89 YJ sputtering through intake and no power after new motor (2.5, manual transmission)

[Saw]

Hello and thank you for letting me post here.
I just put a new 2.5l long block in my 89 wrangler and it started up and ran fine. I proceeded to do the break-in process and drove it after that to a friends house. Ran great, when leaving there, it started running very bad after starting it back up and I tried to make it home but it had no power and coughing through the intake. Since then I have replaced these items to try to fix it:
new cap and rotor
new spark plugs
new plug wires
new ignition module and coil.
I don`t know what it could be and the fact that it started up and ran fine to my buddys house 6.5 miles away and then upon restarting it, thats when it all went bad right now. That would lead me to believe its something that just went bad and not something wrong with the internals of the motor. I just bought it from PowerTrain products and I just dont have reason to suspect it is bad. Could it be something like an ECM reset with the disconnecting battery cables and touching them together for 30 seconds and then turning ignition on and head lights on then turning ignition off? Thank you to anyone who may have had this issue or no something about it because I am stumped

 

[ytradio]

Hello and thank you for letting me post here.
I just put a new 2.5l long block in my 89 wrangler and it started up and ran fine. I proceeded to do the break-in process and drove it after that to a friends house. Ran great, when leaving there, it started running very bad after starting it back up and I tried to make it home but it had no power and coughing through the intake. Since then I have replaced these items to try to fix it:
new cap and rotor
new spark plugs
new plug wires
new ignition module and coil.
I don`t know what it could be and the fact that it started up and ran fine to my buddys house 6.5 miles away and then upon restarting it, thats when it all went bad right now. That would lead me to believe its something that just went bad and not something wrong with the internals of the motor. I just bought it from PowerTrain products and I just dont have reason to suspect it is bad. Could it be something like an ECM reset with the disconnecting battery cables and touching them together for 30 seconds and then turning ignition on and head lights on then turning ignition off? Thank you to anyone who may have had this issue or no something about it because I am stumped

Have you checked all vacuum connections and even the hoses themselves? Something could have come loose or broken in the short drive.

 

[Saw]

Have you checked all vacuum connections and even the hoses themselves? Something could have come loose or broken in the short drive.

yes sir, checked it for vacuume leaks and repaired and checked again. Took the manifold back off to replace the gasket again and inspect manifold. when put back on and tested for leaks, all was good

 

[Saw]

since then, I have reset the computer by disconecting battery terminals and put positive cable to negative for 30 sec. and then turned ignition to on and turned headlight switch on and then off and then turned off ignition and hooked up cables and still misfire.

 

[Gilaguy23]

Is the miss an even miss like in a couple cylinders are not firing? Or is it random sputter?

 

[Saw]

CURED /SOLVED?
or only means vacuum cracks not found but is a red herring here.

All was good meaning no vacuum leaks but l am trying to keep up here I promise, this is just stuff that is sort of new to me and the weather is really bad out right now and I run out and try to work on it as long as I can stand the cold. The clamp on the distributor was always tight and I have brought no 1 cylinder up to top dead center and checked timing marks on harmonic balancer and made sure it was at zero and pulled the distributor cap off and made sure rotor was pointing directly at no 1 plug wire on the cap. Checked and rechecked and even tried to move it a tooth im either direction because it acts like firing order is off but it only runs when all timing marks are lined up correctly . I did spin the oil pump for awhile before initial start up of the motor to oil up the top end. I don't have the equipment to do a compression test but I am going to do this as soon as possible because it's just not looking good. I have not checked the fuel pump yet but know it is working but have not done a volume test or anything. I'm praying it is a fuel pump issue rather then internal parts of the motor like on the valve train. I am disabled and unfortunately I can't work any more due to pulmonary arterial hypertension I only get a little over 1100 a month to live on and spent everything I had on the motor and the parts I have since bought to try to make this happen and I still have something that doesn't work and no money to continue for the moment. I am actually heart broken over this because I have been without a vehicle for almost two months now. I have to take away things that I don't need as much as I need my vehicle and spend whatever I can to try to make it work out but so far I am broke and still have junk . I'm not complaining, these are just the facts of the matter that I have to deal with and it's slow going to get this done. I really appreciate all responses and I am trying to keep up with you guys I promise, weather is just really bad right now

 

[Saw]

Is the miss an even miss like in a couple cylinders are not firing? Or is it random sputter?

It seems to be a random sputter and it does it from the moment it starts. Nothing to do with warming up and then starting trouble. It's just trouble from the moment the motor starts.

 

[ytradio]

It seems to be a random sputter and it does it from the moment it starts. Nothing to do with warming up and then starting trouble. It's just trouble from the moment the motor starts.

