Well Damn..Vacuum problem

Dark_5.0 · 03-14-2004, 08:51 PM

I dont have a vacuum gauge I am going to borrow one tomorrow. But my engine isnt pulling much vacuum.

I dont have any vacuum leaks and the car runs great @WOT.

here are my problems.

I set the fuel pressure @39psi @wot and when I attach the vacuum line the pressure only drops to 37 psi. So it is running rich at an idle.

Also my breaks are not working too great cause of the lack of vacuum.

I guess the E-cam is the problem

I do I fix this problem.

Hozer 88GTConv · 03-14-2004, 09:06 PM

Dark,
I have a GT 40 intake too. Tell me what you are drawing vacuum from and what things you have hooked up.

I have a b-cam with 1.7's and I've got plenty of vacuum. I have only the brake booster, pcv and fpr coming off of the lower tree of the GT 40. Everything else is plugged.

Hozer

Dark_5.0 · 03-14-2004, 09:12 PM

I am running the brake booster off of the same line that goes to the pcv valve. And I have I line going to the fuel pressure regulator off of the big barb on the back of the intake everything else is plugged.

Hozer 88GTConv · 03-14-2004, 09:28 PM

I will give you my readings and vacuum psi tomorrow in return for your valve adjustment tips.

Maybe that can help you diagnose.

RoadWarrior · 03-14-2004, 09:34 PM

Quote:

Originally posted by Dark_5.0
I am running the brake booster off of the same line that goes to the pcv valve. And I have I line going to the fuel pressure regulator off of the big barb on the back of the intake everything else is plugged.

I think thats the reason your brakes arent working well. Run them off a dedicated fitting.

Hozer 88GTConv · 03-14-2004, 09:39 PM

I am running my brake booster line from a single large barb pulling vacuum from the port underneath the main runner from the throttle body.

My fpr and pcv are coming from thr two dinky lines coming off the tree underneath the main plenum by the driver's side valve cover.

I pull too much damn vacuum. I have to run a in line filter from my pcv so it doen's throw oil in the plenum.

Dark_5.0 · 03-14-2004, 10:27 PM

I have always ran the lines like they are ran now without any problems. My problem is my engine is making very little vacuum.

I hope there is a way to fix it.

420nitro · 03-14-2004, 11:32 PM

When I had the similar combo I pulled 11-12inches of vacuum.
I also had a dedicated line for the brake booster as well. Never had an issue with the power brakes either.
Either you have a leak or you do need a dedicated line to the booster. At least a 3/8 ID line.

Dark_5.0 · 03-15-2004, 12:37 AM

I am going to pull the upper intake manifold back off tomorrow and see what I can find out.

Later,

302 LX Eric · 03-17-2004, 05:46 PM

Just as a baseline Dark...with my old 302 H/C/I combo (steeda #19 cam 480/480 lift with 115LSA and duration I can't recall) pulled 11-12 in-hg. at idle (750 rpm).

I'm not sure what you mean by the brake booster line - I've never touched mine.

E

Dark_5.0 · 03-17-2004, 09:47 PM

My engine idles perfectly....The car feels fast when you drive it.

But here is the kicker...............My car isnt making enough vacuum to move the vacuum gauge at an idle.

If I rev the engine a little bit the gauge will go to 4 hg's.

You would think I have a huge vacuum leak but I have checked and rechecked everything over and over.

Upper to lower intake is sealed for sure.

Lower intake to heads is sealed for sure.

Hell if I know. This sux

420nitro · 03-17-2004, 11:37 PM

Just out of curiosity, What is your timing at with the spout connector disconnected?

Dark_5.0 · 03-17-2004, 11:51 PM

15 initial advance

sedanman · 03-17-2004, 11:58 PM

Something has to be run wrong. I had a E cam for a long time and never had problems with vacuum. The brake boster runs off the vacuum tree right? I think maybe you blew a cap off somewhere or something. Your combination should have pleanty of vacuum.

420nitro · 03-18-2004, 12:05 AM

Quote:

Originally posted by sedanman
Something has to be run wrong. I had a E cam for a long time and never had problems with vacuum. The brake boster runs off the vacuum tree right? I think maybe you blew a cap off somewhere or something. Your combination should have pleanty of vacuum.

I agree.

If you have near to stock compression I would try more timing to. I was always able to make more power running anywhere from 16-19 degrees. Each car a little different but same cam and similar parts. All had close to stock compression. 9 to 1--9.5 to 1.

