Topic: Some engine issues- Need help

[jfrabat]

Hey, guys, I need your help!

When I took the Jeep out on my last outing, I felt it a bit underpowered (well, more than ussual).  I remember that before I could accelarate up a hill near my house in 3rd gear, yet now, the speed is slowly drained by the same hill.  I also noticed that if I shut the Jeep off and then try to restart, I have a hard time.  If I let it rest a bit, it then starts up just fine.  Any ideas as to what I could check for this?  I am thinking there may be some gunk in the engine (before my trip to CR about a month or so ago, the plugs were stuffed with what my dad described as "mud").  As a result, I am also starting to look as my injectors as suspect...  I also had some issues with the spark for Cyl 1 jumpint from the top of the distributor boot to the AC Compressor (have not chequed it again, but I did change wires).  So I am thinking about changing out the injectors (I changed them about 4 or 5 years ago), maybe put a new rail in there (already got one, so might as well), check the FPR (if you see my last post, pressure seemed a bit high), check the return line to be sure there are no obstructions there, maybe put a checkvalve to be sure the fuel is not going back through the pump, and changing plugs and wires.  Should I look at anything else?  I already replaced all the vacuum lines (the power issue came up BEFORE this, so this is not the cause) and cleaned the air filter (it was not that dirty anyway).

Any help is greatly appreciated (including the best place to get good quality injectors that are balanced at a reasonable price)...

Felipe

[jfrabat]

Oh, and one more question; what could be causing me to go through Oil Pressure Sending units every 6 months or so?  I am tired of changing this...  And about every 6 months or so, they die on me (granted, I abuse mine with lots of mud and water, but STILL, they should at least last one year!)

[sharpxmen]

Felipe,
if your plugs had something "mud" like looking on them i would do a compression test. As far as a check valve, that should be ok but that doesn't explain why it starts better if you let it sit for a while. Re: your pressure bleeding - can't remember if you fixed your gasoline smell, there are 4 external o-ring quick connect fittings that can also cause this issues, 2 are at the injector fuel rail and 2 are on the frame at the fuel pressure and return lines on the driver side right below the firewall, if any of those o-rings leak (on the pressure side) you would have the pressure bleeding out of the rail, also if any of these 4 leak (on the pressure and return lines) you would have fuel smell. You should also inspect the FPR o-rings, either large or small one not sealing properly would cause the pressure to bleed. Also make sure your pressure is not too high, like i mentioned before should not be higher than 45psi, so have a look at that as well. The PCM temperature sensor is another place i would check (and this can be somewhat related to letting it rest for a bit and would start up ok) and possibly the o2 sensor (could be running to rich due to bad signal from o2).

oil pressure sender - just install a mechanical one, you'd be glad you did (way more accurate and won't fail on you as often) - the only thing i can think of in regards to failing is that they are not quality sensors, they are sealed so it shouldn't matter if they are underwater the whole time unless it's the electrical contact on the terminal that causes the issues (but it would not damage the sensor so from what you are saying that's not it).

[Jeffy]

'mud' would suggest water and oil.

Not sure about the oil pressure sender.  I replaced mine with an OE from a pulled engine.  The senders are cheap for the most part so I'd think that they're jsut failing because of that.  You could replace it with an aftermarket sender if you wanted to.

[jfrabat]

My theory on the mud is that, on the last run some months ago before I took the Jeep back to Panama, there was a vaccuum leak, which is why I replaced all the lines with silicone ones.  My guess is that the engine ingested either dirt (from the air being sucked up), mud (when crossing mud pits), or both, and this got the whole combustion chamber dirty.  I am planning on doing compression tests, and also checking how well it is holding compression (I have both testers; the one that measure compression regularly, and the one you use with the air compressor, so I will use both).

But the reason I am considering changing the injectors is that they could also be causing the Fuel Pressure to drop if they are leaking into the combustion chamber.  As for the pressure, i am not sure what to do; I dont completely trust the fuel pressure testing unit I got, and I quoted a new one locally, and the cheap ones run over $400, so I am not buying one of those...

Anyway, I will start by removing the fuel rail and looking at the O-Rings in both the rail itself and the FPR.  I will also change the O-Rings in the frame that Sharp mentioned...  I may also just get rid of the cat altogether in case that is acting up as well (I dont have to pass any inspections).

Felipe

[Jeffy]

Hmm, I don't think mud would be around for long in the combustion chamber.

[sharpxmen]

you can check the injectors to see if they leak by taking out the fuel rain with the injectors on it, create pressure (without attempting to start the engine) and having the tips of the injectors in some small plastic bottles (to avoid gas being sprayed on the engine, plugs, etc and cause a fire, sometime you get the odd spark when the key is switched on) - if you see drops coming out at the injector tip then they leak.

[jfrabat]

Hmm, I don't think mud would be around for long in the combustion chamber.

Depends how much got in there in the first place, I guess...  But for now, I'll start simple and work my way to the more complicated.  For now, O rings and tests will be done first, along with a plug change (and probably the rotor, cap and wires, since I already got them).

[grumpygy]

Coil could be the reason it starts easier after it cools down.

[jfrabat]

Coil could be the reason it starts easier after it cools down.

That's a good point, but I changed it less than a month ago.  unless it suddenly died, I dont think it is the culprid.  Also, it acts up to start, but once it starts, it runs fine; the coil (I THINK!) would act up whenever it is hot (so it should act up AFTER it starts as well, right?)  Anyway, correct me if I am wrong, and thanks for the help!

[sharpxmen]

 As for the pressure, i am not sure what to do; I dont completely trust the fuel pressure testing unit I got, and I quoted a new one locally, and the cheap ones run over $400, so I am not buying one of those...

all you need is a pressure gauge, one that you would use for air would work since is not permanent install and keep the hose/adapters from the current one. A 60 psi is preferred for better resolution but 100 would work just fine also - just need to match the fitting on it, most of them are 1/4'' NPT (pipe thread) for that size but you'll need to check yours - possibly use an adapter if you can't find a matching one. Use teflon tape to seal the thread and you're good to go.

[grumpygy]

That's a good point, but I changed it less than a month ago.  unless it suddenly died, I dont think it is the culprid.  Also, it acts up to start, but once it starts, it runs fine; the coil (I THINK!) would act up whenever it is hot (so it should act up AFTER it starts as well, right?)  Anyway, correct me if I am wrong, and thanks for the help!

Stock or after market coil.   Not always will it act up, but you may notice a lack of power cause its not working right.  Just at start up it may take a little more to start.

[sharpxmen]

Felipe, how's the battery voltage?

[jfrabat]

Coil IS aftermarket; I have a spare one, so I will replace it and see how that goes (I'll keep the current one as a spare).  Battery was also fine (have not checked voltage, but the starter did not have any issues; I even started in 4L in 1st gear at one point).  I'll give the air PSI gauge a shot and see how that works...

[grumpygy]

I threw back in a stock coil and my Problems went away.  It was not rated at the right Ohms for the stock ignition system.