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Discussion Starter #1
40 year owner of 78 Z and have tackled a lot of different issues over the years and just being a troubleshooter and not a mechanic. I keep the car on a trickle charger and cranked it up this past weekend to pull out of garage. Cranked instantly as it normally does, smoked some, as it normally does after sitting, and pulled out AOk, Turned off after letting idle couple minutes, Cranked back up couple hours later and cranked just fine but as pulling in garage it started bogging down and dies. Turns over fine and only couple times did a I get it fire just a little.

I do not have a fuel pressure gauge but made sure I had a squirt come out of fuel filter when turning key. I have spark but is it strong spark? Then I notice gas dripping out of my cone shape after market air filter. Removed it and hose to air flow meter. Gas dripping from it. Removed AFM and gas won;t stop dripping.

I currently have a rag in the intake opening to allow gas to be absorbed and evaporate.

First I am looking for suggestions to stop the drip so until time to figure out the issue. Then am I looking at something in the throttle body area?

I obviously have had to repair things in last 40 years such as water pumps, alternators, loose connections, fixing vacuum issues for AC/heat, slave cylinder for clutch, brakes etc but usually I find suggestion in reading forum. I did not see my situation exactly but will keep looking.

Suggestions welcome,
Cruizin
 

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My thought is the cold start injector. It's close to the AFM, and if it's leaking, it could send gas down towards the AFM
 
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Discussion Starter #3
As of this morning appears the drip out of throttle (I have AFM off but still connected w wiring) has stopped. Rag I had in throttle stilled smell strong gas but was not saturated like it was yesterday and viewing inside appears dry.
The cold starter injector is on high on my list of possibilities that I have written down and researching forum. Pressure regulator is another and throttle itself. Many want to jump to AFM right off bat but just not thinking that at this point.

Wonder if unplugging the injector would allow to crank so to make sure everything else ok.

Thanks for suggestions and hopeful I can update a solution in near future. Not a daily driver much less a monthly driver so not the urgency IF gas gas stopped dripping and don't think it leaked entire gas tank.
 

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Assuming your rubber fuel lines are still pliable, you can remove the cold start injector while leaving it connected to power and fuel. Put it in some type of clear container and turn the key to the run position. See if fuel is leaking out when the pump is on. It should only come on when the thermotime switch says the temp is low enough to need more fuel upon start up (cranking the car). From my understanding, the cold start injector shouldn't be in use while the engine is running.

I'd also check the thermotime switch to make sure the readings are in spec. Maybe it's gone wonky and keeps telling the cold start injector to spray fuel. Of course I think you would be running super rich and black smoke would be pouring out of the exhaust.
 

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Its gotta be the cold start valve leaking or being stuck on - theres no other place in that engine besides the cylinders where gas would be coming from.
 

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Discussion Starter #6
Thanks for the feedback. My immediate concern on continuation of dripping/leaking and fumes in garage have subsided. With AFM off, I can see inside throttle and there is no leakage in just moving the throttle manually so my concerns on safety hazard are over. It will be into next week before getting to look at closer, put back together, and check out the cold start valve/injector. Several hoses in that area and didn't know if any way a vacuum or way for fuel to get into intake if another problem somewhere else with motor or gaskets allowing fuel to get places it shouldn't.

I truly appreciate the advice and looking forward to seeing if I can make my Z continue its long life.

Cruizin
 

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besides the cold-start injector there is absolutely no way for gas to be in the intake at all. the cold start injector is your problem. it is either leaking due to age, or stuck on due to the thermotime switch. unplug the electrical connector to it.

It is most likely just leaking since fuel in the fuel rail is always pressurized to the injector. I don't think the injector under its own power can squirt enough fuel into the manifold for it to (i) not be used and (ii) saturate the intake manifold to the point of drilling out the AFM.

The cold start injector is leaking - pull it and get a new one.
 

