Engine stalling out
 

On montero sport 3.5....After replacing timing belt, cam and crank seals, cam and crank sensor, timing belt pulleys, timing belt tensioner, water pump, and thermostat due to oil leakage on alternator, which was also replaced, I boosted the battery turned over engine. It ran smooth with no leaks. I took it for a test drive. As I was driving the car seem to want to die when coming to a stop or slowing down. When I pulled in the driveway it stalled out. I turned it back over and pulled it in garage. It was missing as I was doing so and stalled out again. I check under hood everything look ok. After 5 min started it again. It idle smooth for bout 15 min and just shut off. This time I try to turn it over it at act like it didn't want to start.. after fighting with it will start up but stutter bad and stall out. When hit the gas it would backfire ah bit. So at that point it would either just turn over or start stutter and stall out. But if I wait a while and start it it would start and run normal for bout 20 sec then go back to doing same and stalling. What could be the issue. Theres no engine light at the time maybe cause battery died and I had to boost. Anybody got any steps to diagnose this issue

Start with the basics. Do you have fuel in the tank? It sounds like you may have run out.
Then go through the triad: Fuel, Spark, Compression. You have compression since it started. So look for spark. Look for fuel. Is the fuel pump running when you turn on the key (not starting)? Low fuel pressure can cause it to die.

Then go looking for unfortunately your own mistakes. Electrical connections--MAF/Map sensor connections are insanely easy to forget to reconnect or to not click into place. Idle Air controller, same thing. Check your alternator wiring. Did you do it right? Check your ignition wires and coils for proper installation--the wires like to short out onto the engine, right through their "insulation" and should therefore be floating over the cam covers, not touching them.

Also, the fuel filter could be clogged. Have you ever replaced it? On my 94 Montero, it is located down under, on the frame below the driver's seat:

What was the outcome of this?

Yea, let us know RedRum.

That's why I ask.

My 2002 Montero Sport acted up today stranding my daughter. She drove it to a store, no issue, When she started it to leave, ran extremely rough and quit. Crank and crank and nothing. Wife arrives, gets it started, bucks and backfires, quits, restarts, runs like its out of fuel (3/4 tank), but she gets it home. Four hours later I am home and it starts and runs like it always has so no first hand symptoms to assess.

I am not aware of the fuel filter ever being changed on it. It has ~193k on it now. We bought it new. Ordered a WIX 33580 fuel filter and will pick it up tomorrow and futz with it this weekend. Hopefully the fuel line is not too corroded (sprayed penetrant today preemptively).

My saga with this thing is here
https://mitsubishiforum.com/forum/mi...removal-48920/

Larry....... Wow, thats pretty amazing if you have never changed the fuel filter, and with 193k on her. I would think that if you took it on for the service interval work, that they would have changed it at least a couple times. Im sure you cant go wrong by changing it. Those bolts are probably pretty darn tight holding the hard fuel lines onto the filter. I highly reccomend that you use flare nut wrenches (gives extra gripping so you dont tear up the fitting nuts). Its kinda a pain working on your back, and I think you have to loosen the mounting bracket after you break loose the two line fittings. I also use little rubber nipple plugs that I can fit over the fuel line after they come loose from the filter, in an attempt to lessen the amount of fuel that leaks out of the lines.

Larry.......I will have to start reading your thread on the engine work.....looks real informative/interesting, and Im sure I can learn a thing or two.

Good luck on the fuel filter.

Yeah I am concerned on how stubborn the fuel line nut and bracket bolts will be. The link below provides a clear description on the hex sizes and tools needed (see Posts 4 and 6) as well as pictures of the filter and the bracket (I stole a picture from there and reposted here). I will be picking up a 14mm flare nut wrench for the fuel line fitting. The bracket has a bolt which tightens the "band" portion of the bracket which encircles the filter; I will try to loosen this bolt and leave the main bracket bolted to the frame. I watched a Youtube video where the guy disconnected the fuel pump relay (right passenger foot well) and then started the vehicle till it quit; his method of depressurizing the high pressure fuel line.
https://mitsubishiforum.com/forum/mi...861/#post26921

From the Manual:
FUEL FILTER REPLACEMENT M1135001300067
1. Bleed the residual pressure from inside the fuel line. (Refer
to GROUP 13A, On-vehicle Service P.13A-887.)
As there will be some pressure remaining in the fuel pipe
line, cover it with a shop towel to prevent fuel from spray-
ing out.
2. Press the high-pressure fuel hose retainer to disengage the
connector, and then remove the high-pressure fuel hose.
3. Hold the fuel filter with an adjustable wrench and loosen the
flare nut. Then disconnect the main pipe connection.
4. Remove the fuel filter.
5. Install the fuel filter, high-pressure fuel hose and tighten the
flare nut of the main pipe to the specified torque.
Tightening torque: 37 N⋅m (27 ft-lb)
6. After installation, check that there are no fuel leaks.
(1) Apply battery to the fuel pump drive terminal to operate
the fuel pump. (Refer to GROUP 13A, On-vehicle Service
P.13A-888.)
(2) Check for leaks when fuel pressure is applied.
https://cimg4.ibsrv.net/gimg/mitsubi...688619a60a.jpg
https://cimg5.ibsrv.net/gimg/mitsubi...e40ddf2ba4.jpg
https://cimg6.ibsrv.net/gimg/mitsubi...1ea9176ba0.jpg
https://cimg7.ibsrv.net/gimg/mitsubi...ca28ecb263.jpg
https://cimg8.ibsrv.net/gimg/mitsubi...f7478f5b0a.jpg

Yep, thats the filter. Except for my 94 Montero, which had the flare nuts on both sides of the filter.....which I tend to prefer over that clip type connector.

Would be interesting to try blowing air thru your old filter to see how clogged it was, or even flushing backwards with gas to see the crud that comes out. Which leads to another question........have you ever removed the little round cover under the rear seat area, and then taken out the fuel pump? It should have a screen on the inlet side which may be getting clogged with rust/debris. I think there are about 8 small screws holding it down, and I highly reccomend first soaking them with PB Blaster, as they are often getting pretty rusty up there. (I think you have to disconnect the battery to prevent the positive terminal from grounding, causing a spark and a bad fire.....saw some guy do that on youtube, but not sure if it was a Montero).