So my mechanic confirmed that injectors 1 and 5 are bad. Suggestion is to replace all since we're in there. What are your thoughts and do we have to use OEM on these? I hear these cars are finicky. His cost for injectors are a bit high so he suggested find it cheaper and he'll install it. I did find some remanufactured ones for a good price.

I do think it's worth fixing so I want to get it done. I'll drive it around a bit and get the parts eventually.

 

Personally, I hate replacing parts "just in case" even if you don't need it. But it is strictly a personal approach I have. Let's think about this - If only injectors 1 and 5 are bad, why then replace all of them? The only reason I'd see for replacing all injectors is if you flow tested them, and the rest of them are significantly off specks from the new ones. However, that is exactly what determines if injector is good or bad. If you really want to replace more than just two bad injectors - replace 1, 3 and 5. They are all on one bank of the engine, this way the PCM can easily adjust if there is going to be a difference between banks 1 and 2 fuel mixture readings. If all other injectors are OK, I'd replace two bad ones with OEM and stop at that. Maybe pull the rest of injectors out and have them ultrasonically cleaned. When I rebuilt and engine on my other car, I was ready to buy new injectors. It was the same idea - I'm already there, might as well... Instead, I decided to have them bench tested and cleaned. It turned out that all injectors were in spec. Saved a good amount of $$ doing that. Almost tree years later - that car is just as happy as can be with the old injectors.

I guess another factor to consider is the cost of extra injectors vs. cost of labor you'd to pay to your mechanic. Since I do my own work on my Montero - I only have to deal with the cost of parts in my calculations. Did you get a quote for OEM injectors vs. aftermarket? How much is the difference?

I'm very curious to hear what other folks here on the forum think about this - replace only the bad injectors (1+5), replace 1,3+5, or replace all?

 

Exactly how did the mechanic determine the injectors were bad?

I bought a reman injector from Mike's Carburetor Parts for my 2002 3.5L 6g74. Perfect match Denso 195500-3300 to the ones on my motor (not sure which ones you have). Promptly shipped, $21 plus $3.50 shipping. Cheapest I could find on the net.
Mitsubishi Fuel Injector, Reman, 195500-3300

I was (still am) chasing a P0306 Cylinder 6 misfire, so while I had the plenum apart, I replaced the injector on this cylinder along with the plug, compression test, etc.

Still have the misfire with no change, so that tells me my injector was fine and the reman one works as well, and am out $25 for needlessly replacing the injector.

 

I also had a cracked passenger exhaust manifold on mine.

Details here, Post 118
https://mitsubishiforum.com/forum/mi...12/#post316089

 

Thanks again, Hunter for the details ails! Truth is, I have no clue how he got the test done while it was still attached to the car so I took his word that he did. I did find a set of new Denso's at $78 each. I may suggest to the mechanic to do the 1,3&5. I think that'll be a great approach. My other mechanic will actually do the job for free so the labor is no longer an issue. Both mechanics suggested all be replaced the same time. I'm ask the 2nd mechanic what he thinks and revisit the exhaust manifold as well.

Thanks Larry for the suggestions. Had I seen this before I bought the Denso, I would have bought Remans. The GBs were available at a proper rate but I was unsure. I wanted less chance of an error since I have to pay for the 2nd time it's not the correct diagnosis. Why is this truck so finicky? 😂

Thank you again Hunter and Larry. I'll keep you guys updated. I'll have the 2nd mechanic recheck everything first before he starts tearing down.

 

There are two ways to test injectors - 1. take them out and bench test to check the spray pattern and flow rates. 2. You sort of can do flow rate test on the engine without removing injectors. That involves installing a fuel pressure gauge, presurising the fuel system and firing each injector for a set number of cycles. By comparing fuel pressure drop after each cylinder test, you can estimate if one of the injectors is putting out different amount of fuel or if its stuck closed/opened.
The only issue with the Montero (and other similar Mitsubishi engines) - there is no fuel pressure testing port on the fuel supply line and on the fuel rail to make this easy. I'm sure you've see this when you worked on your engine. There is a testing adapter available, but is is a very rear part made just for Mitsubishi and I'm sure that non-dealerships are not likely to have it on hand.

 

Well, all injectors were changed and no luck. No leaks anywhere to be found and I need a SMOG soon. The idle is still at 500 when warmed up. It's triggering the check engine at high RPM on the freeway. I'll check the freeze frame again.

 

So I changed the ECT's and still no luck. My have to try to change the O2 sensors but not sure which ones. Should I replace the ones before the Y or the one after the Y under the driver side for Bank One?

 

Stop throwing parts at it. You are replacing things that do not need to be replaced. It the equivalent of standing next to your Montero and lighting $100 bills on fire in hopes that it will fix something. Yes, eventually, you will "hit" the right part, but this is not the way to approach it. It is pretty obvious that the diagnosis you got from your mechanic (bad injectors) was a wrong one. Ether continue diagnosing the issue yourself, or take it to someone who is better at it. If you have a CEL code - your mechanic should be able to run tests and diagnostics to figure out what is going on.
What is the code that you have now and what is FF data?

 

Understood. It does look like the temp sensors helped a bit. The temp is showing higher than it previously. We changed the O2 sensor today and so far no code when we drove around. Same info from ff showed by the way. Thanks and hopefully we are good with the O2 changed.