P0174 and mutilpy misfires

[chef]

I just picked up this 2003 MS XLS and have been chasing down this code cause. 


Since it needed I replaced plugs, plug wires, installed a Fel Pro intake set that included everything from lower intake to EGR gaskets, valve cover gasket set, Camshaft thrust O-rings, Fuel Pressure Regulator and a bank 2 sensor 1 O2 sensor (only read up to .001), and I've checked all hoses for leaks. I've checked the injector resistance and they are within range.  I've also checked the fuel pressure but it was the pressure out of the fuel filter reading at 49 PSI. 


After I reset the DTC it happens when I put it under load (up hill or hard accel.).  It idles a little rough.  I'm in the process of ripping everything off to check the timing belt.  Any ideas.  I'm gonna also bench test the Engine coolant temp sensor and TPS too since I've got it apart. Any hints as to what to look into would help as this is my first Mits I've worked on. Thank you

[jkdv8]

If it started after the plug and wire change make sure the ignition coils and wires are going to their corresponding cylinders. What plugs and wires did you use.

Firing Order (facing engine)
5 O O 6
3 O O 4
1 O O 2

I think the ignition coil order is stamped on the manifold.


Check the fuel pressure at the rail if you can. Also, the ignition coils and ignition module. Change the fuel filter to if you haven't yet. I don't know what the pressure is suppose to be so can't say if the 49 psi is ok or not but that sounds about right.

[chef]

Ok I just opened the timing cover and there is so much slack in the timing belt that I can lift it off. I'd have to say that just might be the problem.

The codes have been on going. What I've done so far has been an attempt to fix it.



Anyone have any hints that'll help me with the timing belt. I read a little about a different than normal procedure for putting tension on the belt.

Thanks


Edit. The FSM says pressure should be 300-350kPa which 49PSI is like 340ish kPa.

Edit:

I turned engine by hand a couple of revolutions and it tighten right up... I'm thinking the tensioner is bad. Am I right?

[jkdv8]

Yea that quite possible if it jumps timing but it's not really "tight" (so to speak) to begin with. Should of asked you this before, are you getting the P0300 for multiple misfires or just the cylinders on the lean bank.

[chef]

I've got p0300 and for cylinder 2,5,6 but not at the same time. I've cleared the codes each time and then tired to get it to throw a code with it being a p0300 or an individual cylinder misfire.

I'm thinking the guy before only changed the water pump and belt because the idler pullies look original Koyos and the tensioner looks as old as the pullies.

Think I might just replace it all but the belt and pump. Gates belt looks good and the sticker says it was done 18k ago.

I think I see the timing mark on the crank. Is it a small notch on the back of the gear and a small mark on the block. The timing mark on the pully is about an 11 o'clock position.

[chef]

I'm thinking that with a dysfunctional tensioner that when I put it under load that the timing goes out enough to misfire but when I let off the gas it jumps back. Kinda like that slack I found in the belt when I opened the cover. I just got done kicking the engine over to loosing the crank bolt.

[chef]

Apr 26, 2016 17:40:45 GMT -5 jkdv8 said:

Yea that quite possible if it jumps timing but it's not really "tight" (so to speak) to begin with..

There's a huge difference between when the was slack that I could slide the belt off the water pump and when it tightened up after a couple of hand revolutions.

[jkdv8]

You sure the O2s are working correctly after replacing the one. You should replace with oem as some do not play nice.

it would require it to jump teeth to cause a misfire and it would be constant. The little bit of stretching wouldn't be enough to throw timing unless it was real bad but if that was the case you would have bigger issues than just misfires.

Ok ,I was just checking. Some people are under the impression timing belts are tight like an accessory belt but, that isn't the case. Slack opposite the tensioner is normal. Also where the cam is at in the stroke when the engine stops can impact this as well.

[chef]

It was the same gap on both sides.

Attachments:

[chef]

O2 readings in the my OBD2 software was within range according to FSM specs. 

[chef]

Well I tested the tensioner and it was out of spec.
Got a new Gates timing set ordered and hopefully I'll have it in this weekend to fire it up and confirm.
Thank you for the help.

[jkdv8]

Not a problem. Yea I would say that's a little loose. Check the seals and pulleys while you're in there.

[chef]

Got that timing belt done this weekend and decided to replace the exhaust manifold gaskets too since they were soaking in oil from the valve cover leaks. Well when I pulled them off I saw problem 2 to make me go lean, a fat crack and one starting in the other. No more codes but still runs a little rough at idle that I can see a shake in the transfer case shifter.

[ES_97Sport]

May 3, 2016 1:12:54 GMT -5 chef said:

Got that timing belt done this weekend and decided to replace the exhaust manifold gaskets too since they were soaking in oil from the valve cover leaks. Well when I pulled them off I saw problem 2 to make me go lean, a fat crack and one starting in the other. No more codes but still runs a little rough at idle that I can see a shake in the transfer case shifter.

I think you mean rich. Oxygen introduced between the exhaust port and the O2 sensor will appear to the engine as running lean and the ECM/PCM will richen the mixture causing the engine to run rich. And this is not a good thing for your CATs.

Edward

[chef]

I was referring to the code.

So even after all that I was still getting a rough idle and when I tried to accelerate up hills I'd bog down and get a misfire code (multi &/or individual). Read up on here some more and thought I go to the You Pull It and pull off an ICU to trade out and test. My original ICU had tested fine with an ohm meter so I tried it anyways, so I put the wrecking yard part.

Worked like a charm with wrecking yard part. Idle is as smooth as a baby's butt and I can actually pass now uphill. And I just thought it had really shitty acceleration like in all the reviews I read about for the MS.

It's for sure that the last owner hadn't done much or only did enough to get by.