5.9l Misfiring

[Nysm1]

I have the next 3 days off, so I will be ripping the heads off and checking them to make sure there is no obvious signs of distress.

Sent from my SM-G955U using Tapatalk

 

[pacofortacos]

Sounds just like mine did.

When you pull the heads, take off the exhaust springs and hand open and close the valves - other than looking at the exhaust valve seat, this was the only other obvious way that I noticed it.

 

[pacofortacos]

I will say this though, I can almost guarantee your heads are also cracked and usually not worth doing anything to them to fix them - just replace them.

Then you have several choices - steel or aluminum as well as port size, new or remans, etc.

I went with EQ's and if I had to do it over would have went with a smaller stock port vs. the larger EQ port. In fact, I actually had small (hair larger than stock magnum) port heads to replace the EQ's and then traded in the truck on my 16 Ram.

 

[pacofortacos]

Find anything?

 

[Nysm1]

Find anything?

Not yet... we had a bunch go on with Christmas and whatnot that I decided against ripping it apart. I'm just going to buy new heads and change them all at once.

Sent from my SM-G955U using Tapatalk

 

[pacofortacos]

Probably a good plan, the stockers do make good power but aren't worth doing any machine work to due to the cracking.
Mine had cracked in between the valve but also into both valve seats.

Alum. or steel?

 

[Nysm1]

Probably a good plan, the stockers do make good power but aren't worth doing any machine work to due to the cracking.
Mine had cracked in between the valve but also into both valve seats.

Alum. or steel?

Probably gonna go with Steel, but then again I have been thinking about boosting at some point in time so I may just go aluminum. That way I can start scratching off the things on my list.

Sent from my SM-G955U using Tapatalk

 

[pacofortacos]

Yeah, a lot easier to do it once

 

[Nysm1]

Yeah, a lot easier to do it once

My thought exactly.

Sent from my SM-G955U using Tapatalk

 

[dapepper9]

You can run pretty reasonable boost with iron heads. Pretty popular to do on stock longblocks actually. If you are going to swap heads EngineQuest heads flow basically the same as the edelbrock aluminum heads but for significantly lower cost.

I only picked up aluminum for my boost build based on the good deal i got for em and the compression ratio im going to be running. If i was running below 9.5:1 i would have stuck to the EQs i had. Tightening the quench will also help a lot

 

[kyle watson]

I chased a ignition for a long time. it jumped all over the engine to varying cylinders. does that sound like your issue?
isolate the coil off the block! they short out, sending pulse all over to every cylinder at once! ran mine through a splashing puddle and power would bog down and moan! WTF..

 

[kyle watson]

install a set off grommets on the stock bolts and isolate the stock coil off the steel. you may need to use longer bolt and drill to 3/8ths for the grommets. MSD uses rubber mounts on the stutter box and coil WHY! with a tune up, new plug wires, plugs, cap rotor and coil, this isolation mount mod will clean up a lot.
do a test for free! at night, shut all the lights off within 100yrds, running the engine, WATCH. look at it in the dark running. I had a BLUE Christmas tree under there at night! I fired on every cylinder every time whether it was ready or not!
OR
https://www.ebay.com/itm/4pcs-M5-M6...var=413690102524&_trksid=p2060353.m1438.l2649

 

[kyle watson]

or use non conductive bolts on the stock coil location.

 

[kyle watson]

a chrystler oops! I hope this catches on. these coils short out on the block. know it or not, they do! it should be a TSB!

 

[Nysm1]

You guys have given me a good idea and definitely a worthwhile mod. I'll do that tomorrow, today I was installing an SYE kit in my 94 wrangler lol

Sent from my SM-G955U using Tapatalk

 

[kyle watson]

SYE kit? a who

 

[Nysm1]

Slip-yoke eliminator lol its a very necessary upgrade for all Jeeps haha

Sent from my SM-G955U using Tapatalk

 

[dapepper9]

I don't see isolating the coil as very necessary at all. Thousands and thousands of these trucks out there untouched with no issues. Also thousands of other vehicles with similar setups. Many older vehicles with the old bottle coils mounted right to the engine and never had a real issue with it. My honda has an external coil very very similar to these trucks and mounted very very similarly, there's no common issues there. The v10s mounted theirs right on the valve cover as do many modern engines having individual coils for each cylinder.

MSD uses grommets on the box because of the circuitry inside. Their coils aren't quite as simple as ours either and hence the isolating though almost nobody uses them. Most just mount them right on the firewall or valve cover

 

[dapepper9]

You also can't be sending a pulse to every cylinder, physically impossible with the way the distributor works. What you can have is frequency transfer between wires that creates its own pulse and the fix for that is wire looms or tsb style routing. Thicker more insulated wires also does the trick

 

[Nysm1]

You also can't be sending a pulse to every cylinder, physically impossible with the way the distributor works. What you can have is frequency transfer between wires that creates its own pulse and the fix for that is wire looms or tsb style routing. Thicker more insulated wires also does the trick

I have limited it down to the heads being cracked and the valves being caked in carbon. I did a running compression test about a week(ish) ago and can see that a couple cylinders have a bunch of overlap during the compression cycle, which I am thinking is why my cylinders have been having issues. So my plan is to swap heads, lifters, rockers, push rods, cam, and modify my TB.
I have run through all the wiring, swapped injectors 3 times, swapped Ignition coil, cap, rotor, pickup coil, ECU, plugs, and wires with no avail. So I've narrowed it down to just old age and needing to be refreshed/upgraded.

Sent from my SM-G955U using Tapatalk