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Before you do anything, you have a hazardous condition and you need to be very careful. You could literally have an explosion in the crankcase which I'm sure you could guess that could be very baaaaad. First pull your dipstick and see if the oil level has risen. Take the dipstick outside and breath some fresh air, then smell the end of the dipstick. Hopefully it will just smell like oil and not gas. Next pull the coil wire off of the engine and the coil. Then pull the starter energizer lead off of the starter. It's the only one that unplugs. Next locate your fuel pressure regulator. It's in the middle of the fuel rail and it has a vacuum hose coming out of the top. Unplug that hose from the FP regulator, then turn your ignition key to the start position and watch the vacuum port on top of the FP regulator. As long as the starter wire is pulled the engine won't turn over but the fuel pump will energize. If fuel starts squirting out of the vacuum port on the regulator when the pump is energized then you'll have to replace the regulator because it has a ruptured diaphragm. If fuel doesn't come out then it's probably ok. If your oil is contaminated then replace it and the filter, pull your plugs and crank the engine over after you've fixed the fuel excess problem. If no fuel comes out of the holes then put 2 or 3 squirts of oil in each cylinder, wait for 10 minutes then crank the motor over again for 10 seconds. This will make sure that the cylinders are lubed with oil, not gas. A stuck cold start valve is possible but not very likely, same with a stuck injector. Read your spark plugs, and see if all of them or one of them got wet from too much fuel. If it's one of them then it could be a stuck injector which is rare. All of them could more than likely be a bad ECU or a bad AFM if the FP regulator is good. I'd also take off your oil cap and leave it off for a few days to ventilate. Leave your throttle body uncovered and open the throttle plate all the way and stick a screwdriver in the linkage to hold it open. Getting fresh air in there to dry out the excess fuel is a good thing. A small fan directed at the throttle plate is a good idea as well. Last possibility is a bad water temp sensor or bad connections at the sensor on the front of the t-stat housing. DO NOT TOUCH THE CONNECTORS YET. There are 4 wires plugged in with bullet connectors right by the throttle linkage between the throttle body and the t-stat housing. The 4 wires are taped together in groups of 2 and one of the groups has a bad of red tape on both sides of the bullet connectors. Unplug the 2 wires that don't have the red tape and hook up an ohmmeter to the 2 wires. NOTE: It has to be an analog VOM, not a digital. In this case a digi is easily fooled, one of the exceptions to the rule. Anyhow, with the vom hooked up you should have anywhere from 250 to 3000 ohms with a constant needle. Take your hand and grab the connection on the water temp sensor and wiggle it. It's the efi connector on the front of the t-stat housing that is closest to the drivers fender. The needle on the vom still shouldn't move. If the needle starts bouncing around or drops to zero then you have a bad connection at the sensor and they need to be cleaned or replaced. I usually file them and get an electric contact cleaner in an aerosol can and spray them. After the conns are clean and dry, be sure to put di-electric grease on them and plug them back in. Then try your wiggle test again and see what happens. If the plug in on the WTS is broken then replace it. I sell both the stock style of efi connectors as well as the quick disconnect style. Only the stock style can be used on the 2 sensors on the front of the t-stat housing. Good luck on your fix. Z man of Washington 360-668-2979
 

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Discussion Starter #9
Update 6/28/2020
Finally got a few minutes to work/play with my Z. I still have the AFM separated from throttle body plus rag and handle end of a screw driver in throttle to hold flap open to dry it up and it was dry and no gas fumes. Been sitting like this since my last post 12 days ago.

Today I pulled the cold start injector and left electrical plug and fuel line still connected to it and placed in a small jar. Since my fuel lines relatively new (replaced maybe 15 years ago), I was able to turn it to get into a jar AOk. Turned key to on but did not try to start it. Left key in that position for 3 or 4 seconds. No fuel in jar. But my rag in throttle was saturated and fuel literally pouring out. Can't measure but took 2 hand towels and some paper towels to soak it all up.

Next I took air line from fuel regulator off at the regulator and laid a rag under regulator. Turned key and could instantly see a solid squirt of maybe 3 or 4 inches. This air hose runs over close to cold start injector.

Would ya'll conclude that the fuel regulator is gone bad and as ZManofWashington states the fuel regulator has ruptured diaphragm? If not, other suggestions to testcheck prior to looking for a fuel regulator?

Thanks in advance,
Cruizin
 

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Sounds right. That's the vacuum line. Should always be dry
 

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If that's the case, then you definitely need a new fuel pressure regulator.

You MUST attempt to start the car to test if the cold start injector is stuck on or leaking. Plug the AFM back in and just have it crank a couple of times - that's all it will take to test.
 

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Discussion Starter #12
update 7.6.2020
Ordered new fuel regulator from Rock Auto and received today. Installed along with new gas filter, oil and filter change, reconnected the AFM and hoses etc plus reinstalled the cold starter injector. Turned key and without hesitation, the Z fired right up. Thanks to all for the input/suggestions.

some side story notes: After cranking right up, I noticed I had no oil pressure. I shut er down instantly and went back thru what the ell going on now. Then I remembered the oil sender is next to the oil filter and by the gas filter. Went and looked and sure enough, I had knocked the plus off the sender, Plugged back and oil gauge showed right in middle. Had to laugh.

New issue to research on and may start a new thread is when I changed the oil, I had several extra quarts of oil and was mixed with gas. Maybe 3 quarts over the near 5 quarts expected. Need to figure if the regulator caused or some internal motor issue. No knocking and motor sounds sweet, No mixture in with antifreeze as best I can tell. Took a few drops of oil and took to safe location and applied a lighter and it was definitely combustible.

Again thanks for assistance and my Z I've owned 40+ years lives on.

Cruizin
 
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