Contour Enthusiasts Group Archives Forums Modifications 3.0L Duratec ?Help tracking down the stuttering problem....Long...

I have been keeping up with this subject and I do realize that it isn't happening when cold. But we really don't know what is going on then. Other then it is most likely running rich in open or closed loop which ever it is. My car isn't on the road yet but in another month or so it will be. I think I will be hooking up a Data Acquisition System to view my sensors and pump voltage see if that actually has something to do with it. I hope to be working on my MAF modifier soon anyways. It might be just enough to get rid of the annoyance and not be tuned out by the PCM. What I asked earlier, was if anyone with the return style had the problem. Just to make sure that it could possibly be the returnless fuel system. Well if we keep at it we should be able to get this solved. But I have a feeling a chip may be one of the only solutions for the long run though.

I have a return-style 1999 SVT. I never had any issues when the car was stock. Only after I put on my open exhaust system.

warmonger

Hi, I have a returnless system. The numbers are:
Module - XS2A-12A650-AAB
Tear Tag - XGT1
Flash Rev. - 9LCMA

I do have a "reprogram sticker" under the hood...all it says is "reprogrammed PCM" "Module # XS2A12A650AAB". No reference to 9LCMAXE though.

Does any one know the answer to my earlier post...how do you ohm out a vacuum regulator solenoid? It is supposed to have 26~40 ohms resistance. Mine read "0" across the connector pins...did I do this right?

...Ed

EdorFox,

I am looking into the correct procedure for measuring the resistance on the vacume solenoid to confirm with you. I am also going to test my solenoid as well. Ill do that today. I am also still trying to confirm the calibrations. Your sticker is the same as mine, it seems, but you have had a recal done. An Oasis report would say exactly what was done to you calibration along with the original and final cals. I am trying to get an oasis report for my vehicle as well. Just trying to get all the details that can be had for our pcm's basically. Cheers!

I have a return fuel system so what does that mean?

Regarding the question on when my stuttering started, I am pretty sure it happened after I had my tranny break down on me. Ford replaced some parts and billed me 1g . A bolt sheared off of the tranny tower and fell in the transmission. I cannot recall if it was doing it before that or not, but it could easily be a coincidence.

I have had the same exhaust setup for a while now and it has eaten through two hi flow cats. I just have a hollow one in there now because when I took it off the cat was all gone beside a peice the size of my fist.

Another thing worth mentioning is that I used to have superchip maybe one year after I bought the car (I bought it 3 years ago). I pulled it out after a couple of months because of some serious stalling issues. I sent the computer into superchips and they reprogrammed the chip, but it didn't change the results. It was like they just sent it back.

When I pulled the chip out the car ran fine until just this last December/January. I will check my recipts to see if I installed something that I am forgetting.

Oh I also had the IAT sensor modification if that matters. I wired in a POT to trick the car into thinking the air intake temp was lower. I ran premium with it but when the stuttering started I pulled that and my ignition system off and they are still off. I even reverted the intake back to stock and the same thing happens.

I checked my plugs and regapped them. Switched back to the ford wires to see if I had a break soemwhere. No go still.

Just thought I would through out everything.

Later,
Chris

P.S. I am making an appointment today for next week to have my car looked at by a well know performance tuner. Hopefully he doesn't charge me anything to just look at it.

My '95 V6 has a similar problem which it developed over time (it did not do it when new). I've written lots about it and haven't gotten anywhere, but I did pull the SPOUT jumper (which sets timing to base, 10 degrees BTDC, and removes the ability of the computer to change it--I don't think 96 and newer cars have the SPOUT jumper). No change.

Unplugged IRMC control solenoid. No change (this makes it so that the secondaries are always open)

Unplugged O2 sensors. No change (check engine light did come on after 2-3 minutes of driving around, as expected)

Unplugged MAF. No change, in fact it got worse(car was driveable with MAF unplugged)

At this point I think it's either an intake manifold leak or a clogged injector.

Brian

it may not be the same thing, but i have the same symptoms on another car of mine and it was the fuel pump, maybe not though, just a thought

See this goes with my thoery that its a small gasket leak or a airleak somwhere in thye intake.

When you did the 3L swap did you use new gaskets for the intake?

Hey guys, just wanted to mention that when WarMonger did his testing - the stuttering went away when the engine was in open-loop/tricked into believing the engine was very cool, relatively. Whenever he tricked the PCM (via the CTS and a resistor) that the engine was below 60 degrees coolant temp, the stuttering virtually disappeared. Also, this trick can be observed when you first start the engine and it ice cold - drive it around town and its gone until it hits operating temp and at least 2 minutes go by. I have a 2000 svt with 12500 miles on it. Alot of other svts and v6s have this problem scattered here and there. WarMonger was the one to bring the temperature testing to "our" attention, and after confirming the condition, we all began collaborating on it. An update on my end is that I finally got a dealer floor manager (in the service dep) to drive the car around and he was like "dam, there is a nasty problem here". So I have an appointment next Thrusday evening to bring it in. Good fortune will allow them to check every dam thing in that car till they find it. Anyway, ttel.

I am currently getting the car look at. The problem should be solved very soon. Also check out my Ford help post in general its a fun read. I will post info as soon and I find out.

Later,
Chris