Focus Fanatics Forum banner
1 - 20 of 29 Posts

07ZX5SHITBOX

· Registered
2007 ZX5 2.0 | 2007 ZX4ST 2.3
Joined
·
64 Posts
Discussion starter · #1 ·
The miles are definitely starting to show on the old zx5, about to hit 200K probably within a couple days now and have a slew of rattles, clunks and vibrations I’m going to attempt to resolve this weekend but the most concerning is how god awful slow it is. Don’t get me wrong it wasn’t ever a speed demon to begin with but it has abysmal amounts of pickup now like you’re flooring it on an entry ramp, count to ten and you’ve gone from 50 to 60 slow.

I’m leaning towards a clogged primary cat due to Miles, less the fuel filter as it drives fine, doesn’t sputter or hesitate just takes its sweet time.
It doesn’t have the secondary cat(deleted)
Plugs replaced earlier this year w/ Ar103s just checked the gap last week
New air filter, cleaned maf, throttle body, & IAC
I’ll have to pull codes tomorrow when I’m back at work as it’s had a CEL for 2+ years because of air pump (PZEV)

would greatly appreciate any suggestions/opinions

if it helps at all in the 6 months I didn’t own it this year it went thru two owners, the 1st a middle age man, who bought it from me as a commuter

then he sold it to some hillbilly kid who I suspect beat the snot out of it because within two weeks of him owning it he’d managed to sheer the shift pin off in 3 separate places, ruin two almost new motor mounts, blow out a rear drum cylinder with >20K and burn about 1/2 a quart of oil,(never had an issue with it burning/leaking oil, and still don’t) he subsequently parked it for 2 months then I bought it back for 1/3 of what he paid for it and fixed it for $3.. has anyone had a similar issue? What fixed it?
 
What's the mileage?
You definitely need codes before making any guesses. If the car has MPG or power problems there's a good chance that the fuel mixture is off. Lean conditions will make it use up more fuel.
 
Discussion starter · #4 ·
What's the mileage?
You definitely need codes before making any guesses. If the car has MPG or power problems there's a good chance that the fuel mixture is off. Lean conditions will make it use up more fuel.
Mileage is 199,871 gas mileage doesn’t seem to be any different than it was when I previously owned it, as far as drive-ability goes there’s no issues unless trying to accelerate quickly/ being in upper rev range . I’ll be pulling the codes at my dealership tomorrow. I hope it’s something else vs pulling the primary cat out to gut because at least one bolt is bound to ruin my Sunday
 
Discussion starter · #5 ·
This might not be the issue but I had a similar issue with an 01 where it wouldn't go fast at all and the issue ended up being low coolant level. There's some kind of "limp" mode on them if low coolant.
Coolant is right at the top of the range mark I think I’ve read about that limp mode in the owners manual, it’ll alternate cylinders firing to not overheat but I appreciate the thought! Mine will go fast it just takes its sweet time, it’s like I floor it or downshift to speed up and the revs climb poorly
 
It was good to suggest it but limp mode in general is very distinguishable between typical engine maladies.
Get the codes. If it turns out that your cat is clogged then gutting it will just set a new code(s), cause fuel mixture issues, and make it run rich.
 
Discussion starter · #8 ·
It was good to suggest it but limp mode in general is very distinguishable between typical engine maladies.
Get the codes. If it turns out that your cat is clogged then gutting it will just set a new code(s), cause fuel mixture issues, and make it run rich.
If the cat is clogged wouldn’t it already trigger a catalyst efficiency code?
I’d do a compression & leak down test.

You said it’s burning oil....maybe it’s just getting tired?
could be a possibility I’ll have to do that this weekend, it hasn’t burned any oil since I got it back and did an oil change about 2000 miles ago but I assume it had to burn some or just wasn’t changed because it was 1/2 a quart low when I got it
 
If the cat is clogged wouldn’t it already trigger a catalyst efficiency code?

could be a possibility I’ll have to do that this weekend, it hasn’t burned any oil since I got it back and did an oil change about 2000 miles ago but I assume it had to burn some or just wasn’t changed because it was 1/2 a quart low when I got it
Yes, it will register a code if it's clogged/failed but you said that you still have to have it scanned. Without knowing what codes are registered all of this discussion is just hypothetical.
It's possible that the last oil change didn't fill it all the way or maybe you have a leak. Or, if no oil change was done since you last owned it then some oil will get burned on a 200k mile engine.
 
I’ll be pulling the codes at my dealership tomorrow.
Dont just look at codes. Look at live data. What are the O2s doing? What is the RFP? ST and LT FTs?

Paul
 
Discussion starter · #11 ·
Dont just look at codes. Look at live data. What are the O2s doing? What is the RFP? ST and LT FTs?

Paul
I have access to a nice fancy snap on reader here so I already planned on doing that. I used that to try to diagnose a vacuum leak on my other focus, didn't really know what exactly to look for but regardless I found a cracked IMRC hose. It's my understanding the downstream 02 should be stable and not fluctuate much whereas the upstream should be up and down, is that correct? fuel pressure should be around 40 psi at idle right? lastly what do I look for in regards to fuel trims st/lt, is a negative number indicative of being lean/vacuum leak and higher positive a rich condition or vice versa or not at all?
 
