Slight hesitation?

Hi gang. Loving my '96 Passat after 2 days on the road . Quick question: when doing aggressive acceleration, the car has slight hesitations about once every second or two for just a fraction of a second. It's barely noticeable. Is this common? Is there anything I can do about it?

Does anyone have any insight into this? It annoys me a bit and I'd like to find out if there's something wrong or some way to make it not do the hesitation thing... it's like the power sags just a little bit every second or two (only during hard accelleration).

Does it do this in all gears or just the higher gears (3,4,5)? How many miles are on your car? Does the pitch of the engine chagne with the power?

natescape--I had the same thoughts after I got my '96 Passat TDI. I think there are two issues going on here. 1) The TDI is a "drive-by-wire" design that does NOT use a mechanical link between the "go" pedal and the throttle, or intake or whatever. A computer "interprets" the electronic position of the go pedal into fuel requirements, etc. This design necessarily creates a very minor delay from "stepping on it" to action. 2) The turbo. The turbo provides boost from exhuast gasses. At low RPM's, there aren't enough gasses flowing to give much boost. But give it a few revs, and whalla, TURBO BOOST!!! This feeling is different from most naturally aspirated gas engines I have ever driven.--Steve

Check he MAF sensor it may need to be cleaned.

This only occurs when I have my foot firmly pressed on the gas (diesel?) pedal. As in, I'm trying to accelerate to pass on the highway. It's barely noticeable, but every second or two the engine seems to sag just a bit for a tenth of a second or so. My wife didn't notice it, so it's not that big. I was just wondering if this was common for diesels or turbos (this is my first of each).

My car has 93k. I've only been driving it for a week. Where would the MAF sensor be located? I'm not a gear-head by any stretch of the imagination...

[ June 11, 2001: Message edited by: natescape ]

Natescape...could check the N75...that controls your turbo. In the Passat it is located on the driver side firewall with black, red and blue hoses going to it plus an electrical connector.
I know what you are talking about....really frustrating to track down. Mine started out real suttle and then got real bad!
By the way the MAF is the think sensitive wire inside the conical connection to you air box (drivers) side. You'll see electric wires going to the black plastic.
You can clean with isopropal alcohol in a plastic baggie....just drop the whole plastic piece in the bag.

I wouldn't touch the MAF on a Passat unless I was sure it was bad.The Passat MAFs don't give nearly as much trouble as the A4s is my impression.

Any other Passat owners encounter this hesitation? It's almost rhythmic when pushing the engine... every 1.5 seconds or so it sags just a bit.

Hello,

I had such a problem with my 96 Passat TDI 90HP when I had no board instruments because they crashed somehow in a winter and I still drove without them. The car had this hesitation as soon as I stepped on the acceleration
Teo

I am not a Passat owner but I tend to agree with Irpavlo. Additionally, wasn't it DZcad who recently sucked out a lot of oil from the wastegate actuator?

So what should I be looking FOR? All I know to do is look at it and make sure all the hoses are connected, etc.

I believe lrpavlo is headed in the right direction suspecting a problem with the wastegate control system. If there is any way to get a boost gauge on the car and measure the boost I bet you would see it surge and pull back under WOT. Check all the hose connections on the N75 and the other ends of those hoses.(Red to Compressor outlet, Blue to Wastegate, and Black to intake pipe.)

What you are describing mimics a problem I was having the other day and I found it to be that oil had entered the wastegate control system (Most likely via the black hose on the Intake) and had caused the wastegate auctuator to become full of oil. I used the vacuum gun and I did the best I could to get it all out. I replaced the hose and it runs better than it has in a long time. Follow this link to the post I made http://forums.tdiclub.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=005468

Let us know how you make out.

Natescape, was your problem ever resolved?
Did it get worse before it got better?
What's the status on this?

I'm trying to figure out why I've been seeing lags in acceleration lately.

The first time I noticed it was in central CT going up one of those long grades at 80mph against a strong head wind. Since then, it got worse until it got to the point where my cruise control wouldn't hold 75mph.

I stopped using additives this tank, and spent a lot of time revving to 3500rpm trying to even it out. I certainly see an improvement now, but don't know for sure if this is the solution yet.

Regards,

BeetleGo

Funny- I am just experiencing this in my 97 Jetta, but wasn't gonna post anything till I get my boost guage in to monitor stuff.
I am interested to see where this goes