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  #46  
Old June 16th, 2017, 08:57
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Re: Engine miss above 2000 RPM

Quote:
Originally Posted by 90xj06 View Post
does your LTFT ever end up changing?
No, not that I have seen on either jeep, yet. have only monitored it in park.

I changed all the spark plugs, it ran a little bit smother but is still running rich with a steady miss and pop pop pop.... steady exhaust poping sound at 3000 rpm after replacing the plugs tells me there is too much fuel, and some is getting into the exhaust unburned. Some plugs running rich, some fouled worse than others. I had one load back fire out the exhaust earlier this week that smelled of gasoline real strong all around the beast. The STFT and O2 sensor says it is running too rich and the ECU can not compensate enough. So it must be the injectors.

I really think some trash got in them when I fixed the QC fuel line feed to the rail recently. All the dots are looking connected now. I hope!!!

Fuel rail and injectors are next, pulling them today.
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34 MPG , '85 2WD Cherokee Pioneer with custom installed, 64 hp, 2.2 L Nissan SD22 Diesel 5 spd Manual; & 4 Renix XJs, '87 Wagoneer 4.0, 4WD, 89-Cherokee, 4WD, '87 Cherokee 2WD, & '89 Cherokee Pioneer 2WD, all 4dr. #2091
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  #47  
Old June 18th, 2017, 14:40
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Re: Engine miss above 2000 RPM

Well, well, well, pulled the fuel rail today, and as I was moving things out of the way, found a hidden out of view, cracked and bad leaking rubber vac hose holding the plastic tube going from the Throttle body intake Vacuum to the MAP sensor and even a bad part of the plastic tube itself that was cracked.

BINGO!!!! I am sure this was the problem!!!!

I felt since day one this problem was acting like a MAP sensor vacuum line leak and I even looked twice for one, and tested the MAP sensor with the Snap On scanner, and still missed it. Must have been a large enough leak to make it run rich and go haywire when the engine moved the tubing and made the leak bigger, but could not see and quantify that on a scanner during heavy acceleration. But a small enough leak at a smooth idle to go closed loop with a crazy low STFT to compensate.

Fuel injectors have no leaks at 40 PSI!!! Am still going to spray test each injector.... before I reassemble it to make sure they are all OK, as all spark plugs were not equally fouled. But none of them are leaking with 40 psi pressure on the fuel rail.

So this beast may make 300,000 miles with out major engine work after all.

All this fuss, and exotic dual scanner testing, to find a .01 cent piece of rotted rubber. And I'm the damn choir here on that topic LOL.

Happy "Not The Mama" day to all those other dads out there. Oh BTW, Wonder Woman is AWESOME!!!! Got to see it for it for "Not The Mama" Day LOL.
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34 MPG , '85 2WD Cherokee Pioneer with custom installed, 64 hp, 2.2 L Nissan SD22 Diesel 5 spd Manual; & 4 Renix XJs, '87 Wagoneer 4.0, 4WD, 89-Cherokee, 4WD, '87 Cherokee 2WD, & '89 Cherokee Pioneer 2WD, all 4dr. #2091

Last edited by Ecomike; June 18th, 2017 at 14:43.
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  #48  
Old June 18th, 2017, 21:06
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Re: Engine miss above 2000 RPM

Well that was a disappointment. I found an obvious bad plastic and rubber vacuum hose section in the MAP sensor vacuum supply I missed in two prior inspections. Fixed it, the fuel injectors had no leakers , and since I found an obvious MAP vac hose source of the problem I skipped the fuel injector spray tests, put it back together and at first it seemed fixed.

No more super low STFT, runs in closed loop except for 1-2 seconds in rapid decel mode, like it should. STFT at idle is about 55 after clear the ECU memory. STFT at higher RPMs and during acceleration is higher, in the 70s. Decel it gets close to 128 on STFT.

It drives OK 0-30 mph if I do not push the gas too hard (ok up to 2500 rpm it seems). Accelerates better under load, than in park from 750 to 2500-3000 rpm. It runs stable at up to 2500 rpm now some times to 3000 rpm before the pop pop pop starts in the exhaust.

