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5.7 TBI "slightly stinky exhaust" and not as good MPG

Fried the MAP sensor? That would be highly unusual unless you had terminals hanging out of the connector. Either way it would be hard on the ecu because the map sensor grounds thru the ecu.
 
mysunnshine said:
Fried the MAP sensor? That would be highly unusual unless you had terminals hanging out of the connector. Either way it would be hard on the ecu because the map sensor grounds thru the ecu.
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After grounding the spark plug wire incident, I turned the Jeep off. Before turning it off, it ran fine, minus the #6 plug wire being installed.. Upon restarting it, it ran like crap, had a MAP sensor code. I unplugged the MAP sensor, disconnected the battery, touched the terminals, no dice, code would not go away until I changed the MAP sensor. No other codes.

Now, the Jeep wont start up unless the throttle is 1/2 way down, wont idle by itself. You can keep it running with throttle. If you let off the throttle, it will die/run real poor. It is acting like the timing is way out, it will diesel, back fire through throttle body, etc..

So, hopefully after I re-time it, it will run like it did before, and then I can get back to diagnosing the 60psi Cylinder #6 compression, and the 120psi Cylinder #3 compression:crazy::thumbsup:
 
spankrjs said:
I grabbed the end of the wire, off the spark plug, with the engine running, and pulled it off the plug, and it popped the crap out of me, causing me to drop it, it then started firing to ground, on the frame:crazy:
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I'm glad I'm not the only one that does crap like this. Makes me feel better when mechanics like yourself do it too. ;) I hope it didn't fry anything important.
 
Polarfire said:
I'm glad I'm not the only one that does crap like this. Makes me feel better when mechanics like yourself do it too. ;) I hope it didn't fry anything important.
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I'm definitely not a "professional mechanic", I just try to minimize my "boo-boo's",: Paging destroyed Dana 300 output shaft:rolleyes::eek::thumbsup::wave:

Worse case, maybe it screwed up the module in the distributor, or the main TBI computer, hope not:popcorn::fingerscrossed:
 
too bad there wasnt a camera rolling... would have been a funny video for The Youtube.
 
It's hard to believe they wouldn't build something in the system to protect the computer or other components if the plug wire grounded.
 
Bad Karma said:
too bad there wasnt a camera rolling... would have been a funny video for The Youtube.
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It was even funnier watching me repeatedly trying to pick up said wire, with the engine running, popping the crap out of me:rotfl:

jammer1 said:
It's hard to believe they wouldn't build something in the system to protect the computer or other components if the plug wire grounded.
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mysunnshine said:
Lol....that's funny
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Yep:(

Got sidelined with step throat/sinus infection, should re-start the diagnosis soon:wave:
 
Hope it gets better (both you and the cj8). Notice I put you before the cj8, must be a weak moment.:rolleyes: Hope you feel better.
 
jammer1 said:
Hope it gets better (both you and the cj8). Notice I put you before the cj8, must be a weak moment.:rolleyes: Hope you feel better.
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LOL, appreciate it, you old softy:thumbsup::cheers::wave:

I'm feeling a bit better, and got the Scrambler a bit better............................
 
Against doctors orders, I went back and did some more "work" to the Scrambler.

I went ahead and disconnected the coil, pulled fuel pump fuse, pulled #1 plug, and re-checked TDC. It was dead on. I then marked all the plug wires, pulled them off the distributor cap, and pulled the cap. Cap, rotor, and ICM look fine, no burn marks, crack, tracks, etc. Rotor was pointing right at the previous #1 plug wire location, so good to go.

I re-installed #1 plug, disconnected the "computer timing wire", and started the Scrambler up. I had to manually keep the gas down, holding the RPM up around 1200 to keep it running.

The first time I ran a scan, the scan tool was reading "PROM ID=0", so it would not display anything, i.e. no codes, no operating data, nothing.

So, I rescanned, and this time it recognized the PROM, and pulled 3 codes, and I think these codes popped up because I tried to re-start the Scrambler with the MAP sensor and Spark Timing Module unplugged (I had unplugged them when I was pulling off plug wires/distributor cap):

34 - MAF/MAP Sensor too low
43 - Electronic Spark Control Failure
42 - Electronic Spark Timing Monitor Error

After running about 2 minutes at 1200 RPM, the engine suddenly started running better, So, I gently let off the gas, and it was idling like normal again. So, with it idling normally again, checked the timing, it was at 0, like it is supposed to be with the "computer timing wire" unplugged.

