Difficult to start when cold

[Rexkrazy]

Mind if I add a small Hijack?

 

I've been having a similar issue with warm starts.

 

Car always starts strong when cold (though I usually (edit:THINK I) let the pump prime for a couple secs by habit)

 

Car exhibits the warm start issues like a leaky injector. if it rests for over a minute it will start and then die. Might start again and but just sputter alot and die until it gets to rest for at least 10 mins. Then it will start slowly.

 

Only, one hot day (100 deg plus) after sitting over night, the car exhibited the same issues on a cold start. It also never had this problem during colder weather in general. Warm starts would typically take longer with lower idle. I replaced a broken vacuum temp sensor in the winter but it didn't seem to have any effect.

 

The coolant temp sensor reads 2-kOhms cold and under 300-Ohms hot. Is the one wire coolant sensor an over-heating kill switch type thing? Maybe that's messed up. Is there an intake air temp sensor I can chase? Could this still be a leaky injector? any other ideas?

 

Thanks,

Tony

Edited July 30, 2010 by Rexkrazy

[Shelby]

Mind if I add a small Hijack?

 

I've been having a similar issue with warm starts.

 

Car always starts strong when cold (though I usually (edit:THINK I) let the pump prime for a couple secs by habit)

 

Car exhibits the warm start issues like a leaky injector. if it rests for over a minute it will start and then die. Might start again and but just sputter alot and die until it gets to rest for at least 10 mins. Then it will start slowly.

 

Only, one hot day (100 deg plus) after sitting over night, the car exhibited the same issues on a cold start. It also never had this problem during colder weather in general. Warm starts would typically take longer with lower idle. I replaced a broken vacuum temp sensor in the winter but it didn't seem to have any effect.

 

The coolant temp sensor reads 2-kOhms cold and under 300-Ohms hot. Is the one wire coolant sensor an over-heating kill switch type thing? Maybe that's messed up. Is there an intake air temp sensor I can chase? Could this still be a leaky injector? any other ideas?

 

Thanks,

Tony

 

 

 

leaky inj or fuel pressure reg diaphram

[lester]

the air mass was humming inside the car ??? thats a new one

No but the faulty MAF is causing something to hum inside the cabin, maybe some solenoid or similar? After the change to another MAF, all is well with new injectors and fuel pump.

[Rexkrazy]

Thx... I see a drip.

[Rexkrazy]

well now I think the drip was just the injector firing with next to no fuel pressure. I bench tested and back flowed both injectors and they are both great. I took off the uhh... fuel manifold?? can I call it that? anyway I had to drill/easy out the plug to put in a pressure gauge. Reinstalled everything and powered the fuel pump with the test connector. It ran and I got proper pressure at the gauge. then I turned off the pump and the pressure started dropping, but the injectors weren't leaking.

 

The FPR doesn't leak through the vacuum port. Can it still be the problem?

 

Is there another pressure valve at the pump that could be failing?

 

Also, after I ran the pump the first time, it wouldn't run again by powering the connector (or cranking). Also, the test connector only gets about 10 volts when cranking. I assume this is because the starter is running.

 

Now I crank the car and there is no fuel pressure fluctuation whatsoever. I'm sure if I let the car cool the pump will run again.

 

Ideas?

 

Is the ECI relay possibly bad? What else could be heat sensitive and keep the pump from running.

 

EDIT: seems obvious now. it's the pump itself. I'll check to make sure it's getting power before i go droppin the tank (can I get to the pump without droppin the tank?)

 

Tony

Edited August 8, 2010 by Rexkrazy

[mikec]

The FPR doesn't leak through the vacuum port. Can it still be the problem?

Likely not. Fuel pressure regulators typically fail by having the internal rubber diaphragm start leaking. The only other failure would be if the internal spring busts... then it'd fail to regulate to the correct pressure. Pretty rare though.

 

Is there another pressure valve at the pump that could be failing?

