# 84 GTI runs for only 0.5 second---help!!!!



## Lwebster (Dec 23, 2011)

Please help! I bought my GTI with this problem and I have not been able to fix it. I crank the engine, it catches and runs for half a beat and then dies. It immediately recatches if I start it again. I replaced those little rubber donuts around the fuel injectors and about half the vacuum lines. I do not think there's a vacuum leak. 

I'm a bit suspicious of the fuel pump, the one at the tank, but I am completely new to this. 

Any ideas?

Thanks,
Larry


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## PlacerGTI (Sep 11, 2010)

*84 GTI runs for only 0.5 seconds.*

Not an expert, cruising the forum myself, in search of resolving cis issue. 
Have you done the injector spray test ? You do need to pull the injectors, might need the tool for that, change the o-ring at the same time. Every engine I have ever pulled the injectors on, I found bad o-rings and injectors. 
If it's getting fuel and spark, it should at least start, in my opinion.


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## PlacerGTI (Sep 11, 2010)

*Short Youtube link on injector test*

http://www.youtube.com/watch?v=XabbJ3HaeuI&feature=related


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## PlacerGTI (Sep 11, 2010)

*re you tube link*

I know it looks crude, but the fact that the guy is bench testing the cis injectors, makes it easier to identify the components, rather then the usual dark under hood video's.


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## ny_fam (Apr 3, 2004)

Check the Air Flow Sensor Plate height - engine not getting the right fuel to run properly.

Good resource - http://mikegabriel.net/vw/badhabitrabbit/


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## PlacerGTI (Sep 11, 2010)

*badhabitrabbit link*

Thanks, I had forgotten about that one. Very good advise on the homepage.

Just my two cents worth, if you are going to get knee deep into playing with fuel / CIS stuff, you might want to disconnect you catalytic. A large amount of fuel will ruin your cat in a hurry.

I just made myself a test pipe with a bunch of junkyard pipes and a spare down pipe.
You also get to eliminate one more item of your list. A plugged Cat.


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## dieselfumes2 (Jan 31, 2007)

Just guessing . . . can you get your hands on a known good fuel pressure relay and swap it in?


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## dieselfumes2 (Jan 31, 2007)

Fuel pressure REGULATOR, sorry.


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## Lwebster (Dec 23, 2011)

I actually got it running, but so far not smoothly. It coughs and sputters under load, but idles fine. I took it to the local VW mechanic, who was once a dealer tech back when the MK1 was new. He found that the number four injector dribbled fuel, and the control pressure regulator was clogged. He replaced the injector and used my spare regulator and he says the fuel pressure is good.

Car idles fine, but still stumbles. Now he thinks the fuel distributor is bad. Thats a pricey part and I was starting to think he was at that state where throwing parts at it is the only option. Plus I thought that maybe a few tankfuls of fuel injection cleaner might clear out the dizzy ( one can hope..).

So I'm driving the spitting popping car. It idles fine and seems ok at full throttle. I noticed that the frequency valve was not plugged in. I plugged it in and it appears to not be working (I don't hear a hum nor can I feel it vibrates when the engine is running). I immediately called the mechanic and asked why he hadn't looked into it. He said it looked to him like someone had purposes left it unplugged and that back in the day the cars sometimes ran better when the frequency valve was unplugged. 

This seems odd to me since the open frequency valve increases fuel pressure and the amount delivered to the cylinder. Mine is closed and the way it runs feels to me like a lean condition. Bu maybe the frequency valve is just a fine tuning device, that barely changes the mixture.

Two questions, please:
Does anyone else's mk1 run ok with the frequency valve disconnected?
Where is the fuse or relay for the frequency valve? My Bentley manual does not have my fuse box and I can't see all the printed words....

Oh, btw, I measured the resistance in the valve and it's 2.5 ohms, right in spec.


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## Lwebster (Dec 23, 2011)

It turns out that my GTI won't run well without that frequency valve. 

I found that the frequency valve relay was a hot-rusted mess. Pried out said relay, installed a jumper to power the two terminals and the car runs beautifully. 

THanks, everyone for the help. 
Larry


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