Surge

[Coconutrhumb]

I've been reading on some of the surge problems some people have been reporting and mine seems to be different.

Sitting at a light, ideling nicely, suddenly the truck feels like it was bumped from behind... 15 seconds later it happens again. I get out walk to the back, look for a mark, don't see one, scowl at the old guy behind me and I get back in my truck and off I go. The next light it happens again... this time no one is behind me.. it happens infrequently, usually a pair of surges ... but happens when at a light, while in park, or even when driving at speeds under 30 mph. Not happened yet at highway speeds or maybe I don't notice it then. It won't happen when I want to show someone but hardly a day goes by that it dosen't happen at least once. I can see the tach go up appx 50 rpm, then it returns to a normal idle.

I have no codes, according to the tuner, when the condition does not exist... don't know if a code might be generated during an occurance.

Asked the dealer and he had a story for me but I really don't buy it. He says it's normal... the truck senses a fuel starving condition and compensates with a surge of fuel.

I've read in the forum here that problems closely resembling mine, but not exactly as I perceive mine to be, stem from a clogged EGR but would I not have a code if that were the case.

I'm not that familiar with the tuner and how it works.

Any input from anyone?

[autodad]

Originally Posted by Coconutrhumb

I've been reading on some of the surge problems some people have been reporting and mine seems to be different.

Sitting at a light, ideling nicely, suddenly the truck feels like it was bumped from behind... 15 seconds later it happens again. I get out walk to the back, look for a mark, don't see one, scowl at the old guy behind me and I get back in my truck and off I go. The next light it happens again... this time no one is behind me.. it happens infrequently, usually a pair of surges ... but happens when at a light, while in park, or even when driving at speeds under 30 mph. Not happened yet at highway speeds or maybe I don't notice it then. It won't happen when I want to show someone but hardly a day goes by that it dosen't happen at least once. I can see the tach go up appx 50 rpm, then it returns to a normal idle.

I have no codes, according to the tuner, when the condition does not exist... don't know if a code might be generated during an occurance.

Asked the dealer and he had a story for me but I really don't buy it. He says it's normal... the truck senses a fuel starving condition and compensates with a surge of fuel.

I've read in the forum here that problems closely resembling mine, but not exactly as I perceive mine to be, stem from a clogged EGR but would I not have a code if that were the case.

I'm not that familiar with the tuner and how it works.

Any input from anyone?

Bump for info...

[autodad]

Originally Posted by autodad

Bump for info...

No one has any ideas?

[jwiger]

if there is a problem of some kind then you should have a code, and it would light the check engine light too. the fuel surge is probable. My 84' SVO would surge something horrible once i upgraded the fuel pump (apparently it was too much for the regulator and they were fighting at idle) though this situation does sound a little different. the first thing i would try is a regular service to your fuel system, i.e run some diesel fuel system cleaner through then replace your filters and check your water seperator. if it's still doing it after that i would get an in-expensive pressure guage and try to tap into the low pressure side of the fuel system then watch it while the truck idled for a bit ( you could try power-braking it in gear to put more of a load on the system if you don't see any thing at idle). I'm sure others will chime in. we'll help you get it figured out.

[Coconutrhumb]

Thanks James. I'll be doing those things this weekend and maybe it will all go away. Had the truck over a week now, so it's past time for a little wrenching.