ripple effect.

I've read a few posts here about fuel pumps and am not sure if the symptoms my '02 ZX5 are the same.
when cruising at constant speed (not accel / decel) at about 1800rpm
in any gear, my car 'lurches' in a very consistent manner, about 2-3 times per second, such that it can feel as though I am driving along an evenly rippled road. It does not have any problems with hard acceleration.
can anyone suggest what might cause this? I have a trip planned for monday but am hesitant to take this car if it's going to die on me!
thanks heaps, dave.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
focusdave wrote:

My 2000 Focus SE wagon with the 16V DOHC Zetec does *exactly* the same thing.
I wouldn't worry about taking the trip (what, me worry?). Mine has been doing it for some time, and I don't like it, but it's pretty subtle and I fear that no one else but me could discern that there is anything wrong. Of course now that I've said that, it'll probably go bad all of a sudden when I'm 50 miles from nowhere on a cold dark night.
But, I do know what you are talking about. I was actually hoping it would get worse and turn out to be the fuel pump issue, so I could get it repaired for free by Ford.
Please let the group know what happens, as I will do if I ever get a resolution to my problem.
BTW, what sort of gas mileage are you getting? Mine's never been nearly as good as I had expected, up to 30 on long trips, but around town and commuting I only get about 25 mpg (US gallon). It has the 4 speed auto transmission.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
focusdave wrote:

Sounds very much like a malfunctioning DPFE sensor.
Bob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Bob Rutledge wrote:

Would that not set a code in the computer? I have these symptoms and there were no codes the last time I started it up with the tripmeter in diag mode.
Also- is the DPFE sensor covered under an emissions warranty? My 2000 Focus is out of standard 3/36 warranty, but it would be nice to get Ford to pay for a DPFE sensor if it's considered a critical emissions related component.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Mark Olson wrote:

Mine did not throw a code until the dealer flashed the EPROM and re-tested. At that point, it became clear to them. It was covered under the (2001) warranty but I would think it should be covered by the emmisions warranty since the DPFE sensor directly controls the EGR. This problem seems to happen at about 20K miles.
Bob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Bob Rutledge wrote:

Thanks for the confirmation. I decided to do a little experiment to see if the 'ripple' effect was related to the EGR system. I disconnected the vacuum hose to the EGR valve and plugged it with a golf tee. No more ripple effect, and it seemed to have a little more pep at part throttle. The check engine light did come on, which I expected, but the fact that it runs so much smoother now has pretty well convinced me. I'm going to run a tank of gas through it this way to see if my mileage gets any better, I think it will.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
We own a 2000 Focus and just got a letter from Ford addressing this problem. They state it is something with the fuel pump...ALTHOUGH they don't have a fix for it yet. But they stated that it would be available after the first of the year and they would be extending the warrenty to 10year/100,000 miles. Check with your Ford dealer about this. It covers 2000 and 2001 models. I don't see a recall number, but there is this number:
Program 03n01 - Possible Engine Stalling In 2000 And 2001 Ford Focus Vehicles.
They go on to state that if you are having severe problems, bring your car in and see if they have a "interm part"...

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Just a long overdue follow up here - turns out that you (mark and bob) were correct, it was the DPFE sensor and it was covered under the emissions warranty.
thanks for all your help!!!

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Hi Bob / mark, i forgot to mention in my post that my "check engine" light is on, so it sounds like this might be the problem. Am I able to check which 'code' has been identified?... I noticed mark started his car with "tripmeter in diag mode"... how would I do that?
I am also naive to the meanings of DPFE and EGR... sounds like I shoud go get the haynes manual?
dave
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
focusdave wrote:

Well, after I disconnected and plugged the vacuum hose to my EGR valve (in order to see if inappropriate/untimely application of EGR was responsible for the surging, and yes, it was), the CEL lit up. So I tried holding down the tripmeter reset button for five seconds while turning the key to the RUN position (release when you see the word 'test' displayed). Then you press the reset button to cycle through various displays, including some possible DTCs (Diagnostic Trouble Codes). Unfortunately, even though the CEL was lit, the tripmeter reported 'DTC NONE'. Apparently it does not give you the OBD-II codes, just codes related to the instrument panel itself.
Here's a page that says how to do it for a Mustang, the Focus's display sequence is similar but not exactly the same:
http://www.2kgt.com/_tech.asp?item=3

Haynes aren't very good for much beyond simple parts replacements. They tend to advise taking it to the dealer for anything related to fuel injection or engine management. The genuine Ford manual set is pretty expensive- I bought the mechanical and electrical volumes for $180 (IIRC) but unfortunately I didn't buy the engine management/fuel injection volume, which is probably another $150 or so.
DPFE is Differential Pressure Feedback EGR sensor (I think) EGR is Exhaust Gas Recirculation (this I know)
HTH Mark
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Hi Mark, thanks for the follow up. Is replacing these sensors costly / difficult. Is this the kind of problem best solved by a dealer/service center or will the sensors be easy to come by and straight forward to replace? I realize this is a judgement call so I'm just wondering how big a job this is? I am reasonably thrifty and have worked on my past cars to a limited extent - but never dealt with ECS's.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
focusdave wrote:
[re: DPFE sensor]

The DPFE sensor on my 2000 Focus is right out in the open on the firewall just to the left[1] of the brake reservoir . You might need to remove the air intake runner from the air filter box to the throttle body in order to get access to where the hoses attach to the EGR tube. Piece of cake.
I would try to get Ford to pay for it, I will mention the symptoms when I bring my car in for the battery cable/pinch bolt recall.
[1] (when you are standing in front of the car)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

DPFE- differential pressure feedback exhuast (sensor) this monitors exhaust back pressure in the manifold and feeds back a signal to the ECU which it then uses to improve the accuracy in the amount of EGR (exhuast gas recirculation) lift it applies to the EGR valve- basically it knows that when exhuast pressure is high (with a wide throttle) more exhausrt gas is going to pass through the EGR valve at a given opening than when exhuast pressure is low.
Bear in mind that a lazy o2 sensor will give exactly the same symptoms as you are experiencing too. But check the EGR system first- disable it temporarily to check - disconnect and plug hose as per previous post.
tim..
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hi , This ripple effect sounds just like my problem see "Help needed" 23/12/2003. It has the same symptoms except for the horrible smell which has not reoccured since the first episode, I am bringing my focus to my dealer on monday next to try and get it sorted out
-- M.See

--
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com ).
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.