Cooler weather in Upper Michigan...

Yesterday when it was warm, my '73 1.7 D-Jet seemed to idle well.

Today, a bit cooler out. The car starts up and idles for 3 minutes or so (when cold) and then dies. I can start it up and if I keep the idle up I can keep it running, otherwise it will die.

I'm assuming the CSV quits at a certain point and It's still not getting enough gas to keep running? I thought it might have something to do with the cold weather?

Anyone else familiar with this? I will check the d-jet site (pbanders?) site now..

just a train of thought to go off with. it dies after 3 min./warmup (maybe that is when your aar valve closes and stop letting in that extra air)) then you throttle it and it will keep running (when your throttle opens your letting in air). I would start with adjusting the idle screw but not until it is warmed up after the AAR valve closes. The CSV does not even get the go ahead fire from the sensor unitl depending on your exact sensor but they are all within the range of freezeing (farehenhite) give or take 5-10 celcius. So basically unless you have ice on the ground your CSV is should not be working.. (but I expect you do get your share of ICE in Michigan)

Great! Thanks--got the CSV info (maybe it would work in January!)

The AAR thing makes sense. However, it seems like the idle screw doesn't do anything when I back it out. I thought I cleaned the plenum really well this summer...

Yesterday it seemed to idle fine, but it was 15 degrees warmer outside. I adjusted the CO to 3%. I haven't been driving it at all and haven't had much time to work on it until this weekend...

I've checked my hoses--all are new and seem hooked up correctly. I've sorted out the D-Jet recently and everything checked out.

Looking for the next step...

If I created a small vacuum leak I could possibly boost idle (just to check)?

I would check the ohms on the CHT (cylinder head temp sensor) It should read about 2.5K cold and less than 100 OHMS when hot.....If this doesn't work, The ECU will think the engine is still cold and it will keep engine running rich and will stall....See this site for trouble shooting . D JET http://members.rennlist.com/pbanders/djetp...tm#troubleshoot

cht.

If your idle screw does nothing then your to lean, in other words is additional air amounts to squat then your lacking fuel. CHT culprit possibility and also you can adjust if you have the knob on your control unit richness of idle. clockwise richer one notch at a time and wait for the control unit to adj. a minute.

Your going to learn something here so it is best you read the above mentioned djet dance and possibly THE ECU classic thread, but just the part and what parts react in what situations as to which year and set up.. No need to learn firing in pairs internal ecu desighn intentions or sine wave coeffiecints factors...

The best thing I ever did was screw up this really BAD w/ my timming and hook up my decel valve in such a matter that I could never find full power and decent idle at same time, (I did this accidently when installing cylinder heads) then to boot I "genius" thought I could slightly adj. the MPS "by ear" too

Long story short all my screwing around and reading learning and screwing around for 2 days, learned me really well how it works through pain.. Worth every minute, now when I have an issue I know what to do on the side of the road in the dark even before I pull over.

Yep--been scouring that site--thanks!

I've always been skeptical of the CHT--It's new but I think the model number was different than the one I needed.

The funny thing is this (don't laugh now...): Plug wires 3 and 4 were switched (I think my brother had something to do with that...) and we still got the thing running and idling smoothly (CO 3%). It just had no power. I really hadn't driven a 914 that ran right (it previously had a single Weber), and when I put things back together and kept my foot on the gas to rev/drive it WOW did it have power. So, I have something to look forward to, at least...

It's been a great project--there's light at the end of the tunnel...

Started car. Forgot to check CHT cold. Ran for 1.5mins with good idle then idle died out. A quick check of the CHT showed roughly 755 ohms. A bit high but was it warm enough?

I will check to see that the CHT that I bought is the correct one--hopefully I still have the receipt!

If you had the wires switched, then leaned out the ECU for your 3% reading, then put the wires back in the correct order, your too lean now.

I clicked it back to where it was previously after I switched the wires. I didn't hook the Gunson to it because I can't get it to idle...

It seems a little bit quick for this to be a factor, but it's worth checking - are your valves adjusted correctly? Valves that are too tight can cause an engine to die after it warms up because the valves no longer close fully. 1.5-3 minutes seems too short for that symptom, but it's still true that you always check the simple, mechanical things FIRST before chasing after more involved things like AAR or ECU suspicions because a properly set up engine is the foundation for all the other stuff.

Quick update on the car:

Checked the valves--all good.

Marked my fan to help when I have a helper to check the timing. I dialed the dwell in at about 46 degrees.

Still runs and dies. Will check timing tomorrow (hopefully). Does anybody have a good setup for loosening/tightening the dizzy bolt? I've always had a tough time getting a wrench in there...

Dwell is 48-52....there is no about here...be accurate its important.
For timing, keep the dwell meter hooked up so you get a very accurate tach.
Rev it with your free hand...hold timing light with the other hand.

To get the wrench in, come in from the drivers side...you dont need to loosen it to much to twist it...make sure you tighten it...I forgot last night...drove about half way to work and the timing got worse and worse...
It was funny to me...stupid thing to forget.

Rich

Well, 46.1 do be exact. Thank God my local FLAPS had a dwell meter...

