spankrjs's Biloxi, MS '83 Scrambler

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
Also of note - I was having the idle speed vary, too high sometimes. Come to find out, the throttle return spring on the throttle body was NOT closing the throttle all the way at idle. I added an old clutch return spring as a secondary throttle return spring, works perfect now.

I have this issue with my Red Scrambler sometimes, too. I always assumed it was an IAC issue, but I will add a secondary spring to the throttle like I did on my Green Scrambler.

I thought this was kind of "Redneck Ray", but factory 4.0 YJ's and Cherokees came with a secondary throttle return spring, just like what I installed. Pretty sure my 05 LJ does NOT have a secondary return spring.

The secondary throttle spring also makes the pedal a hair stiffer, which helps smooth out the "jerky/responsiveness" at low speeds I had before.
 

Ron84cj

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
West Bend
State
WI
I agree about the o2 sensor. Just about every time I saw that code it was usually the o2 sensor or a vacuum leak. When they fail it's not always right away. They get "lazy" and don't fluctuate fast enough. When you turn your AC on, it might be just enough of a jolt to the system to turn the light on.
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
I agree about the o2 sensor. Just about every time I saw that code it was usually the o2 sensor or a vacuum leak. When they fail it's not always right away. They get "lazy" and don't fluctuate fast enough. When you turn your AC on, it might be just enough of a jolt to the system to turn the light on.

That's what I'm hoping for :fingerscrossed::fingerscrossed::fingerscrossed::fingerscrossed::thumbsup::wave:
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
I worked on this one all weekend, off and on, still not sure if I fixed it, maybe, who knows, time to light it on fire and push it off the cliff in the back yard!!!

Saturday morning, swapped out the O2 sensor. I had a spare, easy enough swap.

This was my spare:

IMG_20190720_091801879.jpg

IMG_20190720_091809079.jpg

It is slightly different then the one that was in there. Old left, new right. The old one looks fine, no strange deposits or anything on it.

IMG_20190720_090554470.jpg

Marking on the replacement O2 sensor, I guess I was bored and took these pictures?

IMG_20190720_090609515.jpg

IMG_20190720_090644111.jpg

So, I installed the spare O2 sensor, and had high hopes for an easy fix. Nope. CEL (Check Engine Light) came on after five minutes of 60 mph highway driving. Let it cool down 5 minutes, cleared the code, everything working fine again.

I noticed this, it's not cracked all the way through, but still kind of odd? This is the inside of the throttle body.

IMG_20190720_160223804.jpg

I have been checking the fuel pressure, both before and after the CEL comes on. It is always at 60 psi. But, when the CEL is on, the gauge is bouncing off 60, not steady, a clue maybe?

IMG_20190720_160240046_HDR.jpg

I have been driving around with the scan tool plugged in. I got tired of having to do a "scan" to bring up the CEL, finally installed a CEL. I had this bulb and plastic clip in a junk box. Wired it up, clipped it to the door strap post, done. Supposed to be "temporary", we know how that goes. Anyway, the CEL I put in my red Scrambler is in a metal bracket, screwed to the dash, which is grounded. It stays halfway lit up whenever the key is on. I think it is half way grounding through the bracket/dash. Anyway, the plastic clip does not provide a ground path, works perfect. It seems like an odd place to mount it, but it is easily visible.

IMG_20190720_173258619.jpg

Thinking back to my original "Code 51 extended lean issue", I am pretty sure it is heat related:

1) turning the AC on aggravates the condition (more engine load, more under hood heat)
2) high speed driving trips the CEL within 10-15 minutes
3) after a 5 - 10 minute cool down, I can clear the code, everything is fine for 10 - 15 minutes
4) wrapping the fuel rail/injectors/manifold shield eliminated the "hot restart issues" completely
5) no problems when it is cold outside
6) no more crap fuel, has good fuel, still have the issue

So, with nothing to loose, spent about $70 on some thermal wrap from the local part stores:

IMG_20190721_133505359.jpg

IMG_20190721_133515304_HDR.jpg

The larger size is really a too big, but it was on the shelf, so i used it on my rubber fuel line. A 5/8" ID would be a tighter fit, but the 3/4 ID will work The smaller stuff worked perfect over my 5/16 hard fuel lines. The smaller stuff also cost twice as much!!!! I bought two boxes of the 3/4 stuff, one box of the smaller stuff. And it matches my DEI fuel rail wrap!!!
 
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spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
Started at the fuel rail, worked backwards to the passenger side frame rail. I had a piece of plastic tubing over this fuel line before, no thermal protection at all, more for abrasion protection.

IMG_20190721_133551447.jpg

I cut one of the 3' pieces of the 3/4 stuff to fit over this rubber line.

