Need some advice & info! My son & I are working on an SWB 89 Montero with a 3.0 V6 in it. I bought this girl cheap with a supposedly blown head gasket. Thought it would make a good starter 4X4 for my 16 year old son. I my self own jeeps, but decided a small SUV would be better for his first car. Well the blown head gasket ended up being an upper plenium gasket which would have been great except, the previous owner had let this unit sit for a couple of years with the coolant in the pistons and oil pan. Due to the fact that I have been a heavy equipment mechanic for more years than I care to count, I thought "No big deal, this is a prime bonding opportunity with said son". Well several hundred dollars later, I'm thinking of bonding this thing out the door!
Now that I've vented, let's get to the subject at hand.

First of all we completely tore down the engine, had the cylinders bored .045" (to get rid of water pits & etching - Told son "For bragging rights and mass power")had heads re-done and ported, new pistons, had injectors cleaned, and all the other misc. should do's: water pump,oil pump, timing belt & tensioner, etc. Put her all back together and got her running. We set the base timing at 5*BTDC as per the FSM we downloaded from the website mentioned in an earlier forum (Thankyou to whomever made that available)Set TPS, SAS, and everything else we could find. Now for the question!

1) The monty starts great (acts a little cold natured-rough idle and such for first 3-4 minutes)but had NO power. We put in a new fuel pump,& filter and tapped into the fuel pressure line. We found the fuel pressure at an idle with the regulator vacuum hose connected to be 43psi (Spec is 38) with the regulator vacuum hose disconnected it was 50psi (Spec is 47-53). One thing we noticed is that with the regulator vacuum hose disconnected the idle smoothed out and the engine no load reving was alot crisper. When the hose is connected the idle rpm drops and bounces, and the no load rev is sluggish. Suspect the regulator may need to be replaced but the results of the pressure test don't make sense to me.Could we be over fueling at an idle? (43psi) if so why does it run better at 50psi?

2) At a base timing of 5* to 7* BTDC the dude falls on it's face at low end and has no power. (I don't normally like to set up engines by ear but after explaining to my son that you should alway's use a meter or gage so you know where you are at) I started cranking the distributor a little at a time to make her fire a little sooner. Low and behold we started seeing some results, we got her set where she performs pretty decent but she still is not very peppy. We checked base timing again and found that we now have it set at 16*BTDC. Seems like a lot but that's where it runs best. When we remove the ground and check the timing she's off the little scale, and we are almost at the end of the adjustment slot on the distributor. Any suggestions or is this common with this engine.

3) Would us boring out the cylinder's to .045" have any thing to do with the engine idling better at the higher fuel pressure?

I never dealt with a Mitsu V6 before so I don't know if they are peppy at low end or kinda doggish. I do know they are expensive to work on. I like this Monty, it seams well built and solid. Any advise would be greatly appreciated. <img src="/forums/images/graemlins/cheers.gif" alt="" />

sounds like crank to cam timeing is off a tooth. have you checked the ECM for any codes. sorry i have an 89 LWB and am still trying to learn about mine also.

We checked the cam timing, it shows good, but I will probably look at it again. There are no codes in the ECM, just a steady, aggravating pulse. (I like codes- they make troubleshooting easy) Thanks for the advice. <img src="/forums/images/graemlins/cheers.gif" alt="" />

Any more out there? Help needed! <img src="/forums/images/graemlins/confused.gif" alt="" />

I suspect a distributor issue.

At TDC compression stroke, the distributor rotor should point to the firewall center. If you have it pointing at the #1 cap tower, it should be changed.

Frank

We checked the location of the distributor rotor when the timing mark on the crank was at TDC compression. It points to the center of the firewall (2 or 3 degrees to the left of the 12:00 position of the distributor itself).

We removed the timing belt cover on the distributor side head and the timing mark lines up with the mark on the backing plate ( 12:00) dead on with the crank at TDC. I haven't removed the fan belt idler pulley assembly to remove the belt cover on the other head to check that timing mark yet but will do that later this evening.

My son and I were thinking that maybe if that side were off one tooth but the distributor side was dead on that maybe that would cause the timing to have to be advanced because the light is reading off of piston #1. Just thinking!

We got to playing with it some more and twisted the distirbutor all the way clockwise, she runs better and if we plug off the fuel pressure regulator vacuum hose, she seems to really start to liven up. We checked Base timing with the distributor there and the mark is about 20 degrees off the scale. (something has to be wrong <img src="/forums/images/graemlins/confused.gif" alt="" />)

I had my son rev the engine and the timing advance seems to be working cause I could watch the mark move.

We checked the balancer and the crank bolt, both are tight and show no signs of movement.

This has really got me puzzled!!!

Something's not quite right.

The distributor foot should be set near the middle of the adjustment slot when base timing is set to 5*.... that's not exact, but where I've found mine to be. When you set base timing, did you ground the wire that deadends under the wiper motor?

If you installed new plug wires, did you notice that #1 and #4 cap towers are out of numeric sequence on the circular pattern?

You might want to check all of the vacuum lines and the EGR system.

