Pelican Parts Forums

Pelican Parts Forums (http://forums.pelicanparts.com/)
-   Porsche 924/944/968 Technical Forum (http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/)
-   -   Vacuum issue after flooding on cold start. (http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/591269-vacuum-issue-after-flooding-cold-start.html)

Dean924s 02-12-2011 12:24 PM

Vacuum issue after flooding on cold start.
 
Started Friday.

It was 8 deg out car started for a couple seconds and then died. It would not re start. I suspected flooding.

So today (Saturday)

I checked spark. All was good.

Pulled plugs and they were soaked with fuel.

Just for S&G's I did a compression test and found all 4 cylinders are 80-100PSI :(

I added oil to the cylinders and it fired up starting one cylinder at a time until I had a cloud of smoke that was truly amazing.

I let things settle down and idle. However it is running like it has a vacuum leak. I have MJLJr so I hooked up the computer and looked at the map and found it was idling at about 50-60 KPa. It should be around 20 KPa. For reference 100 is WOT.

I have searched everywhere and can not find the vacuum leak. The only thing I did not remove was the intake. I inspected the boot and all the vac lines that I could get to. Removed and blocked off the line to the power assist for the brakes.

I used the spray it with carb cleaner trick on just about everything that I could not physically reach (most of the lines to the idle speed control valve.)

It is acting like the idle speed control valve is stuck open.

Oh-ya I don't have a cat so it can not be clogged from the oil I put in the cylinders. I am wondering if the Idle Control Valve? Is there a good way to test this thing?

Any other Ideas are appreciated.

The good is I went from a dead car to a running car today. It is just not running proper at the moment.

John_AZ 02-12-2011 02:38 PM

The easy Q--ICV test
Idle Control Valve Testing - Porsche 951 - www.texasblake.com

I suggest Gumout fuel injector and intake cleaner instead of harsh carb cleaner.

Pure guess on the vac leak:
Did you pull the "J" air intake boot and check the hoses and the black plastic connector?
I pulled mine a couple of months ago and the black connector fell apart--Pelican .

The ICV hoses at the bend crack. Mine were brittle and I replaced both--Pelican .

The short ICV hose connects under the intake----sorry, no easy fix if you find a leak--pull the intake.

My car had a 50 rpm surge at idle. My fuel pump damper leaked/replaced---pull the vac hose and very carfully look for drops of gas. Do the same for the FPR.

Cracks in the air intake "J" boot.

Check the AFM barn door for smooth operation.

Brake booster vac fitting??

GL
John

Dean924s 02-13-2011 08:14 AM

I pulled the J boot and inspected all the hoses around it and those that I could get to under the intake. I disconnected the vac line to the brake booster and plugged it.

I am going to do a compression test while it is hot and see if one of the cylinders is down.

If that does not show anything I guess I am going to have to take the intake off and see what I have.

I was actually thinking of removing and plugging all the vac lines to the intake & the J boot and then and seeing if that does anything.

Thanks for the info!!!!

Dean924s 02-13-2011 11:33 AM

Timing belt
 
The timing belt is toast

Now did I bend the valves?

I was running as if it was down on timing. But running evenly across the board.

I disconnected all the vac lines and plugged everything. I started it again and it was just the same.

Next I then pulled the #1 plug and decided to try to see if the timing was ok. As I was Turing the crank by hand with a wooden dowel in the #1 cylinder i got it about half way up and then I could turn the crank with out the timing belt moving. I looked closely and found that the belt at the crank had sheered off about 5 teeth on the belt.

SO did I get the valves or not. It is acting like it had only jumped one tooth when it was running and it sheered the rest of the teeth when I was turning it over by hand. Since I can not turn the motor over now anyone got a good way to check the calves without disassembly? I have a complete fresh head on the shelf but considering I will have to do this swap outdoors I would like to avoid it if possible.

John_AZ 02-13-2011 12:07 PM

My first step would be to remove the old belt, align the cam and crank to TDC--, put on the new belt & tension and try to turn the crank-----again by hand.

You should be able to tell if the valves are bent by resistance.

It is nice to have a fresh head on the shelf.

Going back to the vacuum leak, the belt may have jumped a couple of teeth before all the current vacuum leak testing was started.

If there is no resistance & all seems well, a leak down test would give you the best answer.
Compression-leakdown test

Again, with the 5 teeth missing on the cam belt, a couple of bent valves would be no surprise.

GL
John

Dean924s 02-13-2011 05:36 PM

Quote:

Originally Posted by John_AZ (Post 5844364)
My first step would be to remove the old belt, align the cam and crank to TDC--, put on the new belt & tension and try to turn the crank-----again by hand.

You should be able to tell if the valves are bent by resistance.

It is nice to have a fresh head on the shelf.

Going back to the vacuum leak, the belt may have jumped a couple of teeth before all the current vacuum leak testing was started.

If there is no resistance & all seems well, a leak down test would give you the best answer.
Compression-leakdown test

Again, with the 5 teeth missing on the cam belt, a couple of bent valves would be no surprise.

GL
John

The teeth came off when I was turning it by hand (I have the cover off the front of the motor). I had spun it around 3-4 revolutions by hand and the belt was fine. I literally watched the teeth strip off the belt as I turned the crank. Kind of a surreal experience.


All times are GMT -8. The time now is 08:23 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2025 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website


DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.