IMG_20190721_145725836.jpg

I had enough left over to cover this rubber line on the passenger side (stock CJ fuel line mounted on frame to YJ under oil pan cross over tube):

IMG_20190721_145628162.jpg

IMG_20190721_145756379.jpg



I used the smaller DEI sleeve to wrap the YJ under oil pan line, it took all 4' of it:

IMG_20190721_145701885.jpg



So, I now was wrapped all the way to the passenger side motor mount bracket.

IMG_20190721_145822250.jpg
 
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spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
Bought another box of the 3/4" stuff, wrapped the passenger side rail back 3'. It is now insulated all the way back to the Dana 300.

IMG_20190721_181459450.jpg

I wasn't too happy with how the wrap looked, especially at the ends, it will fray easier. The box that had the smaller ID stuff had these inside:

IMG_20190721_153603606.jpg

I slid them on the ends of the larger wrap, really cleaned it up:

IMG_20190721_153613591.jpg

IMG_20190721_153619677.jpg

IMG_20190721_181405559.jpg

IMG_20190721_181444676.jpg

Now, all my fuel lines are insulated, from the transfer case all the way to the injectors. And, it looks like the friggin Lunar Lander with all the foil!!!!!!

Does it work? MAYBE.

After I wrapped everything, I took it on the interstate. 90 degrees outside. !5 minutes at 70-75 mph, pulled off the interstate, got right back on, 15 more minutes at 70 - 75 mph. No CEL.

The picture below shows my red neck data logging.

First column is slow neighbor hood driving, before wrap. No CEL, all is OK.

Second column is mid way through an "easy" 55 mph run, before it got the CEL. You can see the O2 counts dropping, the injector duration increasing.

Third column, after clearing the code, return trip home. Same road/distance as second column, BUT got caught in a rain storm, cooled everything down, no CEL.

Fourth column, after wrap, no CEL.

IMG_20190722_160518806_HDR.jpg

The O2 sensor stuff makes sense, voltage drops closer to zero the leaner it runs.

The injector rate makes sense, I could watch this duration increase as the O2 sensor voltage drops off as it gets lean.

Charge temp makes sense, the hotter it is outside, the hotter the incoming air.



What make no sense is the "AIS", which is the idle air control. I thought it was closed once you were off idle?

I am going to drive my red Scrambler, which works fine, has the same 4.0 MPI, and record what its IAC does at different speeds.


The IAC valve on the green Scrambler might be messed up. It would not compensate for the AC, I had to drill a hole in the throttle plate. I plugged this hole back up, now it compensates for the AC.

So, did the thermal wrap work? MAYBE

Do I have an IAC issue? MAYBE
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
I did some more testing/data gathering last night.

I do NOT think the IAC has/had any affect on my problems.

The below picture is my "chart".

Red = Red Scrambler, stock 4.0 (header), supply and return at rail
Green = Green Scrambler, 4.2 bored 40 over, very mild cam, stock exhaust, supply only at rail

IMG_20190723_081926283_HDR.jpg

Cold start, where the IAC is at immediately after start up. Green has a slightly higher initial "flare". Both steadily drop from their high to the idle position during warm up. The green goes to 28 after 45 seconds, then more slowly drops to its idle position.

REV to 2000 cold, revving the engine to 2,000 RPM after start up, or anytime at idle, NO change to the IAC position.

Warm idle, engine up to temp, idling. Red is open to 16, Green is 0 - 2. Kind of strange, I figured the green would be open more at idle. It is not starving for air, idles fine. MAYBE this has to do with the head difference between the two engines?? Maybe a vacuum leak I can't find is supplying some additional air to the engine at idle?

Any speed after idle, what it says. Working up through the gears, accelerating hard, cruising, where the IAC is at. Very interesting that both are almost exactly 8 steps above there base idle point. (16+8=24) (0+8= 8)

I am not an engineer, and do not have FSM for 1991 - 1995 YJ Wranglers. I am "speculating", based off what I have read, that the PCM holds the IAC open some during driving to prevent choking off the engine when you decelerate. When decelerating in either Scrambler, nice and easy or abruptly, no change in the IAC position. Both maintain that "8 steps above idle setting". After slowing down and idling, both IACs return to their base idle position (Red 16, Green 0-2)

Not sure why the Green one was at 24 the other day on the highway?

The Green Scrambler looks to have a non-Mopar IAC valve. I have a spare Mopar valve I might intsall, just to see if anything changes.

Long story short, pretty sure the IAC was not the cause of my issues.

I drove the green Scrambler on the interstate for 30 minutes yesterday, no problems.


Maybe insulting the fuel lines worked :fingerscrossed: :shrug: :fingerscrossed:
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
Swapped out the IAC valve just for the hell of it last night.

