So now that I have my 1.7L with D-jet running I need to do some fine tuning. It's getting pretty cool here now and the last couple of times I have started the engine it has been around 45 deg F and I have to constantly maintain the throttle to keep the engine running. it does start right up though. Shouldn't something keep the rpms up with a rich mixture. I did a some looking on B. Anders D-jet site but didn't really find an answer. AAR? cold start inj? intake air temp sensor?

the AAR should give you a controlled vacuum leak during cold start resulting in higher rpms. maybe your AAR is stuck close ...

you can easily test it by disconnecting the 2 hoses going to it (when cold)
if that results in higher idle, the AAR is stuck shut ...

Andy

The AAR is primarily responsible for cold start enrichment. The cold start valve doesn't kick in until the temp is below freezing -- then it only squirts while cranking. The AARs have a tendency to freeze up (rust) over the years. Most of them can be fixed by spraying some rust penetrating oil into them.

Andy beat me to it

Thanks guys that was my first guess, just so nice to ask the question here and before wasting time.

My carburetted 1.7L was also stalling at idle - warm or cold - turned out to be vacuum leaks at the manifold-head interface. Spraying Gumout on the gaskets identified the problem.

Spoke

Spoke, engine actually idles great after warm-up, and have sprayed for vacume leaks.

I pulled the AAR and air passes through fine when cold.
Any other ideas?

Tight valves will seriously affect the warmup idle.

Valve have been adjusted, but not since I have had the engine running for more than a few minutes. I'll recheck them tonight.

A few minutes running should affect the valve clearence, except with a brand new motor with all new parts.

Still having issues with the start-up idle. Checked the AAR and it is open when cold so it is working. What seems to be happening is one cylinder is not firing when cold. After runnig for 5 min it will kick in after rev up. What would cause a cylinder to not fire when cold but be fine after the engine has warned some?

1. Weakish spark (many causes)

2. Slightly lean (long list)

3. Uhh... hmmm valve on that cyl. out of tolerance when cold..

4. Bad Juju.

5. Negative vibes.

-shrug-



Oh, I also forgot to mention, the AAR valve, it's open when cold... but your car idles low?

I'll bet it never closes warm then... that means you are tuned with an unmetered air leak.


M

Check that AAR again. If it is open when cold, it should be closed when open. Sounds like it might be stuck open and your 914 is tuned for running warm on an open AAR?

Thanks Miles, i'll pull the hose on the AAR after it is warm and see if it closed, if not could be part of the problem.

Then again maybe I should just put my energy into the 2.0 that is half dis-assembled. Yesterday was the first time I was able to take the car out and stretch it's legs. Now I know I want a little more HP.

Yeah, there's your problem right there! You need to replace the AAR with a 2.0.

Checked the AAR after engine was warm and it was closed. Here is something stange - when engine is starting to warm up but not quite there i drive out of the parking lot and there is lots of sputtering and missing. Pulled up on the heater lever to get some warm air flowing into the car (39 deg outside) and the sputtering stops, engine evens out. WTF, push lever back down and sputtering again. Pull lever up, it runs good.

What gives?

GROUND! You have a ground problem!

Do I know where? No, but I'd imagine if you tinker around under there, and get a little more input from others here on the heater rig...




M

I have cleaned all the grounds on the engine block, the ground strap on the trans, should prolly replace the on the battery

Ok.... there is something going on... with..

The heater handle has that notch in the end of travel, that grounds, to turn on the blower motor.

Somehow, sounds like that is getting it grounded better... so..

Test: Take a set of jumper cables, and clamp them on the block somewhere clean, and then to anyplace on the chassis that you can get metal.

Hurry back! I only have forever!



M

OK Miles I would prolly jump right up, run to the garage, do what you advised but my wife would KILL me as I am at home alone with my two small kids, and she could be home any minute with pizza.

And she thinks I spend way to much time out there as it is.

Oh and to make it more strange this only happens with the heater lever when the engine is not completely warmed up. Although maybe its just not as noticeable when up to temp.





