Plugs fouling out?
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Plugs fouling out? - 12/8/2007 8:41:06 AM
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riverjamie
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''''95 Chevy Blazer 4x4 4.3L engine 105K. A while back I posted the same problem. Well I went ahead and installed new plugs Autolite APP25 Platium, Distributor cap, rotor, spark plug wires, Fuel filter, and Fuel Pressure Regulator (part of fuel injection system under Plenum). Also found the EGR valve port almost pluged so I cleaned it out also. Everything ran great for about 500 miles then it started again with hesatation, missing, rough idle. I went out and reved the engine and after a while the idle started to smooth out. Not sure if I want to take into a Chevy dealer. I''''m afaird they''''ll just throw in some spark plugs and say it''''s all fixed. I''''ve installed two sets of APP25''''s, the first set only lasted 1k and this set only 500 miles. Could it be that Autolite APP25''''s foul out easy? Any thoughts. Sorry for any mispellings. Thanks in advance for any suggestions
Also after reading all the feedback on other posts, it seems that most people use AC Delco Double Platinums #1 is that correct? Maybe my problem could be as easy as the Autolite''''s APP25 won''''t work well in this engine? Is the AC DP #1 the correct plug for the 4.3L engine?
Forgot to add that the cataylic converter also rattles internally? So I also thinking maybe it could be blocking the exhaust? Any thoughts on this? My concern with replacing it first is that, I heard if your engine is runing to rich that it could damage the cataylic converter? So I didn''''t want to damage it. Any thoughts on this, or is it okay to install the new one even if the engine is runing rich how long would it take to damage it?
< Message edited by riverjamie -- 12/24/2008 10:10:03 AM >
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RE: Plugs fouling out? - 12/8/2007 2:51:47 PM
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BlazerSS
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There have been many threads on this topic. Any good or even crappy mechanic will tell you to only put AC Delco plugs in especially on a 4.3L motor. I work at a retail/commercial autoparts store and have asked many mechanics at my job and they all say the same thing. They would never put Autolites in a Chevy. They use Champions for Chrysler/Dodge, Ac Delco for GM, Autolites for Ford, and NGKs for Toyota. I would put some Ac delco platinums in and clean everything out again and then see what happens. I would also run a 20 gallon treatment of Chevron Techron Fuel system cleaner with a full tank of gas. If this doesnt solve your issues then you might be looking at a faulty coil pack, distributor, etc.
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RE: Plugs fouling out? - 12/8/2007 5:00:43 PM
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swartlkk
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I would run a fuel pressure test, especially paying attention to the pressure drop after the key is off. It is possible you have an internal fuel leak that is causing a rich condition, thereby fouling the plugs. No plug should foul in 500 miles on their own. I think there are other things going on here.
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RE: Plugs fouling out? - 12/8/2007 8:57:21 PM
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riverjamie
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Can you please tell me what the pressure should be, and how long should it hold after the inginton is off? Also what do you think about the spark plug brand? I did find the passenger side clean when I opened the plenum, that's why I replaced the pressure regulator. Is there any way to test the injector system for leaks with the plenum top half off? This problem has been a pain the !!!! to say the least. Thanks
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RE: Plugs fouling out? - 12/9/2007 6:45:15 AM
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swartlkk
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When you replaced the FPR, did you remove the spider to do so? Did you replace the internal fuel lines (called the 'nut kit') at the same time?
THe fuel pressure should hold at 55-60psi and should not drop more than 10psi over 10 minutes. Typically there will be a drop in line pressure when the pump shuts off as the check valve in the fuel pump closes. There definitely should not be a steady drop in pressure however minute it is. If there is a steady drop, then you have a leak somewhere.
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RE: Plugs fouling out? - 12/9/2007 10:16:52 AM
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riverjamie
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First thank you for replying with the pressure info. Also it's just my unprofessional opinion that the spark plugs are fouling out. They just seem darker than normal. Maybe I can pull them again and take a digtal photo and upload it?
I did not have to remove the spider inorder to replace the FPR. The drivers side was not clean like the passenger side under the plenum so I figured the "Nut Kit" was okay?
If I get a fuel pressure gauge and do the test and find the a pressure loss, how would you proceed? After removing the top plenum can I turn on the fuel pump and just look around for leaks? What about taking out the individual injectors? I'm very mechanical but have never dealt with fuel injection systems.
Also you didn't make any suggestions regarding the spark plug type? AC, Autolite, etc.
I do agree with you that I can't belive that even with Autolite APP25 that they should foul out within 500 miles.
Thanks for all your suggestions and procedures, they've been very helpful
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RE: Plugs fouling out? - 12/9/2007 11:07:39 AM
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swartlkk
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You can just pull the upper plenum and turn the key on to pressurize the system.
