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914World.com _ 914World Garage _ tech question? head temp sensor on a 1.7L

Posted by: A TV dinner Jul 18 2006, 11:51 PM

hello everyone. i currently own a 72 914 with the 1.7L motor. for the past few months i have been gathering fuel injection parts for the car, and finally after almost 20 years of sitting, the car started boldblue.gif boldblue.gif boldblue.gif .

ANYWAYS i basically wanted to make sure the engine would work properly, and so i am running one of those square "7psi" fuel pumps. sad.gif

MY QUESTION IS.....i heard from the previous owner that the engine was rebuilt by a jaguar mechanic about 10 years ago, and so now when i go to find the correct placement for the head temperature sensor, there is no hole (in the passenger side) head for the sensor. SO me and another friend jimmy rigged a bracket (until we make sure everything is working correctly) for the temp sensor to fit on a fin. when we plug the sensor into the harness...the car DOESNT start, and when the sensor is plugged in the car DOES start. what is going on?

and do any of you think it would be worth it to just drop the engine and tap a whole in the head???? blink.gif

any help would be appriciated

the sooner this is fixed, the sooner another 914 will be on the road and running WOOT!!! drunk.gif

Posted by: Stieve Jul 19 2006, 02:12 AM

QUOTE(A TV dinner @ Jul 18 2006, 10:51 PM) *

hello everyone. i currently own a 72 914 with the 1.7L motor. for the past few months i have been gathering fuel injection parts for the car, and finally after almost 20 years of sitting, the car started boldblue.gif boldblue.gif boldblue.gif .

ANYWAYS i basically wanted to make sure the engine would work properly, and so i am running one of those square "7psi" fuel pumps. sad.gif

MY QUESTION IS.....i heard from the previous owner that the engine was rebuilt by a jaguar mechanic about 10 years ago, and so now when i go to find the correct placement for the head temperature sensor, there is no hole (in the passenger side) head for the sensor. SO me and another friend jimmy rigged a bracket (until we make sure everything is working correctly) for the temp sensor to fit on a fin. when we plug the sensor into the harness...the car DOESNT start, and when the sensor is plugged in the car DOES start. what is going on?

and do any of you think it would be worth it to just drop the engine and tap a whole in the head???? blink.gif

any help would be appriciated
\the sooner this is fixed, the sooner another 914 will be on the road and running WOOT!!! drunk.gif



I know I had a bad head temp sensor wire that prevented mine from starting. I noticed both heads on mine where tapped for the sensor, I guess it makes them correct for either side. Perhaps you have a unusual head, I would try to remove the top sheetmetal to check both heads for threads, If needed drill a small hole for a wire if it needed, if you find a boss on the drivers side, unless you feel like swapping heads.


Posted by: tdgray Jul 19 2006, 06:21 AM

Couple things here.

First - in the rebuild it is most likely that the heads got changed. Maybe to bus heads or something of the sort. Look for numbers and post... someone can tell you.

Second - there is no way that a 7 psi fuel pump will operate the fuel injection. It requires 30 psi to run. You need a fuel injection pump.

Do a search for all the fuel injection threads here and read up. Very complicated stuff until you are familar with it.

Good luck

Posted by: ptravnic Jul 19 2006, 06:45 AM

All you wanted to know about D-Jet FI (and a whole lot more) can be found:

http://members.rennlist.com/pbanders/

Enjoy

Posted by: Bleyseng Jul 19 2006, 10:31 AM

Pretty common when rebuilding a 1.7l that if you exchange the heads you'll get bus carb heads as they are the most common for 1.7l cores.

Tap the hole that holds the tin next to the #3 intake manifold so it takes the CHT like on a Ljet bus. Seems to work fine as that is what I did on Blairs 1.7 with bus heads.

Posted by: r_towle Jul 19 2006, 12:28 PM

QUOTE(Bleyseng @ Jul 19 2006, 12:31 PM) *

Pretty common when rebuilding a 1.7l that if you exchange the heads you'll get bus carb heads as they are the most common for 1.7l cores.

Tap the hole that holds the tin next to the #3 intake manifold so it takes the CHT like on a Ljet bus. Seems to work fine as that is what I did on Blairs 1.7 with bus heads.


Explain...
I understand what you said...but others may not quite get it..
a pic would help as I bet this is a common issue on rebuilds..

Rich

Posted by: A TV dinner Jul 19 2006, 04:39 PM

hey thanks for the help. ill try and remove the tin covering the heads this evening and post up pictures as well. we were thinking that maybe the heads were just swapped with one another, to were the passenger side head would now be on the drivers side, but then agian i dont know if thats possible or not???

if it is possible that i do have bus heads on the engine, is there a disadvantage to having them compared to the factory 914 heads?

ill post my progess when it cools down a bit outside biggrin.gif

thanks ~alex~

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