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Engine acts like it quits?????
Topic Started: Jul 20 2012, 05:40 PM (686 Views)
bvilleracer
Advanced Member
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Ok on my 96 Metro, while driving on the interstate 65-75 MPH, no issues, runs great!
(I drive 64 miles round trip daily).

Here is the issue:
When I hit bumpy roads, the engine acts like it is hesitating or is going to quit, but never does, and you definatley feel the power loss.

The odd part is, it starts up fine, runs great, climbs hills, etc. I first noticed it about a year ago, I replaced the fuel filter, air filter, plugs, wires, cap and rotor. Same ol issue. Also, it does not matter what type of gas I run or how full or empty the tank is.

When I run my code reader, nothing comes up.

Could this be a fuel pump going out?
Or a speed sensor?

I am stumped any ideas?

TIA
Clay





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Shinrin
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Something is loose is my guess. I had a bad coil wire awhile back, and every now and then I'd hit a bump and it'd come loose just enough to let the car stall. Check all your wires to make sure everything is tight. Check your battery cables and grounds and make sure everything is tight and clean.
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allmountain40
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:gp This is going to be tough because of intermittent nature. Another thing to check is the power wire for the fuel pump runs under rear seat. Sometimes these will get rubbed down to bare wire and when you hit a bump it shorts and you lose fuel pressure. So while your at it, yank back seat and check that too.
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Woodie
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Check the main sensor and computer ground on the back of the intake manifold, below the throttle body and above the alternator. No, don't check it, remove it, clean it up with a wire brush, and reconnect it. Try wiggling wires, cables, and connectors while the engine is idling to see if you can make it stumble. Battery cables are prone to breaking internally, especially at the ends. Unplug and reconnect every connector you can get your hands on, every connector is a potential problem spot.
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bvilleracer
Advanced Member
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So at this point I am assuming that its pointing to a electrical problem and not a mechanical issue.

Tonight on the way home from work on the interstate, it was really stumbling, and the road was smooth, (well smooth for Utah), but the car still traveled at 70 mph.

Ok so help me to understand, the actual fuel pump, engine, and cat converter is actually good, but its something leading towards electrical?

Also, if the wire on the back of the intake manifold is loose, and it cam un-done, would that cause my engine to totally quit?

I have not checked anything yet, trying to get a picture in my mind of what to look for, when it comes to electrical trouble shooting, I dont enjoy it.

TIA
Clay

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allmountain40
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Yes, the ground wire coming loose on back of manifold will make engine totally quit. Given the intermittent nature of your problem, that would most likely point to electrical. Mechanical things either work or they don't for the most part.
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Shinrin
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Woodie
Jul 21 2012, 06:31 AM
Check the main sensor and computer ground on the back of the intake manifold, below the throttle body and above the alternator. No, don't check it, remove it, clean it up with a wire brush, and reconnect it. Try wiggling wires, cables, and connectors while the engine is idling to see if you can make it stumble. Battery cables are prone to breaking internally, especially at the ends. Unplug and reconnect every connector you can get your hands on, every connector is a potential problem spot.
:gp Best suggestion, pull every ground, scrape it down, and scrape down the surface it contacts. Even if it looks clean. Pull both battery terminals and make them and your posts shine. Bad grounds cause gremlins. May not be your problem, but it's a great starting point.
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Old Man


battery cables tight and clean. check the small battery cable that runs under the fuse block too
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bvilleracer
Advanced Member
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Ok to give a little bit of history, I replaced both battery cables about 2 mos ago trying fix the clicky, clicky starter issue, at that time. I also polished the battery terminals, made them shine.

So tonight, I found what I think is the ground for the ECU, right below the throttle body,
about 2 o clock position and up from the alternator. It was clean and tight, but I cleaned it anyway looked at cable, and it was fine.

Took car for a ride, and still did it.

Now here is a question, it acted like maybe when the car was accelerating, it did not do it, but when you kinda coasted, it may have done it, don't know for sure on this. Could it maybe be a speed sensor?

Also, how are the fuel pump wires routed? And, is there a way I can look at the wires going into the fuel pump with out dropping the tank? I am assuming the fuel pump is in the tank?

Also, is there any grounds that are more important than others?

Is there a schematic that shows where the grounds are?

Thanks everybody for all your help, well get this thing figured out one way or another! :cheers

Clay

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