I’ve got a 1996 Tacoma - manual transmission, 4 cylinder, 2.7 liter engine with close to 170,000 miles on it - owned it for 10 years and 100,000 miles. Wonderful, great truck. Except…
It has two starting problems and I can’t seem to sort them out. The first is it’s incredibly hard to start when the outside air is hot. Living in San Francisco, I usually forget about this problem until I drive to the central valley to visit my mom in August. Nothing like coming out of the rest stop, trying to start the engine and then having the feeling of doooh! again!. Seems to be worse when the outside air temp is over 85 or 90 degrees and the engine has been running than sits for 5-10 minutes. Cranks fine but won’t catch. When it finally catches, it’s like it’s really slow to fire - can’t quite explain it, but it’s like it’s doing a lot of thinking about actually running and has to talk itself into the idea. Can take 5-10 minutes to finally get it going, but usually 30 seconds to a minute. Always worried this’ll be the time it doesn’t want to go. My mechanic has looked at it a few times - but it’s almost impossible to recreate in San Francisco when I get home due to the lack of warm days.
Second problem is trouble cold starting. When I come out in the morning, the engine takes two or three attempts to get it to start. Once it again, it cranks fine, but it’s as if there’s no fuel getting to the engine. If I just keep cranking, it won’t fire but if I crank it, turn it off, crank it, turn it off and crank it again it’ll always catch on the second or third go. Once the engine is at temp, it seems like less of a problem and easier starting. My mechanic say’s “It’s an old truck and it always starts eventually, so don’t worry about it.”
I need a new mechanic I think. He acts like he doesn’t have a boat payment to make - which is usually nice, but I do want him to at least think about the problem.
Are these two problems likely related or am I likely looking at two separate issues?
Any ideas what’s causing each one?
Thank in advance!
For the cold starts, turn the key to run, but stop short of where it cranks - just to where the dash lights come on. Pause a few seconds & go back off…back to run…back off…back to run etc. about 7-8 times. I.e. you’ll sort of do what you’ve been doing but skip the cranking in between. If that gets it to start reliably everytime then you probably need a new fuel pump due to a bad check valve. (The fuel lines go dry over time - the on/off/on/off… is pumping them full again).
For the hot start, hold the gas pedal to the floor while you turn the key to see if that does anything. If it helps then you may have a leaking fuel pressure regulator or fuel injector sending fuel into the intake on hot shut down. The other possibility is heat soaked ignition components. If the pedal on the floor doesn’t help, check for spark. Since it only takes 5-10 minutes, its not so bad. Try leaving you hood open a couple times as you go into the store or whatever. That would allow things to cool down.
Both problems might be fuel related. So you might want to have the fuel pressure tested for low fuel pressure.
The hot start problem might be vapor lock. When the engine is shut down hot, the fuel in the fuel rail can start to boil causing vapor lock. Carry a bottle of water in the vehicle. The next time the vehicle won’t start when hot, pour water over the fuel rail to cool it off then try starting the engine. If the engine starts it’s a vapor lock problem.
For the cold start problem, do the on-off cycle of the ignition switch before starting the engine like cigroller suggested. If this allows the engine to start right up in means the anti drain-back valve on the fuel pump is leaking, allowing the gas to drain out of the fuel rail/line back into the gas tank.
Thanks for the suggestions Cigroller and Tester! For the cold start, I suspect that you’re right about the fuel pump. I’ve got my mechanic looking at it right now. For the hot start, holding the gas pedal down makes no difference - sometimes I suspect that it may actually make things worse, but I have no real data to base that on. I’ll try the check for vapor lock when the weather heats up again.
If Tester is right about the hot start (which wouldn’t surprise me at all) then flooring the gas pedal very well might make it worse. On many vehicles it is actually a flood clearing procedure which is what I had in mind initially - it shuts down the fuel injectors. This would obviously be counterproductive if the fuel in your rail had vaporized.