Bump starting causing starting issues

[1993CivicVX]

Bump starting causes my car to have some rather serious problems.

First few times I do it it's nearly seamless. But then it starts having problems. Hard to explain, it doesn't want to start-- kinda lags... then it threatens to stall. have to drop to a lower gear and try to bump start again after it starts momentarily and then stalls. Second time usually has it bump started successfully. But after more bump starts, it would just stall. I'd start it again and then it would stall again. At one point, key starting it, I was afraid the car wasn't going to start at all after it kept stalling. Eventually it did with some turning over. I think someone at some point was having a similar problem without bump starting. Will see if I can dig up the thread. In the meantime, anyone have any ideas? Bad alternator? Ugh.

[Danronian]

Could be something as easy as a loose ground. Check your grounds in the engine bay to make sure they are free of corrosion, and are nice and tight. But since the VX takes so long to go into lean-burn after the o2 sensor gets cold, you might just want to avoid turning the motor off. But really, I don't know why it wouldn't want to restart with a bump start.

[lunarhighway]

i'm a few decades behind in engine technology, (carbed engine), but when i bump start by just releasing the clutch it really is a "bump" start, however, when i prep the automatich choke, by depressing the gas pedal all the way with the engine off, everything goes smooth, eventhough when i key start (buttonstart catually) when the engine's hot, prepping the choke has an adverse effect.

i'm not entirely sure what the injection eqivalent is a choke is but perhaps you might look in that direction... the engine "thinking" something else is going on, and therefor not adjusting the ammount of fuel to what the engine needs to restart...

[1993CivicVX]

Interesting. Thanks. I am getting an ECU today which might fix the problem. Mechanic said my ECU might be funky because it wasn't reading the RPM when he hooked it up to his $7000 computer.

[JanGeo]

In a carb engine the pressing of the gas to the floor is not needed unless it is really cold outside. That pressing pumps in gas to the intake with the accelerator pump - when used hot it floods the engine so don't pump it when warm. When a little Cold only press it 1/2 to 1/4 the way down so you set the choke up and the throttle stop to fast idle but you don't inject too much fuel to prime the engine. If it keeps stalling it is usually because you fouled a plug or two with too much gas from pumping it all the way to the floor.

[lovemysan]

Does the fuel pump cycle correctly when you eoc. Try double cycling the fuel pump. Key off and then back on, let it build up to fuel pressure and see if this helps.

Sometimes if I muddle the first bump or key start by not giving the engine enough revolutions it goes into what I call "grumpy lean" mode and requires a long key start.

[1993CivicVX]

Originally Posted by JanGeo

In a carb engine the pressing of the gas to the floor is not needed unless it is really cold outside. That pressing pumps in gas to the intake with the accelerator pump - when used hot it floods the engine so don't pump it when warm. When a little Cold only press it 1/2 to 1/4 the way down so you set the choke up and the throttle stop to fast idle but you don't inject too much fuel to prime the engine. If it keeps stalling it is usually because you fouled a plug or two with too much gas from pumping it all the way to the floor.

I don't think I give it any gas when I bump start it. If I do i give it about 1/8th or 1/16th pedal. Just ever so slightly. It seems to only happen on the third and subsequent bump starts on a trip. Like by the third bump start it's out of starting power, so it's gonna give me a hard time. As far as cycling the water pump, I didn't know I had any control of the water pump. Nor would I know how to cycle it. When I bump start, I turn the engine off, then wait about a second or two, turn the key to on. I leave it on for the entire glide (usually about one minute or two) then put it in gear and let out the clutch. Granted some of the EOC I've been doing has been at night and almost always the radio is on. But it was doing this with radio and lights off (the ingition has always been on)

[1993CivicVX]

Originally Posted by Danronian

Could be something as easy as a loose ground. Check your grounds in the engine bay to make sure they are free of corrosion, and are nice and tight. But since the VX takes so long to go into lean-burn after the o2 sensor gets cold, you might just want to avoid turning the motor off. But really, I don't know why it wouldn't want to restart with a bump start.

I don't know if I buy this. How much can the o2 sensor cool down by in such little time? And how long can it take to warm up again? Seems like this would be very negligible. It's not like I'm gliding for 10 minutes at a time. And if I was, seems the cooling down of the o2 sensor in that time would probably be offsetted by the gas saved with the engine off. My idle is high, so I'm probably using twice as much gas in neutral than a healthy VX in neutral.

I feel pretty confident that it not starting has to do with low battery.

[lovemysan]

You could eliminate the battery by testing your voltage with a DVM while your eoc'ing. It does sound a little suspect to me. I always found it real easy to kill the civic battery just because its so small. I can tell that my battery is not the healthiest when eoc'ing at night too.

I wasn't talking about cycling the water pump. I was saying to cycle the fuel pump. Just key off and then back on right before you bump start. This will cycle the fuel pump.

[1993CivicVX]

aww, okay. Maybe I test that tomorrow. (not the DVM, but the cycling of the fuel pump.