I was going by the Pelican article with a range of 44-50. I was at 52 originally! I will tweak it again.

I don't get it--my timing is way off--like not even close. It will idle but I have to keep my hand on the throttle to keep it going. If I rotate it clockwise, it gets closer but I can't get it anywhere near where I'm supposed to be. 3500RPM on the meter. Does anyone have a picture of how the dizzy is supposed to be installed? I'm starting to think I have it backwards or something... So confused.

Take a pic and post yours distributor...from site I can tell you if you are all set.

Rich

Thanks--I'll get one up ASAP. I estimated 5 degrees from the Pelican DIY printout for the fan. Then I set static timing at 5 degrees by rotating the dizzy counterclockwise and picking up where I have 12V from the coil to the #1 plug. It started up and had good throttle response, but still wouldn't hold idle.

I DID notice that if I had my airbox disconnected from the intake the throttle response was better than when I connected it. Maybe when everthing is hooked up it's running too rich because it's not getting enough air? Just a thought.

Anyway, I think the dizzy is now close. Something else may be the culprit?

Do you have a timing light?
A few degrees off with a DJet motor is hell...it will never run right.

Rich

Yep--

I can understand! I thought I was in the ballpark but I was way of once I dialed in static timingf... At least static timing will get me with smooth throttle response--hopefully I can dial it in from here. I'm assuming it will be a small adjustment--very touchy? (Still recruiting somebody to help run the throttle while I adjust--I'm too clumsy to do both at the same time...

Update:

Timing set 3500RPMS, Dwell 48.6. Adjusted TPS per Pelican. Tested the wiring harness connector to ECU. Everything tests out except the CHT which after a brief time (less than 30s) of idling and then cool-off for 10 mins or so registers at 600 ohms. I am not sure if this is a product of the temperature of the block at the time? Air temp is about 45F.

I have good throttle response when I start the car when it is cold. It won't hold idle (if it does, it idles at around 400rpms but mostly dies).

Any suggestions?

CHT

Hm. CHT is new--an 012.... I will throw a meter on it in a sec.

Air Temp: 44F 2400 Ohms. Engine cold.

Start car--beautiful throttle response, I let it run at about 3200 RPMS with my foot on the gas. 30 seconds later hesitation, poor throttle response although I can keep it going if I goose the throttle. It won't idle (Dies).

CHT at this point: 580 Ohms.

That's all I've got.

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


> 2K ohms at 68 deg. F for all but 1973 2.0 L
> 1.2 K ohms for 1973 2.0L


Andy

If the 012 is 2850 ohms at 61F (according to the site), and 191.2 ohms at boiling, then I should pull the CHT and boil it and make sure it isn't stuck in the "open" position--which It could be, and causing a rich running condition and subsequent stalling?

In an earlier post you stated that when hot it was at 750 ohms...
that be broken.

Its a cheap part to replace...get a new one...make sure you get the one that matches the ECU..

Rich

Thanks Rich, yeah, it seems to be running in the 550-750 range when I've been running the engine for a few minutes. I'm not sure how long it takes for those heads to heat up nice and hot, but it seems to me that the CHT should be giving a lower reading...

Frustrating when you buy something and it's no good...

you could try something cheap.
go to Banders site and find out the EXACT reading your supposed to be getting.

Go to radio shack and buy a resistor the exact number for when its hot.
Hook that up to the wire that goes to the CHT and the other end to ground.
See if it runs right...
Or you can use a variable POT, but a simple resistor would work.
Its cheap..a few bucks.

Rich

Great--do you run it in-line with the wire to the CHT? (one end from the harness and the other to the CHT?)

Thanks!

No. You take out the CHT and run the resistor instead of the CHT.

From the brain to your resistor to ground. No CHT.
Andy

What kind of wattage should I get? I was at Radio Shaft and realized they have a selection... They wanted to sell me a 1/2 watter...

K

read brad anders site.
Find the correct reading for your CHT when hot...if its 190 ohms...find that number...

Get a resistor that is the correct OHMS...not watts.

Rich

Yeah, I got the correct ohm value.

The resistors are also rated in watts (10, 2, 1, 1/2, 1/4, 1/8).

I don't think there's a lot of current flowing through that wire, so the wattage really shouldn't matter much ...

If the resistor melts, get one with a higher wattage reading ...
Andy

As watts is a measurement of power and Ohms is a measurement of resistance, I am not sure I can help you attempt to convert them.

If I go to MY radioshack...there is a drawer of RESISTORS...they are measured in ohms at my store.

Rich

Wattage is Volts x Amps ...

I can't imagine a lot of Amps going through that wire. So really, the wattage of the resistor shouldn't matter ...
Andy

I hadn't done that math in awhile...

Rich--look in the drawer of resistors next time you're in the 'Shaft. They're labled for ohms, but they also have a watt rating--strange but true. The guy working there was of little help.

http://www.radioshack.com/product/index.js...oductId=2062315

Anders' site says the resistance can drop to as low as 50 ohms as read by the ECU (I think). I may go get a smaller one tomorrow and give it a whirl.

Not an issue if I melt one--they're like $0.21/piece...