Ok boys & girls. I have (another) engine problem, and this one concerns my 33 mpg daily driver Volkswagen. So, here goes:

1. Engine coughs and wont idle. One time it died on me just as I was passing a car on the freeway. The symptom was almost as I ran out of gas. First I suspected ignition problems. It felt almost as it wouldn´t fire the sparks from time to time. I checked for spark. Spark was there,no problem, but I got new plugs and wires anyway. I bought a new distrubutor cap, rotor and breaker as well. Problem still there ![img]/wwwthreads_images/icons/frown.gif[/img]

2. Checked if it got gas. Yup, the pump worked alright, but I got a new fuelfilter and checked tank ventilation. Still it died on me! [img]/wwwthreads_images/icons/frown.gif[/img][img]/wwwthreads_images/icons/frown.gif[/img]

3. So now I´m irretated and start do dig deep into it. It must be vacuum (eureka!!) or rather, loss of vacuum. So I replace all vacuum-hoses I can see. I clean up the carb and replace the gasket at the carb"foot". I replaced some electrical wiring going to the carb, which btw I have no clue why it´s there for, the choke is manual. Suddenly it will idle better than it ever did before[img]/wwwthreads_images/icons/crazy.gif[/img]. I celebrate this with a couple of beers and thinking to myself: I´m d*mn skilled with engines[img]/wwwthreads_images/icons/wink.gif[/img]

4. Now, when I drove to work earlier today I noticed the following: Everything works fine until I reach 4:th gear. I can NOT throttle it very much until the vacuum is gone, and the engine starts coughing again. I installed a vacuum gauge to see what happened, it fell from good to dead when I throttled it in 4:th gear. I dunno why 4:th gear is the thief here....maybe because the engine have to strain itself the most?
I´ve run out of ideas now[img]/wwwthreads_images/icons/frown.gif[/img]. Is the carb leaking? Intake gasket? It´s equipped with EGR, but I really don´t know what happens when an EGR goes bad ? Heeeeeeeelp !!

Andreas

If a Blazer runs smooth, it isn´t really a Blazer[img]/wwwthreads_images/icons/crazy.gif[/img]

I'd still suspect the fuel pump. Can you run a fuel pressure guage and drive it at the same time? You must be an older VW if its still carbed. My 82 Sciracco had FI. Doesn't sound like a Bug if it has EGR.

Shawn
87 K5
few mods

I could replace the pump at one 3:rd of the cost of what a fuelpressure gauge would cost me [img]/wwwthreads_images/icons/smile.gif[/img]. But I really don´t think the pump is faulty, ´cause when we unhooked the fuelhose from the carb and started the engine (there still was fuel in the carb) it pumped out about a pint of fuel in notime. It still doesn´t explain the mysterious vacuum loss in 4:th gear![img]/wwwthreads_images/icons/frown.gif[/img]. Unless it´s starving for fuel and is about to give up at that speed. I think it should show the same symptoms regardless of gear if the fuelpump is bad. I can rev it in 2:nd gear up to 6000 with no signs of "cough-cough-rrRRrrRR".
The VW model is a "Jetta" made in 1984 with a carbed 1.6 litre engine (VROOOM). Dunno if you had that imported to the U.S? It´s the most boring car you ever seen, but 33 mpg is hard to beat[img]/wwwthreads_images/icons/smile.gif[/img]. Got it from an old lady who only drove around in the summertime, so no rust whatsoever, low miles and I got it ultra cheap.

Andreas

If a Blazer runs smooth, it isn´t really a Blazer[img]/wwwthreads_images/icons/crazy.gif[/img]

I thought you were having problems with your other daily driver. Remember the photo you posted? [img]/wwwthreads_images/icons/cool.gif[/img] The Vdub probably just needs a healthy 350 installed under the hood..........I'm trying to remember the rules if you hook up a vacuum gauge inside the car.[img]/wwwthreads_images/icons/blush.gif[/img] Maybe you have to perform some other tests, check for clogged catalytic converter or a collapsed muffler, then possibly something faulty in the EGR, maybe vacuum lines are not all where they need to be.