My recommendation is to private message macoheadgames and ask him for advice. On the EFI engines he is about as knowledgeable as anyone on here and he will not tell you something if he doesn’t know what he’s talking about.

 

[Gilaguy23]

Have you double checked all the connections you undid when you swapped engines? Pop the dist cap off and see how much play is in the shaft. Just for chits and giggles in the absolute dark of the night fire it up with the hood open and look for spark arching across the plug wires. A few more things to try for you.

 

[Saw]

I can not hear your engine run badly, and matters most of all this. nor can I drive it.

vacuum leaks only cause, hot engine 180f, super high IDLE RPM and FULL POWER and never backfiring to the TBI.
this is a speed density TBI fuel injection system, not MAF. (as in toyota)
the MAP measures vacuum and the PCM injects based on the MAP and RPM. (and offset(trim) by the 02 sensor))
the vacuum leak (present) works exactly like the right toe pushed on the throttle .<<< facts.
yes vacuum hoses dead ,kinked,, clogged or put on wrong sure will fail.
make things like this fail
MAP
FPR.

the HOT RPM is about 800 . if way low that means,weak engine or misfiring or worse.
if the HOT (means 180 norma) is why higher RPM that means, IAC dead, or PCM is in limp home mode or gross vacuum leaks.
key on the CEL lamp glows
engine starts and CEL goes out
if CEL is on now , learn to pull the DTC errors , using the magical FSM stated, key on 3 times and stop keyed on and it flash out
morse code, (like but not really) a blink code, like 21, flash flash short pause flash long pause and EOC , 55 code,
55 means end of transmission.(comms)




all we have is this fact to work with
tell all engine running evidence, fully and answers even get better
or a youtube video of it running.

does it run ok cold (i bet not)
does it fail hot ,sure it does
but what does it do, when it fails.

lost power, (max speed is way way low) even 2nd gear is dead, lacking power.

rpm way below 800 rpm as it sure will do if 1 cylinder is dead. or 1/2 dead.

misfires, heard, seen and felt.

to the blind and deaf only facts and evidence helps, and not thrown parts.

top end oiling must be good. on any rebuilt engine and for sure if theY, never once test stand tested it for good and full oiling

again is the distributor loose

Distributor was never loosely

distributor clamp bolt missing or loose,
rebuilt engines can fail. even cheap chain put in or done wrong. (tension-er)
is this the TBI, throttle body injection system?
pull battery neg lug , for 15min, put back and is now reset, but is not going to fix this. or reset is 100% perfect as stated.
check spark timing first. if wall off , bingo. a tool called a timing lamp.
if ok, next is compression test x4

the coughing back to intake smacks of gross timing errors.
or stuck intake valve (clearances done wrong)
cam timing.
or crazy gross distributor timing. (CKP)) most jeeps here the distributor times injection, called injector sync and CKP sensor sets spark timing but of the distribute grossly timed wrong the rotor points the wrong way and backfire it can
grab the dizzy and try to turn it is step1.
the CKP sensor may be damaged,
the a/t trans page warns ( not yours) installing the tranny wrecks the CKP.
the CKP wiring must be perfect in this car, it is only weak coil type sensor. not the loved by all HALL sensors
loose fly wheel,? nah. making ckp lie.
CKP sensor loose or put in wrong.

to install any new engine in any car
we crank it with no fuel pump relay installed
and check oil pressure, 55psi is common, (pump by pass spec)
then check for top end oiling, cranked, if not we do not run any engine lacking top end oiling. (or it is doomed)
the lifters send oil up the hollow push rods and to the rockers, we make real sure that is happening.
are the lifters/rockers stock? (not high lift , mods)
a good lifter will leak down in 100second (a test of HLA and tool) c9 page 33 testing. and 34.
so if the lilter fails to move at all and not collapse under large force, the lefter is bad. but if was bad compression test fails.


the ICM can be bad, if it gets a false trigger. bad ground or wires to it bad. fsm Chapt. 8w-106)
I do not have a schematic of the ICM guts, would love to strip one down and see what is there (my guess, a huge transistor to charge and fire the coil) as most are that I have dismantled. but not jeeps.