BTW glad the election is over so I can get a few laughs reading some of your posts.

A weak spark on a warm motor just acts like it's laggy when you WOT it... but in my experience, can idle like a champ.

Another thing... if you ever want to be anything, or anybody in the 914 world, let me give you a couple pointers...

Kids? Do you know anyone looking for children? Wife? I am having a hard time figuring out where you'd get even a second to do anything.

Dood, your priorities are just a tad out of adjustment!

I am pretty sure it's legal to sell children, I'll bet Chevy owners have time for kids...



Miles

oh, then it's easy.... PO installed manual choke lever what used to be heater lever. cleverly concealed don't you agree

that's it choke lever and blower motor switch at the same time

Weak spark caused by...

Have: new plugs, wires, cap, rotor. Changed out coil with another of similar age not sure of its condition but nothing changed.

I shall search posts for "weak spark" though I don't expect much, searching this site can be time tedious (sp).

As far as the kids and wife I wouldn't give em up, even though that would leave more 914 time, hmm let me rethink this...

You say your AAR is working. When additional air bypass from the AAR doesn't increase engine speed, it's indicating a lean idle mixture. Assuming that the idle mixture is correct when fully warmed up (is it? have you check it with a shop-quality meter), you may have a defective TS2 (CHT) sensor. Check the cold and hot resistance values and compare with the data in my web page.

As for the heater making things even out, I'm not sure. It could be an igniton effect. Check the heater grounds and the FI grounds cluster on top of the engine block in the back (under the air box).

OK I have an new CHT but have yet to attempt to take the old one out. can i get a hint on a way to take it out. i have read the trick about making room on the socket to get the wire through but I can't see how to get it out.

I will take it to a shop and check the exhaust.

Grounds are clean.

K..

You grind a channel up one side of that socket, and the wire goes in the slot... or you can by sloted sockets.


M

Checked the resistance on the CHT, 6.14 K ohms @ 40 deg F. In line with what Brad Anders site says. I am thinking about trying a new coil to see if that helps, have no idea how old the one I have is but it looks like it has been around a while. Haven't been able to measure the A/F mixture.

If you can pull up on your heater lever and the car runs better, you are getting a poor ground. Just because the ground strap is there, doesn't mean it is working properly. It is probably old and has a ton of resistance. Spend $5 and replace it. Then tell me how your 914 runs after that.

This only happens during warm up, once the car is warm it doesn't seem to have any effect.

But I will get a new ground strap today.

Oh and Dan I will be pulling the heads off to my 2.0 tonight (if I can get some garage time). Will finally add to my other "progress thread".

I knew you couldn't resist. Next you will split the case (I am waving my Jedi hand - mind trick thing).

Ground strap from Transaxle to Chasis is corroded. This is the only link to ground for the motor. Until you introduce the ground from the blower lever contact

I am still fighting this and am not going to let this thread die just yet. Put a new coil on just because, made a bit of difference but still not a great idle when cold. Still stumbling until engine has been run for at least 15-30 min. New ground straps will go on today, but the one from the trans to the body actually looks ok and has been cleaned at the contacts.

Could this be an issue of trigger points, it seems that it's only missing on one cylinder, and don't the trigger points work in pairs?

Another question - what is an easy way to tell if a cylinder is not firing, this may be the problem when the engine is cold, but once it get to temp that cylinder is firing

Thanks for listening, again.

Could be bad grounds as they cause problems when the car is cold as thats when there is the most resistance.
Could be bad valves too as when cold they don't seat too well.

What is the compression of the cylinders?

Geoff

Once you get it warm and it is idling OK, pull one injector electrical connector out/off at a time...Does it make an idle difference...If the idle changes, that paticular injector is probably working...But if it makes no difference, then that injector is not working...

Remove the spark plugs one at a time and make sure they are clipped into their high tension lead correctly, then make certain the body of the plug is grounded good (I use a jumper wire with a large aligator clip on the ends)...Then have someone turn the motor over and see if you get a spark to the plug...If not, you have an ignition problem...This is also a good time to check compression in the cylinders...

