Greggclark
New Member
- Joined
- April 2, 2009
- Messages
- 1
- Reaction score
- 0
- City, State
- Upstate New York
- Year, Model & Trim Level
- 98 mazda B4000 V6 4.0
Hello to everyone. I just joined in order to shed some light on a issue I had to figure out myself and post it here in case it helps someone else down the line.
I spent days researching PO171 and PO174 lean bank 1 and lean bank 2 problems. I pulled codes and here is what happened in the next months:
My sons 98 Mazda B4000 v6 4.0 with 109,000 miles on it. I had new plugs in it about 12K ago and air filter..just for maintenance reasons. I had my son pick up the plugs..NGK's. OK, vehicle continues to run well...months down the road, my son tells me it is running very poorly. I do a fuel filter first as old one looked old..new fuel filter and no improvement. OK, scan for faults as the light went on..pull codes..misfire #5 sorry, forgot code ( po305? ) anyway, I suspect a bad fuel injector, I change #5 injector. Vehicle runs fine again.
Now, months later and after I had told my son NOT to run fuel level low..he had run out of fuel once and ran it low a few times ( Kids!!) Vehicle runs real bad again...I put in fuel treatment like crazy and change fuel filter once again. Still runs lousy. Light is on again so pull codes..lean 1 and 2 and misfire #5. OK, possibly that Autozone injector has failed. Go to Mazda, order gaskets and new fuel injector from them. OK, install. Truck STILL runs poorly, as if coil pack was bad but I had charged that with first injector swap on #5 ( forgot to mention, along with new ing. wires at that time. OK, with ANY load on the engine it bucks very badly and if you very easily press on the gas it may pull somewhat normal but not really..just not as bad as WFO. Anyway, here I am scratching my head as to WTF. So, my son mentions that when he makes a left turn, truck runs better..hummm..possibly a clogged cat? OK, I drop front Y pipe, take truck out..runs just as bad. Re hook up exhaust. My buddie tells me the O2 sensors are reacting correctly with his scanner. OK, I call my bud at the local auto parts store, ask him what plugs are OEM for this truck, he says double platium..I know from checking spark on #5 cylinder a while back that the spark was good BUT was a normal type NGK. I get 6 new Boush plugs and install them. Lord behold!! Truck runs 90% better. ( Opps, forgot to mention I had checked fuel pump pressure before..66 LBS at idle and WFO.
OK, my son is more than happy that truck runs ok. I am NOT happy as the idle is too high and in 5 gear ( manual) it feels on the edge of lean..like it needs jetting is a carb truck. Anyway, the light come on again !! Yes..lean bank 1 and two...NO mis fires. OK..vacume leak, but where?? I change all vacuum hoses and check intake hose and everything I can. No problem found. Now I say fudge it..I am ripping this apart AGAIN to see what is going on ( Oh yeah..I checked #5 compression a while back..it was 130LBS = OK.)
So I take the upper intake OFF the truck and clean it in my safety clean. Rinse with water, spray with Fantastic and air hose dry. I am looking for cracks in the upper plastic intake manifold..see no cracks. Now I take a cigarette ( yep, I still smoke) and blow smoke into the intake runners. I now take the air hose from the compressor in my shop and put the tip over the SEAM of the upper intake. The smoke bellows out in different areas of where I put the air hose. Hummm..I had used carb. clean, ether and propane to test this area and others with with engine running and no increase in idle or change..How is it that forced air makes the smoke move..Well, take no chances. I had some lock tight epoxy in stock , the 5 min set up mix as you push double tube clear stuff. With plastic upper intake clean I run a bead around the ENTIRE two half's on the intake. I let it set up for a few hours, reinstall and start up. Yes!!! It idles correctly AND pulls harder that ever before!! The upper intake was leaking in areas undetectable to sprays while running. Yes, a smoke machine would have been nice but no one has one that I know. So..I just spent the last 15 mins. writing this to inform all of you that this can be/is a issue you must look at with these codes. In all my searching, I found nothing pointing to this issue..maybe it IS here somewhere but I didn't see it. Oh..while I was in there once again, I checked lower intake manifold bolts..yes they were loose..and the fuel rail studs..tightned a little more.. I almost think that the spray while running has no effect on this issue as the PRESSURE wasn't there like with the air hose..Anyway, I feel better now that possibly SOMEONE will look here and fix a ongoing issue with PO174 and PO171. keep the rubber side down
I spent days researching PO171 and PO174 lean bank 1 and lean bank 2 problems. I pulled codes and here is what happened in the next months:
My sons 98 Mazda B4000 v6 4.0 with 109,000 miles on it. I had new plugs in it about 12K ago and air filter..just for maintenance reasons. I had my son pick up the plugs..NGK's. OK, vehicle continues to run well...months down the road, my son tells me it is running very poorly. I do a fuel filter first as old one looked old..new fuel filter and no improvement. OK, scan for faults as the light went on..pull codes..misfire #5 sorry, forgot code ( po305? ) anyway, I suspect a bad fuel injector, I change #5 injector. Vehicle runs fine again.
