HELP! 2.7L runs only when gas poured in.

[Walter_Middie]

Al is correct:

[Walter_Middie]

With the key in the run position, your fuel pump should be running. If you lift up on the air flow plate (under the air filter), do you hear your injectors running? Air in the lines may keep the fuel from getting to the injectors. Be careful not to flood the engine with this test.

[allaircooled]

May I suggest before you do anything follow the link Al gave to familiarize yourself to the cis. Learn some basics and also get a proper cis pressure gauge test set. Also check out the cis for dummies thread on here.

[mark944T]

Originally Posted by fanaudical

I'll confirm that - Line with yellow arrow is vacuum and should be dry.

Here's a link to help with CIS troubleshooting:

https://jimsbasementworkshop.com/CIS/

Thanks, I’ll do some more studying up.

[mark944T]

Originally Posted by Walter_Middie

With the key in the run position, your fuel pump should be running. If you lift up on the air flow plate (under the air filter), do you hear your injectors running? Air in the lines may keep the fuel from getting to the injectors. Be careful not to flood the engine with this test.

Yes I hear a slight squeal.

[nomore]

Disconnect all 6 vacuum lines from the injectors, put them in a jar, lift the sensor plate and see if fuel comes out. The reason for disconnecting the fuel lines is, lifting the sensor plate shoots fuel to all 6 injectors at the same time and will flood the engine if you over do it.

[Walter_Middie]

You have ignition - as it rums with fuel added to the throttle body. You have fuel to the injectors as you hear squealing. These cars are very hard to start without the cold start injector working, but adding fuel to the throttle body should compensate for that. Seems like this car should start.

[mark944T]

Anybody else have a suggestion?

[356911930]

Pull all your injectors out and put each one in a plastic bottle. Lift up on the air flow plate and see if each one is spraying. The spray should be in a perfect cone atomizing as much as possible.

Report back and we can go from there.

Rahl

[mark944T]

Originally Posted by 356911930

Pull all your injectors out and put each one in a plastic bottle. Lift up on the air flow plate and see if each one is spraying. The spray should be in a perfect cone atomizing as much as possible.

Report back and we can go from there.

Rahl

All injectors squirting equally and good pattern.

[fanaudical]

OK - Couple of quick things to check:

- Verify no holes in the rubber boot between the throttle body and the air flow sensor.

- Verify no open ports to the air box.

- Verify that the hand throttle (black-knob next to the parking brake) opens the throttle plate when you pull it up.

Rough starting sequence:

- Hand throttle all the way down.

- Turn key to run position, let fuel pump run ~15 seconds

- Pull hand throttle up ~1 inch

- Crank the starter

- Adjust idle speed with the hand throttle if it catches/runs

It should still start (might be tough) if the cold start valve isn't working.

[mark944T]

Will check in the morning.

[boyt911sc]

Mark,

It would be much easier to help you if you understand the basic CIS fuel flow schematic. You said you have a ‘74 CIS, and that’s a good start. Since you know now the difference between a CSV (cold start valve) and a WUR (warm-up regulator), start reading or learning the different common acronyms people used in this forum.

The first thing I would ask you is what is the ID number of your WUR? If your are not familiar with Bosch WUR identification number (0-438-140-xyz), the last 3 digits identify a particular Bosch WUR. It is located on top near the post where the rubber hose is connected. I could see the numbers from your picture.

Depending on the last 3 digits (xyz), you could identify a particular WUR whether it vacuum assisted or not. Except for a rare or hard to find WUR. Second, the rubber hose with yellow arrow could be vacuum or vent line depending where it is connected at the throttle body. Before we get into further discussion, you need to identify this particular WUR. Thanks.

Tony

[Sharkbitemarky]

Be very careful not to over fuel the airbox, otherwise you will be in danger of an airbox backfire, it will ruin your day.

If all injectors are working well and understanding it runs when fuel is applied directly e.g. a spark is present, it should at least fire if not run. Unless maybe the air flap is closed/blocked in normal operation.

[mark944T]

It will run when gas is put in directly. Just won't keep running. Has good spark. Compression and leak down numbers were good (checked by Vision Motorsports in Laguna Hills). Car has security systems that I disconnected but wonder if they are still somehow effecting it. Could be bad CSV? It's going to be 80 degrees today. Will try what Fanaudical suggested.

WUR is 0-438-140-009

[nomore]

Not sure how you are getting fuel into the TB but if the rubber bellows "popes hat' is not secure and air tight the car won't run.

[mark944T]

Originally Posted by nomore

Not sure how you are getting fuel into the TB but if the rubber bellows "popes hat' is not secure and air tight the car won't run.

Ok didn’t realize pope needed his hat. Buttoned everything up and let fuel pump run for 15 secs. And used hand throttle.

CAR RUNS!!!!!

Thanks to all!!!!

[nomore]

Let the fun begin.

[fanaudical]

Yes, the air boot between the throttle body and the air flow sensor must be installed and sealed well (or else the air flow sensor won't lift and injectors won't get fuel).

FWIW - The "run the fuel pump for 15 seconds before cranking" is either total hogwash or standard operating procedure, depending on who you ask. I find my '75 starts very quickly if I let the fuel pump run/prime things for a few seconds.