It ran this afternoon, but not tonight!

[zevenbergena]

I drove to work and all around town this morning and afternoon, everything running fine, 0 issues.
4 hours later went to start it and [I]nothing[I]. Motor turning over, not starting. Temp guage showed stone cold. Not puffing like it's trying to start or anything. Just turn, turn, turn. A buddy of mine said he smelled a little bit of unburnt fuel coming out of the exhaust. Tried it about 20 min later and still nothing at all.
Any ideas?

[christojen]

You need to try and isolate the problem, I would start by checking for a spark, this is pretty easy.

If you have spark, you basically have a fuel problem. It would be worth turning the car to on, listen for the fuel pump, and if that is running open up the air box and lift the air ratio thingy (push up on the arm insoide the air box).

Then try to restart the car. If it fires it is the cis system playing up.

You need to try to identify if there is spark and/or fuel and then report back. The others will know what is going on.

Chris

[zevenbergena]

fuel pump came on.
i figured it was either a spark issue or a fuel issue.
Im used to some rough starts in the colder weather and gave it a little bit of gas, I'm going to head back out tomorrow morning just in case I flooded it, but I don't think I should have...
If not, I'll start hacking through this stuff and bring back all the details I possibly can

[christojen]

Aaron,

I am pretty sure that "giving it gas" doesn't work like you think compared to a carby engine. When you push the throttle it opens the butterfly, but the airflow has to open the air mixture meter arm "thingy" that allows the fuel to the injectors via the fuel distributor.

A number of parts in the CIS system have to work to gether to get it going.

For example my car gets no "gas" when it is hot because of one of the cis parts.

If it wont go at all, and the fuel pump is going, i reckon it would be a spark issue. Once you determine that it will help.

Chris

[T77911S]

he is correct. throttle does not add gas when starting. the engine is asking for a certain amount of air, and that volume of air raises the sensor plate a certain amount and that is it.

you could have someone lift the sensor plate as you try to start it, that will dump more fuel inthere.

but first, i would verify spark. you can connect a timing light and check it that way, or connect an old plug to one of the wires and look for spark. it could be old ignition parts, and perhaps you fouled some plugs.

it could also be something to do with the cold start valve (CSV), or the wiring for it. the lift sensor plate may help to isolate and let you know if that is the area you need to look at.

it could also be control pressures (CP's). not high on my list. usually when the warm up regulator (WUR) goes bad, it is the warm CP's that are not good. but if all else check ok, i would check the CCP.

did it back fire? do oyu have a pop off valve? is the popoff valve seated properly? any big air leaks?

[dtw]

CDI whining? I'd check spark first, too. Usually if it is a vacuum problem (like a blown airbox or popoff valve), a CIS car will it least fart a couple times on the cold start injector before dying.

[GaryR]

Originally Posted by dtw

CDI whining?

Yep, be the 1st thing I would check in an SC too! Good one minute, dead the next!

[T77911S]

it can whine and still be bad. check for spark, it checks the whole system.

[Spartocracy]

Just had to bump this thread...the exact same thing happened to me yesterday...wondering what the final outcome was...I'll have to mess with mine when I get home from work tonight. Hope it's just a spark issue. I have noticed lately that the idle has been hunting a bit, even when warm...could this be evidence of a vacuum issue?

[na2ub]

Don't overlook the distributor cap. If you can smell fuel at the engine, it is probably a spark problem. That's what mine was. It even looked okay, but once replaced, all was well.

[dtw]

Originally Posted by Spartocracy

Just had to bump this thread...the exact same thing happened to me yesterday...wondering what the final outcome was...I'll have to mess with mine when I get home from work tonight. Hope it's just a spark issue. I have noticed lately that the idle has been hunting a bit, even when warm...could this be evidence of a vacuum issue?

It could be. I had a hunting idle and other weirdness going on w/my CIS '76, and then it just wouldn't start. It had been starting harder and harder for weeks. It would fire up on the cold start injector and then die after a second or two, so I knew I had 'some' fuel and spark. Since the low hanging fruit then became vacuum issues, I looked over the CIS. 10 seconds later I found the popoff valve loose in the airbox. The epoxy had failed and it had slowly worked itself loose.

[Spartocracy]

Originally Posted by dtw

It could be. I had a hunting idle and other weirdness going on w/my CIS '76, and then it just wouldn't start. It had been starting harder and harder for weeks. It would fire up on the cold start injector and then die after a second or two, so I knew I had 'some' fuel and spark. Since the low hanging fruit then became vacuum issues, I looked over the CIS. 10 seconds later I found the popoff valve loose in the airbox. The epoxy had failed and it had slowly worked itself loose.

hmmm...I haven't had a chance to really check anything out yet...but I did make sure the popoff valve was ok...I'm also wondering now if it could be the ignition...Over the past 2 weeks, whenever I first try to start the car, the key locks in the ignition when I try to turn her over...I had to do it 2 or 3 times, before it would turn all the way and start to turn over. Maybe I'm just grasping at straws, but I'm trying to put as much critical thought into it before I actually dig in tomorrow.