It may also be time to replace the upstream O2 sensor. If you do not find an internal leak or the pressure holds fairly well, that may be the next course of action. I typically won't recommend an O2 change without first looking at the output of the O2 sensor, but that is quite difficult to do without the proper tools (scan tool w/ graphing functions). With 105k miles, if the O2 sensor has not been changed, then it may just be time. The sensor you want to change is the on closest to the engine on the exhaust pipes.
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Need help again on Spark Plugs Fouling out - 12/23/2008 3:13:04 PM
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riverjamie
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''95 Chevy Blazer 4x4 4.3L engine 105K. A while back I posted the same problem. Well I went ahead and installed new plugs Autolite APP25 Platium, Distributor cap, rotor, spark plug wires, Fuel filter, and Fuel Pressure Regulator (after market) (part of fuel injection system under Plenum) I did not find alot of gas laying in the intake manifold area, just replaced incase the pressure regulator maybe bad. Also found the EGR valve port almost pluged so I cleaned it out also. Everything ran great for about 500 miles then it started again with hesatation, missing, rough idle. I went out and reved the engine and after a while the idle started to smooth out. Not sure if I want to take into a Chevy dealer. I''m afaird they''ll just throw in some spark plugs and say it''s all fixed. I''ve installed two sets of APP25''s, the first set only lasted 1k and this set only 500 miles. Could it be that Autolite APP25''s foul out easy? Any thoughts. Also the Cataylic Converter also rattles?
Now it''s 12/23/08, I''ve done everything back 6 months ago. The cpu is OD 1.5. I have not had it checked yet. So after so of your help I install a new GM O2 senser and did the fuel pressure check (50-55PSI was not steady but the needle was jumping around in the 50-55PSI range. I can''t remember if it was dropping after shut off, but I would probably say no). So still having the same problem with spark plugs fouling out? It doesn''t seem that all of them are as bad as some of the others? All I know is that if I put in a new set it will run for probably 500 to 1K then start missing and ruff idle. Some feedback say that I should only put in the AC Delco spark plugs? I can''t beleive that any plug should go bad with in 500 to 1K?
What controls the amount of fuel that is sent to the cylinders?
Thanks in advance for any suggestions
< Message edited by riverjamie -- 12/24/2008 10:46:30 AM >
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RE: Need help again on Spark Plugs Fouling out - 12/23/2008 4:39:06 PM
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swartlkk
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The rattle in the cat is not good and could be the cause of the quick plug foul.
When you say that the plugs foul, what do they look like? Can you take some pictures and post them?
When you first start your truck in the morning or when it is just idling, do you see blue smoke come out of the exhaust?
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RE: Need help again on Spark Plugs Fouling out - 12/23/2008 5:32:08 PM
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riverjamie
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First thank you for replying. Well right know it looks like the battery is just to far gone to crank the car. But I was able to do the fuel pressure test again. Even though the car will not crank there was enough power for the fuel pressure pump came up to 55-60PSI and after I shut of the weak battery it still was at the same pressure 30 minutes later.
I can''t remember about the exhaust color? But I will get back to you after I get the new battery.
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RE: Need help again on Spark Plugs Fouling out - 12/23/2008 5:43:36 PM
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riverjamie
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I tried to attach the picture of the old plugs from the past, but the file to to large. So if you don''t mind I could sent them to your personal email if you like?
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RE: Need help again on Spark Plugs Fouling out - 12/24/2008 1:38:09 PM
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riverjamie
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Had trouble trying to attach the photo of the spark plugs. So maybe later my son will help. Also do you aggree that the APP25 plugs still should not foul out the soon? One of the replies said to replace with original AC plugs? What would you recomend?
Also can you please tell me if you know what controls the amount of fuel that is sent to the cylinders?
I agree about the Cat Convert should probably be replaced but I don''t want to replace it if theres to much fuel being dumped in the system, I heard that if the system runs to rich it can cause the Cat to prematurely fail?
Also when I took of the plenum to replace the Fuel Pressure Regulator I also removed the EGR valve and most of the EGR port on the intack manifold was clogged? Of course I cleaned it out. Would the Cat being bad cause this?
Again thank you for all your replies.
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RE: Need help again on Spark Plugs Fouling out - 12/24/2008 7:28:15 PM
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swartlkk
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Did you look at the thread I linked to above? That will detail everything you need to know to get a picture into a post.
No plug should foul out that quickly. Can you describe what the plugs look like?
The O2 sensor controls the IPW (injector pulse width), however, if you have a fuel leak under the plenum... I know you have already replaced the FPR, but have you checked your fuel pressure? If so, did you monitor it after you turned the key off? What does it do?
