Topic: Engine quitting and backfires

[jfrabat]

OK, guys, so after working on the Jeep last weekend and this weekend, something is not right; it seems I messed something up and I dont know what it is, so I need your help.

What I have done is:

Changed oil (put some seafoam in ther as well to undo my "restore" mess!)
Changed Oil filter
changed both engine mounts and brackets (had to take out the alternator and serpintine belt to be able to do this)
Installed the fuseholder

Could an overtighten belt be responsible for this?  I am also thinking it could be the cat that has finally failed (I do hear some ringing there, and the BOOM from the backfire sounds like it is cming from there as well)...  In any case, I will not be able to take a look at it until this weeend (in the mean time, I have to live with this problem, as I have A TON of work!), but if you can give me ideas, they would be most welcome!

Felipe

[oldjeep]

Are you sure that you didn't mess up the front most spark plug or wire when you were working on the alternator and motormounts?  That one is pretty easy to snap off.

[jfrabat]

Are you sure that you didn't mess up the front most spark plug or wire when you were working on the alternator and motormounts?  That one is pretty easy to snap off.

I dont think I did, but I'll check at noon; I checked all plugs cables, and they were all in properly and did not seem torn...  But I did not disconnected the wires to check the plugs.

[st.chevrolet]

I would be looking around the distributor, as thats where you were working when you changed the motor mount.

[jfrabat]

OK, so I checked all plugs and wires, as well as the distributor.  Everything was as it should be, but the engine is still sputtering and misfiring...  I did notice that the positive batery terminal is cracked, but I put a washer in to make sure it is secure (I have to replace it, but since I already ordered the military terminals, I will wait for these instead of buying some cheap ones and then replacing them again), and they seem to be making good contact, so I dont think that's the problem...

So let me describe a bit more in detail what the engine is doing:

At first, it will fire right up as ussual, but once it is hot, it will start to miss at idle and die.  Also, when driving, all of th sudden, it will just quit, as if I had disconnected the coil or something, and it tends to do it when accellarating, although it's done it a couple of times when cruising.  I also got a check engine light, and it was MAP voltage out of range (this could have been caused by the sputtering of the engine, so this symptom could be a result of the engine failing, and not the cause of it).  In any case, I checked the MAP sensor (I replaced it about a year ago, so it should be good) conections and they are all good, as are the vacuum lines.

I do have the old plugs, rotor, cap and wires, and I may try replacing them to see if anything changes, but it will have to be on the weekend...  As long as my wife does not give birth before that!

Anyway, any other hints or tips are greatly appreciated!

Felipe

PS: to top it all off, it seems my wiper motor came loose from the mechanical lever to the wipers, and now I got no wipers at all.  I tried to fix them during lunch, so I went to fold the windshield, only to strip a bolt.  Tried the bolt remover, and broke that as well, so I figured today was just not the day to fix the Jeep!

[jfrabat]

By the way, I wnet to check the fuel pressure (thinking maybe the engine was starving), and I found no pressure whatsoever; but this HAS to be wrong, as the Jeep WILL run, as the sputtering and stalling is sporadic and not constant!  And while it is running, I still get no fuel pressure on the gauge (maybe the gauge itself is broken?) but the Jeep does accellarate and keep speed (again, until it startsto sputter and stalls!).  Also, if it stalls while running, and I keep it in gear and give it some gas, I can hear some throaty sound coming from the exhaust, as if there were some flames somwhere in there but outside of the combustion chamber (I am thinking that the computer is still injecting fuel, and since there is no spark, the fuel is coming out of the exhaust and getting lit up by the cat, but what do I know!).  Anyway, please help me with this, as this is my daily driver and it sucks to be in traffic and having your engine stop suddenly (leaving you in the middle of an intersection!).

[lanulos89]

where did u dump the seafoam in.  cld of shorted out your map or anouther sensor??

[jfrabat]

By the way, I wnet to check the fuel pressure (thinking maybe the engine was starving), and I found no pressure whatsoever; but this HAS to be wrong, as the Jeep WILL run, as the sputtering and stalling is sporadic and not constant!  And while it is running, I still get no fuel pressure on the gauge (maybe the gauge itself is broken?) but the Jeep does accellarate and keep speed (again, until it startsto sputter and stalls!). 

Never mind; fuel pressure was normal (I guess I connected it wrong during lunch or something...).  I also ruled out the ECM (I connected anotehr one I had; thought maybe I shorted it out when I accidentally touched the battery hold down bar with the wrench while undoing the positive terminal for the fuse box install), but I did notice there was some play on the #2 cylinder plug wire, so I replaced it.  The Jeep did not stall while idling (which it did before I replaced it), so lets see how the morning commute goes tomorrow...  (fingers crossed!)  If this is the problem, I'll just get a new set from PD.

[jfrabat]

where did u dump the seafoam in.  cld of shorted out your map or anouther sensor??

Map sensor I also ruled out (put the old one in and same thing; old one was working when I replcaed it).

[jfrabat]

Never mind; fuel pressure was normal (I guess I connected it wrong during lunch or something...).  I also ruled out the ECM (I connected anotehr one I had; thought maybe I shorted it out when I accidentally touched the battery hold down bar with the wrench while undoing the positive terminal for the fuse box install), but I did notice there was some play on the #2 cylinder plug wire, so I replaced it.  The Jeep did not stall while idling (which it did before I replaced it), so lets see how the morning commute goes tomorrow...  (fingers crossed!)  If this is the problem, I'll just get a new set from PD.

OK, this did not fix the problem...  I was all happy coming to work andall of the sudden, when I was almost here, the Jeep started acting up again!  So please let me know if you can think of anything else that may be causing this...

[TrailsLessTaken]

How did your plugs look when you checked them? Do you still have the stock coil in there or have you replaced with a PD kit

[jfrabat]

How did your plugs look when you checked them? Do you still have the stock coil in there or have you replaced with a PD kit

I had an accell coil before I got the PD kit, so I never did get the Screaming Demon.  But the Jeep ran fine before, so I doubt that is the reason.

As for the plugs, I only replaced #2 and #3 last ight, but called it quits after that because I was being eaten alive by mosquitos.  Both looked normal, though.  TOnight I plan to replace #1 (which requires taking the AC compressor out!) and #4 and will put all the old plug cables in to completely rule that out.  I may also replace the cap with the old one (was still in working order) just to rule that out also.

I am thinking the issue is defenetly electrical, but I dont know where it is at...  I also thought fuel for a while (after all, all cylinders are missing; technically, if only one was missing, the Jeep would just run rough and not have as much power, right?) but now I am thinking more electrical...

Also, I should point out, when it stalls while driving, (if I depress the clutch to let the engine run freely) it does not quit all at once, but rather goes down to 3~400 rpm, and coughs, catches, quit, catches and then dies...  With all kind of interesting sounds in between.  When it is idling, on the other hand, it simply dies.

[TrailsLessTaken]

With the accel coil do the gaps on the plugs need to be adjusted from the factory setting?

[jfrabat]

With the accel coil do the gaps on the plugs need to be adjusted from the factory setting?

I was running it fine at .045 if I remember correctly (could have been .042, but I dont remember).

[jfrabat]

Just in case this happens to anyone else, it seems the cause of the problem is found; aparently, some oil fell into the distributor, and pooled around the bottom, and this shorted out taking the accell coil with it.  I already corrected this and put a stock coil until my new Screaming Demon arrives from PD...  Jeep seems to be runing good now (I will report if this changes).