My intake manifold is now running about 30-60 F hotter than it has in the past. What would cause that?? My IAT sensor is just as hot as the CTS readings on the Snap-on scanner, both about 80 *C (I use a 180*F T-stat). This is brand new today, was not doing this before!!!! The intake use to peak at about 160 F, IAT use to peak at 60*C, till I fixed the MAP sensor vac line today.

Quote:
Originally Posted by cruiser54 View Post
Start with a complete set of ZFR5Ns........

And, what is the cPS output? Is it's harness grounding out when the engine torques?
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Quote=8Mud: "Go ahead and put up the best fence you can build, I'll bet on some Mexican with a few dollars of nails and a pile of scrap lumber."
34 MPG , '85 2WD Cherokee Pioneer with custom installed, 64 hp, 2.2 L Nissan SD22 Diesel 5 spd Manual; & 4 Renix XJs, '87 Wagoneer 4.0, 4WD, 89-Cherokee, 4WD, '87 Cherokee 2WD, & '89 Cherokee Pioneer 2WD, all 4dr. #2091
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  #49  
Old June 19th, 2017, 19:41
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Re: Engine miss above 2000 RPM

Pulled the intake off the throttle body and ran an entire LARGE can of gum through the intake. No smoke in the exhaust, zip, nada. Tried three times to see if it was carbon in the head and intake. Did no good.

Tried a new MAP sensor, rechecked the MAP sensor connections 3 more times. No joy. No change. Rechecked the sensor and battery grounds, all good.

Down to sticking injectors, and or bad valves, valves going bad or sticking now.

No other ideas at all. Thinking of trying a quart of MMO in one last desperate move to see if it frees up something sticking in the valve train. I do have a pretty thick oil mix in it, but it is summer time here and the 12 year old, cold weather sticky lifter tick is not present currently.

Next step I guess is pull the valve cover, and fuel rail again. Check the injector spray patterns, and valve train parts. But I suspect since it runs so well at idle, it is not going to be the injectors, unless they choke at high flow rates from trash in them????

Any thoughts on the injectors????

The Injectors past every electrical test. Only test I did not run is a peak flow flow test at higher demand flows, but the fuel pressure is perfect all the time so they have flow and pressure at the rail.
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Quote=8Mud: "Go ahead and put up the best fence you can build, I'll bet on some Mexican with a few dollars of nails and a pile of scrap lumber."
34 MPG , '85 2WD Cherokee Pioneer with custom installed, 64 hp, 2.2 L Nissan SD22 Diesel 5 spd Manual; & 4 Renix XJs, '87 Wagoneer 4.0, 4WD, 89-Cherokee, 4WD, '87 Cherokee 2WD, & '89 Cherokee Pioneer 2WD, all 4dr. #2091
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  #50  
Old June 19th, 2017, 19:49
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Re: Engine miss above 2000 RPM

Quote:
Originally Posted by cruiser54 View Post
Start with a complete set of ZFR5Ns........

And, what is the cPS output? Is it's harness grounding out when the engine torques?
It happens even if I slowly raise the engine speed in park, in stealth mode. It hits a speed where it starts to go pop pop quietly out the exhaust, then it hits speed where it stops going up in speed and starts to miss badly, and I push it further it will back fire out the exhaust hard enough to damage something like the muffler or Cat. It is better under load, which is interesting.

On a 90F day in park, at 2500 rpm, what is the normal intake air manifold temperature?

Edit, I think I am going to clean the MAT-ACT-IAT (Take you pick LOL) the Intake Air Temp sensor before I pull the valve cover.
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Quote=8Mud: "Go ahead and put up the best fence you can build, I'll bet on some Mexican with a few dollars of nails and a pile of scrap lumber."
34 MPG , '85 2WD Cherokee Pioneer with custom installed, 64 hp, 2.2 L Nissan SD22 Diesel 5 spd Manual; & 4 Renix XJs, '87 Wagoneer 4.0, 4WD, 89-Cherokee, 4WD, '87 Cherokee 2WD, & '89 Cherokee Pioneer 2WD, all 4dr. #2091
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  #51  
Old June 19th, 2017, 19:53
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Re: Engine miss above 2000 RPM

You left off a spare head and valve train parts on that list!!!

