Car takes to many cranks to start when cold

[dsmcoder]

I have a 1g auto dsm with ecmlink, 650cc injectors, wally 255 fuel pump with AFPR.

My car might take up to 10 cranks to start if I let it sit overnight. After my car is warm I can shut it off and it will start right away. Now my auromotive fuel pressure regulator drops to 0psi as soon as I shut off the car, so I have the turn the fuel pump on option checked in link to prime it before start up but it doesn't seem to help. Sometimes it will start for a second after cranking and die and then fire right back up perfectly.

I don't think I have any sort of fuel pump leak because when I run my gas tank low and remove the cap you can hear the air rushing in from my tank being in a vacuum.

Could my AFPR be causing this or could it be something else?

 

[deviousgst]

sounds like your coolant temp sensor is unplugged or bad sensor..

 

[SlickGSX]

If all the pressure in the line bleeds off after time that would indicate a leak somewhere. If you're not smelling fuel in/around the car then I would check the fuel pump nipple o-ring, you could be bleeding pressure back into the tank.

 

[dsmcoder]

sounds like your coolant temp sensor is unplugged or bad sensor..

It seems to be reading right in ecmlink.

If all the pressure in the line bleeds off after time that would indicate a leak somewhere. If you're not smelling fuel in/around the car then I would check the fuel pump nipple o-ring, you could be bleeding pressure back into the tank.

If the oring was leaking would it be possible to build a vacuum in the tank?

 

[SlickGSX]

That "whoosh" sound you get when you open the cap is not vacuum, its pressure. If there is a small leak somewhere it will depressurize the line slowly so when you go to crank it the next morning you will have to crank until the pump builds enough pressure in the line to start the car.

Now if the the leak is at the pump on the o-ring the pressurized line will leak back into the tank and you won't smell or see the fuel making it hard to diagnose the problem. I would check all line connections and fittings, if you are using a FPR and plugging one of the ports make sure you are using an o-ring along with the plug.

 

[dsmcoder]

That "whoosh" sound you get when you open the cap is not vacuum, its pressure. If there is a small leak somewhere it will depressurize the line slowly so when you go to crank it the next morning you will have to crank until the pump builds enough pressure in the line to start the car.

Now if the the leak is at the pump on the o-ring the pressurized line will leak back into the tank and you won't smell or see the fuel making it hard to diagnose the problem. I would check all line connections and fittings, if you are using a FPR and plugging one of the ports make sure you are using an o-ring along with the plug.

But when I shut off the car the fuel pressure drops to zero instantly so wouldn't I have no pressure built up in the gas tank if the oring on the fuel pump was leaking?

 

[bryanwheat]

But when I shut off the car the fuel pressure drops to zero instantly so wouldn't I have no pressure built up in the gas tank if the oring on the fuel pump was leaking?

Fuel pressure and tank pressure are different things. Tank pressure is from air in the open space of the tank. The fuel pressure will be kept between the pump and fuel regulator. IF the o ring in pump was defective than you would still have pressure in the tank, but no pressure in the line.

 

[dsmcoder]

Fuel pressure and tank pressure are different things. Tank pressure is from air in the open space of the tank. The fuel pressure will be kept between the pump and fuel regulator. IF the o ring in pump was defective than you would still have pressure in the tank, but no pressure in the line.

Is there anyway to diagnose the problem without tearing the fuel pump out? I tried to be as careful as I could when installing it.

 

[Calan]

What type of fuel are you running?

Since you stated in your first post that the car is hard to start even with the pump running before cranking, I doubt if the pressure bleeding off has much (if anything) to do with it. FWIW, my Aeromotive AFPR has never held pressure for any length of time, even with a new diaphragm and bypassed o-ring at the pump. It seems that some hold pressure, some don't. I wouldn't get too hung up on it.

As for the hard start issue, it could be something in the TB, ignition system, or even low compression. Have you done a compression test?

Another common source is the injector latency (deadtime) values at low voltages, which come into play during cranking. ECMLink has a table that lets you assign different deadtime values at different voltages, and the lower ranges are usually pretty far off from what I've seen recently. You may want to look into that over on the Link forums.

 

[dsmcoder]

And yet you did.

***

OP - What type of fuel are you running?

91 octane, only thing we have around here.

 

[bryanwheat]

Is there anyway to diagnose the problem without tearing the fuel pump out? I tried to be as careful as I could when installing it.

Pretty much the only way to test it for sure would be to remove it and check the o ring. What kind of regulator are you running?

 

[dsmcoder]

Pretty much the only way to test it for sure would be to remove it and check the o ring. What kind of regulator are you running?

I'm running a Aeromotive 13301 fpr.