If you can, post a pic of your vacuum tee and the hoses that goes to the booster and intake. Maybe one of us willl see something obivious??

Worth a shot.

jonnyk · 03-18-2004, 08:30 AM

You sure you don't have a lower to head leak? It could be drawing from the crankcase and you'd never know it.

A huge vacuum leak should be audible if it's external...

Hozer 88GTConv · 03-18-2004, 09:09 AM

Dark,
Where are you measuring your vacuum at?
We have nearly identical setups N/A and I have 10-11 inches of vacuum at 750 RPM idle. Measured at the fpr and at the GT40 tree under the plenum with a vacuum guage.
I am going to measure it at the big barb too for ya. I'll post it in a minute.
I agree with the pic idea too. That might make something jump out at everyone.

88workcar · 03-19-2004, 08:08 AM

2 Things.
1st - Change the guage
2nd - Check the brake booster

Hope this helps a little?

Dark_5.0 · 03-19-2004, 01:49 PM

Even if I plug all vacuum lines except for the one on the gauge I still dont get any vacuum.

I did a compression test just to make sure I didnt have a dead cylinder from setting the valves too tight and everything was fine 155-165.

The lower intake gaskets have got to be sucking air inside the intake valley.

We will see.

03-14-2004, 09:06 PM	#2
Hozer 88GTConv Registered Member Join Date: Feb 2002 Location: Jacksonville, FL Posts: 706	vacuum configuration... Dark, I have a GT 40 intake too. Tell me what you are drawing vacuum from and what things you have hooked up. I have a b-cam with 1.7's and I've got plenty of vacuum. I have only the brake booster, pcv and fpr coming off of the lower tree of the GT 40. Everything else is plugged. Hozer __________________ 1988 GT Convertible 331 10:1 TW heads, GT-40 intake, MSD, TRW flattops, B Cam w/ 1.7's, MAC exhaust, 24's, 70 TB, 76 MAF, 3.73's, Pro 5.0, Koni's, Anderson PMS, Wideband 02, yatta, yatta... One week with new motor, two speeding tickets...joy

03-14-2004, 09:12 PM	#3
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	I am running the brake booster off of the same line that goes to the pcv valve. And I have I line going to the fuel pressure regulator off of the big barb on the back of the intake everything else is plugged. __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

03-14-2004, 09:28 PM	#4
Hozer 88GTConv Registered Member Join Date: Feb 2002 Location: Jacksonville, FL Posts: 706	vacuum configuration... I will give you my readings and vacuum psi tomorrow in return for your valve adjustment tips. Maybe that can help you diagnose. __________________ 1988 GT Convertible 331 10:1 TW heads, GT-40 intake, MSD, TRW flattops, B Cam w/ 1.7's, MAC exhaust, 24's, 70 TB, 76 MAF, 3.73's, Pro 5.0, Koni's, Anderson PMS, Wideband 02, yatta, yatta... One week with new motor, two speeding tickets...joy

03-14-2004, 09:39 PM	#6
Hozer 88GTConv Registered Member Join Date: Feb 2002 Location: Jacksonville, FL Posts: 706	good call I am running my brake booster line from a single large barb pulling vacuum from the port underneath the main runner from the throttle body. My fpr and pcv are coming from thr two dinky lines coming off the tree underneath the main plenum by the driver's side valve cover. I pull too much damn vacuum. I have to run a in line filter from my pcv so it doen's throw oil in the plenum. __________________ 1988 GT Convertible 331 10:1 TW heads, GT-40 intake, MSD, TRW flattops, B Cam w/ 1.7's, MAC exhaust, 24's, 70 TB, 76 MAF, 3.73's, Pro 5.0, Koni's, Anderson PMS, Wideband 02, yatta, yatta... One week with new motor, two speeding tickets...joy

03-14-2004, 10:27 PM	#7
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	I have always ran the lines like they are ran now without any problems. My problem is my engine is making very little vacuum. I hope there is a way to fix it. __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

03-14-2004, 08:51 PM	#1
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	Well Damn..Vacuum problem I dont have a vacuum gauge I am going to borrow one tomorrow. But my engine isnt pulling much vacuum. I dont have any vacuum leaks and the car runs great @WOT. here are my problems. I set the fuel pressure @39psi @wot and when I attach the vacuum line the pressure only drops to 37 psi. So it is running rich at an idle. Also my breaks are not working too great cause of the lack of vacuum. I guess the E-cam is the problem I do I fix this problem. __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

03-14-2004, 11:32 PM	#8
420nitro Registered Member Join Date: Nov 2003 Location: Rockford Posts: 596	When I had the similar combo I pulled 11-12inches of vacuum. I also had a dedicated line for the brake booster as well. Never had an issue with the power brakes either. Either you have a leak or you do need a dedicated line to the booster. At least a 3/8 ID line.