Quote:
Originally Posted by old_man View Post
I recommend you hit a junk yard and pull a set of sensors, including the CPS, MAP, Air Charge Sensor, throttle position. If nothing else, put them in a baggie under the back seat for emergencies. I would also grab a coil and ignition module.

I kind of went through what your are trying on the same issue, and I finally pulled a used CPS out of the bag and tried it and presto. Being an Electrical Engineer and working with sensors all day, I would have given it less than one in a thousand odds that it was the cps, because it ran flawless until it hit the higher rpms.

I have also seen cracked coils and bad ignition modules cause similar issues.
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Quote=8Mud: "Go ahead and put up the best fence you can build, I'll bet on some Mexican with a few dollars of nails and a pile of scrap lumber."
34 MPG , '85 2WD Cherokee Pioneer with custom installed, 64 hp, 2.2 L Nissan SD22 Diesel 5 spd Manual; & 4 Renix XJs, '87 Wagoneer 4.0, 4WD, 89-Cherokee, 4WD, '87 Cherokee 2WD, & '89 Cherokee Pioneer 2WD, all 4dr. #2091
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  #52  
Old June 20th, 2017, 16:23
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Re: Engine miss above 2000 RPM

New problem, started out as a start and dies issue today. Seems I can not get a solid connection on the old MAP to electrical connector. Trying the new one from China from have created the problem. It starts and runs now but just barely touch the connector and it dies now. That was not a problem before I tried the new made in China MAP sensor last night. Gonna replace the connector, I have a stash of new weather packs here.

Then I plan to pull the valve cover, inspect the guts and spray soak the valve train and lifters with MMO and PB Blaster, let it soak in overnight then fire the beast up again. Also going to pull the fuel rail and make sure injectors spray right at WOT using a 9 volt test battery and a primed fuel rail.
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Quote=8Mud: "Go ahead and put up the best fence you can build, I'll bet on some Mexican with a few dollars of nails and a pile of scrap lumber."
34 MPG , '85 2WD Cherokee Pioneer with custom installed, 64 hp, 2.2 L Nissan SD22 Diesel 5 spd Manual; & 4 Renix XJs, '87 Wagoneer 4.0, 4WD, 89-Cherokee, 4WD, '87 Cherokee 2WD, & '89 Cherokee Pioneer 2WD, all 4dr. #2091
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  #53  
Old June 21st, 2017, 17:39
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Re: Engine miss above 2000 RPM

Fixed all the vacuum line and electrical connector issues that developed on the MAP sensor. But now the can of Gum Out I ran through the intake manifold and throttle body has the engine stumbling at just 1200 to 1500 rpm now.

Runs closed loop, Map sensor data is good, TPS data, CTS, IAT....spark, CPS...al working properly still. Still running low on STFT at idle in closed loop.

But since I ran the cleaner through the intake, it now will not even go over 1500 rpm. I was able to slowly get to 3000 rpm before I messed with the MAP sensor and had to sidetrack and fix it. There was zero smoke running the cleaner thought the intake vacuum lines and throttle body. Still runs smooth in closed loop at 750 rpm

But the STFT is still low, indicating the engine is getting too much fuel if it uses the table data fuel setting in closed loop. This suggests sticking open, slow to close, fuel injectors to me.

Also concerned some carbon came loose over night from the can of cleaner I used last night, and is maybe fouling the valve seats causing the miss????


Also when running in the heavy miss mode, the STFT finally went to high range today, up to 200 even. Why???? But it still seemed to be running rich, and a little more pedal and it backfires out the exhaust due to too much fuel.

It stayed in closed loop most of the time this time. Even when miss firing. That is NEW today!!! I could see the O2 sensor in closed loop switching properly.

