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Cold start woes

2048 Views 8 Replies 4 Participants Last post by  drnknmnky13
Weekend work: Car was a wiring mess, so I converted it to OBD1 this weekend. Engine is a mini-me (SOHC ZC block, Z6 head). Car runs great, pulls like a bat out of hell. Went to start it to head back home last night and it took a while to get her started. She just wasn't getting what she wanted to fire up (keep in mind it is SUPER cold out here in Ohio). Anyway, I'll attempt to describe what is happening to the best of my ability.

She cranks, but she just doesn't want to grab. After a few tries she'll finally start to hit and grab 1000rpms but then BAM, bogs back down and dies. Rinse and repeat with lots of weird noises for about 5 minutes and i'll finally get her to idle and warm up. No problems when the car is warm. I'm thinking it is timing? The distributor is all the way advanced and the cam gear is set at zero. Previously the cam gear was +5 (10degrees at crank), but I couldn't adjust the distributor since it was barely stuck on there (have to jimmy rig an OBD0 dizzy onto an OBD1 head). Anyhow, I did retarded the timing a bit last night because the car was making a weird sound (knocking/pinging) and obviously that's bad. It's possible I overcompensated though.

Does anyone know how I should set the timing? Or if timing is even the culprit of this cold start issue? My head is also milled, same w/ the block so I have to compensate by advancing the timing some there, and the mini-me combo also likes some advance, but I'm afraid i'll get that knocking/pinging noise again. Any help is appreciated.

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...Trying to imagine what would happen to the timing belt and cam sprocket if the head is milled and the block is decked...

Imagining process:

- crank and cam would be closer together
- which means even with correct valve timing the t-belt would slack
- and cause the cam sprocket to rotate counter-clockwise a bit in order for the belt to be tight
- which advances everything in and on the head
- valves open and close sooner
- spark also comes sooner

Alright, depending on how much was milled and decked, you may have to retard the cam sprocket one tooth (this means rotate it 1 tooth clockwise looking from the driver's side) then compensate with the distributor and/or the adjustable cam sprocket to obtain ignition timing of 18 degrees btdc. The only way you can know for sure if you need to do this is to get a reading with a timing light while your adj cam is at zero. If you find that you have to crank the distributor all the way to the firewall side just so you'll get 18 degrees btdc, it could mean you might have to do what I described. Once you obtain 18btdc while having the distributor positioned closest to the center of its adjustment, this will be the best starting point to make further valve timing adjustments. You can now open the valves sooner or later and still have room in the distributor travel to fix ignition timing.

Yes, anything other than ideal valve and ignition timing will cause a hard cold start.

Disclaimer: I've never tried to tune adj cam gears. (uhh which one of us has a chassis dyno right) This is just how I perceive the dynamics to happen in our 4 stroke engines.

EDIT: forgot about the jerry-rigged obd0 dizzy. You will have to further the jerrying to get more adjustability out of it.
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OBD0 dizzy is gone. OBD1 is on. I was just saying that previously I had NO adjustability w/ the dizzy and had the adj cam gear at +5 at the cam (so +10 at the crank), which worked out fine. I wish I could work on it more, but because i'm at my apartment w/ no tools, 120 miles from home, I took it to the local Honda/Acura performance shop to let them take care of it.

On a totally different note, your description really helped me understand how timing works lol. I can never wrap my head around it.
Faulty Engine Coolant Temp. Sensor was the culprit! :)
purplecrx said:
Faulty Engine Coolant Temp. Sensor was the culprit! :)
Is that the Water temperature sender? I am having the same symptoms on my car.

Never had a starting issue untill the temps dropped into the 20s :(
Autozone also has a Temperature switch listed.

Temperature Switch for a 1990 Honda Civic CRX
WELLS TU121 $13.99 Normally Stocked

And the above is not the fan switch as they have that listed seperatly with a different part number.

As well as the

Coolant Temperature Sensor for a 1990 Honda Civic CRX
WELLS SU4006 3 MO $24.99 Normally Stocked

I mean for $14 bucks I don't mind picking it up. But am I going to need it?
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It couldn't hurt to replace it. It's just right under the dizzy. Just unplug the old one, unscrew it(3/4" deep well socket will do the trick, 1 extension bar), screw the new one in, plug it in, bleed your cooling system and you're good to go.
tubafreak said:
It couldn't hurt to replace it. It's just right under the dizzy. Just unplug the old one, unscrew it(3/4" deep well socket will do the trick, 1 extension bar), screw the new one in, plug it in, bleed your cooling system and you're good to go.
You mean the temperature switch or the coolant temp switch?
I'm not getting any spark at all. No codes on the ECU. I have replaced the main relay, the ignitor, cap, rotor, wires, and plugs.

Any thoughts?

Also... anyone know if a replacment distro from autozone or the like has everything in it I need? Like the ignitor and coil and such? I'd hate to spend the money and it just be the shell.

Anyone? Anyone? Bueller? Bueller?

Nevermind...figured everything out.Replaced the entire dizzy cause I was tired of messing with it. The new dizzy has everything except the rotor and cap. Also replaced the temp sensor while I had the dizzy out. So far so good. Now to just adjust he valves.
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