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2.0 Zetec 2.0L Engine Issues

7K views 32 replies 5 participants last post by  amc49 
#1 ·
I have a 2000 Focus SE with the 2.0 DOHC engine. Over the last year, I've gone through nearly 4 TPS sensors after having an oil change where the mechanic put too much oil in, and somehow it made its way into the actual wire harness where it connects to the TPS. What it does when it's 'bad' is that the car will start and idle, but any time I push the gas pedal the RPM's will drop and die unless I let off the gas. I replaced it again after it's most recent episode, but the problem persists and this time there were engine codes this time (there weren't any of the times before). I had someone read the codes, and they told me that it was intake issues, but they cleared the codes before I had a chance to write down the exact codes (grr). I'm just at wits end with trying to figure this out, and I thought I'd just throw my issue out here and see what kind of suggestions and info I could gather up about possible causes. As soon as it's warm enough I'm going to check the EPV valve since it decided to not be attached to a filter or anything anymore. The other things I tried before learning of the TPS change was I changed the oil/filter, fuel filter, and spark plugs, so those are all still new.
 
#2 ·
You lost me when you went through 4 tps sensors in a year. No part of that is remotely normal.

Curiosities sake, are you putting in the correct TPS? Auto or manual? The TPS are different, and they don't make one of them anymore (but there is a workaround). Have you tested the TPS with a DMM?
 
#3 ·
LOL on the TPS thing, like it is even possible. And why change the switches over and over when you are so firmly convinced the HARNESS is the issue? Switches do NOT fix a harness issue.

Still trying to figure out what an 'EPV' valve is, no such thing on these.
 
#4 ·
They don't make a separate one for the auto tranny anymore, but mine is a manual. I meant to type PCV, not epv. I know it's not normal at all to go through tps sensors like skittles, but I am extremely destitute at the moment, and really the last two years (families are expensive, turns out lol). I don't know what a DMM is, or how to test a tps. I can't afford a tow or to even have a real mechanic look at it. My reasons for wondering about the PCV is that the hose for it is literally not connected to anything, it's just loose in the engine bay. I also think it might be the throttle body itself, but I'm not sure how hard it's supposed to be to manually move the butterfly flap, if you even can. I don't know if the harness is the issue or not, but regardless I can't afford to change that. $20 is about the most I can afford for the sensors. I just don't know if oil getting onto the pins in the connector would cause the TPS to become faulty. I'm asking the questions because I don't know, and can't afford to turn anywhere else.
 
#5 ·
Good luck on the manual! DMM = digital multi meter (voltmeter)

The TPS is basically a variable resistor. If you hook up a ohm meter between the correct pins and turn the inside part, the resistance should change smoothly and linearly. That will tell you if your TPS is good or bad.

On the PCV, if you try to blow through one way, it should be easy. If you try to blow through the other way, impossible. That hose is supposed to hook from (I think) the back of the cam cover to the airbox. I feel like I should know, I think I replaced mine last year...
 
#6 ·
Oh, if it is the wiring, you should be able to hack what you need out of a harness at a pick and pull. They would probably charge you less than $5. That said, I doubt it's the harness. If (when) it throws a CEL, scan it yourself (for free) at an auto parts store, and write down the codes.

When the TPS on my car went bad like 6 years ago, there was a spot in the pedal range where it would occasionally miss for a split second.
 
#7 ·
Thanks spots, I'll definitely check into that. I wish the guy that scanned my car had written the codes down or had given me the chance before he cleared them. If the PCV connects to the air box, that explains why it's not hooked up.. the airbox is gone, was replaced with one of those cloth cone filters. I guess I need to get one of those intake hoses that has a hook-in for the pcv.
 
#8 ·
Most CAI just jam a little breather filter on the end of the PCV hose, as long as you don't mind venting a little blowby into the atmosphere it shouldn't effect the engine any.

So, do you have a multi meter? I almost hate to do say it, but harbor freight probably sells one for $5. I'm pretty sure amc49 (or someone) has a thread about adapting a mtx tps to an auto car, I think all the relevant info for checking the tps sensor is in the thread.
 
