2002 Protege5 Rough Idle, No Power/Acceleration

[Cosmas]

I'm running dry on ideas.. need some help thinking of other possibilities...

I've got a rough idle that will nearly kill the car on start, though once it gets going its fairly stable. The larger problem however is that it I have no power during accel. I can floor it and it will move but doesn't punch like it normally should. This all comes after repairs in order to fix a Cyl-1 Misfire (which I admittedly sat on for a few months ) which I think may have been caused by either a bad spark or faulty injector. Here's the current state of the engine, note how violently it shakes on that initial acceleration:

Video 1 (Int)
Video 2 (Bay)

Things I've replaced:

1. New Injectors x 4
2. New Coils
3. New Sparks
4. Fuel Pump + Fuel Pump Strainer
5. Fuel Filter (or more accurately the entire plastic housing the pump sits in)
6. Replaced MAF
7. Replaced IAC (motor mechanism only), cleaned out the aluminum housing.

I've purchased a new Fuel Pressure Regular but I have yet to install it. I also picked up an exhaust back pressure test kit and that didn't seem to tell me anything. The pressure barely pushes up past the first needle on either the front or rear cat. (0.25lbs). Part of me thinks maybe the cats are shot but again.. the pressure test didn't show anything. There is however a sort of inconsistent ticking noise coming from the tailpipe which is new to me.

 

[TX_SilverP5]

No codes at all to chase?

 

[MuffinMan06]

Detach your exhaust before the second catalytic converter and see if it runs better. only do this for a short period because the exhaust will get hot.

 

[Cosmas]

No codes at all to chase?

Once I resolved the Cyl 1 Misfire with the new sparks/injectors, no more codes. But obviously it didn't run well.

Detach your exhaust before the second catalytic converter and see if it runs better. only do this for a short period because the exhaust will get hot.

I actually did try something like this with the first O2 sensor socket before the first cat but no dice, still ran bad. I'll give this a try.

 

[Cosmas]

No success on removing the other O2 sensor, though after I thought about it, it shouldn't have mattered since I already tested that with the first O2 socket before the first cat. I was effectively bypassing the whole exhaust system anyway.

On a whim, I went ahead and ordered new coils and a TPS sensor from RockAuto as a 'next things to try.' The only reason I'm getting new coils again is because the first set I got was on eBay from a 'https://www.ebay.com (commissions earned)' and the more I think about it, they probably suck. So we'll see.

Beyond that, maybe I'm looking a new MAP as well? I know I'm basically just throwing money at it at this point but I work in tech support so I'm determined to figure this out.

 

[TX_SilverP5]

FYI, I replaced the front cat and replaced the 2 O2 sensors and it idles and drives noticeably better. No more idling revving high and low and power is there as expected.

 

[KMac]

I'm running dry on ideas.. need some help thinking of other possibilities...

I've got a rough idle that will nearly kill the car on start, though once it gets going its fairly stable. The larger problem however is that it I have no power during accel. I can floor it and it will move but doesn't punch like it normally should. This all comes after repairs in order to fix a Cyl-1 Misfire (which I admittedly sat on for a few months ) which I think may have been caused by either a bad spark or faulty injector. Here's the current state of the engine, note how violently it shakes on that initial acceleration:

Video 1 (Int)
Video 2 (Bay)

Things I've replaced:

1. New Injectors x 4
2. New Coils
3. New Sparks
4. Fuel Pump + Fuel Pump Strainer
5. Fuel Filter (or more accurately the entire plastic housing the pump sits in)
6. Replaced MAF
7. Replaced IAC (motor mechanism only), cleaned out the aluminum housing.

I've purchased a new Fuel Pressure Regular but I have yet to install it. I also picked up an exhaust back pressure test kit and that didn't seem to tell me anything. The pressure barely pushes up past the first needle on either the front or rear cat. (0.25lbs). Part of me thinks maybe the cats are shot but again.. the pressure test didn't show anything. There is however a sort of inconsistent ticking noise coming from the tailpipe which is new to me.

Sounds like a timing issue. Check for TDC, remove the valve cover and make sure the marks line up on the cam gears.

 

[Cosmas]

**** FIXED ****

Just want to leave a note here for anyone else experiencing the issue.

NEVER BUY ULTRA POWER INJECTORS for P5s.

I had purchased a set of 4x from RockAuto and I thought they would be as good as the originals and it turns out that's what was causing my misfires. They could have been defective sure, but after some internet research, I came to the conclusion that they're just cheap crap. As a non-mechanic (but a half decent DIYer) how the hell would I have known that??

Instead I found a set of OEM Nikki remanufactured injectors on eBay from https://www.ebay.com (commissions earned) and they work BEAUTIFULLY. It's like I'm driving a new car.

So I'm back on the road... good thing too because at the time of writing a new Mazda3 hatch would set me back $34k and have a delivery wait time of 3-4 months according to my local dealer. I can't wait for the market to crash, here's hoping 2024 turns it around.

 

[Kreepaevox]

Yeah, vital things like that you can go wrong with Original parts or the og manufacturer. Electronic stuff on the cheap sometimes stuff like this happens

 

[Cosmas]

Yeah, vital things like that you can go wrong with Original parts or the og manufacturer. Electronic stuff on the cheap sometimes stuff like this happens

The thing that gets me is.. why would they offer them if they just flat out don't work? In any other industry, if I buy a part to fix a thing.. it should fix the thing, not make it worse.

And how much SHOULD injectors cost for a 20+ year old car anyway? The Ultras were $30/ea * 4 = $120 which isn't exactly nothing. The remanufactured set was $150. Like, WTF?