Storm from the Gulf coming, I hope it passes us, and lets me tackle the injectors tomorrow
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Quote=8Mud: "Go ahead and put up the best fence you can build, I'll bet on some Mexican with a few dollars of nails and a pile of scrap lumber."
34 MPG , '85 2WD Cherokee Pioneer with custom installed, 64 hp, 2.2 L Nissan SD22 Diesel 5 spd Manual; & 4 Renix XJs, '87 Wagoneer 4.0, 4WD, 89-Cherokee, 4WD, '87 Cherokee 2WD, & '89 Cherokee Pioneer 2WD, all 4dr. #2091
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  #54  
Old June 22nd, 2017, 08:05
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Re: Engine miss above 2000 RPM

I would try another CPS. I don't care how new the old one is.
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  #55  
Old June 24th, 2017, 09:47
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Re: Engine miss above 2000 RPM

Well I pulled the valve cover and cranked the engine, I could not find any signs of problems in the valve train at all. I soaked the valve train with PB Blaster, a second brand of Pen lube, and then drowned it in Marvel Mystery Oil, MMO, in case something is making the valves stick at speeds above idle.

Also pulled the fuel rail, cleaned the grunge and oxidation off some of the fuel injector electrical contacts, male and female as best as I could. Then with the fuel rail primed to 40 psi I tested each injector with a 9 volt battery to see if they sprayed OK and shut off rapidly. As best as I could tell eyeballing them with a falling fuel pressure on spray pattern (they are 4 hole injectors), and doing rapid click tests for on off response time, the injectors all seem to be OK. I don't have a rig for flow testing each one to make sure they are all still a balanced flow as a set.

I'm running out of ideas.
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Quote=8Mud: "Go ahead and put up the best fence you can build, I'll bet on some Mexican with a few dollars of nails and a pile of scrap lumber."
34 MPG , '85 2WD Cherokee Pioneer with custom installed, 64 hp, 2.2 L Nissan SD22 Diesel 5 spd Manual; & 4 Renix XJs, '87 Wagoneer 4.0, 4WD, 89-Cherokee, 4WD, '87 Cherokee 2WD, & '89 Cherokee Pioneer 2WD, all 4dr. #2091
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  #56  
Old June 25th, 2017, 08:49
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Re: Engine miss above 2000 RPM

New question. How much rotational play is OK for the Renix distributor?

Running wise it has gotten way worse, barely runs at idle now, back fires, misses badly, and can not get it above idle at all since I ran the can of Gumout through it and added one can of B-12 to the gas tank, and used the 2 pen lubes and MMO on the valve train.

I checked the dizzy alignment at TDC of cyl #1. It is dead on. So this is not a basic timing, jumped timing change issue. But I do not like the rotational play side to side limits I see. But I do not think it is the problem, if it is a problem at all. I think mine has had this much play for ages.

I swapped the ICM and HV coil with a known working one. No change.

I disconnected the O2 sensor for a test run, no change.

I tested the CPS, I have 0.60 AC volts cranking. Its OK, awesome in fact.

I replaced and cleaned and tightened up the CPS contacts and connector (new) on the wiring harness side of the CPS so it grips/clamps the two ends together nice and tight. No change.

So I pulled the new spark plugs, they were all terribly fouled already, all six brand new plugs completely coated with carbon on the ceramic insulators (which is I think conductive...grounds out the spark, so I am cleaning them right now), one plug was barely hand tight, loose , a second plug, #1 had a totally cracked ceramic external insulator (I must have damaged it some how).

I plan to pull the fuel pump relay, use compressed air and cranking with no fuel (disconnect the CPS), to dry out the cylinders. Then install good cleaned plugs if they clean up well enough (or new ones), inspect them, install them then reconnect the CPS, but with no fuel feed (pulled FP relay), and crank it some more fire off any remaining fuel, try to complete the dry out, then put the fuel pump relay back in and see what she does next.

If I can find my hand Vac-pump-gauge assy, I will test the new MAP sensor using it and MT-2500 scanner to see if it is meeting OEM spec.

I fear the head, piston tops and valves are too fouled with carbon to avoid pulling the head.