One other trick I found quite by accident...Take the Air Cleaner off so you can reach the temp switch on top of the throttle body cannister, the temp switch is screwed into the cannister, it has a two wire conector... Get someone to start it for you, and keep it running with the pedal...Unplug that switch...Does it make a difference ??? Mine did...Idles like a champ now...If it does, just leave it unplugged...

Good luck...

2-OH!

I have done this and it does make a difference (idle is higher with it unplugged). I read somewhere that this is an old trick but doesn't really solve the underlying problem. I plugged it back in.

OK so this afternoon when I get home car will be warm, I will go through the whole ignition, FI and check compression again. Have not done all on a fully warmed up engine.

Damn it I told my wife I was taking the afternoon off, she say "oh will you be in the garage all afternoon" No I say lets do some family stuff. How 'bout I just do an hour with the car?

Hey Sean - keep us posted when you solve this one. My taildragger does the same darned thing with the heater lever. Odd I always thought. So I'll try the ground strap too.
When you solve it let us all know.

You asked how to find which cyl might not be firing? Old aircraft trick was to put a smudge of lipstick (use the stick not the tool wench herself) on the cylinder fins - with engine cold. Fire it up for a few minutes only - the cylinders that are working will have melted smudge of the schtuff and the cold cyl will barely if at all smudge. Of course you'll have to craw under the car to apply this method - or maybe a rottiserie (sorry long day at work)

The real A&P mechanics will chime in on this one for sure

And the saga continues...

Took the car on a little drive (half hour or so) to get it up to operating temp. After driving for 15 min or so engine started missing, then bucking on acceleration especialy between 2K & 4K rpms, got bad enough that I decided to turn around and go home. This is the first time this has happened, though I have only had the car on the road for a week.

Made it home, small search for idle but pretty steady. Pull each injector connector and each one has signigicant effect when diconnected. Seems that all are firing and getting fuel.

Check compression -
Cylinder 1 - 118
Cylinder 2 - 130
Cylinder 3 - 110
Cylinder 4 - 130

3 is a little low but not horrible.

But... While I was messing with the injector connections I bumped the MPS connector and the car sputtered and died. Engine would start right up but if I jiggled that MPS connector at all the car would sputter and sometimes die. Not a very good connection here and plug slides in and out with little resistance. Compared the one on my 2.0 and it has a lot snugger fit. If i had $400 laying around I would just get a new harness from bowlby, but thats not gonna happen.

Oh and I also checked the CHT and it was 216 ohms when warm.

That's it to this point, turned my attention to the 2.0 and pulled the heads, pics on my other thread. My 2.0

Matt - not sure how the heater ground is going to play out but i will definitely update as I figure it out. Like the lipstick idea.

I get up at 5am to see if anybody had some great advice and nothing, come on you guys help a guy out.

Nah, not really, my 10 month old decided that 5am on a Saturday is a perfectly fine time to start the day. :rubbing eyes:

Clean all the effin FI connections and re-connect with a dab of dielectric grease on the prongs.
I think you are suffering with several issues mostly grounds and weak connection.
Wrap black electric tape around the MPS connector to hold it in place securely.
Make sure all the grounds (battery-, tranny strap, under the relay board, FI block on the engine) are polished shiney with a dab of the grease.

Check the ground strap in dizzy to make sure its attached properly. Check the advance plate for movement.

Your compression numbers indicate that the valves are worn so cold starting and warm up are going to be alittle rough.
Bucking is usually a worn or out of adjusted TPS. Could be just the weak spark too.

Geoff

This Morning I...

Replaced both ground straps
Cleaned until shiny the FI grounds on the block
Cleaned up trigger points

Still doesn't want to idle well when cold, probably due to a tired engine.

Once warm it runs OK, stil needs to be timed better.

Took it for a 30 min drive no probs.

The sun is shining, top is off

This car is really fun to drive.

I will share a couple of pics when I can get my card reader to work on this POS Win98 machine.


ps - can't wait to get the 2.0 in there.