CIS Cold Start Problem Did Pressure Tests Now What?

[WyattEarp]

Winter around here is the best driving weather. WUR tune up might be something for the middle of the hot humid summer. I will continue to try and get this sorted a bit more as I would like to have a car that starts instantaneously in all conditions. Testing the CSV is still on my list of things to do but I may save it for a 'while I'm there" task.

[Bob Kontak]

Originally Posted by WyattEarp

Winter around here is the best driving weather. WUR tune up might be something for the middle of the hot humid summer. I will continue to try and get this sorted a bit more as I would lie to have a car that starts instantaneously in all conditions. Testing the CSV is still on my list of things to do but I may save it for a 'while I'm there" task.

Cool beans. Yes, it's definitely in there.

We all learned a thing or two. Merry Christmas.

[gazzerr]

Tony no that was my point. I DID remove them all insitu removing/prying the spring clip and it was a NIGHTMARE. And I ended up breaking a couple of the plugs. It took me probably 2 hours to remove all those damn plugs contorting myself back behind a loose airbox still sitting on top of the engine only attached by the harness. I was able to roll it around to get to the plugs but it was very difficult.

I discovered later on that all you have to do is use a TINY little bit of leverage with a screw driver on the base of the plug and it pops right off quickly and safely. I'm still kicking myself. Learning the hard way is a virtue. Like you said they are only springs. They don't need to be removed at all.

I always laughed at the service manual advice for testing the CSV. How do you pull it from the back of the engine and then test it in that space with the hard lines? I think the best advice I saw was to pull the pope's hat and watch it spray from looking down the throttle body (I think this was a Tony tip). Pull the plug on the coil first or you might lose your eyebrows. .

I took no offence from your post. I think you misread what I was saying. I think opinions should be challenged. That's what makes this forum valuable.

G.

[Bob Kontak]

Originally Posted by gazzerr

I think the best advice I saw was to pull the pope's hat and watch it spray from looking down the throttle body

Pretty sure the later SC's have runners inside the airbox to lessen the airbox explosion. The runners block the view. Maybe 1980 they started?

[WyattEarp]

So doing more investigation today and I found that my pop off valve was loose. Epoxy was no longer holding. So I took it out, cleaned everything up and re-epoxied it.

Don't know if this is all of my problem but could certainly be a contributor I guess.

[gazzerr]

Oh yeah that will cause a massive air leak that can lead to a backfire and blow up your air box anyway.

[Bob Kontak]

Originally Posted by gazzerr

Oh yeah that will cause a massive air leak that can lead to a backfire and blow up your air box anyway.

I can also be a small leak from fatigued (cracked) epoxy. Flopping in the breeze is one thing, a fissure/tear is another.

My bet is the as OP nails these various cooties with reading and hands on work, his car will transition to warm much more smoothly and he will be amazed at the difference in the car's operation.

I still say send the WUR to Tony for a tune up. Remove that variable.

And, of course, the probably CSV issue. Two starts at five seconds duration is too long.

[WyattEarp]

Originally Posted by Bob Kontak

My bet is the as OP nails these various cooties with reading and hands on work, his car will transition to warm much more smoothly and he will be amazed at the difference in the car's operation.

This is what I am hoping for.

[Bob Kontak]

Originally Posted by WyattEarp

This is what I am hoping for.

Persevere. There are only so many variables.

You're not selling? You have years to nail it.

I describe my SC ownership experience as BT and AT. Before and after Tony with respect to CIS. Advanced search will deliver lots of goodies.

[WyattEarp]

Originally Posted by Bob Kontak

You're not selling? You have years to nail it.
.

Nope. Not selling. ... Driving

[pmax]

Originally Posted by Bob Kontak

Pretty sure the later SC's have runners inside the airbox to lessen the airbox explosion. The runners block the view. Maybe 1980 they started?

Yes, added in the 80.

I haven't had the pleasure of observing the CSV operating in situ closeup with the hat off but even with the runners, can't you smell the gas or hear it working ? Ignition disabled of course !!!

[boyt911sc]

Originally, the ‘76~’79(?) CIS air boxes came without the “spider plumbing” found in the late SC’s (‘81~’83). Subsequently, the new replacement CIS airboxes both 34-mm and 38-mm ID now have the “spider plumbing” installed already. Not exactly sure when it was first introduced because I have a couple ‘79 CIS airboxes with the spider on them.

My ‘78 SC still has the old original airbox without the spider plumbing. And will replace it next time I have the motor out. So when you decide to replace your old air boxes, make sure you get the one with the “spider plumbing”.

However, you cannot perform a CSV flow test to airboxes with “spider” in situ. The CSV has to be removed from its mounting for visual test.

Tony

[stlrj]

Originally Posted by boyt911sc

Not exactly sure when it was first introduced because I have a couple ‘79 CIS airboxes with the spider on them.
Tony

All factory replacement air boxes since '81 contained the spider plumbing. So if you encounter an earlier 911 with the plumbing, it just means the airbox had been replaced.

Cheers,

Joe

[WyattEarp]

Got the pop off valve re-epoxied go to start the car this morning and no start. Crank crank ... nothing. Since the top of the air box was off I decided to just do the check with air sensor plate to see if fuel pump was running. Turn the key to the on position and lift the air sensor plate a bit and can just hear a bit of a click click towards the front of the car. Hmmmm. Pump was running fine when I did my pressure tests and car has been running since. So I pull the pump relay and hook up my jumper wire/switch like I was going to do tests. Turn ignition to on and pump runs fine (just ran it 1 sec at most). Hmmmmmm. Put the relay back in. Try to start car and it fires up almost immediately first crank. Little short drive turn it off and as usual car starts right up after its been running. Take the air box cover off again just to make sure I'm not crazy, turn ignition to on and lift the air sensor plate and yep pump immediately runs. So..... flakey fuel pump relay??

[SkiVT]

Try gently spreading the male prongs on the relay with a small screwdriver. Sometimes they get smaller as the relay is wiggled in/out for the jumper. Its also possible the male connectors on your jumper are slightly larger than the relay which may enlargen the female side of the plug. Of course, the relay itself could be going bad but some things to try before buying.

[pmax]

Originally Posted by WyattEarp

Got the pop off valve re-epoxied go to start the car this morning and no start. Crank crank ... nothing. Since the top of the air box was off I decided to just do the check with air sensor plate to see if fuel pump was running. Turn the key to the on position and lift the air sensor plate a bit and can just hear a bit of a click click towards the front of the car. Hmmmm. Pump was running fine when I did my pressure tests and car has been running since. So I pull the pump relay and hook up my jumper wire/switch like I was going to do tests. Turn ignition to on and pump runs fine (just ran it 1 sec at most). Hmmmmmm.

Good to keep a spare relay in the glove box. Yeah, keep a jumper wire and thin blade too for above purpose.

Originally Posted by WyattEarp

Put the relay back in. Try to start car and it fires up almost immediately first crank.

Try start it again on a cold engine without doing the jumper test prior.

The leaky toilet seat valve can cause your original problem.

To Pop Off or not to Pop Off?