Any more ideas????

Haynes manual suggested tapping/hammering the top of the tappets with a hammer to try and clean the valve seats???? Ever heard of this???

One last thing, the valve train was inspected with valve cover off, while cranking and then while running and it is nice and quite and working perfectly, no ticking or knocking...etc.
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Quote=8Mud: "Go ahead and put up the best fence you can build, I'll bet on some Mexican with a few dollars of nails and a pile of scrap lumber."
34 MPG , '85 2WD Cherokee Pioneer with custom installed, 64 hp, 2.2 L Nissan SD22 Diesel 5 spd Manual; & 4 Renix XJs, '87 Wagoneer 4.0, 4WD, 89-Cherokee, 4WD, '87 Cherokee 2WD, & '89 Cherokee Pioneer 2WD, all 4dr. #2091

Last edited by Ecomike; June 25th, 2017 at 08:56.
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  #57  
Old June 25th, 2017, 11:08
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Re: Engine miss above 2000 RPM

What does a visual on the spark tell you. Pretty easy to pull number two plug, open up an old plug to 0.060, ground the plug and look at the spark.

When my idle messes up this is usually my first check. I use my Renix on my hunting lease, mud puddles splash all over the engine compartment. I've had numerous low voltage to the ignition module episodes cause weak spark, line lose through water in the connectors or where ever. If you find you have weak spark you can start back tracking and find the cause.

I don't really know what your issue is, to much fuel (MAP?), CPS missing/skipping pulses causing poor ignition and excess fuel or an ignition issue?
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  #58  
Old June 25th, 2017, 12:50
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Re: Engine miss above 2000 RPM

How the Fork do I turn off the fuel supply so I can crank it, keep the spark and dry it out?

I pulled the FP relay(s) and it primed itself and started anyway LOL, then died. Then it immediately primed itself again? WTF??? 87 Wagoneer XJ, stock, no fuel pump ballast.

Quote:
Originally Posted by 8Mud View Post
What does a visual on the spark tell you. Pretty easy to pull number two plug, open up an old plug to 0.060, ground the plug and look at the spark.

When my idle messes up this is usually my first check. I use my Renix on my hunting lease, mud puddles splash all over the engine compartment. I've had numerous low voltage to the ignition module episodes cause weak spark, line lose through water in the connectors or where ever. If you find you have weak spark you can start back tracking and find the cause.

I don't really know what your issue is, to much fuel (MAP?), CPS missing/skipping pulses causing poor ignition and excess fuel or an ignition issue?
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Quote=8Mud: "Go ahead and put up the best fence you can build, I'll bet on some Mexican with a few dollars of nails and a pile of scrap lumber."
34 MPG , '85 2WD Cherokee Pioneer with custom installed, 64 hp, 2.2 L Nissan SD22 Diesel 5 spd Manual; & 4 Renix XJs, '87 Wagoneer 4.0, 4WD, 89-Cherokee, 4WD, '87 Cherokee 2WD, & '89 Cherokee Pioneer 2WD, all 4dr. #2091
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  #59  
Old June 25th, 2017, 19:18
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Re: Renix Engine miss above 2000 RPM

I used the Matco-Ferret Engine analyzer, which has a magnetic field pick up coil that senses and reports the Min, Max and average HV spark voltage, the rise time and spark duration time for each cylinder and it was all in the normal range when I ran those tests a week ago at idle, when I first started working on this problem. It also tests the current, and timing of the pulse feed to the ICM/HV coil. Far more sensitive than tests in real time in milliseconds. I also swapped out the ICM/HV coil from a running Renix, tested it before the swap, and tested the one from my problem jeep on the good jeep, and have in multiple ways confirmed that should not be a spark issue. I am going to back and check the MAP sensor vacuum line and wiring, as this stinks of MAP sensor issue to me.

I tested each fuel injector and cleaned the connectors, they all seem to be working fine, on/off is very fast, no leakers, fuel pressure is not the problem at all in way shape or form, FPR is not leaking into the Vac line, and I tried running it with the O2 sensor disconnected and it had no effect.