I have access to a nice fancy snap on reader here so I already planned on doing that. I used that to try to diagnose a vacuum leak on my other focus, didn't really know what exactly to look for but regardless I found a cracked IMRC hose. It's my understanding the downstream 02 should be stable and not fluctuate much whereas the upstream should be up and down, is that correct? fuel pressure should be around 40 psi at idle right? lastly what do I look for in regards to fuel trims st/lt, is a negative number indicative of being lean/vacuum leak and higher positive a rich condition or vice versa or not at all?
That's right about the O2 sensors. There should also be a 50-100° difference between the very front of the cat and the very back of it if it's working correctly. Any more or less and it's not doing it's job. Put a temp gun on it when it's fully warmed up.
Yes, any positive long term fuel trim # means it's running that much % richer.
 
Discussion starter · #13 ·
Just pulled codes and live data
Codes:
P0171-System too lean bank 1 (Vacuum leak?)

3 PZEV air injection related codes
P0410
P0491
P2257
Been on forever after the vacuum line running to it cracked, replaced the line and it never worked after.

Live data:
That's right about the O2 sensors. There should also be a 50-100° difference between the very front of the cat and the very back of it if it's working correctly. Any more or less and it's not doing it's job. Put a temp gun on it when it's fully warmed up.
Yes, any positive long term fuel trim # means it's running that much % richer.
Just pulled codes and live data
Codes:
P0171-System too lean bank 1 (Vacuum leak?)

3 PZEV air injection related codes
P0410
P0491
P2257
Been on forever after the vacuum line running to it cracked, replaced the line and it never worked after.

Live data:
on startup (engine already up to operating temp from a drive)

Upstream and downstream were both around .850mV
about 10 seconds into start up upstream 02 dipped to .156 then 93 shot up to .500 (downstream still in .800s)

after running for a couple minutes O2 data was as follows
upstream was bouncing anywhere from .200-.800
downstream alternating as well .80mv-.150

I have a readout for O2s13 assume that's because it's the PZEV those readings were .50V-.80V throughout start up and warm up. Also noted that the tailpipe was cold after being driven roughly 10-15 miles.

LFTRIM was 25

After startup SFTRIM was 1-7 somewhat erratically, on initial startup it was 9-13

Couldn't decipher what readout was fuel pressure

any thoughts?
 
The P0171 means too much air/not enough fuel in the exhaust so the PCM is commanding more fuel to compensate. Long term fuel trim is 25 which is really high. You have 25% more fuel being used than normal. The downstream O2 is fluctuating too much.
In basic order of likelihood: MAF sensor dirty or defective, vacuum leak(PCV is highly suspect) after the MAF somewhere, low fuel pressure(clogged filter, bad regulator/sensor, or weak pump), bad/weak injector(s), exhaust leak before the cat, or a bad upstream O2 sensor.
 
Discussion starter · #15 ·
The P0171 means too much air/not enough fuel in the exhaust so the PCM is commanding more fuel to compensate. Long term fuel trim is 25 which is really high. You have 25% more fuel being used than normal. The downstream O2 is fluctuating too much.
In basic order of likelihood: MAF sensor dirty or defective, vacuum leak(PCV is highly suspect) after the MAF somewhere, low fuel pressure(clogged filter, bad regulator/sensor, or weak pump), bad/weak injector(s), exhaust leak before the cat, or a bad upstream O2 sensor.
it could very well be fuel filter related as I’ve never replaced it and in fact I don’t think it’s ever been replaced but fingers crossed it’s a vacuum leak, I’ll re-check hoses IAC/TB &maf, could be PCV but not the upper hose running off the valve cover as I replaced that after the plastic one disintegrated in my hands. Would a bad regulator/weak pump trigger some sort of stored code? Relative to the O2 sensor, would I be able to swap downstream/upstream to determine if that is a cause or do they have different connectors? Lastly could a fluctuating downstream sensor indicate a end of life cat or is it just related to the 25% extra fuel?
 
You should get another separate fuel pressure code if that condition exists but not necessarily.
You can't swap the upstream and downstream sensors as they're not the same.
The fluctuating rear O2 reading could mean either one but if the cat is truly dead then you usually get another code.
 
Discussion starter · #17 ·
I see. I'm going to go ahead and replace the fuel filter tomorrow as it's only $15 and that at least knocks that out if not fixing the issue, going to replace intake gaskets & hoses as well, as those are all original. Basically, just knocking out all the cheaper items first to hopefully fix it before the O2 sensor, if that doesn't fix it at least I won't have to deal with those in the future, I'll try to pull the upstream sensor and take a look at the cat as well. Wouldn't a weak fuel pump, bad regulator, or injectors cause stumbling and surging? If so, I don't think those would be a problem because it idles fine, revs fine etc just has no power.
 
I saw this while researching my crankshaft position sensor because mine is coated in oil.

3. Slow Response from the Accelerator
 
Discussion starter · #19 ·
I saw this while researching my crankshaft position sensor because mine is coated in oil.

3. Slow Response from the Accelerator
Not exactly sure what fixed it but I replaced the motor mounts, disconnected the battery & removed/reinserted multiple vacuum hoses and now it has its acceleration back. Still need to replace the fuel filter though.
 
Disconnecting the battery would've cleared any of your codes and might temporarily give you a little time of more normal engine performance until the PCM readjusts to whatever is making the lean condition. Unless you happened to fix a loose vacuum line that was causing it the P0171 will be back and so will the sluggish performance.
 
1 - 20 of 29 Posts