Hard starting

hpmaxim

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2003 Mazda Protege5
I've been having this problem for a while now and it seems to have gotten worse (possibly related to outside temperature). The car cranks and cranks and cranks and can take several seconds of cranking before it starts. Up until today it seemed like it wasn't even trying to fire the cylinders for several seconds, but once it fired it'd start pretty easily. Today (when it was OBSCENELY cold) I noticed it seemed like it'd fire and then stall. After repeated attempts to start it finally started. This happened on a "warm" start (car had been driven for 15 minutes and then let sit for maybe 5 minutes) and then re-started.

1) The fuel tank is aftermarket. It's weird. It has two problems... First, when the tank gets down to 2-3 gallons left, gas sloshes away from the pump causing fuel starvation if you make a right turn. Second, if you are trying to fill the tank, the ventilation doesn't seem to work in the last 2-3 gallons. In other words, the fuel pump auto-shutoff kicks in unless you fill very slowly once the tank is within 2 gallons of being full. Doesn't have a problem before that. Fuel tank was replaced because it was leaking.
2) The fuel pump is relatively new. I think it happened after I replaced the fuel pump (but not immediately after), but I don't have a perfect recollection. Fuel pump was replaced to try to address issues after repair #1.
3) There was a a vent solenoid in the back of the car that was stuck and throwing a code. I remember finding it with a smoker. I fixed it somehow (I think I replaced it). That was a while ago. This repair was done to address an OBD code.
4) The EGR assembly stopped working (I found out from it throwing a code). I cleaned the heck out of it and re-assembled (I snapped off two of the screws, so the plate is only held in by two screws). EGR codes went away. I don't think the problem started immediately after cleaning the EGR, but I think it did start relatively shortly after cleaning it. This repair was done to address an OBD code.
5) I had read that the air intake hose likes to rip at the bellows. I didn't believe it, so I took my hose off to look at it. In the process of removing it, it nearly ripped in half. I replaced the air intake hose. The new hose is aftermarket and was a bit of a loose fit (particularly on the throttle body end). I tightened the clamps down pretty good and I don't think its leaking any more. There was no change from replacing the hose, it might have gotten a bit worse but it also got a lot colder.... so.... probably not the issue.

There are no codes currently. Repairs listed are in the order as best as I remember. I think I first noticed the problem relatively shortly after 4, but not immediately after 4, and definitely before 5. Prior to #5, I tried driving around and looking at my fuel trims. Nothing struck me as being out of whack, so I don't think I was leaking air excessively despite having cracks/dryrot in the intake tube (no codes were registered when I replaced the hose).

The fact that it is giving me trouble starting when warm but doesn't have trouble running once started makes no sense to me. The only thing I can think is maybe there is a check valve in the fuel system which has failed which is relieving fuel pressure as soon as the car stops (or quickly after) and the car doesn't want to even try to start for a while. Although its inconsistent, sometimes it starts easier than others. If there is a way to manually turn on the fuel pump to "prime" the system prior to hitting the starter that might allow me to test that theory. Assuming there is a check valve, where is it -- in the pump itself? The only other thought I had was the EGR valve is now somehow leaking air into the intake messing with the mixture when it first starts -- but it doesn't seem to be causing much problem once it starts and I'd think if that were the problem it would be causing a problem.
 
sounds like a fuel pressure problem to me. when the car sits the pressure in the fuel lines bleeds down and it takes it a minute to build the pressure back up enough to make it fire. Chevy trucks used to do the exact same thing just before the fuel pump died.
 
I agree. Sounds like weak fuel pump to me. Over at the BMW forums, long crank means dying fuel pump especially when cold.
 
The fuel pump housing has the high-pressure filter built inside of it. The low pressure filter is the screened "sock" on the intake.

I'm pretty sure I recall hpmaxim replaced it.
 
You recall correctly, pcb, both the high and low pressure filters were replaced. I'm confident that isn't the problem.. and it doesn't make sense. If the fuel filters were obstructed, I'd be having problems when I need fuel the most (full throttle, high engine speed) and not when I only need a moderate amount (on startup). That's the exact opposite of the symptoms I have.

I will say I do have some fears with respect to the pump because I have experienced fuel cut outs. The fuel cut outs are clearly related to being low on fuel and making a right turn which would point to an issue with the tank not the fuel pump, but its conceivable to me that damage was done to the fuel pump...