03-15-2004, 12:37 AM	#9
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	I am going to pull the upper intake manifold back off tomorrow and see what I can find out. Later, __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

03-17-2004, 05:46 PM	#10
302 LX Eric or '331 LX Eric' Join Date: Jan 1999 Location: Columbus, Ohio Posts: 2,142	Just as a baseline Dark...with my old 302 H/C/I combo (steeda #19 cam 480/480 lift with 115LSA and duration I can't recall) pulled 11-12 in-hg. at idle (750 rpm). I'm not sure what you mean by the brake booster line - I've never touched mine. E

03-17-2004, 09:47 PM	#11
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	My engine idles perfectly....The car feels fast when you drive it. But here is the kicker...............My car isnt making enough vacuum to move the vacuum gauge at an idle. If I rev the engine a little bit the gauge will go to 4 hg's. You would think I have a huge vacuum leak but I have checked and rechecked everything over and over. Upper to lower intake is sealed for sure. Lower intake to heads is sealed for sure. Hell if I know. This sux __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

03-17-2004, 11:37 PM	#12
420nitro Registered Member Join Date: Nov 2003 Location: Rockford Posts: 596	Just out of curiosity, What is your timing at with the spout connector disconnected?

03-17-2004, 11:51 PM	#13
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	15 initial advance __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

03-17-2004, 11:58 PM	#14
sedanman Registered Member Join Date: Feb 1999 Location: Indianapolis, IN Posts: 963	Something has to be run wrong. I had a E cam for a long time and never had problems with vacuum. The brake boster runs off the vacuum tree right? I think maybe you blew a cap off somewhere or something. Your combination should have pleanty of vacuum. __________________ 04 Screamin Yellow Cobra KB 2.4 (585/556 pump 626/666 race) 00R brakes, DFX clutch, Level 5's, return fuel system, Lts with 3" exhuast, FR500 wheels and all the other fun stuff. GONE 1991 Lx sedan 5.0, 5spd (Liberty proshifted TKO) S-trim, Ported TF heads everything parted out.

03-18-2004, 08:30 AM	#16
jonnyk Being stroked is great Join Date: Oct 1998 Location: Alberta, Canada Posts: 772	You sure you don't have a lower to head leak? It could be drawing from the crankcase and you'd never know it. A huge vacuum leak should be audible if it's external... __________________ Novi 2000 now spinning off the snout of the 331... Mods Pics

03-18-2004, 09:09 AM	#17
Hozer 88GTConv Registered Member Join Date: Feb 2002 Location: Jacksonville, FL Posts: 706	Measuring vacuum... Dark, Where are you measuring your vacuum at? We have nearly identical setups N/A and I have 10-11 inches of vacuum at 750 RPM idle. Measured at the fpr and at the GT40 tree under the plenum with a vacuum guage. I am going to measure it at the big barb too for ya. I'll post it in a minute. I agree with the pic idea too. That might make something jump out at everyone. __________________ 1988 GT Convertible 331 10:1 TW heads, GT-40 intake, MSD, TRW flattops, B Cam w/ 1.7's, MAC exhaust, 24's, 70 TB, 76 MAF, 3.73's, Pro 5.0, Koni's, Anderson PMS, Wideband 02, yatta, yatta... One week with new motor, two speeding tickets...joy

03-19-2004, 08:08 AM	#18
88workcar Registered Member Join Date: Oct 1999 Location: Pierre Part, La. U.S.A. Posts: 1,850	2 Things. 1st - Change the guage 2nd - Check the brake booster Hope this helps a little? __________________ 88workcar 1988 Mustang LX 342. 417rwhp @ 6800. 28 X 10 ET Drag, 4.30s, 10.69 @ 126.43 1.42 60ft. 11.13 @ 127.7 on BFGs 1.72 60ft Rice Hater # 42 To be old and wise, You must first be young and stupid I'm somewhere in tthe middle.

03-19-2004, 01:49 PM	#19
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	Even if I plug all vacuum lines except for the one on the gauge I still dont get any vacuum. I did a compression test just to make sure I didnt have a dead cylinder from setting the valves too tight and everything was fine 155-165. The lower intake gaskets have got to be sucking air inside the intake valley. We will see. __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

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