Running Very Rich ... help

[pauleatstoomuch]

Hello, New member here.

I have a 89 Montero SWB 3.0 v6 5 speed 4wd with 135,000 mi

It was running great for the first year I had it, then all of a sudden it began to run very rough. I replaced the spark plugs, plug wires, fuel filter, o2 sensor, fuel pressure regulator, timing belt, and the ECU. I also cleaned the mass air sensor and the idle air control valve.

It does not run any better. It is running extremely rich, and I am getting terrible fuel economy.

I took it to a garage, and they could not pull any codes, and could not figure out what was wrong with it.

My only guess from here is fuel injectors... Anyone have any other ideas?

Thanks!

[peter92]

i had a similar problen with my nh, it turned out to be the injectors
they can get there and test the injectors for you with out taking the off
cost me 450 to get mine done
i think it was called
co2 fuel test, thats how they found out about my injectors
it checks the hole fuel system
hope this helps you out
regards peter

[Sl9]

you replaced te ECU? seems pretty extreme unless there was another fault with it.
if your pretty nifty with a tool set you can take your injectors out yourself and send them to a mechanic who has a injector test bench.
they'll flow them and see if they are putting out the right amount of fuel and clean and re flow them. this often improves the injector alot and is often pretty cheap in comparison to what peter92 said about the co2 fuel test.

but if your unsure or unwilling to say its your injectors id do what peter mentioned.


also this may sound a bit stupid but you havent been messing around with the timing at all? and does your car have a MAP or MAF sensor because ive heard on other cars (im not to sure about pajeros) but they can be faulty and be reading the wrong amounts but not throw a code because the sensor sees no faults. so might be worth getting out the workshop manual and checking what the sensor should be reading at certain pressures and times and check that against an output voltage.

thanks.

[pauleatstoomuch]

Thank you both for the input. The ECU was cheaper than the injectors. Got it for $130. I found a injector servicing / turbo shop locally, and they will refurbish them for $20 each. I think I will go ahead and do that. No, I didn't mess with the timing. Yes, it does have a MAF sensor. I cleaned it, and I don't think that is it. I will try getting the injectors refurbished and let you all know the results. Should be in the next 2 weeks. Thank you.

[mr moose]

An air leak in the intake plenum/manifold will also cause it to run rough and rich. This could be at the gasket or at the injector o-rings. Also a weak coil could cause these symptoms too.

[pauleatstoomuch]

Update! not better

Since I last posted, I had the injectors remanufactured. They did a flow test before and after, and they were really bad. Aprox half flow. They also cleaned the fuel rail. I reinstalled them, and it runs the same. I replaced the fuel filter earlier and had it on backwards, so I put it on the right way. I replaced the ignition coil, the distributor cap and rotor and I put in another bottle of fuel system cleaner. I am stumped. Any help would be appreciated.

Thanks

[dolphin]

how is the condition of your Exhaust System ? mufflers not blocked or Cat Convertor ? has the TPS [ throttle position sensor ] be checked and or adjusted correctly ? have a look at these 2 guys as you never know.

[Pauly Faulkner]

An air leak in the intake plenum/manifold will also cause it to run rough and rich. This could be at the gasket or at the injector o-rings. Also a weak coil could cause these symptoms too.

A very possible contender

Inspect the plenum, manifold for cracks etc and/or remove them and replace the gaskets. Also check to see if there is any possible leaks after the MAF sensor. Throttle position sensor could be stuffed, air cleaner could be majorly obstructed just to name a few.

[Yonnee]

Tastes like Spam!!

[4ePikanini]

did you check the coolant sensor? If the ecu sees cold temps in the coolant it will richen the mixture.

http://www.pajeroclub.co.za/forum/viewtopic.php?t=1512

http://www.pajeroclub.co.za/forum/viewtopic.php?f=27&t=1382