high idle, 3000rpm idle Options

[StarBear]

Ahhh. Didn’t pick up on that. Thanks!

[slotty008]

AARs are available. One sold here just a few days ago. Big thread on testing and maintaining the a few weeks ago. If can find, also indicates comparable Nissan part #.

(IMG:style_emoticons/default/agree.gif) best to replace the AAR. It progressively closes as an internal heating element warms up, versus an electric valve would be open or closed. You can also take an AAR apart and may be able to free up the mechanism. There's a you tube video on that.

I've seen the youtube video. I cleaned out the AAR a couple of months ago and it closed when I put current on it. My mechanic already took apart the AAR 2 times several weeks ago,apparently with no result. We'll see next week when the throttle is repaired. (IMG:style_emoticons/default/unsure.gif) (IMG:style_emoticons/default/unsure.gif) (IMG:style_emoticons/default/unsure.gif)

[wonkipop]

AARs are available. One sold here just a few days ago. Big thread on testing and maintaining the a few weeks ago. If can find, also indicates comparable Nissan part #.

(IMG:style_emoticons/default/agree.gif) best to replace the AAR. It progressively closes as an internal heating element warms up, versus an electric valve would be open or closed. You can also take an AAR apart and may be able to free up the mechanism. There's a you tube video on that.

I've seen the youtube video. I cleaned out the AAR a couple of months ago and it closed when I put current on it. My mechanic already took apart the AAR 2 times several weeks ago,apparently with no result. We'll see next week when the throttle is repaired. (IMG:style_emoticons/default/unsure.gif) (IMG:style_emoticons/default/unsure.gif) (IMG:style_emoticons/default/unsure.gif)

yes @slotty008 - i've got a theory on these old AAVs and them seeming to work when you test them.

i will qualify this by saying mine is a 1,8 L jet which has a different design of AAV mounted directly on the engine block.

i cleaned and tested mine 2.5 years ago and yes it seemed to work.
but what i have retrospectively thought is that i had it out of the car and i tested it on a bench.

i now wonder if the cold engine block conducted cold into the body of the AAR means that when installed on the engine, and with an age weakened spring that it just can't warm up and close like it did new. so it sort of sits there. in fact in my case its jammed closed.

i did have a really weird thing happen about 2 weeks ago when it actually worked.
thats because here in australia we have been having record cold temps. somehow i think it was so cold that it caused the AAV to contract open past some point it had been sticking at - maybe due to a small ridge of corrosion.

they are very fickle at this point in time half a century down the track. (IMG:style_emoticons/default/beerchug.gif)

[slotty008]

Update: I ordered a throttle body gasket and the rubber to the airfilter. My mechanic installed them today but the problem is not gone. (IMG:style_emoticons/default/headbang.gif) He thinks that the throttle valve is worn( axle and bushings) I suppose throttle bodies are no longer available so is it possible to repair this? (IMG:style_emoticons/default/wacko.gif)

[DRPHIL914]

Update: I ordered a throttle body gasket and the rubber to the airfilter. My mechanic installed them today but the problem is not gone. (IMG:style_emoticons/default/headbang.gif) He thinks that the throttle valve is worn( axle and bushings) I suppose throttle bodies are no longer available so is it possible to repair this? (IMG:style_emoticons/default/wacko.gif)

yes they can be rebuild and have new bushings installed, there is a member here that does this service. Phil i believe, he rebuilt my with all new stuff a couple years ago.

Smoke machine would help you find any other leaks, but also with d-jet, if you are running lean you will have a fast idle.

Phil

[rjames]

Throttle body is likely worn to some degree (they all are by now if they haven't been repaired), but I would still do as Zach and Phil suggested and do a smoke test.

Also, if you haven't already, remove and plug all of the vacuum hoses except for the one going to the MPS. If the idle drops significantly, add them back one at a time until the problem returns. If the idle doesn't drop significantly, the problem lies elsewhere- like the intake runner gaskets or a cracked plenum.

