New o2 and knock sensor.. Still issues

[gsxeclipse97]

So I have replace the u2 and knock sensor and right at about 4500rpms the car has a lot of hesitation still. I also have a 99ecu. And a 1g cam sensor. Below that mark it seems ok but it's like right at that point it gives me the finger and says have a nice day.

 

[gofer]

• What AFR's do you see on your Autometer air/fuel ratio gauge when it happens?
• Have you checked your spark plugs/plug wires?
• How much boost are you running on that 14b with stock 450 injectors?

Wondering also, what gave you the idea that replacing your front o2 sensor would fix the problem? The knock sensor is still a long shot in the dark but it at least MIGHT have fixed the issue, hopefully the one your replaced looked bad and needed it anyway.

 

[Brandon1ggsx]

Anymore info on how it hesitates? I Does it fill like it's fighting it's self, still picking up speed just not as fast, or does it nose dive like you threw out a boat anchor? Sounds like an ark in the ignition system, how old are the wires and coil?

 

[BurrowZ]

Hard to tell from your post but for a few suggestions (since I've fought this myself a few times)

1. Check your spark plug gap. I get spark blowout any bigger than .025 on my BP7ES

2. Disconnect your MAF and see if it still does it. If it doesn't, your MAF could be the culprit.

3. As Gofer suggested, too much boost can be a problem. Try lowering it a bit if possible.

4. I'm sure you've checked for boost leaks.. but have you checked after the throttle body?

 

[gsxeclipse97]

• What AFR's do you see on your Autometer air/fuel ratio gauge when it happens?
• Have you checked your spark plugs/plug wires?
• How much boost are you running on that 14b with stock 450 injectors?

Wondering also, what gave you the idea that replacing your front o2 sensor would fix the problem? The knock sensor is still a long shot in the dark but it at least MIGHT have fixed the issue, hopefully the one your replaced looked bad and needed it anyway.

I disconnected the af gauge recently because it was useless. I replaced the front o2 sensor because it was throwing a code for it. The car wouldn't idle before and it couldn't cruise. Replaced o2 those issues are now fixed.

Knock sensor was bad for sure. Not only was it bad but it was a 1g knock sensor and there was no tar left in it at all practically.

14b is boosting 10psi on 450cc injectors

Plugs are new gapped at .28 but wires are not new.

Car runs funny if maf is unplugged and eventually dies.

It has power but feels like it's having trouble keeping up with it. A serious misfire maybe. It sputters and throws put blackish gray smoke also so I assume it's running richer than normal at wot.

Actually that's a good way to describe it.. It kind of feels like when the maf is unplugged. But only above the 4.5k mark and only at wot

 

[gofer]

There was a 1g KS in there, you swapped it back to a 2g KS then I hope?

You gapped your spark plugs over .25", how about .028"? If the spark plug cables haven't been replaced in awhile or look like they need replaced, replace them. Its money well spent even if it doesn't correct the problem you're describing.

If there's anyway to check your fuel pressure do it, FSM specs are 42-45psi with the vacuum line disconnected from the fuel pressure regulator.

I mention that it could be the fpr because the Evo IX fuel pump you've got flows 225lph, which could potentially overrun your stock 2g fpr and cause the car to go extremely rich.

 

[gsxeclipse97]

There was a 1g KS in there, you swapped it back to a 2g KS then I hope?

You gapped your spark plugs over .25", how about .028"? If the spark plug cables haven't been replaced in awhile or look like they need replaced, replace them. Its money well spent even if it doesn't correct the problem you're describing.

If there's anyway to check your fuel pressure do it, FSM specs are 42-45psi with the vacuum line disconnected from the fuel pressure regulator.

I mention that it could be the fpr because the Evo IX fuel pump you've got flows 225lph, which could potentially overrun your stock 2g fpr and cause the car to go extremely rich.

Yes I swapped it out for a 2g one and it made a huge difference.. But it still hesitates.. The plugs are gapped at .28 currently. From what I read the fuel pump flows 205lph so it shouldn't overrun the fpr. For some reason my logger won't connect to the ecu it keeps saying it cannot get a signal.

 

[gofer]

From what I read the fuel pump flows 205lph so it shouldn't overrun the fpr.

Wherever you saw 205lph you were reading bad info.
Read, under Evo Factoids ---> 2006 Mitsubishi EVO IX - Budget Boost-Up

Your car shouldn't be running hesitating going into boost either, but it is, which means something is bad. I'm trying to help you fix the problem with logical troubleshooting (checking base fuel pressure) and you're responding with arguments of why it shouldn't be that. I'm not saying this is definitely your problem, I'm saying its the next step to take so you can eliminate the fpr. Besides, if the fpr shouldn't be the problem then prove me wrong and check base fuel pressure so we can move on or you can fix your bad fuel pressure regulator.

Regarding the logger connecting, have you ever had problems with it connecting in the past and what software are you running on in? Either way, it seems its a separate issue or else you'd have a lot more problems than a hesitation going into boost.

 

[gsxeclipse97]

Ok.. I had to re-read some of this stuff here ok so I'll re gap them to .22 as I do have an evo3 head on my car. I did see where it said 225lph that's a considerable difference from 190-205. so I will try these and see where it sits after that. I wad able to get the logger working so I took a quick look and it goes from 25-27 degrees down to 17 so.. That a huge issue. Regappibg them right now. I do not have a way to check fuel pressure at this time, if the fpr was being over ran would fuel come out of the vaccum line?

 

[jcarmichael]

I'm curious to see the end result to this, my car in first gear if I give it a decent amount of gas gives me a big miss sounds to be the same issue.

 

[gofer]

Bad fpr check --->fpr overrun check

It's seems that you're maybe doing it as you go into boost, something that will be hard to test.

 

[jcarmichael]

I think I am going to try that as I am running a 255 on a auto regulator until I get a afpr(cpl weeks been running it like this since april when I got the car) my miss only happens in first gear though wot in any other gear I am fine.

 

[riopgtmn]

So it started doing this after the replacement of the knock sensor and 02?

Curious, Do you still have the old parts?

 

[jcarmichael]

So it started doing this after the replacement of the knock sensor and 02?

Curious, Do you still have the old parts?

name of the thread says replaced knock sensor and o2 sensor still issues. I take this to mean he had the issues replaced these two things hoping to fix the issue, did not and still has the issue. however I think gofer is on the right track just a matter of eliminating each thing that could cause the issue. checking the fpr seems easy enough to try first. If it is in every gear? I would think boost leak especially if it idles down bad when coming to a stop. however when my car had a boost leak. All depending on how bad it was it would happen sooner then 4500 rpms and different conditions like going up a hill had to baby it or it would feel like I was being rear ended repeatedly.

 

[gsxeclipse97]

So I redid the plugs and issue is still present..but it did seem to rev a bit quicker than before. I will test the fpr tomorrow and see of that is the culprit. I do not have the old parts I threw them away. Also it changed the idle a bit. Before I was constant for the most part, but it seems to have more trouble now. It still idles but it dips a bit.

Ok so I checked for fpr overrun and there was no fuel coming out an the pitch of the engine did change so I guess back to the drawing board.