Engine turns and fires, then revs then dies, ?Rule out catastrophic engine failure |
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
Engine turns and fires, then revs then dies, ?Rule out catastrophic engine failure |
echocanyons |
Apr 17 2005, 04:54 PM
Post
#1
|
Advanced Member Group: Benefactors Posts: 2,096 Joined: 24-December 02 From: Bay Area, CA Member No.: 7 Region Association: Central California |
Sorted through the fuel pump issues that I was having with the boards help.
Went through the vacuum hoses for the FI system and it all appears to be correct. car is a stock 72 1.7 D-jet NOW: The car turn over fires then revs high to 3000 for a couple of seconds then dies. I remember this happening to my 74 right after it needed a top end rebuild for failure of which I cant recall How should I go about checking to see if the engine has had a failure Compression test? anthing else? Other open ended possibilities that run through my mind are MPS problems, incorrect fuel pressure cuz I still havent been able to find a guage/tester that I can run with inline with this setup. |
bd1308 |
Apr 17 2005, 04:58 PM
Post
#2
|
Sir Post-a-lot Group: Members Posts: 8,020 Joined: 24-January 05 From: Louisville,KY Member No.: 3,501 |
how does it die....just cut out and die (liek turning the key to off) or does it stumble and sputter
|
echocanyons |
Apr 17 2005, 05:05 PM
Post
#3
|
Advanced Member Group: Benefactors Posts: 2,096 Joined: 24-December 02 From: Bay Area, CA Member No.: 7 Region Association: Central California |
It seems to start then rev high then tapers off then cuts off. The throttle does seem to have any effect on what the engine does either.
|
Allan |
Apr 17 2005, 05:08 PM
Post
#4
|
Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
Maybe your fuel pressure is too low. Does you pump run. Why not jut go get a cheap 0-50 lb gauge and tap into the feed side and see what pressure it's got?
|
Joe Bob |
Apr 17 2005, 05:11 PM
Post
#5
|
Retired admin, banned a few times Group: Members Posts: 17,427 Joined: 24-December 02 From: Boulder CO Member No.: 5 Region Association: None |
Pressure or filter....
|
TheCabinetmaker |
Apr 17 2005, 05:22 PM
Post
#6
|
I drive my car everyday Group: Members Posts: 8,309 Joined: 8-May 03 From: Tulsa, Ok. Member No.: 666 |
does the fuel pump run when the starter is engaged? Sounds like you are getting enough fuel to start when the key is first turned on, and the pump first runs. Make sure it continues to run when the starter cranks.
|
bd1308 |
Apr 17 2005, 06:27 PM
Post
#7
|
Sir Post-a-lot Group: Members Posts: 8,020 Joined: 24-January 05 From: Louisville,KY Member No.: 3,501 |
ayup. agreed
|
echocanyons |
Apr 17 2005, 06:44 PM
Post
#8
|
Advanced Member Group: Benefactors Posts: 2,096 Joined: 24-December 02 From: Bay Area, CA Member No.: 7 Region Association: Central California |
So I tested the PSI at the D side of the fuel pump =52 PSI
The reference I have says it should be 28.5-30.8 but I think this is after the pressure regulator. I am going to attempt to tap into the regulator and meaure that |
Allan |
Apr 17 2005, 06:48 PM
Post
#9
|
Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
Mine was really high because the pressure regulator was in backwards. I don't know if the 1.7 has a cold start valve but you might also want to check down into the plenumn and take a look for a lake of fuel. Mine was forcing fuel through the valve and just dumping it in. I'm glad it didn't fire. (IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif)
Oh yeah, injectors don't like high pressure. |
echocanyons |
Apr 17 2005, 08:02 PM
Post
#10
|
Advanced Member Group: Benefactors Posts: 2,096 Joined: 24-December 02 From: Bay Area, CA Member No.: 7 Region Association: Central California |
Across the regulator I measured 30-51 PSI
52 while cranking and 30 at rest. Should I adjust the regulator so the peak is 30? How do I tell if it is on backwards? |
Joe Bob |
Apr 17 2005, 08:04 PM
Post
#11
|
Retired admin, banned a few times Group: Members Posts: 17,427 Joined: 24-December 02 From: Boulder CO Member No.: 5 Region Association: None |
That's NOT bad....have you pulled a plug to see if they are wet? Are you sure you are getting spark? The injectors are pulsing?
|
echocanyons |
Apr 17 2005, 08:06 PM
Post
#12
|
Advanced Member Group: Benefactors Posts: 2,096 Joined: 24-December 02 From: Bay Area, CA Member No.: 7 Region Association: Central California |
I pulled one injector and the spray looked good.
I havent pulled a plug, I guess that is my next step |
Allan |
Apr 17 2005, 08:07 PM
Post
#13
|
||
Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
Is is basically a one way flow valve. Pull the line on the side currently going to the return and see if anything comes out. I don't think you want anymore than about 30 lbs. of pressure. See if you can reduce the cranking pressure down to that and see if it is stable. |
||
TheCabinetmaker |
Apr 17 2005, 09:59 PM
Post
#14
|
I drive my car everyday Group: Members Posts: 8,309 Joined: 8-May 03 From: Tulsa, Ok. Member No.: 666 |
52 while cranking is too high. There is something wrong. Maybe a kinked return hose, or like Allan said, the regulator is in backwards. The adjustable side of the regulator is the "out"side.
|
echocanyons |
Apr 18 2005, 08:02 AM
Post
#15
|
Advanced Member Group: Benefactors Posts: 2,096 Joined: 24-December 02 From: Bay Area, CA Member No.: 7 Region Association: Central California |
This was not testing inline but rather at the line so in essence the return line was kinked with the pressure guage.
I will have to rig the tested with a tee so I can test inline. |
Lo-Fi Version | Time is now: 27th September 2024 - 10:17 AM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |