NateTheShake

iTrader: (3)

So I went to do emissions, besides failing (miserable and I'll address that later) I noticed my car would not hold a steady rpm. The test was at a steady 2500 rpm and every full cycle the engine would droop to about 2200 rpm and then back up to 2500. I went home and tried the same test at a few different rpms between 2k-3500 and it did the same every time.

Any ideas what could be causing this?

It's a very brief cutoff and according to TunerStudio the fuel load seems to spike slightly at the same time (from about 30% to 35% load).



Not sure if this is related, but when I start the car it idles perfect right around 1000 rpm however when I drive for a short period of time it idles at 1500rpm. Still smooth, but it won't go beneath 1500. A few times it will idle closer to 2k rpm, but I can touch the throttle once or twice and it will come back down to 1500.

Techsalvager

log\msq of said happening?

fooger03

iTrader: (2)

Perhaps something in your car is creating a load. Is your fan kicking on and off?

What do you mean "every cycle"? Every RPM? Every Minute?

If you had an on/off load kick on while holding the throttle constant, your RPMs would quickly drop. To compensate, you would have to increase manifold pressure, which would cause a "fuel spike" in order to return the car to the previous operating RPMs.

Braineack

iTrader: (62)

post your msq, it could be a number of things, idle could be idle settings, the weird surge could be an untuned VE cell

NateTheShake

iTrader: (3)

The fan is on constant, both of them. The original owner had them wired that way and I haven't bothered fixing it yet. So no extra load is being put on the car past that, which is why I assume the idle hangs around 1k normally.


I should have been more specific with the description, it isn't every engine cycle but it is timed exactly. It's approximately every three seconds, but constant and like clockwork.

I will try to post up an msq tomorrow.