[slotty008]

Update:
By the end of August we finally had some result. My mechanic took the AAR apart again and it's working now. But we still have a minor vacuum leak on the throttle body. Rpm when cold is between 1400 and 1600 but it drops to 1000rpm after a few minutes. I can live with that. I tried to find someone in Europe to fix the throttle body but no succes so far. I also found a new throttle body in Germany but it was so expensive...
BTW, do all 914's have the same throttle body?
In the mean time , I made some long test drives and everything works well. (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif)

[76-914]

Update:
By the end of August we finally had some result. My mechanic took the AAR apart again and it's working now. But we still have a minor vacuum leak on the throttle body. Rpm when cold is between 1400 and 1600 but it drops to 1000rpm after a few minutes. I can live with that. I tried to find someone in Europe to fix the throttle body but no succes so far. I also found a new throttle body in Germany but it was so expensive...
BTW, do all 914's have the same throttle body?
In the mean time , I made some long test drives and everything works well. (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif)

Do you have an airport near. Throttle body shaft bushings are a common problem on light aircraft engines. A good A&P can take care of that quickly. As a side note: If one inadvertently connects the Oil Temp sending wire where the CHT sender wire should be connected you will have a 3500 rpm idle - warm or cold! Ask me how I know. (IMG:style_emoticons/default/headbang.gif)

[Dave_Darling]

BTW, do all 914's have the same throttle body?

No, they do not.

All of the 2-liter 914 throttle bodies are the same, but the1.7 and 1.8 ones are a different size and sit sideways rather than straight up-and-down. I think the 1.7 ones are different from the 1.8 ones as well, but I'm less sure on that.


Can you please ask your mechanic if he has a smoke machine? This has been suggested at least four or five times so far in the thread--for a good reason. It can help you find exactly where leaks are.

Really, seriously. SMOKE MACHINE. Fill the intake with smoke and see where it comes out. You really really want to know where the problem is rather than firing the "parts cannon" at the engine and hoping the problem goes away.

--DD

[wonkipop]

BTW, do all 914's have the same throttle body?

I think the 1.7 ones are different from the 1.8 ones as well, but I'm less sure on that.



--DD

yes 1.8 is a different throttle body in detail than a 1.7.

[slotty008]

BTW, do all 914's have the same throttle body?

No, they do not.

All of the 2-liter 914 throttle bodies are the same, but the1.7 and 1.8 ones are a different size and sit sideways rather than straight up-and-down. I think the 1.7 ones are different from the 1.8 ones as well, but I'm less sure on that.


Can you please ask your mechanic if he has a smoke machine? This has been suggested at least four or five times so far in the thread--for a good reason. It can help you find exactly where leaks are.

Really, seriously. SMOKE MACHINE. Fill the intake with smoke and see where it comes out. You really really want to know where the problem is rather than firing the "parts cannon" at the engine and hoping the problem goes away.

--DD

My mechanic still doesn't have a smoke machine, but I have all the ingredients for making one myself. I'm gonna put everything together but I have another job to do first:put extra isolation on my attick (IMG:style_emoticons/default/dry.gif) (IMG:style_emoticons/default/dry.gif)

[slotty008]

Now that I'm retired, I've finally found the time to finish the smoke machine. I used a pickle jar, 2 car valves, an old bicycle pump, a 10€ soldering iron and an old tube from a tire pressure pump. I had to seal the car valves and the soldering iron with Tec-7 because too much smoke escaped there. I mounted a lid from an aerosol can on the tube of the tire pressure pump. It fits exactly on the throttle body. (IMG:style_emoticons/default/smilie_pokal.gif) Yesterday we did the test and a little smoke is escaping along the axle of the throttle valve. So I will have to look for a better throttle body or find someone to repair it. All the vacuum lines were tight.

[slotty008]

[VaccaRabite]

Mine leaked at the same place. Ended up replacing the entire throttle body.

Zach

[76-914]

Those can be re-bushed. Is there such a word? Any machinist can do it. It will need to be drilled out then reamed for a proper surface for the new bushings. Don't try this yourself because the surface must be perfect and final reamed with a reamer that is .001" undersized for a press fit. You can also go to a local airport and find the A&P who works on small aircraft that will do this for you. (IMG:style_emoticons/default/beerchug.gif)

[emerygt350]

On my car the idle screw even leaks when fully closed. Maybe I will get around to rebuilding it this year. At least it's easy to pull and work on. Luckily it leaks exactly what I need for the car to idle where it is supposed to.

[slotty008]

After disassembling the AAR several times, I gave up. Once installed , everything went fine until the next day and then it jammed again. So I constructed a system with a solenoid valve instead of the AAR that I can open or close from the cockpit. I open it when I start the car and after two minutes I close and I have a 1000rpm idle. It's not perfect because it's all or nothing but certainly better than an unreliable AAR.

[slotty008]

Here it is installed.

[slotty008]

I've put a box on it to protect it. The bottom of the box has been cut out.

[slotty008]

And this is the knob in the cockpit.