626 fails to start when hot. dealer perplexed.
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626 fails to start when hot. dealer perplexed. - 5/26/2006 3:16:09 PM
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twitme
Posts: 4
Joined: 5/26/2006
Status: offline
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Hi there. I see that there are a lot of knowledgeable people on this forum so I figured I'd ask my question here!
I've got a 2001 4cyl mazda 626 with 88k miles. For the past year the vehicle has intermittently failed to start in warm weather, generally when the vehicle has been running for a while, shut off, and [attempted to be] started again, anywhere from just a couple mins to 45 mins after it was shut off. It performed flawlessly in less than 50 degree farenheit weather [didn't have a single problem all winter long], but once it got warm again, the problem returned.
What happens when I try to start the car is that it will fire a few times, sounding like it's going to start. Sputter a bit then die. I can try a couple more times, get a few sputters, then nothing but dry cranking. And after a few attempts all I get is starter rotation with no ignition.
It almost* always starts when it's been off for an hour or two or longer.
So far I have taken the vehicle to 4 different shops including two mazda dealerships but to no avail. None were able to reproduce or troubleshoot the problem since it is intermittent and never occurred while the car was in the shop.
Here is what I have replaced so far since the problem began:
Plugs
Wires
Battery
Fuel Filter
Fuel Pressure Regulator (x2)
Fuel tank sensors of some sort. I wasn't involved in this repair so I don't know exactly what was replaced, but it had no affect on the problem.
One potentially valuable piece of information is that the fuel pressure regulator has gone bad twice in two years. So I can only suspect that something else in the vehicle is my problem, and causing the pressure regulator to fail. Could anyone tell me what components could possibly cause damage to this part? Any ideas what else could be wrong?
thank you.
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RE: 626 fails to start when hot. dealer perplexed. - 5/27/2006 2:21:14 PM
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twitme
Posts: 4
Joined: 5/26/2006
Status: offline
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thanks a lot for your reply. I'm not opposed to putting money into trouble shooting at this point....since no-one seems able to pinpoint the problem, and I wish to get it fixed..so I'm probably going to try the fuel pump next (yours wasn't the only opinion that it could possibly be the pump, you just encouraged that as a possibility :D)
ok I took at look at the relays. there are six on my vehicle in the fuse box housing. two different types.
type 1:
H/L Relay
Horn Relay
Air Con Relay
TNS Relay
type 2:
EGI Main relay
Circuit Relay.
So I'm guessing the EGI relay is related to the fuel system, and the relay you were speaking of? or the Cicruit relay? or both? unfortunately neither of those are the same as the horn relay, so I can't follow that advice I'm afraid.
The mechanics who replaced the FPR only said "you have a bad fuel pressure regulator", nothing more specific or in depth as far as an explanation goes. and no I haven't tried disconnecting the fuel supply to the FPR when it's not starting. should I do that and crank the engine to see if fuel comes out? actually I seem to remember one mechanic/friend of mine doing this when the car WAS running, and not getting any fuel to come through...then he said something to the effect of "god I'm an idiot, this is a reverse flow fuel system"...although I didn't know what that really meant.
I tried calling mazda today to check on prices of relays but they were closed for the weekend. would it be reasonable to replace both the Main Circuit and EGI relays as a trouble shooting step? do you have a rough idea of approximately how much these cost?
thank you!
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RE: 626 fails to start when hot. dealer perplexed. - 7/5/2006 5:58:32 PM
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twitme
Posts: 4
Joined: 5/26/2006
Status: offline
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I just thought I'd give an update of information based on the last time my car failed to start. it was hot and humid out, so one of those two things is causing the lack of a running vehicle.
when I first tried to start the car the engine made a sort of gurgling noise. it fired once or twice, gurgled a bit, then killed. I was able to do this a few times and finally there was no ignition at all...just dry cranking. finally about an hour and a half later after trying every 20 minutes or so to start the vehicle it fired right up, and I smelled gas REALLY strong right after it started. so I suspect I flooded the engine in my attempts to start the car, which MIGHT mean the problem I'm having is too much fuel, as opposed to not enough.
so at this point I'm thinking the issue is either improper fuel supply (which would be what, bad fuel pump? bad 'computer'?) [most likely too much* fuel as the fuel pressure regulator keeps failing]; or improper timing between the fuel supply, crank position and ignition pack/spark plug. (the reason being if the spark is igniting the gasoline when the piston is in the wrong position I would get a weak rotation/firing correct? I'm hypothesizing here). [could the problem be a bad crank positioning sensor? would that cause weak firing on engine start?]
any input is much appreciated.
< Message edited by twitme -- 7/5/2006 6:00:03 PM >
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RE: 626 fails to start when hot. dealer perplexed. - 7/6/2006 3:06:43 PM
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twitme
Posts: 4
Joined: 5/26/2006
Status: offline
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another trouble shooting question, this one should be more basic.
if my fuel pump is pumping through too much fuel, could that flood the engine? or would the fuel injectors only inject the proper amount of fuel regardless of what the fuel pump is putting out?
thanks.
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Printable Version
Frustrating!!!! My Mazda would never show a code so my mechanic could fix the problem. So my mechanic suggested that I drive my vehicle until I get a code. 