ICM failing (by all the ways) can cause false spark. that is why using a timing light (a strobe) finds this easy. seeing gross misfire.

if the cam i time wrong spark and injections both fail.
at TDC 0degre #1 firing, both valves #1 are both closed 100% and leak down tests pass too.

back firing like that means an intake valve failed to close,
or spark is crazy wrong, so bad the rotor is pointing dead wrong.

now my wild guess so common here, the distributorbase clamp bolt missing or loose.
the bolt is R, PITA to reach on only on the 2.5L, do not overtighten it. do it to spec.
the rotor spins CCW so if loose the distributor would want to go CCW and be super retarded spark/injections
the CKP sets spark timing but if CCW the rotor at #1 the walks (1,3,4,2 Firing order) to firing #1 to spark plug 2. oops BOOM
Ive never tried that but spark timing must be right, and CAM and the rotor must be on #1 at #1 firing point.

on some cars I've seen cheap (12,000 mile away) junk rotors that fit on 3 ways. 1 right 2 wrong, (a horror when found)
but not jeeps, not seen that here.

It seems a little weird that the tab on the rotor is so wide. But I guess it works. I set the timing up to the middle of the tab on the rotor. The tab is like
and it is a pain to get to the nut on this one but it's tight

Have you double checked all the connections you undid when you swapped engines? Pop the dist cap off and see how much play is in the shaft. Just for chits and giggles in the absolute dark of the night fire it up with the hood open and look for spark arching across the plug wires. A few more things to try for you.

Yes I have checked and rechecked all vacuum lines and connections. I even pulled the manifold off to inspect it again closer then the first time to see if I could find a problem in it . I put on a new gasket and while it was running I checked it to see if it was leaking and it seems like I have no vacuum leaks. I am waiting for the weather to stop raining and will do a smoke test to see if it leaks anywhere

 

[Gilaguy23]

IMO you'd have to have one huge vac leak to cause what you describe. Also typically the idle speed would be quite a bit higher with a vac leak. I have to admit Im not that familiar with the 87 thru 90 as Ive avoided them purposely for various reasons. Have you tried pulling any codes yet?

 

[Flyer58]

Sputtering through intake. Just to clarify, does that mean it's backfiring out the carb? If it is then typically that's a spark or valve timing, or stuck valve/ lifter.

 

[deadpool1]

REDUX 1; condensed
the RENIX ECU has no 3key turns to get DTC, that happend with first SBEC ecu, not this car.
vacuum leaks cause too high idle RPM, not misfire. (unless egr valve hoses connected up wrong)
no history told
no photos of engine, or of how flywheel was installed, photos let the blind see, gee wrong parts, or put on wrong.
PowerTrain products, sells rebuilt and used engine. which one is yours?. and their jeep page ends at 1990
what is the engine serial number top right side of block near grounds bad there.
first digit is year.s/n

1. did you buy the jeep with dead 2.5L/? does the vin code for this car have "E" + 2.5L, engine coded?
2. or did it fail the old engine, out of the blue. or did it thow a rod.
3. did you use the 87/90 flywheel if not , it will never ever work with early ECU.
4. did you wreck the CKP (cps) sensor as you installed the tranny bell to engine? never do that, remove the CPS first then replace the engine. this flywheel is super rare, so getting the wrong one now is SUPER EASY
5. did you index the correct flywheel to the end of crankshaft, some have and index pin or dowl pin.
6. did the car sit for years with a dead engine, and fuel is completly bad, clogging the injector ,pump and filter , all?

the RENIX ECU is not easy to work with, (DTCs need a real scan tool to see) DTC = diagnostic trouble codes (errors)
on newer jeeps code 11 is bad CPS, my jeep early yJ book skips DTC pages.
the seller of the engine, has this page

the shipping costs to you from them are hidden (inpart) , inside the engine sales price, so returns will be very expensive.(ship)
always buy engines close to home or find a local machine shop to do it and save real cash. (huge cash in fact) shop local. win.

After our engines are fully assembled they are run through asimulation test which confirms that the engine has been assembled correctly and that it produces the correct amount of oil pressure & compression. As well as pressure testing the cooling system. This is all done with quality control scheduled inspections of completed engines to ensure that the product you receive is in proper working order & when properly installed will stay that way for years to come.

It is not run tested there. (the dyno claim is bogus and overkill)
they just do simple spin and compression and oil pressure tests. just like you would do )

not saying en engine is bad, only that the engines are not tested fully on a live engine stand ,under running real condictions.(sans trans)

there are 3 grades of tests, 4 counting nothing. sim test (them) engine stand live, and dyno(over kill as seen in race shops)
knowning these facts tell the tech, mech what might be wrong out of the crate.
the flywheel is wrong. or put on wrong, cps bad.
please tell the history first
even post a youtube video of engine messing up, (sounds, or post MP3 file of the bad sounds)
bad engine
bad spark
bad fuel or bad fueling EFI rates.

history is first
then tests
and found problems
then parts.



this fly is super rare to find USED now. BUT ONLY 4.0l SOLD BY CROWN, NOT 2.5L SADLY

87 -90 fly. see that pattern see why it must be indexed and not just be throw on to crank shaft rear end./?