When you replaced the FPR, did you remove the CPI spider to replace it?
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RE: Need help again on Spark Plugs Fouling out - 12/24/2008 11:57:38 PM
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riverjamie
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I tried to follow the instructions for posted the picture but I could not get it to work? So tomorrow I''ll have my son work with me on posting the picture.
When I removed the plenum for the fuel pressure reg it looked good not alot of moisture, but there was signs of brown areas like I saw on some posts with gas leakage. I did not replace the spider or the nut assy. I did replace the O2 sensor with the correct AC Delco. I did the fuel pressure check even though I could not start the car there was enough juice to run the pump 55-60PSI and with it off after 30 minutes it was still at 55PSI. Tonight (Weds) I got the car runing by jumping the battery. I engine was surging up and down. It seems to smooth out when I would give it more gas but when I let it idle it would start surging up and down. I removed all the plugs APP25. They all look equally fouled, pretty black. What else could cause so much fuel to get into the system? My mileage also was very low before the plugs quit. Can the MAP or the Air charge Temp sensors cause this problem or the Cataylic Converter, I seem to have pretty good pressure at the tail pipe. On Friday I''m going to pick up some CR43TSM AC Delco plugs but I don''t believe that the plugs are the problem. But at this point their bad. Do you think I should take it in to a dealer after getting it runing and have them check the diagnostics? When it was surging it did create a msg "have engine serviced".
Again thank you for all your help.
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RE: Need help again on Spark Plugs Fouling out - 12/25/2008 8:12:17 AM
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swartlkk
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When you had it running, how did it perform? Did it feel sluggish? It is quite possible that the cat is plugged or restricted, causing the plugs to foul. If it runs sluggish, try removing upstream O2 sensor completely from the vehicle and run it again. If that shows a change in performance (not just noise level), then your catalytic converter is plugged.
You would have codes present if the MAP or ECT have failed causing these problems. You have checked the codes, correct?
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RE: Need help again on Spark Plugs Fouling out - 12/25/2008 9:46:24 AM
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riverjamie
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I was only able to drive to car back into the garage from the street where it had been sitting for 2-3 months. But if I let it idle the rpm''s would go up an down and almost die, unless I gave it more gas (which I call the surging?), after it warmed up it settled down a bit, but still surged. I also I think I mentioned this in my earlier posts, after doing all the tune-up stuff, FPR, plugs, I put in Seafoam in the intake, and gas tank. It seemed to help for a while, probably just cleaned off the plugs, I guess. I guess in any case I should get the Cat replaced anyhow, just been putting it off becasue I heard that if the engine is runing to rich it could cause the Cat the fail again? Is that true? So what would you do? Also I have not been able to check the codes because the one from from Auto Zone won''t read OD 1.5. So I guess the only way to get it checked is to have it done a the dealer? I''m not sure if Firestone type garage could fix a problem like this? I think it probably should go to the dealer? One last question what do think about putting in a after market cat not an GM one? There''s a place near by that told me for $200 I could get it replaced. Should I take out the O2 sensor after the cat is replaced and clean it with some Electrical contact cleaner? Now if I should take the car to the dealer if that inspect the plenum I would imagne that it would probably look wet because of the Seafoam going down into the air intake valve? The car itself is not worth a lot to begin with. This problem has really been a nighmare.
I really appreciate all your assistance.
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RE: Need help again on Spark Plugs Fouling out - 12/25/2008 10:04:27 AM
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swartlkk
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That is true, but a bad cat can cause over-fueling symptoms (fouled plugs, etc). Since you know you have a rattling cat, that would be the next step in the process since you either cannot or will not go through what has been suggested. Suggestions that I make are to help you help us determine the true cause of the problem before you replace any parts.
Who cares if it is wet inside, the only reason to look at that is if a fuel pressure check indicated that there was a leak.
As far as cleaning the O2 sensor... Well, sometimes that can cause more harm then good. I would just leave it.
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RE: Need help again on Spark Plugs Fouling out - 12/25/2008 11:35:26 AM
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riverjamie
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Thank you for the feedback. So I''ll get the new plugs so it will run, take it to get the cat replaced. Then what would you suggest, should I just run it for a while, because more that likely it will run. Pull the plugs at 500 miles inspect or should I just take it in an have the dealer do a diagonstic on it?
Again thank you for all the prompt feedback. Happy Holidays to you and your family
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RE: Need help again on Spark Plugs Fouling out - 12/25/2008 11:54:40 AM
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swartlkk
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You do not have to wait 500 miles to read the plugs. A hard run or two was all that it took to assess my tune on my Chevelle when I was running it.
One more question on the plugs, do they all look the same or similar in the amount of buildup, color? Have you tried just cleaning the plugs?
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