Hi verybody: Any help here is greatly apprecialted. My 74 2.0 studders, hesitates and runs rough 1 min after starting up for about 10 min. It runs ok when warmed up fully, but I think it would run even better warm and cold if this problem was solved. I've checked for the obvious vacume leeks - found none, and I checked the temp head sensor neat # 3 cylinder. When I connected the harness wire to negative batt terminal the car would barely run. I guess the sensor is OK?. Thank you for any help on this, everyone on this site has been really helpful - great site!. Thanks, Joe

Do an Ohm meter test on your CHT.
Do it when cold, then when hot.
You should have low ohms when cold, and high when hot.
See Pbanders Djet site on Rennlist for the exact readings your CHT must adhere to in order to function properly.
Each year is different so look up your year CHT (ECU dependent)

Aside from that, points, plugs, wires, valve adjustment work wonders.

Rich

I can tell you how to fix this but it involves buying a new Honda... No seriously, check your AAR as well.

Check your cold start valve - that's what it usually turned out to be on my 73 2L when giving the cold running symptoms you note.

Here's a link to the part if you need it, but shop around as the price can vary:
http://www.automotion.com/product.asp?pf_i...mp;dept_id=4678

Tom,
I thought of that and ruled it out in my head... The cold start injector is supposed to give a little squirt of gas and then shut down right at start up. If it were leaking, it would leak all the time and cause a rich condition all the time. It is under the same pressure as all of the injectors.

The AAR is either supposed to be open or closed (I forget which) on start up and then close as the engine warms. If it were stuck in the warm position, it would cause the car to run rough for the first few minutes and then clean up as it warms. That is why I am thinking AAR.

Although, I have to admit that playing around with misbehaving DJet is a bit like playing that Whack-A-Mole game at the arcade. You throw one new part at it and a new lame part shows up. One after another until you have replaced everything you possibly can. That is why there are so few DJet cars still around. Keeping it DJet is definitely worthwhile just not a simple task.

The cold start valve only fires in approx freezing tempatures at farenhiet F'. actaull funtionality is dependent upon on your ts1 sensor which by parts # for years varies from 5 deg - 15 deg celcius C'..

The CHT resistance as more to do with actual communication to the ECU on engine warmth ect.. Possible to long between or since valve adjustment time..

Thank you do you know how I can test and/or repair the Aux air regulator or cold start valve?

Does "cold" mean 15 degrees F outside, or just the engine has not yet been warmed up to regular operating temperature?

Eric

I am still leaning on your cht or valve adjustment..

but to test the aar, first take an observation notice. does your idle speed drop a little after it is warmed up say 15 minutes idle or longer.. or you can take it out and apply voltage and watched the valve inside? if not then the aar is stuck...

i would not worry about the cold start valve yet, but you can pull it out and turn the key without staring it a few times and see if it is leaking.. the cold start valve does not even operate (or at least not supposed too) unless your in freezing tempature weather as stated above.. it get the signal from your ts1...

your description suggest symptoms of warm start over enrichment without the warm start over, cold cold start right? not warm cold start?

djet trouble shooting tips and guide analysis ... read link below

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

air valve when cold (room temp is considered cold) is open, you can blow air thru it with your mouth. when fully wamred up, the vlave closes, you cant then blow air thru it. it should have a working electric heater in it, power via the body for ground,a dn the single wire for positive. hook up the wire to positve 12 volt,a nd with body grounded, the valve should heat up and close.

if it stays open, you will have a very high idle speed when engine is warmed up. if it stays closed, your idle may be too low when cold (ie it will die unless you keep the gas peddle pressed) but once the engine is warmed up, you wont need it and all will be fine, when you warmed up.

the cold start valve only comes into play when it is very cold (like near freezing) the vale is actually a fifth injector, and it is powered by a positve wire and a ground wire, the ground wire goes to the cold start switch which is bolted to teh case, the switch will conduct tot eh injecotr when warmed up by the case transfering heat and by a bimetallic switch internally.

frankly where i live where it rarely ever freezes, my cold start valve is not used.

cold for the engine means ambient tempature( in so. cal. that means about 70 degress in the afternoon), cold for the cold start valve means near freezing ambient tempatures (montana winter ect..)...

Agreed. I was trying to better understand how Joe was using the term.

Eric