I can completely believe that the problem is that I'm losing fuel pressure when the car is off, that actually makes the most sense to me of anything. Again, I suspect I could test this easily if there was some way to "hot-wire" the pump to be always on, so that I could guarantee the lines were pressurized before I start. That said, this doesn't make me think its a pump failure unless there is a check valve (or some mechanism to block drain-back) in the pump. There is no indication that I have inadequate fuel pressure when the car is running and that is when the highest demand is on the pump (or at least that's when the highest demand SHOULD be on the pump since it actually has to flow the most fuel). Am I wrong?
 
....Again, I suspect I could test this easily if there was some way to "hot-wire" the pump to be always on, so that I could guarantee the lines were pressurized before I start.

There is... Just run a wire from the FP terminal to a switch in the cab with the other side of the switch going to ground.

 
Another picture of the DLC terminal. It's the one under the hood in or near the fusebox.

This one is for working on the brakes... Don't use this terminal...

 
I will say I do have some fears with respect to the pump because I have experienced fuel cut outs. The fuel cut outs are clearly related to being low on fuel and making a right turn which would point to an issue with the tank not the fuel pump, but its conceivable to me that damage was done to the fuel pump...

That's what I was thinking. I know a guy that ran out of gas twice in two weeks and wrecked his fuel pump. (different vehicle but same idea). But your car runs fine once it's started.
I'm pretty sure there is no check valve to stop back flow and it's just the physical/mechanical properties of the impellor sealing in it's little housing that stops back flow.

You may have damaged that seal and are losing pressure.
I found theses specs..





It looks like the pressure is supposed to stay above 50 lbs. for five minutes but there's lots of times you may not have started your car for a week or more where you would figure the pressure would drop to zero so the fuel pump should kick in as soon as the key is turned to run.
I would assume you should be able to just turn your key to "on", wait a few seconds to prime, then it should start ??

However,... The one chart above shows that the fuel pressure is supposed to increase during a hot start with the IAT, ECT and TP being monitored to determine the "hot" condition. Perhaps that is where your problem lies.

I think you should try the jumper wire to "prime" the fuel system (although I can't figure out why it wouldn't self prime??)... Then if it works, just install a momentary switch (the kind you have to hold on and switches off when you let go) in the empty spot beside the dash light dimmer and just prime it when you need to... And keep your car above a quarter tank.

It sounds like making it work 100% involves a new OEM fuel tank and a new fuel pump... Which is a big expensive pain in the ass.

You may be able to make a reasonable workaround.
 
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You may be able to make a reasonable workaround.

I would agree, sounds like likely fix is an oem tank and new pump.
or...
workaround solved.

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I would agree, sounds like likely fix is an oem tank and new pump.
or...
workaround solved.

maxresdefault.jpg

Yea but,...







My way costs two bucks plus he'd have the only P5 with a primer button !!

Or,.. Just replace your fuel pump and keep your car above a quarter tank !!?! It's not that hard to do !!!

 
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So, bit of an update since I haven't posted in a while.

The DLC jumper trick worked great, and I had about 4 starts in a row which were pretty effortless, so I'm willing to blame the pump unless there is an external check valve that I don't know about. Since the pump only runs when the ignition is on I'll probably just leave it in for now and give it a few seconds before I go from ignition on to start.

I bought a used tank a while back for $50, so I'll throw that and a new pump in, when it warms up enough that I feel comfortable doing the work. Working on cars when its freezing out sucks.

Regarding RockAuto, should I be worried about getting "Economy" parts?
 
I usually get the cheapest parts when I order from Rockauto they've all been pretty good so far.
I'm pretty sure Rockauto doesn't sell crap because they don't want to deal with it being returned.

I should have bought the more expensive name brand front bearings though they've got proper seals in them and mine just had dust caps, and it's tons of labor to replace them.

I don't think I'd get the "Universal Fit" fuel pump though..
You want to make sure it fits inside the housing and plugs in snugly. You don't want to have to strap the thing to the side of the housing or something ??
 
with all the problems you've been seeing, you need to get rid of that junky aftermarket fuel tank and replace it with the used tank that you got... so long as it's a P5 one... it's specific to the P5 and sedan ones won't really work... this should fix your emissions problems, fuel starvation issues... clean the fuel tank first before putting it on, though

I would also replace the fuel pump... stay away from the cheapest aftermarket parts... they fit poorly and don't work well/last long... try to get something that's made by an OEM supplier, such as Denso... they're more expensive, but gives you the peace of mind of reliability

for the EGR valve... you should replace it also, even a good used one... the broken screws might cause a leak and lead to start up/idle issues
 
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