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Intermittent idle/running issues MABYE solved!; Looks like fuel injector problem...
Topic Started: Mar 15 2013, 12:22 PM (701 Views)
cwatkin


I am pretty sure I was having MAJOR issues with my fuel injector. I had checked spray pattern before and my problems would come and go on a very intermittent basis but were usually worse when started for the first time of the day. I thought it was ignition related as I was having a problem with my plug wires jumping spark and it was clearly visible when I opened the hood at night.

The problems were as follows...
1. Car starts and runs great for 5-10 seconds and starts missing like crazy at idle after that.
2. Car will run and drive ok in this condition as long as RPMs are up. Then it would run like crap and/or stall out completely.
3. The problem would go away as the engine warmed up.
4. It seemed to be getting worse with time.
5. There was an unbelievable unburned gas odor while it was running so poorly. It smelled like a smoky old 2 cycle outboard boat motor but worse.

I started reading about my symptoms and everything was pointing me to a fuel injector issue and my spray pattern didn't look all that great either when I checked. So, I swapped with a spare injector from a junk engine. I cleaned it off (externally) and installed it. The car definitely runs MUCH better than before I did this so we will see...

The spare injector had a darker, dirtier color of varnish even after spraying it off with carb cleaner so I was somewhat concerned it might be bad and not function at all. The one I removed was spotless and clean which may be due to the strict use of top tier gas in the car. Is it possible that a dirt particle lodged in the injector or is it likely toast? I don't see how anything could get past the filter screen that is around the upstream part of the injector.

I was also wondering about getting a new injector for good measure if this seems to solve my problem. This one came from an engine that had quite a few miles on it so I thought it might not be a bad idea to get a new one. Now, I see these ranging from $20 to almost $200 (parts stores) and was wondering if there is a preferred brand that people here use.

Thanks,

Conor

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jkeney


I am very curious of peoples opinion of injectors myself.
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Vkhelldog
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I got a reman one from rock auto. It was 89$ but when I sent my old one back they gave me 43$ back.
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DesmondGhostRider
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Id suggest going to a local auto scrap yard and pulling a handful to keep just in case. Also check the little gasket that goes in the bottom of the injector.

Does it have trouble starting? You might consider replacing/checking the fuel injector relay. If its going bad it might be getting stuck open and flooding out the engine.

Lastly check to make sure your fuel return line isnt clogged. If it is, it can build up pressure and flood out the car and it will hurt your mpg
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cwatkin


I checked fuel pressure when I first started having problems. I drove the car with the fuel pressure gage taped to my windshield wiper so I could see it while in use. Pressure was good and stayed where it belonged under load/no load conditions. I think the fuel return is good and I recently changed the filter too.

The car did ok under load or at higher RPMs with this issue so I guess fuel was leaking at a constant rate that became less of an issue when demands were higher. It also seemed that outside air temp as well as engine temp helped as things warmed up.

Conor
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jkeney


I want to see if the injector helps your idle issues.
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cwatkin


The injector seemed to help a lot but something else I had looked at before also helped. I had cleaned up the two ground connections on the rear of the intake before but not to the extent of what I did today. I decided to loosen and tighten these during one of my bad idle episodes and the idle immediately improved.

So, I took them completely off, buffed both the connectors as well as the intake with steel wool, wiped all mating surfaces down with carb cleaner, and applied electrical terminal grease to the surfaces, and then re-assembled. Everything seems to be working SO MUCH BETTER. I had cleaned them off before but I got them surgical instrument clean today. These guys are important so make sure they are clean and making good connection! It was like my map sensor wasn't responding and I wondered about the grounds again. As soon as I starting messing with them, the idle improved so I considered them another suspect.

Conor
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jkeney


I know my grounds are clean but I wonder about the wires leading to the tabs.
I also have a rough looking lead coming off my distributor that looks like it needs replacing.
My grounds on the rad support and the trans have been replaced but I have done nothing but clean the contacts on the ones back on the manifold. I think I need to find a wiring harness for a 95 thats in better shape than mine.
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cwatkin


Is the wire lead on the distributor a single wire or two wire lead? The single wire is a ground. I believe the two wire is the pickup coil.

Conor
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cwatkin


I went out today and tested out my Metro to see if it really ran OK after sitting overnight. We got an inch of rain last night and this cool, damp, and dreary weather are PERFECT conditions for it to mess up and run like crap. It fired up and ran like a champ! I think this issue may be resolved once and for all but we will see. It would be nice if I could have a few months of nothing needing work on my Metro besides routine stuff like oil changes.

Although I completely reworked the distributor ground a while back, I am going to do a major cleaning on these connections and coat them in silicone grease like I did on the sensor grounds for good measure. I may also change my oil after all this as there seemed to be a lot of unburned gas during some of these episodes.

MORAL OF THE STORY: If you have intermittent odd running issues and there is no check engine light, check your electrical grounds. At the very least, loosen and re-tighten these connections and see if that makes a difference. If yes, do a cleaning like I just did.

Conor
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