Fuel injection experts needed, no start while it's HOT |
|
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. |
|
Fuel injection experts needed, no start while it's HOT |
mtndawg |
Jul 18 2010, 05:35 PM
Post
#1
|
Member Group: Members Posts: 414 Joined: 26-January 09 From: Granite Bay, Ca Member No.: 9,985 Region Association: None |
I'm running a 1.7 with original djet.
I drive the car yesterday while it was 100+ here in Sacramento. After driving about 40 miles, I turned the car off. After only 2 minutes I turned the key and the sounded like it was going to start, then died. I cranked it a few more times and nothing happened. i let it cool for about 10 mins, then cranked it again. It started right up on the 3rd crank and ran great for the drive home. I've had this hard to start situation a couple of other times in the heat. I also have imperfect idle when the engine is warm. It idles between 1300 and 800. I know that's pretty good, but I would like to get it idling at 800 to 850 every time. All new vacuum lines Clean trigger points Clean Trottle Position Sensor Good MPS Virtually new injectors New fuel press regulator New rubber fuel lines New screen in the tank New fuel filter I have never touched the temp sensor Could this be the problem?...and yes I have read pbanders site many times, that's how I learned to operate on djet. |
Jeffs9146 |
Jul 18 2010, 05:52 PM
Post
#2
|
Ski Bum Group: Members Posts: 4,062 Joined: 10-January 03 From: Discovery Bay, Ca Member No.: 128 |
CHT Sensor!
|
JRust |
Jul 18 2010, 05:54 PM
Post
#3
|
914 Guru Group: Members Posts: 6,307 Joined: 10-January 03 From: Corvallis Oregon Member No.: 129 Region Association: Pacific Northwest |
I'm running a 1.7 with original djet. I drive the car yesterday while it was 100+ here in Sacramento. After driving about 40 miles, I turned the car off. After only 2 minutes I turned the key and the sounded like it was going to start, then died. I cranked it a few more times and nothing happened. i let it cool for about 10 mins, then cranked it again. It started right up on the 3rd crank and ran great for the drive home. I've had this hard to start situation a couple of other times in the heat. I also have imperfect idle when the engine is warm. It idles between 1300 and 800. I know that's pretty good, but I would like to get it idling at 800 to 850 every time. All new vacuum lines Clean trigger points Clean Trottle Position Sensor Good MPS Virtually new injectors New fuel press regulator New rubber fuel lines New screen in the tank New fuel filter I have never touched the temp sensor Could this be the problem?...and yes I have read pbanders site many times, that's how I learned to operate on djet. It may be the common hot start vapor lock problem. Your fuel pump sits below the bettery under the engine tin. Lots of heat in this area. They moved the fuel pump to the front trunk to cure the problem in later years. I think there are some other tricks to cure the problem. |
swl |
Jul 18 2010, 07:13 PM
Post
#4
|
Senior Member Group: Members Posts: 1,409 Joined: 7-August 05 From: Kingston,On,Canada Member No.: 4,550 Region Association: Canada |
I have a CHT that is high in resistance but it makes it hard to start cold. Starts ok hot. Easy to check though - pull the lead and measure resistance to ground. Then check your results against those on Brad Anders' web site.
|
detoxcowboy |
Jul 18 2010, 11:24 PM
Post
#5
|
Senior Member Group: Members Posts: 1,294 Joined: 30-January 08 Member No.: 8,642 Region Association: Africa |
I'm running a 1.7 with original djet. I drive the car yesterday while it was 100+ here in Sacramento. After driving about 40 miles, I turned the car off. After only 2 minutes I turned the key and the sounded like it was going to start, then died. I cranked it a few more times and nothing happened. i let it cool for about 10 mins, then cranked it again. It started right up on the 3rd crank and ran great for the drive home. I've had this hard to start situation a couple of other times in the heat. I also have imperfect idle when the engine is warm. It idles between 1300 and 800. I know that's pretty good, but I would like to get it idling at 800 to 850 every time. All new vacuum lines Clean trigger points Clean Trottle Position Sensor Good MPS Virtually new injectors New fuel press regulator New rubber fuel lines New screen in the tank New fuel filter I have never touched the temp sensor Could this be the problem?...and yes I have read pbanders site many times, that's how I learned to operate on djet. Sounds exactly like the hot start vapor lock issue, 100 deg. is hot, I have the fuel pump moved up front under the gas tank by the p.o. , and I still get that in So. CAl. when temps hit the upper '80' s and I am running around town not using the freeway in stop go traffic.. I would not chase any gremmlin ghosts without addrss that fuel pump location or live with it, Sacramento does get hot... Sounds like you take care of your car and pay regular attention to it, .. |
pilothyer |
Jul 18 2010, 11:50 PM
Post
#6
|
Member Group: Members Posts: 838 Joined: 21-May 08 From: N. Alabama Member No.: 9,080 Region Association: South East States |
Considering 1.7 D-Jet your CHTS should give pin 23 on the brain about 2K ohms when cold (68 degree F) after warm up it gives very little resistance (goes almost to short to ground) To see if it is your CHTS and not the dreaded vapor lock, next time this happens disconnect the CHTS and take an aligator test lead and clip it to the connector your CHTS was plugged into, connect the other end of the test lead to a good ground, even better connect it to the battery negative terminal. If the CHTS is at fault the car will start, if it is not the problem will persist.
|
underthetire |
Jul 19 2010, 08:24 AM
Post
#7
|
914 Guru Group: Members Posts: 5,062 Joined: 7-October 08 From: Brentwood Member No.: 9,623 Region Association: Northern California |
|
detoxcowboy |
Jul 19 2010, 08:34 AM
Post
#8
|
Senior Member Group: Members Posts: 1,294 Joined: 30-January 08 Member No.: 8,642 Region Association: Africa |
The above hotstart vapor lock, will occur with a new CHT.. It may be your CHT. And if so, and you start right up in 100 deg. wether after driving around, let me know where you fuel pump is mounted so I can put mine there.. (IMG:style_emoticons/default/icon_bump.gif)
|
Lo-Fi Version | Time is now: 10th June 2024 - 04:03 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 ... |