Frank

I went out to the shop and tore the front of this @%$$## engine down and put an eye ball to the timing marks on both cams and the crank gear. All three are lined up perfectly (I was really hoping to find one off kelter!)

I pulled the damper/crank pulley to make sure nothing had slipped there- it was good.

I went ahead and pulled the distributor and looked at it real close. The internals look new. Added a new cap and rotor (just in case) and stuck her back in the hole like I new what I was doing. The rotor points just to left of the center of the distributor toward the center of the fly wheel. I am certain the mechanical timing set up is correct.

I set the base timing with a light (whilst the connector pin was grounded) to 5 degrees again. with it here it still idles a little rough, and doesn't seem to have any low end power. I moved her to 10 degrees (the lug on the distributor base is just past the stud) She idles a little better but power still seams to be lacking.

If I remove and plug the fuel regulator vacuum hose she speed up a little (approx 100 rpm) and smooth out. Power seems better but not what I expect.

I got to digging in the FSM and found in the "Engine Adjustment" section, where it says engine vacuum should be 20 in.Hg. I'm only getting 15. It is steady (no bounce what so ever) The book says this means the timing is retarded.
If I crank the distributor on around the vacuum stays at 15 in.Hg. I am begining to think the timing is a result of some other problem.

I keep wondering about the fuel pressure. With the vacuum line installed at an idle I'm getting 40psi (spec is 38psi) and with the vacuum line removed I'm only getting 50 (spec is 47 to 53) could the fuel pressure be messing with me and the timing? <img src="/forums/images/graemlins/confused.gif" alt="" />

A couple of things that might have an effect, I don't know:
1) The cat is long gone. <img src="/forums/images/graemlins/ignore.gif" alt="" />
2) We had this engine bored .045". <img src="/forums/images/graemlins/notooth.gif" alt="" />
3) Whats up with a six cylinder that has a firing order of 123456? : <img src="/forums/images/graemlins/scared.gif" alt="" />
4)While trying to figure this out I noticed that if you stare into the barrel of a pistol with both eyes open it looks like a double barrel! "CLICK" Darn out of Bullets! <img src="/forums/images/graemlins/zombie.gif" alt="" />

OK, it's possible that the balancer has spun and giving you false ignition timing readings. Now that you know the valve timing is correct, remove the cam sprocket cover on the driver side, turn the engine to align the mark on the cam sprocket with the mark on the rear cam cover. Look at the crankshaft balancer timing mark.... if it's not on zero you have a spun balancer hub and it should be replaced.

As for the ignition wires, did you notice that the cap is marked? As you look at the engine from the front, the 3 wires on the towers to the passenger side go to cylinders 1-3-5 and the 3 on the driver side go to cylinders 2-4-6.... like this:


Frank

Frank, Nice to meet you,

Once I got her back together I did exactly as you suggested and checked TDC vs Cam sprocket alignment. She's right there at zero.

Now about the spark plug wires, I learned that lesson first thing when we got the engine back together after the rebuild. I set the distributor just like I do on my jeeps, rotor facing #1 tower. Boy that stumped me for a few minutes what with her coughing and bucking and all. After fiddleing with it for a while I turned the cap upside down and found that the japs played a trick and didn't put the contacts under the towers. Had a good laugh about that with my son! <img src="/forums/images/graemlins/lol.gif" alt="" /> Once we got her corrected she fired up and ran. I do like how they keep the wires running straight tho.

Do you know what vacuum and fuel pressure yours runs at? Also if you have ever checked your stall speed? The fsm says 2100 - 2400 rpm ( I'm a long way from that @ 1600)

By the way, That sure is a purty engine <img src="/forums/images/graemlins/cheers.gif" alt="" />

James

My engine is now far from original, so the numbers won't translate, but the engine you see in the picture was a fresh rebuild as OE a few years ago. It idled at 18 in/Hg.... don't know what the fuel pressure was, since it so much trouble to test it.



If you mean the torque converter stall speed, yes, my original transmision was somewhere around 2200 rpms. I now have a rebuilt transmission with a lockup converter and I haven't remembered to check the stall speed on launch.... and I can't right now because I have a blown engine (in more ways than one).



15 is not terrible, but I'd hope for a little more once the idle quality is good. I don't know if you noticed, but the lower intake manifold has a habit of warping up from the middle toward the ends - sometimes allowing an air leak and/or a coolant leak. I don't know if yours is a problem - just passing along the results of what I've seen on a few 3.0L engines.

I'd check every vacuum line thoroughly. Check the nipples on the vacuum switch located on the front of the intake manifold water box.... they have a habit of cracking/breaking. Check the EGR system operation. Check the purge valve solenoid operation. You can find those tests in the emission section of the FSM.

Test the coil with a meter.

What about the o2 sensor?

If you can find a junkyard truck of the same year, try swapping the ECU, distributor and MAF sensor.

The 3.0L truck combination is quite peppy below 3000 rpms, so you still have some work to do. Once you sort through it, I think you and your son will be very impressed with the truck. I think it's one of the best and toughest vehicles around for it's size and price. Once you understand the systems, it becomes very easy to maintain.

Frank