Hi Guys,
Got a 99 F250 7.3D that has a surging problem. I live in Fl and this winter has been cold. When i start the truck on a cold morning the idle of the truck surges and it sounds like the exhaust is sucking in??? Im new to diesels and have had the truck for 6months. Any thoughts???

Thx Guys

 

Two things: oil weight you're using, and how long are you cycling the glow plugs?

The cold start "romps" are pretty common on these trucks when temps take a dive. If you're using 15w40 oil, you'll typically start to experience romps when temps are in the 30's. Oil doesn't flow as easily when it's cold, and since the injectors fire off of oil pressure, you can see where the problem lies. Most people switch to a lighter weight oil in the winter, or switch to synthetic (5w40). That will take care of much of the romps unless temps start getting really cold. For instance, my truck runs 5w40 year round, and I get the romps when temps creep into the single digits.

Second is the glow plugs. The dash indicator light for the glow plugs has nothing to do with the actual glow plug relay itself. It's a separate function in the PCM. If it's cold, and you crank immediately after the glow plug light goes out, sometimes you can get a bit of extra romping. Depending on temps, your glow plugs can actually stay on for up to two minutes. You can try turning the key on, and leaving it on for 2 minutes. Then cycle the key again, and when the glow plug light goes out, crank it and see if it helps a little. It just gives a bit of extra time for the glow plugs to do their job.

As for the exhaust noise, that's normal. It's part of the exhaust backpressure valve (EBPV). Being in Florida, you're probably not used to it engaging. It's just a valve right before the downpipe that closes off the exhaust, and adds additional load to the engine to aid in warm up.

 

The surging on start up is not unusual. when the engine is very cold. Are you letting the glo-plugs cycle fully before starting? Doing so may cure the surge.

 

Thanks curtis, ill try the tip on letting the glo-plugs cycle. Im going up to maryland in a wk for work so ill try the lighter engine oil also.

Question? Now i know with gas engines if you switch to synthetic you have to stay with synthetic. Is that true with diesels???

Question? Fuel Mileage: I bought my truck used, how do i tell if it has a chip?? And if it doesnt what you guys suggest for a 99 F250 with 192,xxx K.

 

No, and it's not even true with gas engines either. Not anymore.

Years ago, yes that would be the case. But with today's motor oils, you can switch back and forth without a problem.

If it has an actual chip, it would be plugged into the PCM. A quick look at the PCM itself (sits right behind the e-brake pedal) will tell you.

Now if it has a tune loaded from a programmer, you wouldn't be able to physically tell. Only if your truck has added power that you can feel, that's when you could tell.

 

curious what temperature are you having these problems?