Now, months later and after I had told my son NOT to run fuel level low..he had run out of fuel once and ran it low a few times ( Kids!!) Vehicle runs real bad again...I put in fuel treatment like crazy and change fuel filter once again. Still runs lousy. Light is on again so pull codes..lean 1 and 2 and misfire #5. OK, possibly that Autozone injector has failed. Go to Mazda, order gaskets and new fuel injector from them. OK, install. Truck STILL runs poorly, as if coil pack was bad but I had charged that with first injector swap on #5 ( forgot to mention, along with new ing. wires at that time. OK, with ANY load on the engine it bucks very badly and if you very easily press on the gas it may pull somewhat normal but not really..just not as bad as WFO. Anyway, here I am scratching my head as to WTF. So, my son mentions that when he makes a left turn, truck runs better..hummm..possibly a clogged cat? OK, I drop front Y pipe, take truck out..runs just as bad. Re hook up exhaust. My buddie tells me the O2 sensors are reacting correctly with his scanner. OK, I call my bud at the local auto parts store, ask him what plugs are OEM for this truck, he says double platium..I know from checking spark on #5 cylinder a while back that the spark was good BUT was a normal type NGK. I get 6 new Boush plugs and install them. Lord behold!! Truck runs 90% better. ( Opps, forgot to mention I had checked fuel pump pressure before..66 LBS at idle and WFO.
OK, my son is more than happy that truck runs ok. I am NOT happy as the idle is too high and in 5 gear ( manual) it feels on the edge of lean..like it needs jetting is a carb truck. Anyway, the light come on again !! Yes..lean bank 1 and two...NO mis fires. OK..vacume leak, but where?? I change all vacuum hoses and check intake hose and everything I can. No problem found. Now I say fudge it..I am ripping this apart AGAIN to see what is going on ( Oh yeah..I checked #5 compression a while back..it was 130LBS = OK.)
So I take the upper intake OFF the truck and clean it in my safety clean. Rinse with water, spray with Fantastic and air hose dry. I am looking for cracks in the upper plastic intake manifold..see no cracks. Now I take a cigarette ( yep, I still smoke) and blow smoke into the intake runners. I now take the air hose from the compressor in my shop and put the tip over the SEAM of the upper intake. The smoke bellows out in different areas of where I put the air hose. Hummm..I had used carb. clean, ether and propane to test this area and others with with engine running and no increase in idle or change..How is it that forced air makes the smoke move..Well, take no chances. I had some lock tight epoxy in stock , the 5 min set up mix as you push double tube clear stuff. With plastic upper intake clean I run a bead around the ENTIRE two half's on the intake. I let it set up for a few hours, reinstall and start up. Yes!!! It idles correctly AND pulls harder that ever before!! The upper intake was leaking in areas undetectable to sprays while running. Yes, a smoke machine would have been nice but no one has one that I know. So..I just spent the last 15 mins. writing this to inform all of you that this can be/is a issue you must look at with these codes. In all my searching, I found nothing pointing to this issue..maybe it IS here somewhere but I didn't see it. Oh..while I was in there once again, I checked lower intake manifold bolts..yes they were loose..and the fuel rail studs..tightned a little more.. I almost think that the spray while running has no effect on this issue as the PRESSURE wasn't there like with the air hose..Anyway, I feel better now that possibly SOMEONE will look here and fix a ongoing issue with PO174 and PO171. keep the rubber side down