UGLY BUT SHOWS RING GEAR AND TONE WHEEL BOTH FOR SPARK CLEARLY.

THE VACUUM LEAK IS NOT THE PROBLEMS (ONLY CAUSES TOO FAST RPM IT IDLE AND NEVER MISFIRES)

THE VACUUM HOSES BAD OR ROUTED WRONG CAN CAUSE PROBLEMS
THE EGR VALVE MUST BE CLOSED AT IDLE OR IT WILL MISFIRE GROSSLY. SEE ENGINE SHACK HARD.
MAP GOOD AND ITS VACUUM HOSE ROUTED CORRECLTY OR FUEL MIXTURES WILL BE GROSSLY WRONG.
THE ISA DEAD. AND RPM IS 500 NOT 800 STEADY
ISA IS THE IDLE SPEED ADJUSTER MOUNTED TO THE TBI BODY
ECT SENSOR NOT READING ALASKA TEMPERATURES.
INJECTOR LEAKS , IT HAS ONLY 1.
THE INJECTOR IS COGGED. I PART
THE CAT MELTED.
END LIST THERE ARE MORE, For sure inside engines.

 

[Saw]

Sputtering through intake. Just to clarify, does that mean it's backfiring out the carb? If it is then typically that's a spark or valve timing, or stuck valve/ lifter.

Well I did what I was afraid to do... I pulled the valve cover this morning and no. 3 cylinder has a bent pushrod and will be removing the head to see. What I have to replace. Why would it bind up and bend a pushrod?

 

[deadpool1]

I found my oldest RENIX manual now. and am OCR'ing it now, to find all references to DTC and SCANS and DRB
I will now report that now
The French ECU does not work like 1991 up SBEC AMC jeep real ECU's it is the wirst jeep ECU.(Bendix/Renix made) under contract from jeep AMC
it does not store DTCs only live DTC work. ( yes a pain) live and running.
cmp rules
chapter C76

There are originally 44 teeth around the flywheel
circumference. Two of the teeth are machined
off every 1 8 0 ° to define a precise point 9 0 °
before T D C and BDC, so only 40 teeth remain.

CMP
The T D C sensor senses TDC , and BDC, and engine
speed(RPM). It is non-adjustable (preset at the
factory in its mounting during engine assembly).
The T D C s e n s o r is s e c u r e d by s p e c i a l
shouldered bolts to the flywheel/drive plate
housing.
the distrutor has no low voltage sensors at all , like 4L has.
the CMP>>ECY> ICM > spark coil make spark and the cap rotor sends it to the spark plugs ,rotor turns CW only
the rotor looks round'ish, not like pointer.(arror) if not round it is the wrong rotor.
the first Renix car (mine) had no CEL lamp, it is not OBD1 at all it is RENIX and only DRB scan tools(and Snap-on) work and are mostly all dead now , busted , lost or thrown to the trash by shops, that ever see 87 to 95 cars,GM or jeep now. 30 years old , the cars are gone now of 700,000 made how many GEN 1, YJ still run? and licensed to the road now, (mine is)

renix = Renault+Bendix. this is the truth of the name , it is not SBEC at all
here is MT2500 like mine reading RENIX. (a used tool $150 now)

DRB tool yes, Snap one tools many can. do not listen to lies, no scan tools exist. , this is true for new tools, most do not.
the Renix is reverse engineered here, byte by bit, and MT2500 too.
using the serial TX/RX pins on ECU. communications. Just to show you how hard it is to work on this car lacking real scan tool.
also learn the data is raw binary, not formatted as all 1996 (USA) and up ECU are. << so even if you saw the date raw you'd not understand it.(a french secret for sure)

Bendix Jeep 2.5L ECU Datastream

Here is my reverse engineering work on the Bendix 2.5L Electronic Control Unit found in 86-90 Renix Jeeps. This self contained unit is in charge of running the engines Renix Throttle Body Fuel Inje…

nickintimedesign.com

The Renix may have limphome mode too. (as do 99% of all ECU/ECM/PCM DO)
so if one sensor fails the ECU sees that and then simulates the dead sensor (so the engine can still run)
TPS dead, ecu simluates TPS using MAP and RPM.
if CPS is dead there will be no spark and not fuel.
in limphome mode fueling goes huge nasty rich and misfires hard (and in 1996 USA , does not do that so bad)
the scan tool above shows crazy injection rates (PW called injector pulse widths)
the ECU is in limphome. I bet.
no dead sensors allowed.
for sure MAP, TPS< ECT, CPS (CKP) nor EGR stuck open , that too makes the ECU go MAD.
huge PW, means ECU did this on PURPOSE
for limphome
or for MAP is dead. or reads crazy wrong
if the vacuum is bouncing hard, (a tool) that means valve are bad in head or timed wrong)
vacuum at hot idle is near 20"inches of Hg. on the hand gauge.
if it bounces this will make the ECU goe mad. Map data doing same makes ECU go mad.
the old ECU are slow and can not average vacuum readings. so fails.