77 GMC Jimmy aka the Greyghost
UNLIMITED SLIPS in both ends
"Went through it's first three legs pretty quick. Thank God for the last one."

My only experience with VW is with sandrails![img]/wwwthreads_images/icons/cool.gif[/img]
but it sounds like an intake leak to me !

Scooby Dooby Doo !!!

Greyghost. Yeah, I remember the other daily driver [img]/wwwthreads_images/icons/laugh.gif[/img]. I ditched that old tired Camaro for something else. Here´s a pic of me getting some milk[img]/wwwthreads_images/icons/laugh.gif[/img][img]/wwwthreads_images/icons/laugh.gif[/img]:
http://www.swedishprostreetnews.com/tullinge/6/014.JPG
A stock 350, even the smog 165 hp slowdogs from 75-76, would twist everything on the Jetta into...well, into nuclear meldown[img]/wwwthreads_images/icons/smile.gif[/img]. I do have a spare 350, but I´m saving that for something funnier than a VW Jetta. Anyway, there´s no cat on the VW and the exhaust system is in great condition. Vacuumlines are where they supposed to be, and as I said, they´re all replaced. So no cracked hoses. What happens when the EGR goes bad? Does it steal/leak vacuum, does it choke the engine, or what ? I know it´s supposed to feed burned gasses into the engine for another round, but that´s all I know.

Scooby. I pray every night it´s not the intake gasket, ´cause it´s impossible to take the intake off without lifting the whole damn engine out of the car. This overhead cam stuff are just a pain in the butt, with the intakemanifold 1/2 inch above the exhaustmanifold (and the bolts holding it all in place are, yup, in between[img]/wwwthreads_images/icons/frown.gif[/img]). God bless pushrods[img]/wwwthreads_images/icons/smile.gif[/img]. The ppl at WV told me those gaskets almost never goes bad, so I REALLY hope it´s not the case.

Andreas

If a Blazer runs smooth, it isn´t really a Blazer[img]/wwwthreads_images/icons/crazy.gif[/img]

I've heard of similar problems and had one myself, al caused by a damaged fuel line. In my case, the front of my muffler came unhooked and hit the road. This jammed the rest of the exhaust into the fuel line and crushed it. I would just get it into high gear and it would sputter and buck. It just wouldn't pull enuf fuel thru the smashed line to run. I think your loss of vacuum is just a symptom. Opening the throttle on a dying engine SHOULD kill the vacuum, I think.
They sell El Cheapo vacuum/pressure gages for diagnostic purposes, I've used mine to measure fuel pressure. I think mine only goes to 15PSI, but you're only looking for 4-7 anyway. Good luck.
Pete

Yeah I know Pete, that opening a throttle on a dying engine should kill the vacuum. But in my case the engine died BECAUSE I opened the throttle[img]/wwwthreads_images/icons/frown.gif[/img]. Needless to say, my style of driving nowdays is very economical......
I think I´ll buy a pressure gauge, like you said, to see if something weird is happening in there. Big downer for me is the only ones available in Sweden are "Autometer" gauges, which is a little pricey[img]/wwwthreads_images/icons/frown.gif[/img]. Would look cool though, a fuelpressure gauge on a VW Jetta LOL [img]/wwwthreads_images/icons/laugh.gif[/img]

Andreas

If a Blazer runs smooth, it isn´t really a Blazer[img]/wwwthreads_images/icons/crazy.gif[/img]

I have an Autometer 10psi FP gauge that I'd almost give you but the shipping may be too much. It's a mech gauge which means not to mount it inside for safety reasons. Wouldn't want you to become a toasted Swedish marshmellow!

[img]/wwwthreads_images/icons/laugh.gif[/img]

Shawn
87 K5
few mods

If you toast me, I´ll toast you, that´s how it works [img]/wwwthreads_images/icons/smile.gif[/img]. Thanks anyway. I´ll work it out somehow, even if it includes hiring engineering wizards from NASA (and I thought Autometer gauges were pricey)

Andreas

If a Blazer runs smooth, it isn´t really a Blazer[img]/wwwthreads_images/icons/crazy.gif[/img]