something resembling varnish over long periods of time? My first thought is that your fuel injectors have become clogged with varnish - with the time involved, you'd be best to look for a local fuel injector service house (something aking to Coast Fuel Injection here in San Jose,) remove the injectors totally, and take them in for a full flushing. They'll run solvent through the things (make sure to tell them what you want done and why - it's useful!) check the flow rate once they're clean (to make sure there is no residual blockage,) and generally test them for function. You should be able to pick up new o-rings when you pick up your new fuel injectors.

Failing that, try replacing the injectors - but having them cleaned should be the less expensive option. However, that is my first thought on the matter - and it's something I've seen before, so it's not unlikely.

Good luck, and I hope this helps!

 

[joe_peters]

I would invest in a NOID light, $3, and see if the injectors are getting a signal.

 

[goodburbon]

I would invest in a NOID light, $3, and see if the injectors are getting a signal.

X2 you have verified that you are getting spark and lack of fuel is your problem. It is important to verify that your computer is sending the signal to the injectors. Once you know that your injectors are getting the signal to fire, you've narrowed it down to 3 possible problems.

1. injectors are clogged as Jon suggests.

2. Fuel pressure is inadeaquate.

3. Fuel in tank has gone bad despite treatment ( or due to inadequate treatment) .

You're on the right track.

 

[XJ&CHZ4ME]

Having gone through a very similar delima on an XJ I bought that had sat for an extended period of time, I belive it to possibly be in the fuel delivery system. Aside from replacing the fuel filter the fuel pump needs to be checked for proper PSI at the rail. I know on some models there is an intank filter as well, often refered to as a "sock" that is on the pick up side of the pump. Start by checking the pressure on the rail and if it is not within +/- 5 lbs I would think that he culprit is the fuel pump/delivery system. It is alot easier to check the pressure on the rail then to drop the tank and start replacing parts (and cheaper too! ) My problem was a failing fuel pump, so I replaced it as well as all filters and it ran for years w/o any problems. Hope this helps.


Cheeseman-OUT!

 

[95' heep]

before you do anything else, i would recommend change the gas filter AGAIN because its likely clogged with crap from the old gas and the fuel additive which can greatly restricts the fuel flow and reduced the pressure at the rail.

i would try that first before doing anything else. also if its still a problem i suggest you invest a good fuel pressure gauge so you can check the # of the fuel psi at the rail at least to confirm, such as make sure the regulator's good, etc.

 

[RedHeep]

Both times I've had a no start condition on the XJ, it was a fuel filter.

Worked 5 minutes ago, now nothing. Just like that.

If you've got a vehicle that sat with a half a tank of gas in it for 4 years, you're wasting your time spending a ton of money on troubleshooting and injectors until you know for sure you have brand new gas in the tank and that new gas making it all the way to the fuel rail.

Do what it takes to drain the tank and check the system all the way to the engine. It will only cost you your time. Then you can spend some money on everything else.

 

[CMNCHE]

ECMs on 4cyl. YJs are notorious for failing. I would do as stated and make sure you are getting a signal. Id be willing to bet the ECM is the problem.

 

[Ghost]

ECMs on 4cyl. YJs are notorious for failing. I would do as stated and make sure you are getting a signal. Id be willing to bet the ECM is the problem.

Not really if he is getting it to run with fuel in the TB. Easy test. Key on and see if you hear the pump. If you dont hear it then it is where you need to look. If you hear it, go to the fuel rail and remover the cover for the fuel pressure test port. press it with a screwdriver and see if fuel squirts out. If it does then you have some fuel pressure at the rail. Once you determine if there is fuel to the rail you need to check for pressure or if the injectors are working.

 

[RedHeep]

Yeah, I said that too. He must have gotten it fixed, because he's not frantically posting about it still being broken.

 

[Ghost]

Yeah, I said that too. He must have gotten it fixed, because he's not frantically posting about it still being broken.

Good point! you still in the sand box?

 

[RedHeep]

Got home on the 14th.

 

[Ghost]

Got home on the 14th.

Welcome home and TY! You see some of us hitting up URE this weekend?

 

[RedHeep]

Yeah, unfortunately I've still got guys on the boat. Some of us came home a couple of weeks early and I've got to be at work this weekend making sure the rest of them come home safe.

I've got a whole laundry list of junk to do to the heep anyways. Rest assured, I'm going to be camped out at that place next year. Even my wife is on board.

 

[Ghost]

Yeah, unfortunately I've still got guys on the boat. Some of us came home a couple of weeks early and I've got to be at work this weekend making sure the rest of them come home safe.

I've got a whole laundry list of junk to do to the heep anyways. Rest assured, I'm going to be camped out at that place next year. Even my wife is on board.

Well glad you are back and hope all the others get back safe!