What type of fuel are you running?

Since you stated in your first post that the car is hard to start even with the pump running before cranking, I doubt if the pressure bleeding off has much (if anything) to do with it. FWIW, my Aeromotive AFPR has never held pressure for any length of time, even with a new diaphragm and bypassed o-ring at the pump. It seems that some hold pressure, some don't. I wouldn't get too hung up on it.

As for the hard start issue, it could be something in the TB, ignition system, or even low compression. Have you done a compression test?

Another common source is the injector latency (deadtime) values at low voltages, which come into play during cranking. ECMLink has a table that lets you assign different deadtime values at different voltages, and the lower ranges are usually pretty far off from what I've seen recently. You may want to look into that over on the Link forums.

I did a compression test and I have about 145-50 across the board and that's after about 10 cranks on each cylinder. I suppose I will look at the link settings first and if that doesn't do anything then I will look at the other stuff. What in my TB could cause this? What would I look for in the ignition system?

 

[Calan]

What in my TB could cause this? What would I look for in the ignition system?

Tired old ignition components like coils and the power transistor can cause all kinds of strange and hard-to-find issues, that seem to vary with temperature, fuel, and other factors.

Do you have a cranking log? Have you checked to see what your battery voltage drops to while cranking?

 

[DSM1G90]

But when I shut off the car the fuel pressure drops to zero instantly

Need a check valve in the fuel line to keep the pressure up.

If it was a stock pump, the check valve within the pump is leaking causing line pressure drop (mine is leaking causing my pressure to drop as well, thus I have to crank a bit for it to catch-that's a fix job down the road..
), but wonder if the wally doesn't have a check valve where it needs an external valve to keep pressue in the line?

 

[dsmcoder]

Tired old ignition components like coils and the power transistor can cause all kinds of strange and hard-to-find issues, that seem to vary with temperature, fuel, and other factors.

Do you have a cranking log? Have you checked to see what your battery voltage drops to while cranking?

No I don't, my exhaust is apart right now but when I get it all together I will see.

Need a check valve in the fuel line to keep the pressure up.

If it was a stock pump, the check valve within the pump is leaking causing line pressure drop (mine is leaking causing my pressure to drop as well, thus I have to crank a bit for it to catch-that's a fix job down the road..
), but wonder if the wally doesn't have a check valve where it needs an external valve to keep pressue in the line?

Where exactly would I put a check vavle? Would a check valve restrict flow.

 

[Purple_Demon]

I had the same issues with my 2G. It would take 5-7 cranks before it would start. I had low compression in every cylinder(rings are shot) and was smelling a tad bit of gas, so I assume a gas line was leaky. So i would check every gas related line you can, and make sure the compression test you did is correct.

 

[DSM1G90]

Where exactly would I put a check valve? Would a check valve restrict flow

Probably before the fuel filter and no, it will not restrict flow.

and was smelling a tad bit of gas, so I assume a gas line was leaky

...more like a rich mixture heading into the cylinders before ignition, for if you did have a leak, it wouldn't be stopping.

 

[dsmcoder]

I forgot to mention before that I had all the same problems when I had my stock injectors, stock fuel pump and stock fpr.

 

[DSM1G90]

If so, then I'm looking at a possible tired ECU then.

Ever since I had mine replaced, those issues disappeared as well, outside of my longer starting thing -knowing that I have a weak check valve in my fuel pump .. and I'm all stock also.

 

[dsmcoder]

My ECM has been rebuilt. Is there anyway to check the if it is the ECM?

 

[MY1GDSM]

Hmmm just seen this

Everyone can sit here guessing all day with little info... .


Craig the Dead times are appropriate and AFR's are good for a 45* cold start... .

Tired old ignition components like coils and the power transistor can cause all kinds of strange and hard-to-find issues, that seem to vary with temperature, fuel, and other factors.

Do you have a cranking log? Have you checked to see what your battery voltage drops to while cranking?

OP look at This ^ Old tired ignition... If the car is doing this randomly that sound like the issue

The battery cold very well might not be up to par and holding the CCA it should. 10 volts is pretty low while cranking and 11.4 after just sitting for the night is as well IMO. firing up on the Second try like that is pretty good IMO... .(first being less then 2sec turn of the key)

 

[wasabi37]

I don't mean to hijack the threat but can someone please take a quick look on my log. I have problem with the cold start every morning (takes at least 4-5 cranks before it would start and it would idle high like 2200rpm before it comes down as the coolant temp goes up. Is 9.3v during cranking is too low? I know my AFPR does not hold pressure when the car is off, but I know that's not the root of the problem( I activated the fuel pump with link to confirm it). Any help would be really appreciated it.

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