car won't start when hot

sc91183 · Post by **sc91183** » Sat Sep 09, 2006 11:14 am

Well this is a new problem. The car is a Porsche 911SC 3.0 litre with MSII version 3.0 with Megatune 2.25. The car has ITB's and has been running pretty good except a stubborn idle. All of a sudden yesterday it runs like crap, hunting at light throttle setting and then it died on me and wouldn't restart. I had it towed home and once cool she fired up. I did have spark when hot so I don't think it's that.Any ideas on what this might be? I have a DE payed for on next weekend and I really need to get this solved.

65looter · Post by **65looter** » Sat Sep 09, 2006 11:31 am

hello,

I have no answer for you, but I had the same issue yesterday, how strange.
same thing, was running ok until at one point the idle was very very choppy.... A pain to restart (engine was hot by then).

Today, no issues at all.

bizarre!!!!

sc91183 · Post by **sc91183** » Sun Sep 10, 2006 12:16 pm

Well today I noticed that the throttle position % gauge reads about 90% at idle why would that be? I'm idling at about 800 rpms so I know my butterflies are not open very far. But when I try to calibrate my TPS the idle setting auto populates around 700..................what gives?

steve911sc · Post by **steve911sc** » Thu Sep 14, 2006 10:28 am

simple answer is too rich. set 170f pulse width to 1 ms there is a Yahoo group for CIS to EFI on 911's

http://autos.groups.yahoo.com/group/bitzracing/

Steve

sc91183 · Post by **sc91183** » Thu Sep 14, 2006 3:49 pm

It turned out my TPS sensor was bad. I replaced with another one and she fires right up. Thanks for the link.

Bernard Fife · Post by **Bernard Fife** » Thu Sep 14, 2006 3:53 pm

sc91183,

Thanks for letting us know, this is very interesting (though frustrating for you). We have a lot of info in the manual for setting up a TPS, but not much for troubleshooting a failing one. I'll add some notes on this shortly.

Lance.

tebriel · Post by **tebriel** » Fri Sep 15, 2006 5:10 am

lance and sc91183,
my tps failed on my saturn (but the tps is from a buick riveria) and the same thing happened to me earlier this summer. I also for the life of me couldn't get it to calibrate correctly. Which sucked though cause the replacement was like 60 bucks!
-teb

sc91183 · Post by **sc91183** » Fri Sep 15, 2006 9:34 am

I have a question on TPS sensors, is it true most of them read from 0 to 5 volts? The reason I ask is from my research the TPS sensor that was supplied with my TWM throttle bodies is a Rover part ! Not exactly a over the counter part. I have the old ( bad ) one that I plan on taking to local parts stores to try and match up with a readily available one. By chance does anyone know of one?

diegom6 · Post by **diegom6** » Fri Sep 15, 2006 12:26 pm

I had the same trouble once, I turned off the engine, tried to re start it and the thing didn't wan't to coperate. Two days came back where she is parked and she fired up at the first. never knew what the hell was happening. By that time i got PW's, RPM's etc while cranking, but the engine only crancked, good fuel pressur eand strong spark.

weird

Jack · Post by **Jack** » Fri Sep 15, 2006 12:36 pm

sc91183 wrote:I have a question on TPS sensors, is it true most of them read from 0 to 5 volts? The reason I ask is from my research the TPS sensor that was supplied with my TWM throttle bodies is a Rover part ! Not exactly a over the counter part. I have the old ( bad ) one that I plan on taking to local parts stores to try and match up with a readily available one. By chance does anyone know of one?

Try Dave at Grampas Retired Rovers 802-827-3048 for good used Rover parts. He is reasonable and quick. If he can't supply a match, PM me. I'll dig up some other names.

Jack, putting a Rover SD1 intake on a Triumph TR8

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car won't start when hot

car won't start when hot

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