Truck died on highway

[MikelB]

I girlfriend has a 1999 QX4 with 180K on the clock. The truck always runs like a swiss watch but the other day it stumbled then died on the highway. The night before our trip she filled the tank up and overnight lows were in the high 20's and we set out early the next morning and about 28 miles from home while slowing down from 60mph to a 45 zone the truck felt like it shut off for a moment. I turned around and pulled into a gas station and it idled smooth so I headed back home but it continued to stumble and finally just lost power and died.

No check engine lights so first thought was water in fuel and clogged filter. My thoughts are filter change, fuel check,ignition but not sure about MAP as in my Volvo I can disconnect it and the car wilt run in an emergency. ?????

Thanks, Michael

[fleurys]

It has to be something that would not trigger a code, so you're thought about fuel related issue is probably the right way to go... but I would thing more a fuel pump issue than a filter issue...

The map will not cause a failure like that.. Like all maf, when it is faulty, if you disconnect it , it will revert to defaullt mode...which means the computer will simply give a pre-established mixture of fuel and air and not rely on the maf sensor..

Start with the fuel pump, check if it works, then go on the distributor. let us know how it turns out.

[Chuck Tribolet]

Unlikely to be fuel filter. A failing fuel filter will first show up under hard acceleration or very high speed (lots of fuel flow), not deceleration.

Chuck

[MikelB]

Thanks for the replies guys. Will update this weekend.

[Slumpert]

Pull a spark plug and using. a straw lightly sniff the inside. Then have someone crank the engine while you have the sparkplug plugged in but grounded to the intake.

Do you see sparks

Right after the cranking sniff the hole againmif it didnt smell like a gas tank the first time it definately should this time

If your not seeing sparks and your not smelling gas then your likely looking at ecu or electrical issues

[MikelB]

Ok, fuel pump came in and I installed pump and new filter. Old pump did run on bench but fine aluminum particles were present so the pump was marginal.
Started the truck up and it came up to idle,smooth at first but then would stumble and then compensate and idle. It acts like its not running on all cylinders as it stumbles but then recovers for a moment and the cycle starts all over again until it finally dies. It didn't want to start once it was warm but let it sit for awhile and it did its dance again. It will take throttle but stumble the whole time.

Pulled a plug wire from the distributor and held it off cap with my insulated plug pliers and there is a healthy spark. There is no check engine light on at the moment and it acts like ignition bu not sure where to go next without an obvious fault. The truck up until this dying on the road incident has been flawless with 180K on the clock.

Thanks in advance, Michael

[Leo1998]

What if the check engine light is faulty? I know AutoZone will do a code scan for free, just to be sure.

[Towncivilian]

You can verify the functionality of the service engine soon bulb by turning the ignition switch to "ON". It should illuminate. Nonetheless, there may be stored or pending codes - so if you can pull codes yourself, give it a try and see if anything shows up.

[MikelB]

pulled a 340 code CPS or Bank1. Bank one makes sense as it feels like it idles on just a few cylinders.

[MikelB]

Update, with a 340 code cam position sensor I tracked down the sensor. The documentation on line at first was leading me to the front of the motor at the cam ends but finally discovered the Cam sensor is actually inside the distributor. It's actually an encoder type metal disk with an optical reader which was contaminated by aluminum dust particles from the distributor. When I rotated the shaft it was very lumpy and stiff in spots.

Installed new distributor and it now runs smoooooth. Truck has 180K on the clock (3.3 litre)

[Leo1998]

Nice! Glad we could help figure it out and thanks for the update.
There was a code with no Check Engine Light?

[MikelB]

There was no check engine light but I purchased and OBII reader and it pushed out the 340 code for cam position sensor. I didn't own a tester up to this point as my 95 Volvo 850 (318K) can be read without one and the QX4 has been a rock.