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Hard to start cold. Not cts.


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liquidzorch
New User

Oct 16, 2012, 3:08 PM

Post #1 of 4 (2021 views)
Hard to start cold. Not cts. Sign In

Hello. I am still having trouble starting my 94 corsa b 1.4l c14se. The problem is in the morning and after leaving it for a couple hours. It cranks but It takes a long time to get it running, but once it starts it drives perfectly. There is a spark on all plugs.

Things i have checked already:
No CEL codes.
Changed crank sensor - exact same
changed coolant temperature sensor - exact same
Checked map sensor (it is working good)
There is fuel at fuel rail.
Checked for spark and there always is.

It seems as if it is not injecting enough gas on first start. I wired the ground from the injectors to a button i can press to inject more gas and if i press it quickly while cranking it will fire up quickly. If I dont it takes about two minutes of constant cranking. But what could cause it not getting enough gas ONLY at cold start?

If I turn it off right after cold start and try again it will start right up.
One other symptom is poor fuel economy (about 6 - 7 km/L). But that might not even have anything to do with my starting problem.

What else can I try or what could it be?
Thank you.


nickwarner
Veteran / Moderator
nickwarner profile image

Oct 16, 2012, 7:26 PM

Post #2 of 4 (1976 views)
Re: Hard to start cold. Not cts. Sign In

There may be fuel at the rail, but at what pressure? It could be also possible to have bad fuel injectors, which would explain why your mileage sucks and why commanding them to add more fuel manually helps.

What is the compression on your cylinders? With an engine this old you could simply have a worn out motor, also would give you bad fuel mileage.

Have you checked very closely for vacuum leaks, which would slow the velocity of the air carrying the fuel into your cylinders if it was a big enough leak.

This car isn't sold here in the US so I don't have any access to tech data for it. I can only tell you what I'd be looking at on any car with the same issues.


liquidzorch
New User

Oct 17, 2012, 9:27 PM

Post #3 of 4 (1947 views)
Re: Hard to start cold. Not cts. Sign In

Hello, thank you for your reply. I will get a compressor checker soon to check compression and I will check fuel pressure also. I am thinking it might be fuel pressure. It as a port to check the fuel pressure on the rail and when on and pressing it gas spills out. But once I turn off the car the pressure completly goes away by the time I get to press the button, not one drop. If I am correct there should still be pressure when its turned off like my civic. Could that be the problem? If so Why will it start right away when its warm? And could that be cause of bad mileage? The injectors are fine, i removed and sent them to be cleaned and checked.


nickwarner
Veteran / Moderator
nickwarner profile image

Oct 18, 2012, 4:27 PM

Post #4 of 4 (1918 views)
Re: Hard to start cold. Not cts. Sign In

You could have just a couple pounds of pressure in the fuel rail and it would squirt when you push in the valve, which is why you need to know what the pressure actually is. You are correct in assuming that it should hold pressure when shut off. If it doesn't you either have a stuck open injector, you are leaking fuel at the fuel rail, or your fuel pressure regulator is bad. Most all that I've seen are on the return side of the fuel rail and have a small vacuum hose on them. Pop off the vacuum hose and plug it then run the engine. If the regulator is bad it will leak past its diaphragm and come out of the nipple the vacuum line goes onto. You'll be able to see it come out. Then you have confirmed the problem. A ruptured regulator will dump extra fuel in the engine via that vacuum line and will cause major driveability headaches along with terrible mileage. It also keeps you from running the proper pressure that the injectors need to spray fuel properly. When the fuel passes through the tiny nozzles in an injector under the proper pressure, it forms a misty spray full of very small particles of gas which mixes nicely with air and burns very well. But under lower pressure you don't get the misting effect, its the difference between water coming from a pressure washer versus a garden hose. .






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