View Full Version : Car stalling when coasting up to a stoplight
05-27-2003, 12:54 PM
Today, my car stalled on me 5 times when letting off the gas and slowing down for a stoplight. I had driven the car for an hour and 20 minutes with no problems. Then I got into town and the car stalled out when I had to slow for a stop light. Usually the RPM's will drop down below a thousand when letting off the gas, but this time it dropped all the way down and the car stalled out. I had to crank the motor a few times for it to fire back up. It did this 4 more times before I got to my office. I was low on gas, but not that low. I went to a gas station and put in 12.14 gallons. I have put in over 13 gallons before. Do I need to adjust my idle slightly higher? When warm, my car will drop down to about 550 rpms, so this might be too low. Just thought this was weird coming on all of a sudden. Anyone have any ideas? We will see what happens on my way home. Right now I am commuting 1.5 hrs each way to work, so the Supra has to be running tip-top!
05-27-2003, 01:06 PM
You might have a fuel filter that is getting old. Restricted fuel flow combinded with a low tank level might cause what you are describing.
05-27-2003, 01:52 PM
Could be a vacuum leak. Check to make sure all your lines connected to the intake tube are not split/torn too. make sure there isn't a leak between the air sensor and the throttle body. Make sure you didn't loosen any connectors there. Also check under the intake resonator if you still have one and make sure it hasn't cracked/melted.
05-27-2003, 01:56 PM
I will check for vacuum leaks tonight. Last time I had a vacuum leak I could only boost to 5 psi, I will check to see if I am boosting to 7 psi when I leave work. If anyone else has suggestion, fire away.
05-27-2003, 02:19 PM
I decided to try adjusting my timing by ear. I set the idle a little lower and I also had the stalling problem too. I would say check your timing. I put mine back and it is better.
05-27-2003, 10:38 PM
I will turn the idle up a little, but I don't think that is the problem. Driving home from work, the car died on me 6 times. Only once was I slowing for a stop sign/light. The other 5 times it did it while I was cruising at a steady speed. It is really weird. The only way I would even know it had died, was that when I pressed on the accelerator to speed up, there was no go. I would put it in neutral and the rpms would go to 0 and the battery light would come on. I would crank it over a few times, then it would fire back up. I have no vacuum leak according to my boost guage, I am sitting right at 20 inches of vacuum at idle, just like normal. I am also able to hit 7 psi with no problems, although I only did it once. I don't want to chance being in the boost when the car dies, since I don't know what is wrong. Any other suggestions. Right now the only one that seems possible is the fuel filter suggestion, although, I don't understand why it would run at all. ????????
05-28-2003, 04:58 AM
Fuel Pump???? Can't remember if you did a FP upgrade. I know Mike Wilkes & Chris Wick didn't, when they had the car.
Does the car start to slow down when you have your foot on the gas, or is it only behaving like this when coasting to a stop???
Only other thing I can think of is the ISC valve (idle speed control valve). And yes, possibly the filter. Did you ever change it out when you were doing the motor rebuild last year???
05-28-2003, 05:00 AM
I have experienced this incident a few years ago.... I have an automatic then... well if you have a manual, I don't know if it applies too... but it was getting hot already and once the motor get up to temperature, the idle was below what it was set last winter which is 850 rpm... so I guess with the good running car on the winter season is set right but when summer came in w/ more hot temperatures caused the cooling system runs a little hotter but still in the range (gauge reads middle) caused the sensor to say the cooling system is hotter than before telling the computer to do such a thing like lower the idle rpm from changing the dwell of the injectors and timing... so the best solution is raise the idle up and see from there if any changes after raising the idle up.... just my 0.02 cent
well another consideration is also the chance of a vacuum leak for our AFM are notorious of sensing vacuum leak... just one small puncture of hole in the intake system makes eratic false alrms to the AFM sending the computer some wack adjustments to compensate for the leak
05-28-2003, 09:42 AM
We'll I had this same symptom happen to me on two different occasions in my Celica. First time turns out it was a clogged fuel filter, second time turns out my alternator crapped out and I was only running on battery power. I was able to drive the car for maybe 30 minutes or so, then when I would slow down the car would stall (actually more like die). If it was an electrical issue like this I'm sure you'd know it right away as all your lights etc.... would go out too. Not sure if these apply to you at all but if you've exhausted every other avenue here are two more to look at. Good luck.