IMG_20190723_173923038.jpg

The unit on top was a new OEM Mopar spare I had. The one on the bottom is the one I pulled out. The one I pulled out has the same stampings in the plastic as the Mopar one. Probably the exact same part, who knows?

I checked the IAC cavity in the throttle body, it was clean. This does not surprise me, it only has like 1,000 miles on it, and I had just sprayed a bunch cleaner into it on Saturday.

Swapped them out and started it up, idled like crap the first minute or two, then smoothed out. I had the scan tool plugged in, the PCM was moving it all over the place at first, then it "learned" where it needed to go.

One cold start and drive yesterday, one this morning:

IMG_20190724_080305230.jpg

The idle is a bit smoother now, holds steady 704-736 RPM. When I turn the AC on, it drops to around 650, then picks back up to the 704-736 idle, once the PCM moves the IAC valve. The 24 while running is new, same as my Red Scrambler now?

Anyway, seems to be idling smoother. I am going to drive it at work the next few days, lots of stop and go, hot restarts, etc. Hopefully it is "fixed" :fingerscrossed:

I need to correct my speedometer gear, I am 11% off since I putt he 31" tires on (60 MPH actual/55 MPH indicated).

One pleasant surprise since the fuel line insulation, the MPG has picked up.

Two tanks of fuel with the "CEL/Lean" issue, around 13.5 MPG.

1/2 a tank/fixed, 1/2 a tank "CEL/Lean" issue, around 15.25 MPG.

No CEL, yet :fingerscrossed:
 

Ron84cj

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
West Bend
State
WI
That's awesome, glad things are going well. As far as fuel economy goes. You're actually getting better mileage than what are clocking on the odometer. You're speedo gear is also affecting how many miles you put on odometer as well. Since the speedo is reading slower than what you are really doing, your odometer isn't putting on as many miles as what you are really doing. Not sure if you posted this already, but are bringing this one to sandblast?
 

FLCJ8

Legacy Registered User
City
Palm Bay
State
FL
That's awesome, glad things are going well. As far as fuel economy goes. You're actually getting better mileage than what are clocking on the odometer. You're speedo gear is also affecting how many miles you put on odometer as well. Since the speedo is reading slower than what you are really doing, your odometer isn't putting on as many miles as what you are really doing. Not sure if you posted this already, but are bringing this one to sandblast?
Good point... the fuel economy theoretically can be increased by ~9% just with the speedo gear change.

I think I should change the gears on my vehicles to increase their fuel economy. :rotfl:
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
That's awesome, glad things are going well. As far as fuel economy goes. You're actually getting better mileage than what are clocking on the odometer. You're speedo gear is also affecting how many miles you put on odometer as well. Since the speedo is reading slower than what you are really doing, your odometer isn't putting on as many miles as what you are really doing. Not sure if you posted this already, but are bringing this one to sandblast?
The MPG calculations were modified to reflect the 11% difference, so the 13 -15 is it, so far. Hoping that the lean issue is resolved, maybe MPG will go up a hair.

Not sure on taking this one to Sand Blast, still not 100% confident in it yet. The red Scrambler made it to Moab and back earlier this year, it should be good to go :fingerscrossed:

Prepping this one as "back up" for the Red Scrambler. There are still a few things I want to do to it before a long trip, mainly front wheel bearing/hub maintenance. No real problems in this area, but I have never repacked the front wheel bearings./spindle bearings. It also has the 5 bolt hubs, I want to install some studs to better secure the hubs. If I can get it done before Sand Blast, I might take it.

The only thing the Red Scrambler needs is an oil change :fingerscrossed::shrug:
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
Good point... the fuel economy theoretically can be increased by ~9% just with the speedo gear change.

I think I should change the gears on my vehicles to increase their fuel economy. :rotfl:
Probably the cheapest/easiest way to do it :thumbsup:
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
Temperature outside, 87, with humidity, only 90.
Max engine temp - 195


Drive in to work, city/highway, no AC, no problems, around 7am.

Drove around an hour this morning, 9-10am, city, stop and go, extended idling, AC on, no problems.

Left office, went to a meeting at 12:30, 10 minute drive with AC on, no problem.

Left meeting, AC on, a few stop and goes, no problem.

Next stop, 3 minute sit and idle, AC on, it starts missing and choking down, smells like raw gas, turn AC off, still missing, turn engine off:banghead:

Let it sit five minutes, starts up fine, no AC, runs fine.

Drove 10 minutes stop and go, no AC, no problems.

Last stop, start up, AC on, drive for 10 minutes back to office, let idle 10 minutes, no problems :shrug:


Not getting a warm and fuzzy feeling.

