did you just try to tell me that my engine produces no vacuum on acceleration? I'm pretty sure that my engine produces more vacuum on acceleration because that's when it's sucking all the air. Unless you have something productive to say don't say anything. Yeah I noticed we're all the check valves and vacuum lines were placed thanks but no thanks I still don't know what the problem is.

 

sorry I did not understand at first. I read this https://en.m.wikipedia.org/wiki/Manifold_vacuum now I understand what you are saying. I don't know what the check valves have to do with this. Now I'm thinking it's my valves or my piston. I may just replace the whole entire vacuum system because it's a 98 and see if that does anything. I'm not going to bother with the valves I'm putting a new engine in here. I'm just trying to make sure that all the auxiliary systems they're not directly attached to the engine or working properly so that when I do nothing is left that needs to be done.

 

A new engine won't change the problem. All of the HVAC controls are vacuum powered. (except the blend door) If you don't have vacuum, they don't work. It really is that easy. The problem you are experiencing is because at large throttle openings/high load, manifold vacuum is essentially zero. So, no vacuum to hold your vents in place. The idea with the check valves is, so vacuum doesn't bleed off quite so rapidly when manifold vacuum is essentially nonexistent.

 

I do understand that now that I've read some things so I can understand what you were saying thank you for that advice. That's not the reason I'm going to swap the engine. I certainly have another problem too. When I go into open loop my RPM shoots from 2000 to 3000. I also need to paint my engine and change all of the gaskets and seals and remove the rust but I need to drive it everyday to so that means I'm going to put a different engine in there well I do that. If that vacuum line problem gets fixed and I'm still experiencing a 1000 RPM increase after going into open loop and I know it wasn't my valves. Personally I suspect something's wrong with the engine. I guess I'll just have to see if it's about him line because I know that needs to be fixed anyway. I don't even have cruise control that's a wiring problem I think the buttons don't work on the steering wheel. I am worried about the vent flipping onto the dash so yeah I need to fix that too. I actually found this problem coincidentally while I was looking for some solutions to the problem that I noticed originally.

 

1000 RPM increase when you go into open loop? Could you explain that in a bit more detail?

 

open loop is engaged when I go uphill everyday. I know because my rpm goes from somewhere around 2000 to somewhere around (or above) 3000 rpm and my heater/ac switched to dash. I just installed a fuel pump so that fixed the starting problem. Now I crank it one time to start it. It is acting like it's not getting enough fuel under load when it switches from closed loop to open loop. Does fine at lower speeds before it engages closed loop and cruises ok too. It's when I hit the gas on level surface it acts like I'm pulling a trailer too. Right up to 3k rpm even on a level surface.

 

I think you are confusing terms.

Closed loop is when the PCM is paying attention to the O2 sensor. Open loop, it is not. Once the engine and sensors reach operating temp, the only time the engine drops out of closed loop is when you step on the gas hard enough, which may also convince the trans to drop out of Overdrive. Which would account for the big jump on the tach.

 

Yes! That! This is confusing to me because I'm only at half throttle or quarter throttle when this happens. This van is supposed to do zero to 60 8 Seconds with stock 318. Because of this it only goes 30 mph then has a friggin heart attack till I take my foot off the gas for a second then I'm only allowed to tap it till I get to 40 and if I go up a hill it starts sputtering sometimes.

 

That sounds like a clogged cat, or failing crank sensor..... Getting any codes?

 

I already put a new cat on because it failed. New O2 sensors too. Same problem. Then my fuel pump. I might just change all these sensors just for the hell of it when I pull this thing out to clean it. The problem with the cat was overheating. It either got clogged or ran too lean or both. Back to problem with open loop. I think I am running lean in open loop.