1999 Chevrolet Malibu stalling while driving problem

Tiny
JAYNADO
  • MEMBER
  • 1999 CHEVROLET MALIBU
  • 3.1L
  • V6
  • FWD
  • AUTOMATIC
  • 280,000 MILES
Hi,
I have a 1999 chevy Malibu 3.1L V6
For the past year it has been having issues while starting up, it only happens sometimes but when I try to turn the engine over all my dash lights will flicker, and the gages and tachometer flip up and down violently then the car dies, sometimes I can try to crank it for 5 minutes before it turns over and sometimes it will turn over on the first or second try, this started out as only an issue when trying to start the car, but now it happens while driving, ill be driving along (doesnt matter what speed) and the dash lights will flicker then the car will just die while im driving, it seems that everytime I change a part the problem is fixed for a week then returns,
I have had the fuel pump and filter changed at the advice of a mechanic, that worked for a few days, I changed the pcv valve and hose and made sure theres no vaccum leaks, that seemed to fix it for a few days, I cleans the mass airflow sensor which didnt do anything, then I recently changed the camshaft position sensor becuase of a code on my obd2, when I changed it the camshaft position sensor was frayed and looked like it was burned, after changing it the car ran fine for weeks, but last week I just started having the same problem again, yesterday I siliconed all the vacuum connections to make sure there was a tight seal, im womdering if I have missed a vaccum hose somwhere or if anyone has had this issue and how do I fix it, just today I got the p0341 code again ( camshaft position sensor). Could that cause these problems? Other than that the only codes I get once in a while are p0113 and p0442, any of these likely to cause this issue?

Thanks
Do you
have the same problem?
Yes
No
Thursday, April 30th, 2015 AT 12:40 AM

3 Replies

Tiny
CARADIODOC
  • EXPERT
By now you should have figured out that replacing random parts is the most expensive and least effective way to diagnose a problem. If not, you need a more accurate dart board. None of the parts you mentioned will affect an electrical problem with the dash board. One thing you can do yourself without a scanner is to follow the smaller positive battery wire to the under-hood fuse box. Be sure that connection is clean and tight. Follow the smaller black negative wire to the body and be sure that one isn't rusty.

You might also want to have the charging system tested, in particular for maximum output current and "ripple" voltage. If those are suspect, the generator is a common cause on GM vehicles for elusive engine running problems. I can explain that in more detail if it comes to that. For now, the test must show that you're getting in the area of 90 to perhaps as much as 120 amps. What we don't want to see is exactly one third of the maximum rating which is around 30 to 35 amps.
Was this
answer
helpful?
Yes
No
Thursday, April 30th, 2015 AT 12:57 AM
Tiny
JAYNADO
  • MEMBER
Thanks for the fast reply I will try all those steps next chance I get and let you know how it works, is testing the maximum output and ripple current something I can do on a basic multimeter?
Also fyi, I have never replaced any "random" parts, all the parts I replaced showed signs of wear, and would have needed to be replaced at some point anyways, (frayed wire, fuel sending unit not working, leakiing pcv hose etc.)

Thanks again
Was this
answer
helpful?
Yes
No
Thursday, April 30th, 2015 AT 11:11 AM
Tiny
CARADIODOC
  • EXPERT
Dandy. The charging system problem I'm concerned with requires a professional load tester so you'll have to visit a shop for that. Due to their design, starting with the '87 models, these GM generators develop huge voltage spikes that can damage the internal diodes and voltage regulator, and interfere with computer sensor signals. The battery is the key component in damping and absorbing those spikes, but as they age and the lead flakes off the plates, they lose their ability to do that. It is common to go through four to six replacement generators in the life of the vehicle, but to reduce the number of repeat failures, replace the battery whenever the generator has to be replaced, unless it is less than about two years old.

When one of the six diodes fails, you'll lose exactly two thirds of the generator's capacity. 30 amps from the common 90 amp generator isn't enough to run the entire electrical system under all conditions. The battery will have to make up the difference until it slowly runs down over days or weeks.

Those voltage spikes also radiate into other wires magnetically and cause weird signals to show up as sensor signals. The Engine Computer can interpret those as legitimate signals and try to run on them. That's where those elusive running problems come from that defy diagnosis. One trick to identifying them is to disconnect the small plug on the side / rear of the generator to disable it. If the running problem clears up, the charging system should be tested.

You can start the testing on any charging system by simply measuring battery voltage with the engine running. It must be between 13.75 and 14.75 volts. If that is okay, it just means the rest of the tests will have validity. The first thing the load tester will do is draw the maximum full-load current to see how much can be developed. That is either going to be very near the generator's rated current or one third of that. If it's one third, one of the diodes has failed and the generator must be replaced. It's not practical economically on other brands to replace the diodes because rebuilt generators aren't that expensive, but on GM's generators it is nearly impossible to do so without destroying other parts when trying to get them apart. These generators weren't designed to be repaired.

AC generators have three-phase output. When one phase is missing due to a failed diode, "ripple" voltage will be very high. That is also measured by most professional load testers. Some show it as a voltage, and others use a bar graph to show relative voltage. That can't be measured accurately with a digital voltmeter. You'd have to use the AC voltage scales and those are only accurate at 60 Hz as in house wiring.
Was this
answer
helpful?
Yes
No
Thursday, April 30th, 2015 AT 9:19 PM

Please login or register to post a reply.

Recommended Guides