What bothers me is the valve train passed a visual operating, cranking and running test, but all this started in 3 stages.

One was a 3-6 week slow creep of issues at 3000 rpm cold and under heavy acceleration it would stumble and back fire. Then stage two could not accelerate fast or run at 2000-3000 rpm (rpm varied as to where it would miss and back fire), then I found the MAP sensor Vac line problem, thought I fixed it (it was an obvious source of this type of problem was the vac line was more than bad enough to cause it), then I worked on it some more, both electrical connector and the Vac line and changed the MAP sensor. But it did not fix the stage 2 problem of not running past 1200 rpm with out backfiring and stumbling. Then when I soaked the valve train with PB blaster, (and a second pen lube product and MMO), overnight and ran a can of gum out through the intake and let it set overnight it barely runs now at 500 rpm, at idle or even at WOT for 60 seconds on the throttle body-TPS, it just runs at 500 rpm stumbling and popping out the exhaust. It never once smoked out the exhaust like I hear Gum out should do.

Quote:
Originally Posted by 8Mud View Post
What does a visual on the spark tell you. Pretty easy to pull number two plug, open up an old plug to 0.060, ground the plug and look at the spark.

When my idle messes up this is usually my first check. I use my Renix on my hunting lease, mud puddles splash all over the engine compartment. I've had numerous low voltage to the ignition module episodes cause weak spark, line lose through water in the connectors or where ever. If you find you have weak spark you can start back tracking and find the cause.

I don't really know what your issue is, to much fuel (MAP?), CPS missing/skipping pulses causing poor ignition and excess fuel or an ignition issue?
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Quote=8Mud: "Go ahead and put up the best fence you can build, I'll bet on some Mexican with a few dollars of nails and a pile of scrap lumber."
34 MPG , '85 2WD Cherokee Pioneer with custom installed, 64 hp, 2.2 L Nissan SD22 Diesel 5 spd Manual; & 4 Renix XJs, '87 Wagoneer 4.0, 4WD, 89-Cherokee, 4WD, '87 Cherokee 2WD, & '89 Cherokee Pioneer 2WD, all 4dr. #2091
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Old June 25th, 2017, 19:36
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Re: Engine miss above 2000 RPM

OK, here is the summary of today's efforts.

I pulled all the plugs last night, soaked them in a solvent based carbon remover. Cleaned them, and dried them.

I used compressed air and blow gun to blow dry the combustion chambers, and with the CPS disconnected I cranked it 5 times for about 15 seconds. Then I used compressed air again to blow dry via the open spark plug holes.

Then I tested compression.

As I thought cyl 3,4,5,6, all rock solid at exactly 150 psi each.

Cyl 1 is still 135 psi, and cyl #2 is still 140 psi. (been like that for 11 years, 70,000 miles).

Then I installed the plugs and plug wires, verified the right wires going to the proper plugs 3 times.

I tried to start it with the fuel pump relay pulled (wanted to get spark and no fuel for a bit before letting fuel in there, yes am I anal-overkill-methodical LOL). But the damn timed fuel prime bypasses the fuel pump relay???? REALLY???? AMC strikes again???? Seriously??
It starts right up and dies after 3-4 seconds. Repeated that 1-2 times. Then I put the FP relay in fired it up, and got the ha-ha you wasted your time message.

NO CHANGE, dido. At idle and at WOT it will idle at 500 rpm and puke, stumble, back fire a little here and there, but nothing else.

HELP!!!!

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Quote=8Mud: "Go ahead and put up the best fence you can build, I'll bet on some Mexican with a few dollars of nails and a pile of scrap lumber."
34 MPG , '85 2WD Cherokee Pioneer with custom installed, 64 hp, 2.2 L Nissan SD22 Diesel 5 spd Manual; & 4 Renix XJs, '87 Wagoneer 4.0, 4WD, 89-Cherokee, 4WD, '87 Cherokee 2WD, & '89 Cherokee Pioneer 2WD, all 4dr. #2091
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