# Hot start pulse relay question



## UROLLIN (Oct 8, 2005)

I have an 83 rabbit gti and I'm running rich when cold and having hot start issues.
I've checked the cold start valve, but I'm looking for the Hot start pulse relay and I dont seem to have one. Would an 83 rabbit gti have this relay? 
The bentley manual has a bunch of different fuse/relay panel diagrams and mine seems to be a mix of all of them. Maybe i'll post a pic of my panel when I get home.

I havent checked the thermo time switch yet by the way.
Also, are there any other things I should check when troubleshooting hot start / running rich issues? Help!


_Modified by UROLLIN at 1:54 PM 5-3-2010_


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## GDR (Sep 25, 2000)

*Re: Hot start pulse relay question (UROLLIN)*

You should check your fuel system and control pressures. Low control pressure will run rich . Lambda will compensate for some of that after it warms up. Check the duty cycle or dwell of the frequency valve. Low values means it trying to lean the mixture.
Check the residual pressure after shut down. A bad check valve or leaking diaphragm won't hold pressure and you get vapor lock. You could have a leaky injector also.You should have a hot pulse start relay but that only helps when everything else works.
My diaphragm leaks. (







I forgot the exact name of the thing that has the diaphragm) I've sealed the leak but I have zero residual pressure. Hot restarts can be tricky at times but I'm used to it. It will sound like its running on 3 cylinders(which it probably is) for 30 seconds or so before it clears up.


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## UROLLIN (Oct 8, 2005)

*Re: Hot start pulse relay question (GDR)*

Thanks for the help man. So far i've replaced my fuel distributor, fuel injectors and leaky fuel return and injector lines so those shouldnt be the issue.
I think the thing that youre referring to with the diaphragm is the fuel accumulator. I was keeping that as a last resort to replace because its more expensive. I did find a control pressure regulator for 50 bucks so I might as well throw that in.
Do you think the thermo time switch could be faulty and is keeping the cold start injector open? That was my initial explanation for the fuel richness. However many people have suggested in other posts to check the WUR/control pressure regulator so I'll give that a shot.
Also, the car has 349k on it so I wouldnt be surprised if the diaphragm in the fuel accumulator is busted or isnt in tip top shape. I'll be hitting a junkyard to grab some of that stuff this weekend. I'll keep you posted. Thanks again.


_Modified by UROLLIN at 11:18 PM 5-3-2010_


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## GDR (Sep 25, 2000)

*Re: Hot start pulse relay question (UROLLIN)*

I think the cold start injector gets blamed too much for starting problems. The injector only runs when the starter is cranking.The tts will limit the time of run while cranking to about 8 to 12 seconds so if you crank for like 30 seconds the injector doesn't keep running.The temp part will not let the injector run when the engine is hot but the pulse start relay should pulse it a few times to help with vapor. Time and temp will be stamped on the tts. You can check it but I don't think thats the problem.
You should really look into getting a cis fuel pressure gauge. It will tell you everything. You can find them for around $100. How much time and money have you already thrown into your car?


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## ny_fam (Apr 3, 2004)

Take a look at the control pressure regulator, clean it if necessary then check fuel pump check valve. If you run your gas down to E or close to it your likely to get the check valve plugged that will exhibit similar results. 

Here is a good link on fixing CIS issues 
http://www.scientificrabbit.com/node/12


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