Both my truck and my girlfriends truck are surging like defueling under light acceleration. This problem comes and goes. I tried different fuel in both but no change. Not loosing fuel pressure in either truck (idles at 20 and 17 on hard pull.) Both trucks are running drag comp and 100 hp injectors now. Shes got a stock charger with boost elbow and I got a S300. It dont matter what level your on it will still do it.

Could it be a map sensor going bad????

 

i've been playing around with diablo puck & smarty... between the 2, mine is surging I think because of the timing that the programmers are doing

 

Well in my truck in any gear if you just lay into it below 2000 rpm in will almost kill the truck from dumpin so much fuel into it, i guess just from runnin low compression with such a mild cam, you have to slowly ease into then above 2k just put her to the floor and she will hall *****! But it doesnt surge! So i would think it might be something to do with the edge box or your apps!

 

Noticing it too. Even with Edge off I can feel it surge and flutter at light load conditions. Getting worse as it is becoming colder. Have new VP pump, map, and iat sensor in this engine. I am starting to think it is an apps but hate to spend the money on it if it isn't the culprit. The APPS and the ECM are the only two remaining items that are the same between my old and new engine.

 

Yeah as its turnin colder its gettin worse. Hate to sink the money into an apps hers still has a warranty just got to strip it down... Any other ideas?

 

mine does the samething as someone said earlier its timing surge at least thats what everyone told me cardboard in front of the raditor helps i block off all but a 8 inch square in the middle and mine doesn't get hot but keep an eye on it i turn the low boost fueling to setting 1 on my juice and that helps also

 

OK, to bring this back up, I recently removed my comp and installed a PM3 and switched out my 100HP's to my slightly larger 7X.018 Lightning's and am still having a severe surging problem. The problem is still identical so apparently its something else. Its not everytime but when I get on it and am over 30psi it will buck and do a fuel defuel fuel defuel (roals coal and stops and starts and stops.) While its doing this boost flutters back and forth about 5psi. Fuel pressure at VP never drops pass 15 psi. Could I be sucking air in a fuel line somewhere???? ANY HELP PLEASE!!!!

 

Increased timing and cold weather don't mix. Wait til spring.

 

mine does the same with the edge ez on i have 220hp injectors and a sps62 light throttle wil surge if i roll into it it wil buck.i also have a tst pm3 fueling box and with that on it doese'nt seem to do it.so if i am gonna get on it i turn the tst on.also i have a shied street cam.
scott

 

I cured the surging on my TST comp with a new alternator. If your alternator is leaking any AC current into the charging system it will cause a surge. Both Mark at TST and Chip at Blue Chip Diesel told me to check all the connections on my fuel box first then check out my alternator. It was the alternator.

 

Ok but I am not running any timing box now. Just stock ECM programing and am still gettin this surge/buck. If I turn down the TST fuel only box, it lessens but it is still there. I really dont think its a timing problem now sense Im not changing it from stock.

 

From TST website. It's not uncommon for a blown diode in the alternator to cause a pulsating signal in the power circuit. Check if the alternator has a blown diode.

 

having the same problem 1999 no codes checked the alt tested good replaced the tp sensor 5 times solves the problem for a while then starts again
any ideas.......

 

Looks like ill try an alternator.......

 

Redliner before you change out your alternator, disconnect the main pos lead from the back of the alternator. Take the truck for a ride with it disconnected and if it runs good the problem is the alternator. Mack sure you tape up the lead so it can't ground out on anything. Also diconnect your batteries before taking the positive lead off of the alternator.