Engine Misses

[rtjennin]

I have a 1999 Georgie Boy motorhome with a Ford V-10 engine. The engine misses when driving through a rain storm. I had it serviced and they could not find anything wrong. Any suggestions?

[tbutler]

In the old days I would say it was a crack in the distributor cap, but I don't think modern engines have distributor caps! Somewhere there is likely a point in a spark plug wire with worn insulation which shorts when it gets wet. Next time you take it to the service center, take a hose and wash the engine down good so they are testing it when it's wet.

[supersquid571]

I have a 1999 Georgie Boy motorhome with a Ford V-10 engine. The engine misses when driving through a rain storm. I had it serviced and they could not find anything wrong. Any suggestions?

I had the same problem with a v-10 on a Winnebago. Turned out it was water ingestion from the rain into the air intake which faced down. They cured it by running a large flex hose from the intake to the very top on the engine compartment

[Jon796]

Do not spray the engine down with water! On newer engines there are thousands of dollars worth of little sensors the can be distroyed by water allowing even the smallest amount of amps to travel into these sensors and distroying them instantly if there seal isn't tight. One way to see if it is your plug wires, is to put a load on the engine. Put it into drive and while holding down the brake give it gas to get the R.P.M.'s up to about 3000. If it starts to miss, it is most likely your wires. Plug wires today, carry a large amount of volts and will jump to ground even on wires that look good. Most wires need to be changed before ten years are up, because of this. I hope this helps you.

[Guest 2driftrs]

If the engine is misfiring, you should be getting an engine warning light from the on board diagnostics (OBD). If you're not getting a code, I would look for cracked ceramic in the spark plug or stiff plug boots. The plug boots will get hard and brittle over time, and they will absorb moisture, providing an alternate and easier voltage path than the one that has to jump the plug gap. A good shop with a scope should be able to find the problem.

[wolfe10]

Water ingestion into the intake snorkel is a know issue with your Ford chassis.

Ford has a service bulletin and parts to address it.

Here is a photo of one of the solutions from Ford: Ford Air Intake Modification

Brett Wolfe

[tedmaryk@roadrunner.com]

I have a 8.1 Workhorse in a 2004 Scottsdale (Newmar) 38'. In any mild rain, could not climb a grade or go over 40 mph withou engin missing. The more rain, the worse it got. Scottsdale suggested that the dealer put a splash guard of galvanized sheet metal between the right wheel and the engine. Did absolutely no good. Workhorse told the dealer to install an extension on the air intake so that it was up behind the cowl instead of behind the grille. Workhorse said that the problem was water getting into the air intake. Hogwash!. Intake was dry and so was the air filter. Mycar mechanic said that it sounded to hm like bad plug wires or ignition coil (Unit doesn't have a distributor cap). Each plug wire has its own little coil and replacing all 8 would be rather expensive. I took the cheap way out and just replaced the wires. Wunderbar! Came thru a trash movin' gully-washer of a rain storm with nary a buck!

[pianodan]

I have a 1999 Georgie Boy motorhome with a Ford V-10 engine. The engine misses when driving through a rain storm. I had it serviced and they could not find anything wrong. Any suggestions?

TButler said:In the old days I would say it was a crack in the distributor cap, but I don't think modern engines have distributor caps! Somewhere there is likely a point in a spark plug wire with worn insulation which shorts when it gets wet. Next time you take it to the service center, take a hose and wash the engine down good so they are testing it when it's wet.

Tom, that is the case with most new engines, however, I'm currently working on a '97 Chrysler Sebring with a 2.5L Misubishi V6, and it still has a distributor with a cap, rotor and all the associated problems. So, there might be something out there before the year 2000, but in the '90s with a distributor. I thought they were gone too. This particular line of SOHC engines all had distributors, and I know some of the lesser known motorhomes had many different engine suppliers. Now, as far as I know, none of the big block Chev or Ford engines had distributors in that time period.

Be warned, owners of Chrysler/Dodge Sebring/Intrepid series of autos, these things are a bear to work on and extremely labor intensive when they get beyond simple maintenance/repairs. this one I'm working on is pushing $1800 in labor and $500.00 in parts to get it running again.