[old_skul]

I'm getting a lot of hesitation on midrange acceleration. It idles fine, doesn't need any throttle to stay running. On wide open throttle, it doesn't hesitate.
I have recently (<1 month) replaced plugs, wires, cap, rotor, air filter and fuel filter.
What's up with my car?

 

[old_skul]

Re: Engine trouble 8V MKII - Thoughts? (old_skul)

Okay, tried to go out for some lunch - it was barely able to get it back into the lot. It's hesitating really bad now. I think it's my Hall sender connection since I wiggled it before going out. Sigh.

 

[Kameirocco]

Re: Engine trouble 8V MKII - Thoughts? (old_skul)

do you have an air fuel gauge?....gotta love roccos..lol

 

[old_skul]

Re: Engine trouble 8V MKII - Thoughts? (Kameirocco)

Nope. It's pretty much stock.
It feels like it's bogging down with no spark, because it was doing a little bit of backfiring after trying to run with wide open throttle for a while. I hope I didn't ruin my cat by doing that.
I'll wiggle the Hall sender connector again before I leave.

 

[VWVan]

Re: Engine trouble 8V MKII - Thoughts? (old_skul)

Hows the temperature there? I had a simlar kind of problem when it got real cold, i think my fuel lines were freezing up. I couldn't go more that 40kph and 2500 rpms until the car warmed up. I dunno, I'm just giving you ideas.

 

[Kameirocco]

Re: Engine trouble 8V MKII - Thoughts? (VWVancouver)

my car does the same thing when it's cold here too...very cold blooded animal i have

it bogs down for awile...
but a temporary solution i have come up with was after it started idling i'd slowly put it up to about 2k-ish and held it for about 30-45 seconds and after that it'd run like a champ (still a lil bogging but that went away after a few mins of drving)
but my car is frozen as well as the roads, so no driving for awhile it looks like!

 

[old_skul]

Re: Engine trouble 8V MKII - Thoughts? (Kameirocco)

It's real cold outside. This started when we had a cold snap into the teens.
I just replaced the fuel filter, and have ran STP injector cleaner through it, as well as a bottle of Techron. I just changed the oil even!
I'll report back in a couple of hours.

 

[robw_z]

Re: Engine trouble 8V MKII - Thoughts? (old_skul)

Check you're spark at the plugs. If you rule out spark problems, pop out the fuel injectors, lift the flow plate up and down whilst watching their spray patterns.

 

[old_skul]

Re: Engine trouble 8V MKII - Thoughts? (robw_z)

I'm reasonably certain I have spark for the most part. I don't know if I have the skill to pop out injectors and check the spray pattern. I did run injector cleaner and Techron through it a couple of weeks ago, and it was running fine for a couple of days until it got cold.
I made it home from work, by the way. It would run at partial throttle for maybe 3 or 4 minutes at a time, bog down, and quit. I had to stop on an interstate 5 different times to go 21 miles. It was terrifying.
I replaced my fuel filter just this past Sunday. If it had a tiny, tiny leak, could this cause this kind of problem?

 

[DarthStitch]

Re: Engine trouble 8V MKII - Thoughts? (old_skul)

vacume leak maybe? fuel system (filter or pumps?)

 

[Dimitri16V]

Re: Engine trouble 8V MKII - Thoughts? (DarthStitch)

make sure the big connector on the Jetronic box isn't detouched. Check the transfer pump too

 

[Beowulf-X]

Re: Engine trouble 8V MKII - Thoughts? (Dimitri16V)

could be the injecter O rings, maybe the timing is off. My car used to run like crap till it warmed up when the timing was badly off. same with the injector o rings, it ran like crap untill i tapped them in, or it warmed up enough to expand the rubber. Maybe yourcold start injector is bad?

 

[old_skul]

Re: Engine trouble 8V MKII - Thoughts? (old_skul)

Finally fixed it. It was the in-tank fuel pump. Replaced it with the Pierburg unit that was advertised on Ebay.
When I replaced the pump, the ground wire for the pump was practically hanging loose. I tightened that down and replaced the pump anyway. Runs like a top again!
Now to get through the emissions test....

 

[Freerevving]

I was slowly reading this, I was going to guess it was a fuel pump problem.lol.