Odd occurance in the 944 last night......help!

944S Boyeee · 02-28-2003, 07:20 AM

Last night when driving home on the highway, I was in forth gear and driving along with no problems. Then I hit the gas and the car reacted like someone had unplugged two spark plugs. It felt like there was sand coming through the fuel lines. A very choppy, "bangy" sensation. It would not take any throttle, it ran on a very slight throttle, but as soon as I pushed down the pedal, it would stumble.

I thought right away - "Damn - timing belts!!"....but the motor sounded fine, until I hit the gas. Even when I put it in neutral, I could rev it better than when in gear.

Anywho - coasted (these cars will coast forever) to the end of the highway (expecting to shut it down and start searching for a problem). Everything was back to normal. Put it in first, started driving (expecting the hesitation again) and there have been no problems since.

Now here is what is strange. Before all this happened, my car had a very slight stumble when I went from 0 throttle to giving it gas in high gears (usually 4th and 5th). Sometimes when gearing down from 3rd to 2nd, the car would bog and feel like it was flooded and I'd have to put it in neutral and rev it and then put it back in gear.

Now that problem is gone. I drove around last night in 4th while going slow and there was no hesitation what so ever.

When I experienced the problem on the highway, it felt like it was flooding itself, but it also felt like something was "stuck" in the fuel system. Could something have been lodged somewhere and worked it's way through? I have a new fuel filter, wires, cap, roter, plugs, etc, etc - so I don't think it's that.

I think it could be a fuel pump (but, don't they just go at once?). It could be a bad FPR. Maybe a clogged CAT? Perhaps a clogged injector or an injector going bad? What I have also been leaning towards is the fact that I haven't put any fuel line antifreeze in the car all winter and it was very mild here a few days ago, then went back to a ridiculously low temp. Could there have been water somewhere in the tank from the temperature change or perhaps the lines were just frozen or something?

I dunno??? Anyone ever experience this?

944S Boyeee

Rot 911 · 02-28-2003, 07:59 AM

My guess water in the fuel line, partially frozen fuel line, temporarily clogged fuel intake screen on the gas tanks.

Dark Skies · 02-28-2003, 08:08 AM

How about a sticking air sensor flap (just beyond the air filter? It sends info back to the DME so's to control the fuel system.

944S Boyeee · 02-28-2003, 08:36 AM

Could something clogged in the airbox cause this also??

944S Boyeee

AFJuvat · 02-28-2003, 09:24 AM

clear the airbox.

Also, check your fuel pressure - may have blown FPR or FPD.

Can rule out a cat as you haven't had temp issues.

AFJuvat

944S Boyeee · 02-28-2003, 09:49 AM

Why would this problem raise it's head in the high gears, yet doesn't do it in the lower ones.

Could it be transmission-related somehow? I have heard that when the cars "buck", that it could be a transmission thing.

944S Boyeee

Dark Skies · 02-28-2003, 04:19 PM

Possibly because you're generally making less demands on the fuel / air system when a lower gear is required. In nuetral you're not loading the system (other than to turn the engine over) You said initially that it happened when you hit the gas - as everything is new other than your fuel pump it sounds like the best place to check is the breathing end of the system.

I had a fuel injected z1000 kwacker that had a Bosche airmeter pretty much the same as the Porker and sometimes, if a little grit somehow got past the filter or oil it would cause the flap to lag and get the fuel mix to rich and cause it to bog down.

A failing fuel pump, in my experience, is all downhill without any reprieve - eventually just not able to provide the necessary pressure.

AFJuvat · 02-28-2003, 09:38 PM

Quote:

Originally posted by Dark Skies
Possibly because you're generally making less demands on the fuel / air system when a lower gear is required. In nuetral you're not loading the system (other than to turn the engine over) You said initially that it happened when you hit the gas - as everything is new other than your fuel pump it sounds like the best place to check is the breathing end of the system.

I had a fuel injected z1000 kwacker that had a Bosche airmeter pretty much the same as the Porker and sometimes, if a little grit somehow got past the filter or oil it would cause the flap to lag and get the fuel mix to rich and cause it to bog down.

A failing fuel pump, in my experience, is all downhill without any reprieve - eventually just not able to provide the necessary pressure.

A little cockney by Yank standards

, but a very complete description. (I've earned the right to poke a little fun, I lived in East Angelia for about 12 months)

We can rule out tranny/clutch problems for the moment because you have no other symptoms

Personally, I would clear the airbox, verify fuel pressure, and put a tank or two of the good stuff in there (with techron) in the absence of other issues

AFJuvat

overkill · 03-01-2003, 08:55 AM

Dude, my car was bucking in 5th gear too that day I brought the car home from my friends house after we dud the commpression test!!! Did the car fell like it was slippin or somthing before the car started to buck? I was driven along and all of the sudden it felt like the car was slippin in gear or somthing and then it began to buck in 5th gear. I pushed the clutch in and let go of the gas. I then let go of the clutch and applied gas and continues driving. It was ok but then began to do it again. I am almost sure that it happened after hitting a bump, not sure though. Whats the deal? GOD I HOPE IT DOESNT HAPPEN WHEN I GET THE CAR RUNNING!!! I DONT WANT TO FIX ANYTHING ELSE!!!! JUST WANT TO SELL HER!!!