Background: I completed a clutch job last month and this is when all my problems started. I thought I might have messed up the CPS, so I replaced with new, nothing changed. After reading FixYa issues/solutions, I ordered a TPS/IAC/MAP/O2 sensor. I replaced the O2 sensor, IAC and MAP and discovered the PCV hose was cracked. Replaced the hose and engine performance returned to normal (no more high/low idle surge). Additionally I conducted a tune-up. The following is still happening: 1-Starting cold, engine will turn over to 3000 rpms and backdown gradually to 1000. 2-Will not start when hot. Have to wait. 3-Rough Idle 4-Black Smoke Questions: 1- Do I need to change my oil? Could fuel have mixed with oil? 2- Does the injector normally tick? My last options are to change out the TPS, Fuel Injector, Fuel Filter, Fuel Pump. Any thoughts??
Thrown parts never fixes cars. 50 causes, can be 49 time guesing wrong or worse added a new defective part to the mix.
yes finish the tune up, why did you do it last>? odd no?
vacuum leaks cause, high idle on all jeeps!!
and then the ECU sees bad idle and tries over and over to reach
700rpm (spec) and cant so hunts it (that hunting today is deemed ******* , ask toyota why , fines)
all vacuum leaks do that , if it sucks AIR , illegally it will do that.
illegalll means air not from the ISC stepper drive device.
bad hoses, bad gaskets what ever.
does engine reach and hold 180f coolant temperatures???
this is first. it must, does it?
ill not guess, I propose doing a thing called TESTING.
lots of thoughts, really .... here are mine, plus RENIX facts.
I owed 2 , 1988s, with dang REnix french EFI? a horrid system.
TBI is yours TBI not MPI? (count the injectors there) mpi is 4.
no sold scan tools work on it and no CEL lamp. on RENIX.
nor does the key on 3 times trick. work before 91, dang!
1991 it changed to far better and the 3 key trick works then...
black smoke is: (rich)
high fuel pressure. (id be all over this)
then
injector leaks, (do a leak down test )
then
ECT bad, e (old name CTS)
on a hot engine, it reads (ohmmeter tests)
25,000 ohms is wrong, for 0degr. F.
317 ohms is about par for 180f normal temp , is yours 300 hot unplugged??????. a simple 5 min test.
if not the thermostat is bad or CTS bad. (IR gun it to learn this)
i see that rough idle , its MISFIRING and its really flooding .
and black smoke is always results of that, and most CATcons this old are now dead, (cat converter on all mine broke-up to bits and gone inside, and stinks any time it's rich or misfiring) par for 90s./:
the 1990 wangler books are rare, but can be found on ebay
buy one is my best advice,
its and old jeep
and its best to check compression on all old cars.
did you? x5 warm or hot, and WOT tested, (throttle open)
the 2.5L most 1990(not 91)
have TBI and ****** RENIX EFI (French junk)
only jeep dealer scan tools work here, not you.
the injector must not leak. just 1 injector here,
(key off running does it dribble now? must not) looking with eyes./
(the SM is in my hands) service manual..
2.5L (NOT 4.2L)
conducted a tune-up last
cap,rotor, wires, sparks and filters is a full tuneup on any neglected 90s jeep.
good engine first
good spark
then fueling last.
order matters, on old cars,
new cps.
yes all injectors tick but yours has only 1.
and takes a stethoscope to hear. (or my mag sensor tool)
this AMC spark system uses and ICM 2.5L only
and 50 tooth CMP sensors in the Distributor. (CPS you called it?)
my guess you replaced the TDC sensor
TDC sensor (mounted at the rear of the engine on the flywheel housing) CKP its called today. (yes names all changed long ago)
in a real shop we sCOPE the spark to see if its ok.
then check
Fuel pressure, the EFI in this car can not correct bad fuel pressure
its blind to it.
this engine has a very odd TBI
it has a pressure test port
and a FPR pressure adjustment screw.
here are the SM words on this, and I quote.
Fuel pump operating pressure is 14.5 psi (100 kPa). The fuel pressure regulator is adjustable by means of a Torx® head screw on the bottom of the pressure regulator.
top is test port
bottom is adj screw. (this is like 1st test on rich fuel)
recap.
1: cyl compression at spec, WOT.
2: a real tuneup completed ,not just spark plugs. (ICM bad?)
3: ECT reads 300 ohms hot (CTS)
4: fuel pressure at spec. 14.5psi.
5: injector not leaking. (had bad fuel in the last year, or now?)
6: there are no sold scan tools work here, so id have to scope
all ecu pins to find cause. sorry but its sticking RENIX.
has the car sat unused for a year, ? no history
when was car a good daily driver, ? last decade? last week?
I notice in your statement that at no time did you have the fault codes read
you just went ahead and wasted a heap of time and money.
reading the fault codes gives you a place to start to fix a fault
Guessing just keeps us all guessing as to if you replaced a faulty part or didn't fit the new part correctly
SOURCE: high idleing
Try pulling the engine coolant temp sensor, They often crack not sure why but the ceramic tip cracks makes the car hard to start, the car's idle may race while shifting gears, and often smokes. The sensor is on the right side of the engine when looking at it on the head. Easy to change and get too
SOURCE: 1992 gmc chevy 350 wont idle when warm
This could be a number of things but i think that your problem sounds like a vacuum leak or an EGR problem. Try listening for leaks and try un-plugging the EGR solenoid valve one time.
SOURCE: 1987 chevy S10 engine idle problem
relace the throtle air idle valve.The temp switch will allso cause this problem.
SOURCE: Misfire problem... engine stumbles at idle
my jeep was misfiring and i changed the same parts you changed.... When you changed your crank sensor, did you get parts from the dealer? if not u should trying changing the crank senor part from tne dealer. After market parts do not work good on Jeeps I had to learn the hard way..
SOURCE: 1996 Honda Accord Rough Idle Even After tune up
Perform a valve clearance inspection and adjust if necessary. Tight or sticking valves will cause a misfire or rough running concern. Note: Perform valve adjustment when the engine is stone cold. 4cyl: INT 0.26mm EXH: 0.30mm (V6 engine are hydraulic and no adjust necessary.) Also check for a sticking or stuck open EGR valve. For diagnostic purposes only: Remove the EGR valve. Place a business card over the EGR passage and bolt the EGR valve back on. This plugs the EGR ports and if the misfire goes away the EGR valve is partially stuck open and is defective.
Check for low fuel pressure. Check for low compression. Check cam timing. Check for a weak ignition coil. Also don't over look the possibility of worn or broken engine mounts which cause excessive engine movement and engine vibration. -hope this helps
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