2nd clue is a hot idle , CLOSED loop Fuel mix AFR is dead. called open loop. we bird dog this firt.
there is just taste of using a scan tool. on RENIX.

read the above as why does limphome mode cause gross rich as a pig fueling and HORRIBLE 10mpG fuel usage?
the older the car the worse limphome behaves. (old slow/dumb processors then)

so are spark plug tips black now?

 

[deadpool1]

SOLVED now. as I typed , RENIX facts
rod bent is intake or exhaust. ??????

your question now are super easy to answer
any tech can , it's called basics (the enigne is a huge air pump first)
a compressor in fact (air)

it bends for these reasons

1. not doing DAY1`the top end oiling test , before running any new engine, fuel pump relay pulled,oops.
2. then the lack of oil made 1 or more head valves stem/guide seize up and valve bent or push rod.
3. HLA valve last adjuster , bad or jammed or will not compress under load. even bending the valve as it hits the piston top
4. the #3 cylinder is full of oil or coolant. hydralocking this cylinder. (or fording streams? nah)
5. the valve end,poppet is damaged and hits the pistion (bent valve) yes head off is PRIME next act.
6. one can use bore scope camera to inspect the cyclinder via spark hole , plug out. for damage signs , any.
7. the spark plug tip again not looked at first. is key fact missing here, soaked or the tip looks like hit from huge hammer.damage max. spark tips speak loudly if seen.
8. the HLA may be bad, or even it jammed in its own bore. inside or outside it jammed. cheap import HLA can do that.
9. wrong pistons used, stock are reverse domed if not wrong. the dome is cut for normal valve lift + milling for 30+ years.

now we know 3 things failed.
compression dead #3
vacuum gauge bouncing like mad,
and spark tip #3 looks super ugly.
and sure inspections do work and only cost is 10mm socket wrench. we love the 10mm jokes but this time is true.
way to go and thanks for feed back,!!!
scan tool shows MAP reads wild and crazy readings. SOVLED.
pulled the lid and SOLVED


if any HLA jams up, the valve can be fully stuck open and if is the piston hits it.

or the valve guide is bad and the valve stuck open. boom.

 

[deadpool1]

crate engines 101
what I do?
I pull the bell off the tranny to the engine, M>T bell off m/t box to the engine back end,.
make sure the flywheel is one, not later, or it will fail.(cmp fails later) no need for a clutch
and mount the starter (plus battery and my starter jumper button kit)
and crank the engine on the pellet. with full engine oil put in it.
for good compression (a tool) $29
and 55psi oil pressure at the oil sender port (a guage) $15
then off the valve cover and and check for top end oiling
and valve action normal.

they say they did that but , I never put in any engine unless my test pass.
wasting 10 yours labor put in any engine, and finding it dead is not fun. nor cheap.
at the least this.
never trust rebuilders. do the basic tests.
make sure cam timing is spot on. I'd trust nothing . valves down piston up is not going to work.

 

[deadpool1]

head off ,arrow front
and damage hit marks on top are not good
if it got hit the rod bearing can get damaged.
the HLA are leak down tested before insertion, they must leak down. per FSM. chapter 9 engine.
the leak down allows them to self adjust lash.
note the asymmetry here. left/right

 

[deadpool1]

they said compression was checked but to what standard, 150PSI not 100.
if at 100 the cam was timed wrong.
or your discovery was the tip of the ice berg.
only all damage seen , helps to know cause. , timed wrong and HLA failed.

 

[Gilaguy23]

Well I did what I was afraid to do... I pulled the valve cover this morning and no. 3 cylinder has a bent pushrod and will be removing the head to see. What I have to replace. Why would it bind up and bend a pushrod?

You need to talk with the engine shop or seller and tell them what you've found. They might deny warranty if you screw with it to much. Hate to say it but you may also have a damaged camshaft as well. I feel for you man. Last vehicle Id own if I was financially limited is a jeep. Its frustrating enough with all the crap china parts and no can do shops of lately. Frankly I sold my last jeep a couple weeks ago and possibly will never own another. This is after 45 years of wrenching and emptying a bank account keeping them on the road. Best of luck getting things sorted out.