Hey guys I got a 90 na the problem is that when the rpms hit 5500 it surges and won't gain any more rpm. anyone have a clue to why this is?

 

anyone ever had this problem?

 

I would start by checking the port actuators.
Check and make sure their not stuck.
I believe on an NA, the actuators should open fully at 5500 rpms.
Try searching for 5th/6th ports, actuators, etc...

 

5ht and 6th ports open at 3800 rpms. VDI opens at 5200ish. (number varies by whomever is answering the question)

Surging isnt a very precise description of what happens. Does the car fall on its face? Does it make a kind of rumbling sound like its missing. Does the exhaust backfire? Does it matter if the car is floored or at part throttle?


BC

 

hey i have the same roblem and the car pretty much dies out around 4000 when im at full throtal ut when i lightly bring it up and then it has no problem, any clue?

 

if you bring it past 4000 and then floor it does the car dive on its face? Can you bring it to redline at part throttle? My guess would be that you are having secondary fueling problems. I.E. the secondary injectors arent coming online, or are only partly coming online (1 injector is working, one isnt). Ine ither case at full throttle there isnt enough fuel, but if you are keeping it at part throttle there is sufficient fuel to bring the engine up.

Now if you can bring it up past 4k, then floor it and it doesnt fall on its face then I have no idea what your issue is. Possibly bad grounding...? Look at the FAQ for 3800 rpm hesitation. Maybe 5th/6th ports....


BC

 

i floor it then the car pretty much takes a **** and fells like its loosing half its horse power

 

I would start by checking your 5th/6th port activation, then checking the battery grounds. How to do both can bef found in the FAQ. Finally see if its a fueling issue. Check to see that all the injector plugs are in, and see if you are getting power to them.


BC

 

What i ment by surging is that when it his 5500rpm its like its not getting any fuel. Now before this happend when i would hit 5500 it was like it was hitting the power band. At this rpm what would be going on to give it that extra push, would it be the secondary fuel injectors? I have look in the tech threads but i think i got different issues than whats posted about the 3800rpm problems.