Stumbling on start up? culprit?
Thread Starter
Team Owner
Joined: Mar 2002
Posts: 24,160
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Stumbling on start up? culprit?
Lately my '02 Coupe has developed a slight "stumble" occasionally when I start it up though it's always started up fine. It seems to happen most often after being parked for a 3-4 hours, but I've had it happen from cold starts as well. Air filter is clean, so it's not getting choked there. I've heard a few people mention a fuel return line check valve, but I don't think that's it as I always wait for the pumps to cycle off before cranking (force of habit). Filter seems unlikely for the same reason.
any thoughts?
any thoughts?
Advanced
Joined: Aug 2006
Posts: 95
Likes: 4
From: Santa Fe, NM
Mine had just started to do this right before my oil pressure sender went bad. I removed and cleaned the MAF, throttle body and intake in the process of replacing the sender and it hasn't happened since. Don't know if they were related, but it might be a place to start looking.
John
John
Tech Contributor
Joined: Dec 2006
Posts: 10,962
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From: Van Buren Arkansas
Wounded Warrior Escort '11
I think I would agree with cleaning the MAF out first. How old is your battery and have you check the voltage on it without starting it? The C-5's need full power to run normally which is why I ask. There could be other contributing factors as well... have you checked for codes?
Thread Starter
Team Owner
Joined: Mar 2002
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Yep, MAF, TB, and air filter are all spotless. That's where I started because I've had cars do this in past with dirty air filters choking them off. Oil sender was replaced < 500 miles ago.
I've now read a few reports of people cycling the fuel pump on and off multiple times (via the ignition switch) before getting adequate fuel pressure. So I guess the pump can still cut off even if fuel pressure isn't good? I've also noticed it seems to happen more (or only?) when I'm at 1/4 tank or less. I wonder if the pump is cavitating slightly on low fuel? I know my old Integra used to do same thing. Get it down to the 'E' and it would always crank over a few extra times before firing.
I think I'll replace the fuel filter this weekend. 72k miles, and I doubt it's ever been touched.
Oh and I have no real codes. Just a perpetual ABS losing communication with the SDM and 2 HVAC codes ... all showing history.
I've now read a few reports of people cycling the fuel pump on and off multiple times (via the ignition switch) before getting adequate fuel pressure. So I guess the pump can still cut off even if fuel pressure isn't good? I've also noticed it seems to happen more (or only?) when I'm at 1/4 tank or less. I wonder if the pump is cavitating slightly on low fuel? I know my old Integra used to do same thing. Get it down to the 'E' and it would always crank over a few extra times before firing.
I think I'll replace the fuel filter this weekend. 72k miles, and I doubt it's ever been touched.
Oh and I have no real codes. Just a perpetual ABS losing communication with the SDM and 2 HVAC codes ... all showing history.
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
Yes, it can. Now another thought that I don't know if it applies to the '02's or not... if you have a PCV valve, there is possibility that the connection tube from it to the intake port can and will develop holes in it on the bottom side....sort of out of sight. It would cause more than just starting problems such as lugging at taking off from a light and wierd idle issues too. How many miles on your plugs? You might should send a PM ti Bill Dearborn on this.
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Thread Starter
Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
Yes, it can. Now another thought that I don't know if it applies to the '02's or not... if you have a PCV valve, there is possibility that the connection tube from it to the intake port can and will develop holes in it on the bottom side....sort of out of sight. It would cause more than just starting problems such as lugging at taking off from a light and wierd idle issues too. How many miles on your plugs? You might should send a PM ti Bill Dearborn on this.
Yeah, ignition was where I was going to look next. I don't know how many miles are on the plugs/wires. The car has 72k, and the plugs are iridium and look fine. Wires ... who knows.