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Engine dies, starts right back up

38K views 11 replies 4 participants last post by  green03malibu 
#1 ·
Hello,

This is my first post here and I am hoping someone can provide some insight with a problem that I have been having. My fiancé has a 1999 Malibu with 115k miles. A little over a month ago she destroyed her engine (Who would have thought you needed to keep oil in it???). We replaced the motor with a used one with 65k miles.

We pick it up from the shop and the next day the car dies on her while doing to work. She pulls to the side of the road and it starts right back up. She described it as though the engine just shut off. Lights, radio and heat didn't cut off, just the engine. This happens a few more times throughout the week so we bring it back to the shop.

The shop cleans out the throttle body and tells us that we should be fine. Two days later it happens again. There does not seem to be any pattern either. It will happen when the car is cold, or when it’s up to temp. It happens on the highway, and when driving in town. Back to the shop we go.

The car stays at the shop for a week and half. Throughout this time they are driving it and letting it run to try to duplicate the issue, but nothing happens. I pick it up on Friday and cross my fingers.

I drive the car into work and back on Saturday (about 25 mi each way with a mix of highway and stop and go) and it seems to be fine. I drive it again on Sunday and it is fine on the way in, but on the way home it cuts off on me. There was no sputtering or hesitation, it just died.

I was getting onto the highway and doing about 35 mph and as I attempted to accelerate I notice I wasn't getting any power. I look down at the tach and it reads 0 RPM. Everything is still on, but the motor has cut off.

It was raining on Sunday when it happened so when I was almost home I ran through a massive pool of water thinking that if it was water causing the issue the car would cut off, but no luck. I have also tried hitting bumps to see if it is something jarring loose and wiggling the keys in the ignition with the car running to see if it is the switch but I have not been able to get this issue to happen on command.

The guys at the shop have been great. I feel bad that I they are investing all of this time on this issue and it won't show itself to them, but once we get the car back it happens within a day. My uneducated guess is that it’s not fuel related because there is no sputtering, but something electrical; perhaps a bad sensor. I just don’t know why this would present itself now and not before the engine swap. Oh, and I already check the battery terminals, they where free of any corrosion.

If anyone has any ideas on what could be causing this you input would be greatly appreciated.
 
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#2 ·
Hmmm... Is it throwing any codes, as in the Service Engine Soon light is on? What engine was in it before, was it the 2.4 4 cyl. or was it the 3.1 V6 originally and did you have the engines switched? Another question is what year did the other engine come out of, starting with the 2001 model year, they modded the 3.1
My friend was having a similar problem with his 06 Colorado and it was a sensor that was bad. It could also be the PCM (Power Control Module).
 
#3 ·
Throttle Position Sensor?
 
#4 ·
From your description it sounds electrical to me as well. Do a wiggle test. Sounds simplistic, but it's a free test. Start the car and wiggle everything that's wired, on or off the engine. Check for connectors that look plugged in all the way but may be loose. Look for wires not fully inserted into plugs, too. Check for ground wires that haven't been connected or are loose.

A good guess of where to wiggle is to find out where they worked. Did they do anything somewhere else on the car? Under the dash? At the firewall by the pedals?

It'll take some time before you find it, but keep using logic to eliminate what it isn't, then what you're left with is what it is.

And, yeah, I loaned a friend an old car of mine and he didn't know about oil, either. Thankfully when I saw the car the next time I caught it in time. It had just enough to put a drop on the end of the dipstick!

Now you know why someone way back when nicknamed them "idiot lights".
 
#7 · (Edited)
Thanks for the replies everyone. I haven't been able to do any troubleshooting yet myself yet because the car was sitting in the shop since last Sunday. They told me they have been driving it around trying to get the issue to duplicate, but they didn't put a single mile on the car. As I was driving it home tonight it cut off on me three times, but I think I have found a pattern.

The motor is a 3.1L V6 California Emissions. It was replaced with another 3.1 from a 99

I the first time it cut off on me I notice the lights on the dash dimmed and the blower for the heat slowed down very slightly. I started the car back up and continued driving. I noticed the lights on the dash dim again and the blower motor slow down again when I took my foot off the gas after getting to speed. While it didn't shut off I did catch the RPMs drop to almost 500 for a second. I'm able to duplicate this drop in RPM almost every time I take my foot off the gas after accelerating, it does not happen when the car is idling though. It seems to happen 3-10 seconds after I take my foot off the gas.

Is something sucking too much power?
 
#9 ·
Good info! Being able to duplicate it at will is excellent.

Happening at such a slow speed makes me think that the TC (torque convertor) lock-up isn't supposed to be happening, but if there's an error in the tranny, say from a bad VSS (veh speed sensor) or a bad VSS signal (like a crushed wire, or shorted to another or ground), it leaves room for this to be possible.

You also have a MAP (manifold absolute pressure) sensor - basically a vacuum sensor - that could be causing issues by a bad signal, or lack of one. It could be causing the TCC (TC clutch) to engage improperly, pulling the RPMs too low.

The evidence of the lights and blower dimming suggests something like you're thinking, that something is sucking too much power, or that with that much of a load on the alternator, the engine speed being too low means that the alternator can't keep up with the load and you're depending on the battery to make up the difference. Since the battery is more like a glass with a valve at the bottom that flows electrons, if the alternator isn't pumping more electrons in the top it'll lose capacity as it drains. If the load is bigger, i.e. lights and blower, then the voltage drop is bigger, too.

Look for a dirty or loose battery terminal or grounding cable. Look for a dirty, loose, or frayed charging wire at the alternator (the BIG one). If the alternator's output can't get to the battery easily enough then any load on the battery will be amplified as it increases, resulting in dimming lights and/or slower blowers.

Make sure the grounding strap from the engine to the frame has been reinstalled tightly and makes a good electrical path. If the mechanics just threw it on any bolt but didn't make sure it was clean, the resistance can be part of all of your problem.

Lots more to look for, but you've done a great job narrowing it down. Please, please, please share with us when you finally resolve, okay? Even if it's something completely different from where I'm suggesting. I don't have a problem with being wrong, I just don't want to do nothing. Keep using the evidence you collect and you'll get it!
 
#10 ·
The problem with the N-body is that lights dimming are normal... that's if your hitting the brakes, are you hitting the brakes when they dim? My Malibu's lights dim and blower blows less when I hate the breaks, but only for a second. Something isn't clicking, I'm guessing something might have not been tuned properly or done right.
 
#11 ·
It doesn't only happen when I hit the brakes, it will happen if I just take my foot off the gas. I also noticed this morning that it will only happen after the car gets to temp, about 180 degrees.

Next day I have off is Sunday so im going to dig in on it then.
 
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