Maybe the IAC is still "learning":fingerscrossed:

'
More then likely, I have some other problem that is contributing to this condition that I have just not found yet :shrug::twocents:
 

tmancj7

Basic User
City
Denver
State
CO
Intermittent issue with the MAP sensor? I have the MOPAR MPI single line kit on an 85 CJ7 and purchased a new map sensor over a year ago after a drive home where it was displaying the same issues you are having, missing, trying to stall, raw gas smell out the exhaust. Never replaced the MAP sensor as the problem went away until a cold start two days ago. Turned it off immediately and let it sit for about a minute, started up and ran fine the rest of the day. I don't clearly recall what led me to suspect the MAP sensor, probably nosing around on the HESCO forum site pointed me in that direction. I am running the Novak in tank pump and regulator.
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
Intermittent issue with the MAP sensor? I have the MOPAR MPI single line kit on an 85 CJ7 and purchased a new map sensor over a year ago after a drive home where it was displaying the same issues you are having, missing, trying to stall, raw gas smell out the exhaust. Never replaced the MAP sensor as the problem went away until a cold start two days ago. Turned it off immediately and let it sit for about a minute, started up and ran fine the rest of the day. I don't clearly recall what led me to suspect the MAP sensor, probably nosing around on the HESCO forum site pointed me in that direction. I am running the Novak in tank pump and regulator.
I have "casually" looked at the MAP pressure/voltage readings, I will actively log them and see if anything strange is going on :thumbsup:

On the "input" sensors,

O2 seems fine
intake air temp seems fine
throttle position switch seems fine
MAP seems fine, will double check

When I say "seems fine", the voltages check out and the "readings"; i.e, on the TPS, voltage is correct, % of throttle is correct.
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
On the way home yesterday:

20 minutes at 70-75 MPH AC on, no problem
10 minutes at 55-60 MPH AC on, no problem
15 minutes of 65-70 MPH AC on, no problem
15 minutes of 35-55 MPH AC on, no problem
20 minutes of city stop/go AC on, no problem
5 minutes of 75-80 MPH AC on, no problem
5 minutes of idling at my house, AC on, no problem

Drive in to work this morning:

65-70 MPH AC on 10 minutes, no problem
10 minutes city stop/go AC on no problem

Maybe it just had a "brain fart" yesterday afternoon :fingerscrossed::fingerscrossed::shrug::shrug:

On the engine temp, at high speeds, AC on, it will run up to 205, never hotter.
My red Scrambler, no AC, gets to 208, never hotter.

These temps don't concern me, my TJ/LJ run at 210.

With no carpet in the green Scrambler, you can feel the increased heat load of high speed driving. Once off the interstate, anything under 60 MPH, including stop/go and extended idling, with the AC on, it stays at 195.
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
Two hour drive this morning, AC on the whole time, lots of stop and go, lots of 5 minute idling time, a few hot restarts.

Only one minor/slight stumble after an extended idle once I started driving it down the road, no big deal.

One "issue" with the Hesco/Mopar MPI kit computer vs an OEM Mopar 4.0 computer - I have no AC provisions. I will have to call them and see if i can "add" the AC circuit to it. But, the programming might not support AC??

On this Jeep, with AC off or on, it idles at 700-736. This is a hair low with the AC on.

My TJ/LJ idle up higher with the AC on.

A slightly higher idle speed "might" clear up my extended idle time 'issue" :shrug:

Factory 4.0 AC equipped Jeeps also have a built in "AC clutch delay until the IAC idles the engine up". On mine, when I turn the AC on, the clutch instantly engages, the idle drops about 75 RPM, then picks back up. On my LJ, the engine idles up slightly BEFORE the Ac clutch engages.


This might not be possible with the HESCO/Mopar computer.
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
Another stumble while slow speed driving after an extended AC idle, no other issues.

Almost positive it is heat related.

I have been driving around with my "hole in the throttle plate" plugged. The next time I drive it all day, with the AC on, on a hot day, I will unplug it, see if the slightly higher idle with the AC on has any affect.
 

tmancj7

Basic User
City
Denver
State
CO
Intermittent problems are so GRRRR! Is the PCM still throwing a Code #51 Lean Condition when the engine stumbles? Did you or HESCO adjust the timing on the PCM or is it at the factory setting? I know you can subtract 6 degrees of timing in the PCM but it takes one of the factory Jeep/MOPAR diagnostic computers.

On the HESCO/Mopar PCM I understood that HESCO deleted the a/c and voltage inputs/programming so their computer would not throw CEL's. On non HESCO factory computers the missing a/c input will throw a code but not trigger the CEL, the missing voltage input will throw a low voltage code and a CEL.
 
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