05-28-2003, 11:00 AM
Just a stab in the dark, but could it be the TP sensor?
05-28-2003, 11:16 AM
Sure sounds like a fuel pump going bad to me. These are the exact same symptoms I had, twice, in my 85 Celica GTS. Car died when depressing the clutch, pull off the road and it would start right up.
Question: Do you notice if the car ever has a slight "bucking" feel? Say, while you're cruising at a steady speed down the hi-way on a nice, smooth road surface, have you ever felt the car lurch or hesitate? It would feel like you hit a small swall in the road causing you to rock a little in the seat.
Replace the fuel pump ASAP or you could soon be stranded. If you're lucky it could continue like this and last for quite some time. If you're not one of the luck ones it could up and decide to quit on you tomorrow. Then you're in for a real treat trying to drive when you need three feet. One on the gas, one riding the clutch to keep the rpm's up and one on the brake so you can make those stops...have a strong battery, a good starter and patience.
Don't take life too seriously, you won't get out alive.
05-28-2003, 11:33 AM
I had this same problem many times. In one case the speedo cable was disengaged from the tranny.
It has to do with the engine getting hot and that affecting some component. Perhaps the TPS.
05-28-2003, 12:10 PM
"...Then you're in for a real treat trying to drive when you need three feet. One on the gas, one riding the clutch to keep the rpm's up and one on the brake so you can make those stops..."
For the first two weeks I owned the car... =) Great, great fun. Never EVER trust a used-car salesman. Though for $1990, I have no regrets.
05-28-2003, 08:24 PM
Thanks for all the replies. Ok, Fuel pump is brand new, and I am not talking about an Autozone special, I have a brand new Toyota fuel pump. However, I have not changed the fuel filter since I bought the car, I know I should have done it when the head was off. I am going to raise the idle a touch this weekend and get the fuel filter replaced next week. Otherwise I am pretty positive there are no vacuum leaks. I will check my TSRM and see what it says about the TPS and the ISCV. Speedo cable, hmmm, I will have to check on that too, although I don't understand how that would cause the car to stall out while running down the road, my speedometer is working???
My gut feeling is the fuel filter...we will see.
05-28-2003, 08:32 PM
Does the car stall while you've got the boost up to 7 psi at WOT? That's where a weak fuel pump or clogged fuel filter will really be noticeable. Try cruising along at 50 MPH in 3rd and then shift from 3rd into 5th and step on the gas and see if it spits and sputters or stalls. Don't worry too much about the fuel mix going lean. The Carter Knock Eliminator will retard the spark if any detonation takes place... as long as that unit isn't part of the problem. :roll: Hmmm, on second thought, play it safe and check your fuel pressure with a fuel pressure gauge while the car is parked and idling. This is where I really wish the MKII fuel rail had a fuel pressure test port! :mad:
05-28-2003, 08:37 PM
I missed your post where you said that your fuel pump is new. Replace the fuel filter if the fuel pressure checks low. Also, I'm not sure, but does the 82 have that tiny little filter screen insert like thing in the fuel line just after the fuel pump?
05-28-2003, 08:54 PM
I will have to check on that. When I had the fuel pump replaced, they had to replace some of the fuel line because it had been buggered up. Don't remember anything about a fuel screen?
05-28-2003, 08:57 PM
Local dealer said they would change my filter for 1 hour labor + the filter cost. So I am going to avoid the gas in the eyes trick and let them do it. Let's hope for the best. :roll:
Consider this a long shot, but it only takes a minute to check. My new 82 was running nice when RPMs were over 1200, but would stumble and die at idle due to a bad battery. EFI cars need good voltage to run right.
Get a voltmeter and test the voltage across the two battery terminals when the car has not been run for an hour or two. Should be a bit over 12 volts. If it is 11 volts or less, your battery is probably toast.
Then, check it with the engine running with RPMs over 1200. Should be 14.4 volts. If not, your alternator (or its built in regulator) is shot.
Hope that helps.
