1994 Plymouth Voyager Engine stalls when stopping or corner

Tiny
JMYSR
  • MEMBER
  • 1994 PLYMOUTH VOYAGER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 235,000 MILES
The car will stall when you slow to take the off ramp or are coming to a stop but runs fine on the open road. When you try to restart it the engine seems like it has run out of gas but after a few seconds of cranking sputters, like it is getting fuel again and starts right up. I have also noticed a drop in the RPM's to below 750 when it seems to happen. It almost acts like the fuel pump stops getting power for an instant and then turns back on. I have changed the fuel pump, fuel filter. Is there anything like a rollover safety or any kind of sensor for the fuel system that could cause this?
Wednesday, April 22nd, 2009 AT 10:40 PM

4 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
You may have a vacuum leak, get a can of spray throttle body cleaner, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs! If that doesnt do it, you may need a new idle air control valve, it's bolted to the throttlebody.
Is your check engine light on? If yes turn the key from off to on three times, on the fourth one leave it in the on position, count the flasshes.22 would flash as 2 blinks, then a short puase, then 2 more blinks. If several codes are stored, the pause is longer between codes, code 55 will be the last code. Do this and post all codes found.
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Friday, April 24th, 2009 AT 3:59 PM
Tiny
JMYSR
  • MEMBER
  • 2 POSTS
No light and only code is 55. I will pick up carb cleaner & do as you requested in the next day or two!
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Sunday, April 26th, 2009 AT 10:19 PM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Throttle body cleaner NOT carb cleaner!


https://www.2carpros.com/forum/automotive_pictures/62217_CRC_Throttle_Body_20.jpg

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Monday, April 27th, 2009 AT 3:07 PM
Tiny
CARADIODOC
  • MECHANIC
  • 33,916 POSTS
I'm going to make an educated guess that you replaced only the pump, not the complete assembly. Your excellent description is exactly what happens when the pickup screen is plugged or collapses. I learned this the hard way when I was a long way from home. Took me four hours to nurse it though Minneapolis, then ran fine on the highway for two hours to get home. Stalled as soon as I slowed to turn off the highway.

Had I only known then... To prove this is the problem, disconnect and plug the vacuum hose from the fuel pressure regulator on the engine. You will get some black smoke out of the tail pipe, but it won't stall. What's happening is the pickup screen is able to pass enough fuel for the engine to run at highway speeds, but it has to pass much MORE fuel when coasting or slowing down. Doesn't make sense at first, but just remember, fuel being pumped and fuel entering the engine are not the same. A lot goes through the regulator and back to the tank.

The regulator looks at manifold vacuum, (hence, the vacuum hose), and adjusts fuel pressure accordingly. Higher vacuum, such as when coasting, pulls fuel in harder. Lowering fuel pressure compensates by reducing the "push" when the "pull" goes up. A lower setting in the regulator means it's easier for fuel to flow through it so more fuel flows. The pump has to pump a higher volume of fuel but most of it just goes back into the tank.

You can check if the pickup screen is available from the dealer. If not, and you don't want to buy the whole assembly, cut a slit in the top of it. I personally don't recommend this because repeat pump failures are caused by microscopic debris jamming the pump impellers. Many shops now recommend steam cleaning the tank to prevent failure of a new pump. Other than that, the fuel filter along the frame rail can handle any dirt in the fuel. They typically last the life of the vehicle on Chrysler products. Of my five cars, I only changed one filter at 195,000 miles because it started leaking. That was the same van that had the plugged screen six years earlier.

Caradiodoc
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Wednesday, April 29th, 2009 AT 5:12 AM

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