#9 ·
I don't have one, but I can definitely pick one up. I think the last TPS I got has a warranty, so if it's bad (again) I can hopefully just take it back and swap it. I'll check around for the thread on how to do that and go about checking it. I looked around to try and find another throttle body to just replace it, but I could barely find any new ones. And then the ones I did find were hundreds of dollars, so I'll probably just clean mine up a bit and see if that does anything for it too.
 
#10 ·
There are 2 crankcase vent hoses, the one you referred to that goes into the airbox is just a vent hose for the head, the actual PCV (positive crankcase ventilation) hose goes into the intake manifold (IM) under the TB. That PCV hose is notorious for getting a leak... check or have someone check it to see if it is soft and spongy or if they can see or feel a hole near where it goes into the IM. The new ones are armored and won't get weak like the stock ones.

Another problem may be the DPFE sensor that activates the EGR valve... have that checked or just replace it (they go bad all the time, due to moisture, and are fairly cheap).

Another problem may be in the MAFS or the pigtail that goes to it... try cleaning the sensor and push on the wires going to the connector after you plug it back in.
 
#14 ·
Update: I have found the PCV hose that leads from the bottom of the throttle body was mushy, and completely collapsed, fused internally, and with a hole at the L turn. My new one should be in tomorrow or tuesday, and if that fixes the issue I'll let everyone know.
 
#15 ·
(DPFE sensor) '...they go bad all the time, due to moisture...'

After losing like three before 30K miles I created a workaround that works so well I haven't changed one now in 4 years. No codes either. I remote mount mine up on the airtube to TB to raise it higher and then use 3 ft. of hose on each then let all the extra droop behind engine to create a 1 1/2 ft. tall water trap. Every time I think of it I pull the hoses and dump any accumulated water in them.

The supershort 1 inch long rubber stubs are the problem there, the closer to the raw exhaust the DPFE is the faster water creeps inside it to ruin it. The bad ones you yank will all be full of water. Why the firewall mounted ones last longer too, longer hose path and a water trap made by the location.
 
#16 ·
I replaced the hose, re-cleaned the MAF, put in the new TPS, and I still have the issue. I'm going to check the other things suggested as soon as I can monetarily, just kinda wanting to give an update to everyone that was helping me out
 
#18 ·
Well, it always had fixed it before, so there wasn't really much reason to not try it again since it is about the cheapest part under the hood. I'd take it to a pro, but right now the most I can genuinely spare per month is 15-25 bucks =/
 
#20 ·
Which is especially why we (you) need to get this figured out.

A few years ago my friend had a Supra. It ran great, but kept cutting out and leaving him stranded. I helped him replace the fuel pump 3 times, but it kept having problems. He wanted to replace the fuel pump a 4th time. I refused until we actually diagnosed the problem. Turns out spark was intermittently working, and the distributor was bad. He wasted a lot of $$ and time fixing something that wasn't the problem. Proper diagnosis took 30 min.
 
#19 ·
If something inside the throttle body is chewing up tps's then do yourself a favor and grab one from a pick n pull yard. Shouldn't be more than $20 and most likely with a working tps. I bet there is too much shaft play that is wearing the tps down inside or something of the sort.
 
#21 ·
Just checking to see if you had a chance to test the DPFE yet... see Focushacks for how to do the golf-tee hack to check if the DPFE sensor is bad.
 
#22 ·
I replaced both the DPFE sensor and the EGR actuator, and the problem persists. The EGR valve was too expensive to try and replace right now, else I would have done that one too. I have begun to notice that when I press the gas and the RPMs drop to zero and kills it, that I smell gasoline and a thick exhaust smell immediately after. It doesn't misfire and idles fine, but I'm wondering if an old plug wire might cause the issue? Maybe it carries the load well enough to idle, but can't keep up with open throttle and bogs the engine out? Cause normally I can crank the car just fine, but if I let it die this way then it's a little while before I can start it up again.
 
