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So first to introduce my car, it’s a small euro hatchback from 1994 called Renault Twingo. It has a 1.2 liter 8 valve engine with monopoint injection, basically a carb with one injector over it.
Recently, the car began to act up. This happened 2 times in last 5 days. Here’s the rundown:
– I start the car in the morning to go to work, car starts immediately with no problems
– there’s some slight signs of acceleration hesitation when I press the throttle, as if the car loses momentum for a brief moment, but that goes away after a minute
– 5 minutes later and I stop at my local grocery store, turn the car off
– when I get back in the car and try to start it again, the car barely starts, I need to keep the engine cranking for 5 seconds or more
– when I get the car going, it drives normally, and with absolutely no hesitation
– after couple of hours I get in the car again and this time it starts normally and drives normally, no hesitation like the morning driveSo, I hope some of you can understand my play-by-play breakdown of my car problems and I hope I’ll get a proper diagnosis. Thanks guys.
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Hey, TM45!
Thought about this, and I think I know what’s going on.
Before I give you my guess, let me ask a question or two.
1) After your 5 minute drive to the store, how long does your car sit before you try starting it again? Five minutes? Ten? Less? More?2) Have you tried asking a mate to try and start the car while you’re holding the valves open on the carburetor? (Is that even possible with this one? I’m not very familiar with a fuel-injected carb like you’re describing).
3) Have you tried waiting another five minutes after arriving at the store before shutting your car down? If so, did it still have difficulty starting?
4) Have you tried adding a spray of starter fluid into the carburetor or airbox?
Now on to what I’m GUESSING is going on, here. I’m reasonably sure you’re vapor-locking the carburetor, fuel lines, or fuel pump itself.
Here’s a link to another forum with a vehicle that was having very similar symptoms with the same resolution (Short drive followed by an hour-long wait, and it’ll start ok).
http://www.jalopyjournal.com/forum/showthread.php?t=593616
Try mitigating this by more thoroughly warming the car up before shutting her down, and check the routing of the fuel lines to see where they are in relation to the exhaust. They might be vapor-locking, as might the carb. If it does die on you again, try ventilating the carb by holding open the valve plates (if this is even feasible on this particular arrangement).
Good luck, and keep us posted!
-Hinoki
Hey thanks for you input.
To answer your questions;
1) 2-3 minutes, I’m just going in and out the store.
So, to sum it up and avoid confusion – I start the car up in the morning, car starts immediately, I start driving and it kinda hesitates and makes those “I’m working on 3 cylinders” sounds, those symptoms go away after a minute of driving
Then, after 5 minutes of driving normally, I stop at the local store to get my breakfast. I turn the car off, finish my shopping and get back in after few minutes.
This time, car barely starts. I have to crank it for 10 seconds to get it going, and when it finally starts – it runs normally, drivers and accelerates smoothly. And even later in the day when I drive around, the car starts and drivers normally.
Maybe it’s a “morning” thing maybe it’s random, I can’t say.
This is my carb, I’ll check fuel pressure.
Could these be some ignition symptoms? I’ll be honest, I bought the car with 150,000 miles on it and now it shows over 200,000 miles on the clock, and I didn’t change my plug wires or fuel pump, or fuel filter 🙁
One important thing I forgot to mention! One time at my daily commute the symptoms were a bit different;
– The car started normally in the morning, drove 5 minutes to the grocery store without any hiccups, left the car running in front of the store, got out in 5 minutes and as soon as I got back in fastening my belt, the car just died while idling.
And I tried to start it again, and it kept cranking and cranking with no results. Left it alone for 5 minutes and tried again, and after a long 10 second crank, the car finally started.
To me it sounds fuel related. I don’t know if it’s in the delivery or the pressure. The next time you try and start it after sitting, try holding your foot to the floor on the gas. This should turn the injector off. If you can start it right up, perhaps the injector is leaking fuel into the engine while it’s off. If that’s the case, then it can also cause the performance problem you mentioned.
To verify you could also check the fuel pressure after you shut the engine off. It should hold pressure for at least 30min. If it doesn’t then you have a leak somewhere.
More information on diagnosing performance issues like this can be found in this article.
http://www.ericthecarguy.com/faq/solving-automotive-performance-issues
Keep us posted on your progress.
Thanks Eric, I learned something new today, didn’t know about the flooring-cutting injectors trick. Seems logical and I hope my car has that “feature” built in.
I don’t have much tools at home, I’ll try to check this at my friends garage this weekend.
The worst thing is that this occurs inconsistently. For instance, I started the car this morning, it started immediately, drove normally for 20 miles, then I stopped for an hour, started it normally again, stopped after couple of minutes to get some gas, and drove off, the car started normally.
:dry:
I asked a buddy of mine on this issue and he told me I should check the plugs and plug wires…I didn’t change those in a while, but given that the weather was incredibly damp today, I don’t think they’re the problem.
PS – I tested the car’s fuel economy 2 times in past 3 months, by filling it up, measuring the traveled distance with GPS and filling it up again, I get 55 mpg. If the leaky injector is the problem, will it eventually ruin my mpg?
Yes a leaking injector can ruin your mpg. That said, they can also fail intermittently. Something else to consider is the coolant temp sensor. If that fails, it can also upset the fuel mixture. You can observe the temp reading on a scan tool and take the actual temperature of the coolant to see if they match. Do this both hot and cold. If they match, then you’re good. If they don’t, then replace the sensor and recheck for the problem.
There’s more information and possibilities on what the problem might be in the article I gave you a link to.
Keep us posted.
Thanks, Eric.
Funny you mentioned coolant temp sensor, because I had 3 breakdowns with this car in 4 years, 2 of those 3 involved coolant temp sensor.
First time it happened was after some 30,000 miles of me driving the car. One morning the car just didn’t start. My buddy came over to check it out the same day, and said I needed to change the coolant temp sensor because its cold outside and the car doesn’t recognize the water temp hence automatic choke isn’t working. I replaced it, the car was back to normal instantly.
10,000 miles later, same problem, one morning, car just kept hopelessly cranking. Went to the store, another $10 for 2nd coolant temp sensor in 1 year, screwed it in place, and the car was working.
And my recent car breakdown, 2 months ago. Tried to start the car, didn’t start, just kept cranking with accented smell of fuel under the hood.
Local mechanic said that the car is throwing too much fuel into the carb, so injector needs cleaning. So he apparently cleaned the injector and now the car is driving with these freshly occurring hiccups.
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