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DISCUSSION => Engine + Driveline => Topic started by: 16v of Fury on August 05, 2007, 09:33:15 PM

Title: Locating A Vacuum Leak...?
Post by: 16v of Fury on August 05, 2007, 09:33:15 PM

How do you isolate a vacuum leak, with all the hoses on these damn cars?

I have just put a new HG on my car, and reassembled it all --- it runs but there is definitely a vacuum leak somewhere.  But where?!?  GRRRR!!!

Title: Locating A Vacuum Leak...?
Post by: Wise Old Dog on August 05, 2007, 10:23:29 PM

Spray can of carb cleaner. Use the spray extension. Small squirts near the offending leak will smooth out the idle. E-Z

Title: Locating A Vacuum Leak...?
Post by: 16v of Fury on August 05, 2007, 10:28:03 PM

Quote from: Wise Old Dog;31112

Spray can of carb cleaner. Use the spray extension. Small squirts near the offending leak will smooth out the idle. E-Z

Thanks for the info.

I can't get it to idle and stay running, though --- I have to keep bumping the gas to keep the car running, otherwise it dies.  It won't idle by itself, at all.

Title: Locating A Vacuum Leak...?
Post by: D. Clay on August 05, 2007, 10:35:50 PM

I use a can of WD-40 with a tube in the nozzle. When you hit the leak it will temporarily seal it or reduce it and the motor will change speed slightly or smooth out a little. There's 3 lines to the throttle body and a line from the idle control valve to the intake boot.Here's a picture:
(http://www.m42club.com/forums/attachment.php?attachmentid=381&d=1156043563)

Title: Locating A Vacuum Leak...?
Post by: 16v of Fury on August 05, 2007, 10:36:56 PM

I appreciate the info --- but I can't get the motor to stay running, to be able to try all this.  I have to keep pumping the gas pedal, otherwise the RPM drops and the motor quits.  

Any suggestions?

Title: Locating A Vacuum Leak...?
Post by: dude8383 on August 05, 2007, 10:43:38 PM

Quote from: 16v of Fury;31115

I appreciate the info --- but I can't get the motor to stay running, to be able to try all this.  I have to keep pumping the gas pedal, otherwise the RPM drops and the motor quits.  

Any suggestions?

Check the fuel pump, and I'd also check that ECU. My car had the same symptoms...It wouldn't hold idle and after checking everything, I eventually tried another ECU.

I'd also check out the ICV valve and the TPS sensor...make sure you clean out those connections with some of the electric cleaner in an aerosol can.

Glad it has started at the very least!!!

Title: Locating A Vacuum Leak...?
Post by: 16v of Fury on August 06, 2007, 05:22:04 PM

Quote from: dude8383;31116

Check the fuel pump, and I'd also check that ECU. My car had the same symptoms...It wouldn't hold idle and after checking everything, I eventually tried another ECU.

I'd also check out the ICV valve and the TPS sensor...make sure you clean out those connections with some of the electric cleaner in an aerosol can.

Glad it has started at the very least!!!

- Check the fuel pump?  Do you mean listen to it to see if it's buzzing?

- Yeah, might swap out the ECU and see what happens.

- Good call - I'll hit the ICV / TPS.

Thanks D.

Title: Locating A Vacuum Leak...?
Post by: dude8383 on August 06, 2007, 05:34:02 PM

The manual should have a procedure on how to check if the fuel pump is in good working order. I doubt that the fuel pump is the culprit, but never hurts to check.

Quote from: 16v of Fury;31150

- Check the fuel pump?  Do you mean listen to it to see if it's buzzing?

- Yeah, might swap out the ECU and see what happens.

- Good call - I'll hit the ICV / TPS.

Thanks D.