I tightened the distributor back down, turned the Jeep back off. I pugged the "computer timing wire" back in. I then disconnected the battery for a few minutes, and touched the battery cable ends together. I re-connected the battery, Scrambler fired right up. Checked the timing, it was around 16 degrees advance, like before.

So, what happened to it, I don't know? It is running just like before now, with no codes. I turned it off and on several times, let it run about 45 minutes, running like before now.

So, that's good. The bad, my Scan tool took a dump, screen is stuck on "initializing", no longer works. I will try to update the software, see if that fixes it up.
 
So, after all that, with the Scrambler running "normal" again, curiosity got the best of me. I pulled off the passenger side valve cover, since it is easier, and because cylinder #6 was showing 60psi compression before.

With the valve cover removed, oil deflectors installed, engine idling, watching the rockers/springs/pushrods, the #6 set of valves did not look the same, did not seem to be at the same "rhythm" as the other, not moving up and down quite as much, looked a bit weaker, just did not seem "right".

When I changed the valve stem oil seals, I was super anal about the valve adjustment. When I removed the rockers, I kept detailed notes on how many turns each rocker nut was down. Before I ever messed with the valve train, when I removed the rocker nuts, they all took almost exactly the same amount of turns to come off. When I readjusted the valves, I used this as a base line, and my readjustment was almost identical to the previous setting.

With that being said, I figured what the hell, and slightly tightened the nuts a bit more, maybe a quarter turn each. Almost instantly, the RPM picked up about 100 RPM, and the engine was running much, much smoother. I was really happy, for about 5 minutes.

I turned the Jeep off, pulled the #6 plug, and re-installed the compression tester. It is now reading 30psi?????????

Adjustment on the rear valve of the pair made the most difference when slightly tightened. Not sure if that was intake or exhaust, it was getting dark, couldn't tell if that was the valve over the spark plug or exhaust manifold port??

All the valve train appears to be in "sync" now. So, I have a smoother running engine, slightly higher idle, but lost 30psi on a cylinder that previously only had 60psi compression, and it seems to run better:shrug:

I plan on pulling off the driver side valve cover this weekend to take a look at #3.

On the passenger side, I had Tiffany take a look at the valve train before I made any adjustment. She had no "prejudice" against #6, but she even pointed out it looked different from the other cylinder pairs.
 
The bad, my Scan tool took a dump, screen is stuck on "initializing", no longer works. I will try to update the software, see if that fixes it up.
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Sounds like you downloaded the gremlin from your ecm to your scan tool.
 
I will probably go ahead and readjust all the valves again.

I will do it the "messy way", engine hot and running. Loosen each adjustment nut till it starts to clatter, then a 1/4 turn tight, see if that changes anything:shrug::fingerscrossed:
 
MAJOR EDIT - When I re-checked the compression on #3, I forgot to hold the throttle open. So, the new measurement is not comparative to the original measurement. I will re-check #3 with the throttle open and post the compression reading.

I am also going to add a tablespoon of oil to the other 6 cylinders that all have 190-200 psi readings. IF they go up 30 pounds, I am going to assume that this "back yard/redneck check" will eliminate a ring issue.

IF that plays out, and I run a leak down test to confirm the rings are good, and a valve adjustment does not fix the low compression (doubt it but fingers crossed), looks like I will just be pulling heads.

IF the bottom end seems to have issues, I might just bite the bullet and install a GM long block, hopefully it does not come to this, we will see :fingerscrossed:

Ill try to post up any new findings over the weekend, in case anyone is reading this with baited breath:rotfl::wave:
 
You need to twist the ecu case while it's running. Those tbi ecu's are prone to getting cracks in the traces on the circuit board which expand and contract with heat. When you twist the case, you can test for those issues.
 
Retested cylinder #3. Engine cold, throttle open, 45psi. So, a gain of 15. Removing driver side valve cover now. Will check ECM case. It is mounted in stock AMC computer location/bracket under dash.

Scan tool works again.
 
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