Fuel...my new 4 letter word

[kicknchick]

I need some serious help. I have an 87 Cherokee Laredo, 4.0, inline 6, 4x4, fuel injected, standard tranny. I had leaky injectors, didn't have a bunch of money so I ordered used injectors on ebay. Put them in, it ran great for about 20 miles, and then I let it sit. I got back in it, and it was running like it was out of gas. It was low, but not that low. I put gas in it, and it didn't get any better. Very BLACK exhaust, running rough, oil went from pretty clean to BLACK in a matter of 10 days of running it this way (my daily driver). It dies when I stop, and doesn't want to idle after restart. I have power, just not as much. I can do 60-70 on the hwy, but as soon as I stop, it dies, but restarts easily with a puff of dark exhaust. Someone told me it might be a MAP sensor, or internal injector leaking. This is what is just killing me...I changed the oil, and the oil level is rising, and I think it's getting gas in the oil, and I don't know enough about this stupid thing to figure out why. Should I buy new injectors, or could it be the fuel pressure regulator? I'm pretty strapped for cash, and can't afford a mechanic, and would really appreciate anything you all might know about this situation. I have changed these injectors out myself several times, and am actualy pretty good at figuring this kinda stuff out, but this has me over a barrel. I've also ran injector cleaner through it, thinking it might have just been clogged, and it did nothing. Thanks for any help you may have for me!

 

[XJourney]

You will get a better/quicker response in the OEM forum.

But my educated guess is injectors sticking in the open position. Giving you a run rich situation, plus extra fuel on shut down draining down past your rings into your oil.

But go check with some of the Gurus in the OEM forum, they are more knowledgeable than I.

 

[kicknchick]

Thanks for responding, I have the same thread on there also. Can sticking injectors UN-stick? Should I run cleaner again, or do you think they need repalaced? If you have any thoughts, I would appreciate them. Oh, and do you think I would have to replace the rings, I had thought about the fuel draining past the rings, and wondered if that would make them bad. Thanks for your insight, I really do appreciate it!

 

[bcsavage]

i know you are broke, but I'd take all 12 of your injectors in for testing and cross your fingers that you can come away with a fairly matched set of six that'll work for you.

 

[WheelinJR]

TPS or Map sensor...

possibly

 

[Blkxjkrawler]

playing devils advocate:firedevil
I know your say your strapped for cash. It might be worth spending some of your limited means on diag time at a shop. It will be cheaper than taking several random guesses on components that you cant return once you've installed them.
just for reference,
NAPA online
Fuel injector NEW $49.99-$107.00 EACH
Fuel pressure regulator $86.99
MAP $39.99
TPS 104.00

I dont know about your area, but shop rates for diag in this area run 65-95 dollars an hour. So if you spend 100 bucks up front it might save you 600 in the long run. I sold Parts for many years and am now a technician. I have seen people dump a ton of money on this sort of thing when it was something easy that a pro with a little experiance and the right tools figured out in 5 minutes. Not trying to insult your abilities, just giving you some food for thought.

That being said.
If you do continue on your own Hook up a fuel pressure guage and watch it after you shut down if it bleeds pressure off reletively quickly. try pulling you spark plugs and inspecting them. if they are wet, and smell like gas, thats a big indicator. also use a flash light and inspect each of your cylinders though the holes, look to see if there is any fuel in the cylinders ( NOW BE VERY CAREFUL) disable your ignition system, and turn the key to run postion but do not crank. Allow the fuel pump to prime the system, wearing eye/face protection look to see if you have any fuel flowing or dripping into a cylinder.
If thats the case, then see about getting your injectors flow tested.or replace the ones that exhibited leakage. If you are dumping raw fuel into the cylinders AFTER shutdown that would rule out the map, tps.
Hope that helps
-Ryan

 

[kicknchick]

I really appreciate the advice, and am thinking of doing that exact thing. My husband gets a bonus check in April, and am gonna put it in the shop and have someone else trouble shoot it for me. I've done all of this work myself, he is very un-mechanical, and his solution is a for-sale sign.:soapbox:

If nothing else, this has become my personal challenge, and I'm hell bent on fixing it so I don't have to drive his truck anymore. I will keep watching on here, as I really have learned a lot on this website, and I will definitely post my new findings when I get them, so maybe someone else can save themselves some trouble, and the money. Thanks for your help, it is much appreciated!