Stalls while trying to take off from a long idle.

[Guest ReattaFan1]

Occasionally the car will stall while Im trying to take off from a stop after sitting at a long idle, like at a traffic light. It's only done it on a few occasions, and it's only happened when the car reaches normal operating temp. After it's happened it runs but accelerating is a bit sluggish, and the idle is a little slower than normal, almost to the point of stalling at idle. I have to be careful pulling out crossing traffic to give myself time if it stalls accelerating

[Ronnie]

Two things come to mind. MAF sensor and Throttle Position sensor. When you suspect it is giving problems try tapping on the MAF lightly with the handle of a screwdriver and see if it effects idle. If it does try cleaning the MAF and see if it helps. If cleaning doesn't help I would replace it. Good used ones are cheap at the wrecking yards. TPS can be checked with on-board diagnostics. Don't remember the range off the top of my head but the important thing is a smooth transition as you move the throttle for idle to full throttle. Engine shouldn't be running of course.

[Guest ReattaFan1]

Two things come to mind. MAF sensor and Throttle Position sensor. When you suspect it is giving problems try tapping on the MAF lightly with the handle of a screwdriver and see if it effects idle. If it does try cleaning the MAF and see if it helps. If cleaning doesn't help I would replace it. Good used ones are cheap at the wrecking yards. TPS can be checked with on-board diagnostics. Don't remember the range off the top of my head but the important thing is a smooth transition as you move the throttle for idle to full throttle. Engine shouldn't be running of course.

Thanks Ronnie! I'll check these things out.

[padgett]

TPS should be .38-.42 at idle and over 4.00 at full throttle. Source is a 5v supply referenced to ground.

It will affect performance if bad.

BTW, if you change the TPS, put something underneath to catch the screws if you drop one. They cannot be picked up with a magnet.

Edited February 5, 2011 by padgett (see edit history)

[Guest 88atta]

Doug,

Have you ever tried "Seafoam" to clean your fuel system; it can't hurt? Check this out on Ronnie's Site:

Cleaning The Fuel System With Seafoam

I would try one can through the intake first; you may not need the second can but there is always time to put one in the gas tank later. You can pick it up at a lot of parts stores like Pepboys, Advanced Auto but I find it about a dollar cheaper at Wal-Mart($8.97). It does go on sale recurrently at a lot of parts stores.

[Guest ReattaFan1]

Padgett introduced me to Seafoam for the transmission. That stuff worked pretty well. I'll have to get the Fuel System Cleaner. Thanks RD

[Guest 88atta]

Doug,

Read those instructions on Ronnie's site carefully especially:

"Dumping Seafoam into the engine too fast could result in engine damage due to the pistons trying to compress the liquid!"

[Guest ReattaFan1]

TPS should be .38-.42 at idle and over 4.00 at full throttle. Source is a 5v supply referenced to ground.

It will affect performance if bad.

BTW, if you change the TPS, put something underneath to catch the screws if you drop one. They cannot be picked up with a magnet.

On the TPS Im getting .38 at idle and over 4.18 at full throttle. And the value steadily increases fluently. However when I first started the diagnostics Im getting a current code of EO41 and that's the code for Cam Sensor Circuit. Is that code coming up because Im running the diagnostic mode with key on engine off?

[Guest ReattaFan1]

...Im getting a current code of EO41 and that's the code for Cam Sensor Circuit. Is that code coming up because Im running the diagnostic mode with key on engine off?

Well, I reset the ECM codes and even while driving EO41 came back up. Thats strange, I thought the cam timing is crucial to spark timing. How is my engine even running at all with a bad cam sensor?

Edited February 10, 2011 by ReattaFan1 (see edit history)

[Ronnie]

Well, I reset the ECM codes and even while driving EO41 came back up. Thats strange, I thought the cam timing is crucial to spark timing. How is my engine running at all with a bad cam sensor?

The crankshaft sensor is necessary for the engine to run. It will still run with a bad cam sensor. Cam sensor is fairly easy to replace but the problem is more likely the magnet that triggers the cam sensor has fell out of the camshaft. It will set a code 041. Padgett has an easy fix. I doubt it is causing your idle problem.

Simple 3800 Cam Magnet Replacement*-*ReattaOwner.com

[Guest ReattaFan1]

Thanks Ronnie! That looks pretty easy. I found the magnet on eBay. http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=130472384940&ssPageName=ADME:B:EF:MOTORS:1123#ht_1975wt_1167 The only question I have is if the magnet is floating around in the motor is there a chance it'll fling around inside, hit or bind components, destroying the engine?

Edited February 10, 2011 by ReattaFan1 (see edit history)

[2seater]

The magnet shouldn't be a problem. As a matter of fact, I tried removing the magnet from an old one I had and it appears to be made of magnetic powder and pressed together inside the plastic holder. I suspect the magnet actually dissolves into small pieces or powder? Many of these have failed in the past and I have never heard of any additional damage aside from the Code 041. The engine will start and run fine without the cam sensor although injector sequence may be incorrect. This may cause a somewhat rougher idle and low speed operation, but is otherwise not harmful.

[Guest ReattaFan1]

...The engine will start and run fine without the cam sensor although injector sequence may be incorrect. This may cause a somewhat rougher idle and low speed operation, but is otherwise not harmful.

...you know, come to think of it the exhaust does seem to smell like its running rich. I bet without the cam sensor working properly, the injectors are dumping too much gas into the system. After long idles it may be flooding the engine. ... just guessing

[Guest Mc_Reatta]

You can find the magnet at your FLAPS probably for less and no waiting rather than from eBay.

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Camshaft-Interrupter-BWD_3461181-P_1305_R|GRPFUELAMS_539515094___

[padgett]

A "real" 041 will show up with a diagnostics scream very soon as the car starts. A lost magnet will not heal so for an intermittant, look to the wiring or the sensor itself.

[2seater]

The lack of cam sensor signal shouldn't really have much effect on the actual fueling of the engine. The only thing that happens is the fuel sits on the intake valve for a split second before the valve opens. The sequential part of the fuel injection is only really effective at low speeds and at higher rpms the injector is actually open longer than the intake valve event and many makes of cars get along just fine using batch fired injectors rather than timed. The O2 sensor should take care of the air fuel ratio when in closed loop and the engine warm. Have you checked the actual fuel pressure and/or the Fuel Integrator and Block Learn in the diagnostics? Is the O2 sensor good and active? Check cross counts in diagnostics. A sticking EGR valve can cause rough idle and off idle stumble also. I believe the MAF was mentioned in previous posts and will cause poor operation from off idle if it does not respond immediately when the throttle is opened. From you original post, it sounds like the stumble is only a problem after the engine warms and goes into closed loop? Vacuum leaks are also a source of low speed misbehavior. I know this is a large grab bag of items but most sensors can be checked for proper operation in diagnostics, with the engine warmed up, to see if anything is out of whack. If a sensor is operating, but giving bogus information, it will not necessarily set a code.