#23 ·
I did a complete look-over of every single attachable part that was remotely involved with the vacuum/intake system, and I discovered the issue. A piece of the old PCV hose that had went to hell had fused itself to the inside of the connection port, which I hadn't seen until this last-ditch look over. I can now drive it, which is completely awesome news! The only issue I'm having now is that my Idle RPM starts out at 1900-2000 RPMs and stays there for about 3 minutes, unless I pump the clutch which causes it to go down a little bit faster. I've seen a lot of threads saying that this is 'normal', but it didn't do that until about a year ago. It also does it when I press the clutch to shift gears while driving; I shift at about 3200 RPMs and when I release the gas and depress the clutch to shift, my RPMs will shoot up to around 3800 in the interim. I have no idea what the issue is now, but I did have an issue with the battery not starting it a couple of days ago and I had Advance Auto check it. They said it was dead (even though it's a month old) and that I should replace it. I told them to just test the battery poles and not the connectors, and the battery tested fine. They used a socket to tighten my connectors and it started working again, and it even stopped doing the idle thing! They sold me a post and connector cleaner brush and instructed me to go home and clean them thoroughly, which I did. I went through every standard imperial socket I have (I don't have any metric) and not a single one fit the nut, so I had to use my channel locks the best I could to tighten them back. The idle/RPM issue returned immediately, and has not alleviated since no matter what I seem to do.
 
#25 · (Edited)
I was afraid that's what it was, I've been using my chiltons and trying to at least locate it visually but I haven't really had much luck. I'm hoping to find a good video tutorial somewhere
Edit: Immediately after posting this I found a decent video on it, and while the physical location looks like a pain, taking it off and cleaning it shouldn't really be much of a problem. Will update after I get it taken care of.
 
#26 ·
You simply CANNOT keep working on a metric car with no metric tools. The battery terminals are 10 mm. and exactly halfway between 3/8" and 7/16" and 10 is used in like 500 other places on the cars. I have to say it............stupid.

If the IAC is one with an outside breather on it then 'cleaning' it often wrecks it, it has a vacuum diaphragm inside and any solvent used ruins it.

The TB gasket can easily flaw to let the IAC channel short to then mess the idle up but good. Won't matter then at all what the IAC is doing. If you have reused that gasket then well.....................have fun, the car could care less.

Cleaning batter terminals on these often creates more problems when the terminals then refuse to get tight, the bolt will be but you can twist the terminal by hand, more problems coming up! Change the terminals to fix that. The Ford ones absolutely suck.
 
#27 ·
Most of the other screws and bolts I've ever encountered have all been imperial, those and the engine shield bolts are the only ones that I've touched that are metric. I now have a full set of sockets again, and I always knew that it was less than ideal to do things without them. I'm just so absolutely destitute that it's often "Do I get this thing I need to work on my car, or forgo a few meal items for myself so my family still eats". The IAC doesn't have an outside breather, and if I use any solvent it's going to be throttle body cleaner. And my terminals are now tight and secure, though I do need new battery connector cables at some point cause these look kinda rough, but still that's cash I can't justify spending right now. I appreciate the comment, and I'm not a complete idiot, I never do or touch anything unless I know exactly what it does, what I'm doing, and how to do it. And if I don't know, or can't find it online, I work at a testing center that administers ASE tests, I'll ask those guys, or my mechanic buddies. The only real constraint I have from getting this thing running top notch again is the fact that it costs money, and I have so absolutely little to spare it's pathetic. I'm going to have to wait on the IAC though, there's absolutely no way to get it off (I tried from every conceivable angle) without removing the intake manifold, which will require new gaskets and all that jazz. So one of these days I'll get enough put back to get those, but it does run fine. It's just the thing is a little annoying, mostly.
 
#28 ·
Most of the other screws and bolts I've ever encountered have all been imperial, those and the engine shield bolts are the only ones that I've touched that are metric.
Not on the Focus, I don't think there is a single imperial bolt on the whole thing. You may have gotten it to work (I don't own the proper metric socket for the CV axle nut, but an imperial is close enough) but that doesn't make it so.

Anyways, I think you can get the iac off if you take off the alternator, but i'm not 100% on that
 
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