The output of the pump connects to a check valve which is a one-way device. It lets fuel flow towards the engine when the pump is running; when the pump is OFF it traps the fuel between the check valve and engine. That leaves pressure in the fuel lines ready for the next time you try to start the engine. It's common for this check valve to fail with age, allowing the fuel pressure to ooze back through the pump to the fuel tank. All it means is that the engine may need 1 to 2 more seconds of cranking before it'll start since it takes a second or two to re-pressurize the fuel lines. Some folks have totally removed this check valve - it's NOT essential.

 

Also, after I ran the pump the first time, it wouldn't run again by powering the connector (or cranking). Also, the test connector only gets about 10 volts when cranking. I assume this is because the starter is running.

If the pump runs when you feed the test port with battery voltage for a while... and then won't run with the test port re-connected to the battery, either the pump is bad or the wiring to the pump is bad. Most dying fuel pumps will work (sort-of) when physically cold and then jam after they've warmed up a bit.

 

10 volts while cranking is not surprising if you've been trying to start the engine multiple times.

 

Now I crank the car and there is no fuel pressure fluctuation whatsoever. I'm sure if I let the car cool the pump will run again.

 

Ideas?

 

Is the ECI relay possibly bad? What else could be heat sensitive and keep the pump from running.

likely not. If you get battery voltage (or even 10 volts) on the test connector while trying to start, then the relay is doing its job.

 

EDIT: seems obvious now. it's the pump itself. I'll check to make sure it's getting power before i go droppin the tank (can I get to the pump without droppin the tank?)

 

Tony

You can see the pump through the access hole in the trunk area - lift the trunk false floor, look on the driver side for a black metal plate. One screw and a lot of sticky goo hold it. Get it out, you'll see the pump's electrical connection and some of the hoses. You'll be able to see the back of the pump too but won't be able to undo it.

 

To remove/replace the pump, you have two options:

1: the "factory" way: drop the fuel tank. It's NOT that hard really - folks make it sound like a nightmare job when it's really just common sense. You do need a good floor jack and a flat slab of wood to support the tank while you undo stuff. Once the tank is "free", lower it just a little bit to access some of the fuel lines - you can't reach them all prior to moving the tank a little. Note too that there is an access panel in the driver side rear wheel well: remove the wheel and you'll see the back portion of the liner is screwed in place. Remove it and you'll be able to access more of the pump stuff AND the fuel filler hose that you have to undo/unbolt to have wiggle room for the tank. I like to remove the fuel filler bodywork stuff too; at least get it loose, so you can wiggle the fill pipe easier.

 

2: Cut some of the vehicle floor away, expanding the factory cutout forwards. Then you'll have to make your own cover plate. It does make it easier to change the pump again (if needed...); some folks wonder though if it weakens the body structure. In theory, any hole/opening in a unit body structure (a "shear" structure) weakens it. But that may or may not be an issue: is the trunk floor a key structure piece (i.e. does it carry significant "shear" loads) or not? Several folks have done this... I've never done it. I dropped the tank the normal way - it gave me a chance to clean it and do other inspections too.

 

mike c.

[Rexkrazy]

Likely not. Fuel pressure regulators typically fail by having the internal rubber diaphragm start leaking. The only other failure would be if the internal spring busts... then it'd fail to regulate to the correct pressure. Pretty rare though.

Ya, it's fine. I watched the pressure when I finally got he car to start.

 

The output of the pump connects to a check valve which is a one-way device. It lets fuel flow towards the engine when the pump is running; when the pump is OFF it traps the fuel between the check valve and engine. That leaves pressure in the fuel lines ready for the next time you try to start the engine. It's common for this check valve to fail with age, allowing the fuel pressure to ooze back through the pump to the fuel tank. All it means is that the engine may need 1 to 2 more seconds of cranking before it'll start since it takes a second or two to re-pressurize the fuel lines. Some folks have totally removed this check valve - it's NOT essential.