05-29-2003, 01:47 AM
I really doubt it's your fuel filter, if it's so clogged that it's lowering the pressure at idle the car wouldn't run at high speed. You may have a loose wire either at the fuel pump or somewhere in the ignition module. If the pump thinks the ignition switch gets shut off it will stop and then when you turn off the key and restart it, it will re-energize the circuit. Other than that I don't really know, my bet would be an electrical problem though. Good luck with it.
05-29-2003, 11:05 AM
Ok, the alternator is brand new (Toyota), and the battery is also new, and I haven't ever run the battery down. Also the guage reads right at 14-15 volts.
A loose wire in the ignition seems like a possibility. The car runs great, no problems, then all of a sudden, the engine shuts off, it is really weird. I am going to mess with it this Saturday. I have a test light, but need to get an ohm meter for real testing. For now I am sharing my wife's car....not fun!
05-30-2003, 12:39 AM
CelicaDude has a good point! If the fuel pressure were low enough to cause stalling at idle then the engine would certainly stall while under load. Thanks for clarifying this, CelicaDude! Another possibility comes to my mind here. Does you 82 have the original vacuum advance distributor?? If so, the pickup coil in the distributor could be the culprit. Engine vacuum gets applied to the advance diaphragm at idle and during cruising at light throttle. The pickup coil is rotated slightly whenever vacuum is applied to the diaphragm and sometimes one of the two wires, or both, on the pickup coil can break and cause intermittent connection when the spark is advanced. The tricky part is that usually only the conductor(s) break and the outside wire insulation remains intact, making the problem invisible to the naked eye. Try this: disconnect and plug the two vacuum lines on the distributor. Find a plastic vacuum tee fitting and connect this to the two ports on the diaphragm with some lengths of vacuum hose. Start the engine and let it run at idle. Then, manually apply vacuum to the advance diaphragm and see if that makes the engine stall. Repeat this test several times to give the pickup coil wiring a good test. If the engine stalls with vacuum applied, replace the pickup coil in the distributor. You might also try jiggling the ignition switch with the key while the engine is running to check for bad contacts in the ignition switch and see if that makes it stall. My gut tells me that the pickup coil is the culprit at this point though. :wink: Let us know what you find!
05-30-2003, 01:05 AM
82 spearco are you running a RRFPR it might be sticking or metal diaphragm is getting bent, if so maybe the car is stalling due to alittle to high fuel pressure and fouling plugs out, until pressure drops to near normal range then clears out and will restart. Fuel pressure gauge on a turbo is a must IMO.
05-30-2003, 09:29 AM
OK, I do have the vacuum-advance distributor. I will try to troubleshoot it the way you described.
I do have a Cartech rrfpr. Sounds like I really need a fuel pressure guage installed after the rrfpr, as you mentioned. How could you test an rrfpr to make sure it was working properly?
05-30-2003, 11:25 AM
To test the rrfpr -- get a boost gauge next to the rrfpr and ensure that it's increasing fuel pressure as boost increases.
05-30-2003, 09:28 PM
Try cleaning the RRFPR parts,remove top cover with hex screws,remove rubber gasket ,metal diaphragm and metal cylinder which gets rusty over time,polish up metal cylinder.Clean air bleed screw out and put back in the order you took apart.How are you setting RRFPR without a fuel pressure gauge.
05-31-2003, 09:17 PM
Chad, are you running both the stock FPR and a RRFPR? Is your fuel system still stock or did you swap injectors?
06-02-2003, 10:25 AM
The rrfpr has been in the car since I bought it in 2001. I am not sure if I am using the rrfpr and the stock fpr, I have never bothered to check.
When we replaced the head last year, I put in 210 cc injectors. When I get the MAF conversion installed, I will probably upgrade to 295's.
Anyway, I was wondering about the Distributor possibility. Would replacing the distibutor with a new/working one fix that type of problem? Let me know.
06-03-2003, 12:36 AM
Yes, you can either swap the complete distributor base (everything but cap and rotor) or just replace the pickup coil. How's it going with the RRFPR?
06-10-2003, 12:21 AM
I have been so busy with stuff around the house, I haven't been able to work on the car. Anyway, I turned up the idle a touch and drove the car today. I didn't have any problems. I drove it about 40 miles with a mix of city and highway. This is really weird. Anyway, we will see how it fares the rest of the week.
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