'95 525iT surge during acceleration and going up hills

[duckloads]

Greetings,

My e34 has had a surge since I bought it last summer. This is not a miss-fire. It has received plugs, plug boots, valve cover gaskets, fuel filter, o-rings at the intake connector and PVC, and various vacuum hoses. most recently I replaced the fuel pump because it needed a new fuel gage sending unit. All the above has had no effect on the surge. The intake boot is in great shape, and I cannot identify ANY more vacuum leaks.

I have searched the forums and have seen similar surging problems, but I haven't been able to find an actual diagnoses. any help would be appreciated.

[632 Regal]

No diagnosis but look into the intake manifold gasket. They do fail after years.

[genphreak]

+2, it's gotta be unmetered air.

Also, double check all the hoses, esp the ones around the throttle body, connectors under the intake manifold, the one near the cam sprocket housing. Perhaps first check the hose running form the rear of the intake manifold to the Fuel Pressure Regulator is 100%, it is critical. A little split and your engine will never get the fuel pressure it needs. You should remove it and inspect it carefully before putting it back on. It should fit snug and tight to the little nipples on both ends (be careful, it is easy to break it the one under the manifold)!


(Note: It could always be a bad FPR too)

[duckloads]

Thanks for the suggestions. The FPR hose is good. The FPR itself holds vacuum. I tested it with a mighty-vac hand pump. I'll pick up some carb cleaner this weekend and test the intake and injector seals for leaks.

[632 Regal]

Thanks for the suggestions. The FPR hose is good. The FPR itself holds vacuum. I tested it with a mighty-vac hand pump. I'll pick up some carb cleaner this weekend and test the intake and injector seals for leaks.

I tried the carb cleaner trick with no results and after the fact the gaskets were like a hard plastic that was leaking. Once you compare the old ones with the new you'll know what I mean.

[genphreak]

+2 they die out, if unknown, change them. Also, 4 strategically placed dabs of sealer else the new ones will move during installation and leak still. You sure the connector from ICV hose to inside of the intake manifold is good? The clip is holding it soundly? Spray around them...