Cold start issue and maybe hot start too

[allaircooled]

I have been chasing this cold start issue I have been having. It takes a lot of cranking and stumbling, popping and then it will start to run on its on with low rpms, very rough. Finally after about 30 seconds it catches and I can give it a little gas to say 2500 rpms and it will idle on its own after that.

When hot it would start right up until today. I had to crank it until I thought the battery was going to die. Opened up the engine lid, didn't see anything obvious. Turned the key and it fired right up.

I did check my pressures yesterday:
Ambient temp 88F or 31C
System 5 bar
cold 2.7 bar
warm 3.6 bar
residual after 10 mins 1.6 bar, 20 minutes 1.5 bar

This car sits a lot and I have only put 400 miles on it since I first got it running again a couple of years ago. I replaced all seals at that time, new fuel lines, got a rebuilt wur from Tony, a rebuilt FD and many other parts that where either broken, in bad shape, or not working. (This car was a basket case when I got it.)

I have checked for air leaks and corrected them but it has been about 3 years now. I also set the co using my gunston at that time as well. Maybe I should check them again?

I switched back to points from pertronix while trying to figure this problem out but it made no difference. I set timing to 5 degrees ATDC with vacuum plugged into distributor.

Looking for ideas or suggestions.

This is a 77 2.7L

[lsf911]

It could be a spark problem not fuel. How old is your CDI unit?

Missed the fact you went to points with no change. Interesting problem.

[gomezoneill]

Thermo time switch or the cold start valve and wiring for both.

[allaircooled]

Originally Posted by lsf911

It could be a spark problem not fuel. How old is your CDI unit?

Missed the fact you went to points with no change. Interesting problem.

I have thought of the possibility of spark not fuel. Plugs, cap, and rotor are new. Plug wires are magnacore and were installed around 2003 along with a rebuilt cdi.

Thermo time switch or the cold start valve and wiring for both.

I will look into these next.

Thanks guys.

[Paulporsche]

Was the popping out the intake (lean) or exhaust (rich)? Hot starts are difficult when mix is too rich and, while engines start more easily when rich, a too rich mix often keeps the idle revs low and erratic. Your mix may be off.

How old is the fuel? Did you use a stabilizer?

Did you check the condition of your spark?

Is your sensor plate correctly set and moving freely?

Make sure the plug for the ignition under the dash is fully seated. Check fuel pump wiring and relay

[allaircooled]

How old is the fuel? Did you use a stabilizer?

I didn’t think of this, the gas is at least a year old. I did put stabilizer in it at the time. I’m going to go see if I can burn this gas out and fill it with some fresh gas. Thanks.

[jlex]

Wouldn't be surprised if water settled in on that old gas. Tough to burn water. May want to try fresh fuel and dry-gas.

[lsf911]

Year old gas is not that old, especially since you treated it with stabilizer.

[allaircooled]

Originally Posted by lsf911

Year old gas is not that old, especially since you treated it with stabilizer.

I took it for a nice long drive to burn out most of it anyways. Put in some fresh gas, then while it was at operating temp, hooked up my gunson analyzer. Turns out it was very lean. I could have messed this up before or possibly developed some kind of air leak. All though all the seals and rubber bits are new so not sure where I could have developed an air leak. I will check for leaks just to be sure.

[allaircooled]

Was snooping around the other day and found two loose connections on the same pipe, the one that connects the AAR and AAV to the cold start valve base. Pretty sure those were a source of a air leak. Tighten them up and tested out the AAV while I was there.

Afterwards I started it up and drove it to get to operating temp and adjusted the co to 3.3%.

Today it started right up and I thought I had it. Couple hours later it was difficult to start again, but not as bad.

I need to test the cold start valve circuit and I want to check for more air leaks. All seals and rubber bits are new so my guess is the most likely source of any air leaks if there are more is the air box. I had sent this air box to Tony a couple years back and he had sealed it for me but it's possible it developed new leaks.

Did you check the condition of your spark?

Is your sensor plate correctly set and moving freely?

Make sure the plug for the ignition under the dash is fully seated. Check fuel pump wiring and relay

I checked and adjusted sensor plate and it is moving freely.

Not sure of hour to check the condition of my spark.

Fuel pump was moved from the rear to the front of the car and I used new wiring. No fuel pump relay on my car. Thanks.