What causes engine surge when rpm reaches 1950 to 2050.
Asked by jawjr Aug 03, 2014 at 10:52 AM about the 1990 Nissan Pickup 2 Dr STD Standard Cab SB
Question type: Maintenance & Repair
Engine starts and idles good. When rpm reaches 1950 engine surges up to 2050 and back down to 1950. Above or below 1950-2050 engine runs good. Engine is a 2400 with a 5 speed trans with 306000 miles.
7 Answers
surging or bogging if you hold down cuts out backfires, black smoke,????
Engine does not cut out ,backfire or smoke while surging.
Tom may have the answer vacuum leak my answer was addressing a more drastic actual cutting out of engine power.
Tried testing for a vacuum leak with propane while holding throttle at 2000 rpm.This did not help the surge problem. it kinda acts like a rev limiter but at such a low rpm there is no way that it could be hitting the rev limiter because it will rev past that after it reaches 2050 rpm.
Thanks for the help. If you have any other suggestions I would appreciate it.
I did have surging with my 86 but found that to be due to loose EGR valve The bolts holding it were loose and it would move on the studs causing the engine to surge. Easy check to see if yours is loose.
Nissanhardbody answered 6 years ago
Jawjr hi I have same issue with my 86 Nissan did you ever find what was the issue with it mine also acts like it has a rev. Limiter I already did full tune up and changed tps sensor it idle really good and drives great but when i try taking off to quick it cuts off can’t go over 2500 rpm I have to baby it or it cuts of I already checked for vacuum leaks and found none and suggestions i really appreciate it thanks
