Contour Enthusiasts Group Archives Forums General Troubleshooting Rough Idle, Backfire, Missfire, No Power, Hiccups

This is a second post on the same issue. Sorry I do not know how to get a link to the previous post but you can find it by searching the same title. I just want to give some updates after the suggestins from the rest of you guys, and also cry for help again.

98 Contour V6 Duratec 24v 2.5L Auto

1. I bought the car not running so I have no history on it.
2. The engine was turning and kinda trying to start
3. Replaced the cam position sensor with a known working one, reset the ECU, turned the key 3 times to build fuel pressure (I could hear the fuel pump building it up)
4. Turned the key and the car started. It runs but it is idling rough, misfires and backfires in the intake tubes. Has no power, hard to rev and more pops come when trying to step on the gas.
5. Replaced the crank position sensor with a known working one - Runs as described in # 4.
6. Replaced spark plugs, wires and coil. Cleaned the MAF, new air filter and PCV valve. No obvious vacuum leak, at least nothing visible on the plastic and rubber hoses. Fuel valve sprays strong. Runs as described in # 4.
7. Took it for an OBD II check although there was no CEL. 2 codes came up
P0171 - System Too Lean - Bank No. 1
P1152 - Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Rich - Bank No. 2.
8. Replaced the fuel filter - Runs as described in # 4.
9. Replaced the fuel pump - Runs as described in # 4.
10. The spark plugs on the front side of the car were black with carbon. The ones by the firewall were clean like washed from the gas. All of 6 of them smelled like fuel.
11. Rebuilt the UIM & LIM, as described in the MODS section in this site and installed new spark plugs - Runs as described in # 4.

After the forum posts

12. Got a donor working coil pack, wires and plugs. Veryfied the firing order - Runs as described in # 4.
13. Got donor precats O2 sensors - Runs as described in # 4.
14. Checked the three harnesses on the passenger head to make sure they are COMPLETELY clicked together. They are!
15. Replaces the IAC - Runs as described in # 4.
16. Everything on the fuel delivery system side checks OK
17. Wiring harness looks pretty good, as far as i can see
18. Could not check the computer from my donor car. VIN sensitive i guess
19. It is NOT the MAF

Sorry i am not really sure how to check for vaccuum leaks, and i have not done a compression test, but more and more i knock off possible reasons, more i think it is a timing chain issue (chain slipped few gears but not broken) or bad valves, because one of my friends said he doesn't feel any vaccuum suction. I am not really sure how he got that or whta exactly he was talking about. However, please i need a lot of help because i am in a position to drive this car off of a cliff ASAP.
Thanks

Here's the original post

Ross - It sounds like you are describing the Contour that I'm working on.

Here's my origninal post. http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=trouble&Number=698015&page=&view=&sb=5&o=&fpart=1&vc=1
(Sorry, I don't know how to make the address any shorter.)

When I finally put a vacuum gauge on my motor and saw 8" of vacuum, I figured it was something serious and started tearing the engine down. I am now suspecting (like you) that one of the timing chains has jumped a tooth or two. When I pulled the UIM, like yours, the rear banks ports were dripping with fuel, while the front banks were black from running rich.

My theory is that the front bank is running okay (and the cam sensor drives off the front bank so the ECM figured out which order to fire the injectors in). But I think the rear banks chain has slipped, causing the rear banks to blow the injector spray back into the intake track (thats why the rear LIM is dripping with fuel) and what does go out the exhaust valves of the rear bank hasn't been burned so the O2 sensor 'senses' the oxygen (since it hasn't been consumed by combustion) and tells the ECM, which in its wisdom then drives the injectors rich, which is why the front bank is black with carbon.

I'm gonna try and get the cam covers off tomorrow to check the timing chain marks to see if my theory proves correct, but I have some questions re: the timing marks - see my last post at this site:
http://www.fordcontour.org/fcoforums/showthread.php?t=4125

If you have any ideas, I'm all "ears".

i got a 96 contour.. V-6 automatic.. the coil pack went out ( the No. 2 and No. 6 wires) were not getting fire.. and the car was running like you described in No. 4..... it could be a bad primary wire going to the coil pack... i also got the No. 171 or 172 error code??? cant remember...
also the vacuum hose going back from the PCV to the line running to the firewall on the passenger side was relaced to get rid of the codes..... runs great now.. might be your problem?????

This may be a stupid question.........but are you sure you have the spark plug wires in the correct cylinders? If not........the car will run EXACTLY as you are describing. Double check the pistons and coil pack location.

CHECK THE EGR TUBE TO SEE IF IT IS CLOGGED WITH CARBON< CHECK THE EGR ITSELF> TRY TO LOWER THE SPARK PLUG GAP AND SEE IF IT HELPS> IF ALL ELSE FAILS YOUR CAR MIGHT HAVE A FEW BENT VALVES WHICH WOULD CAUSE THE INTAKE BACKFIRE> OR SKIPPED TIMING CHAIN> holy caps lock

Yeah, sorry to dissapoint you MystiqueSVT but i had it tested with 3 different coils, 2 sets of plugs and 2 sets of spark plug wires and it is still the same. I had a donor car and the firing order is exactly the same as my running one was, as well as the substitute ciols wires and plugs. did not help. And what do you mean bu check the pistons and the coil pack location?
And dallasb84, you might be right. i will check the EGR valve and tube (whitch look fine on first sight) but i wil check them again. I am also thinking the worst option as you are - valves or timing chain... and how i wish we are both wrong

I was saying make sure the coil # pack matches the correct piston #.

problem is my last motor did exactly what your symptoms are when i blew it up. thing is i really dont think i blew it up because my new motor runs real rough like your does. i lowered the gap to about .03 and it helped 100%. full throttle it runs like crap. tps was one problem on my car and the other problem was i had a backfire that blew up my egr tube. still havent replaced it yet which might be the answer to my problems. my old motor melted the tips off my spark plugs, missed, knocked, timing was bad, and still reaks like gas. also it would backfire throug the intake. try starting your car and very slowly ease on the gas. if it picks up power when you feather the throttle me and you are in the same boat. my car used to throw a air metering cel and cyl4 misfire. since shortening the gap it only throws a egr cel.

Yes MystiqueSVT, it matches...