I thought i read something like this somewhere, looks like mine is bad... I probably won't bother with it.

 

If the pump runs when you feed the test port with battery voltage for a while... and then won't run with the test port re-connected to the battery, either the pump is bad or the wiring to the pump is bad. Most dying fuel pumps will work (sort-of) when physically cold and then jam after they've warmed up a bit.

Thanks, I think this is the problem.

 

likely not. If you get battery voltage (or even 10 volts) on the test connector while trying to start, then the relay is doing its job.

so the test connector is tied directly to the fuel pump power and not the relay input? I was going to test fuel pump power directly before I replaced it, but maybe I did inadvertently.

 

You can see the pump through the access hole in the trunk area - lift the trunk false floor, look on the driver side for a black metal plate. One screw and a lot of sticky goo hold it. Get it out, you'll see the pump's electrical connection and some of the hoses. You'll be able to see the back of the pump too but won't be able to undo it.

 

To remove/replace the pump, you have two options:

1: the "factory" way: drop the fuel tank. It's NOT that hard really - folks make it sound like a nightmare job when it's really just common sense. You do need a good floor jack and a flat slab of wood to support the tank while you undo stuff. Once the tank is "free", lower it just a little bit to access some of the fuel lines - you can't reach them all prior to moving the tank a little. Note too that there is an access panel in the driver side rear wheel well: remove the wheel and you'll see the back portion of the liner is screwed in place. Remove it and you'll be able to access more of the pump stuff AND the fuel filler hose that you have to undo/unbolt to have wiggle room for the tank. I like to remove the fuel filler bodywork stuff too; at least get it loose, so you can wiggle the fill pipe easier.

 

2: Cut some of the vehicle floor away, expanding the factory cutout forwards. Then you'll have to make your own cover plate. It does make it easier to change the pump again (if needed...); some folks wonder though if it weakens the body structure. In theory, any hole/opening in a unit body structure (a "shear" structure) weakens it. But that may or may not be an issue: is the trunk floor a key structure piece (i.e. does it carry significant "shear" loads) or not? Several folks have done this... I've never done it. I dropped the tank the normal way - it gave me a chance to clean it and do other inspections too.

 

mike c.

 

Guess I'll just drop the tank like a big boy. haha! I was trying to avoid it for fear of rusty bolts, etc. I've dropped my share and you're right, not as bad as everyone acts like. I'm just lazy.

 

Thanks for the input Mike!

 

Tony

[Indiana]

Leave the test port jumper on and try that over and over again, if the ECI fuse link is dirty that test wire will replace it but the car won't run right but it bypasses the saftey of the control relay to let the pump run.

 

Only OEM pumps have this check valve function, the Walbro pumps don't I've used them they do not have a check valve in them so pressure does leak down but maybe not 100%. If there is even a piece of dirt under the seat of the stock valve it will leak you can't assume the pump is bad and replace it. If there is no power to the ECU, from that ECI fuse link, the ECU has no power but the injectors fire to start the car from the ignition signal and you force the pump to run with a jumper wire.

 

Clean that fuse link, the wires on the bottom of the holder and where the wire that feeds the holder box attaches to the + battery terminal. Then look under the access hole in the truck floor and see if you have an OEM pump or someone else already replaced it. Maybe you have a clogged up filter.

 

Stock pump, old valve put on Walbro pump, only takes one little piece of dirt or rust to prevent that valve from seating.

http://www.b2600turbo.com/images/IM002885.JPG http://www.b2600turbo.com/images/IM002887.JPG

 

http://www.b2600turbo.com/images/IM002888.JPG

 

 

[Rexkrazy]

Amazon has the Bosch pump that doesn't need a dampener (69400) for $100 so I just ordered one. I don't mind spending for the piece of mind. Pumps just not running at all when hot, so I'm gunna point my finger :-). I cleaned the fusible link etc etc, and got noting, so I believe electronics are OK.

 

Thanks again Indiana,

Tony