Isuzu Mechanic Needed- new problems

[Bigcypresshunter]

Re: Isuzu Mechanic Needed- problem still not solved

Water in the tank/plugged filter. You have to remove the tank to drain it, or punch a hole in the lowest level. Plug punched hole with a rubber washered sheet metal screw. Running out of gas does not drain the tank. After you put more gas in, guess what? Your right back where you started. Maybe a filter that you have overlooked? A pinched line? My old C-J gave me fits. Finally replaced a rubber fuel line. It wasn't leaking fuel, but sucking air.

First thing I changed was the fuel filter. I dropped the gas tank to replace the sensor. I have all new gas. Fuel pressure is good at 45 pounds. Ive been driving several weeks filled up twice. Thanks.

 

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[Bigcypresshunter]

Re: Isuzu Mechanic Needed- problem still not solved

I know that you said that you replaced the converter, but it really sounds like the exaust is stopped up somewhere. Can you get under it, and take the pipes away from the manifold, and try driving it like that. It will be very loud, but it will let you know if it is in the exaust.

Also, is this a fuel injected engine ? Does it have 4 seperate injectors for each cylinder, or is it a throttle body ?I know you are getting enough fuel pressure, but you may have an injector not busting open, or staying open.

When you run it, pull the plugs out and see what they look like. Are they wet, with gas, or even water ? Are they black and dry ?

That o2 code could yet be the problem. I don't know but does your scanner, read as a graph to watch the o2 sensors ?

I too believe its plugged somewhere in the exhaust. Manhatter Muffler shop put a new convertor on today. Im going outside before it gets dark Ill be back. Thanks I appreciate it.

 

[Bigcypresshunter]

Re: Isuzu Mechanic Needed- problem still not solved

If you have a bad o2 sensor like your scanner is saying, it could be telling the computer to give it more gas, or even less gas. That just made me think of something else ! Take and unplug the mass air flow sensor and see how it runs then.

What will that tell me?

 

[Bigcypresshunter]

Re: Isuzu Mechanic Needed- problem still not solved

Could it make that much difference? The front O2 sensor code came up and I replaced it. Now the back O2 code is bad. I fix 2 codes and 2 more pop up it seems.

 

[lincha]

Re: Isuzu Mechanic Needed- problem still not solved

Have you changed the crankshaft sensor?

 

[Bigcypresshunter]

Re: Isuzu Mechanic Needed- problem still not solved

I dont have time to respond to every question at this moment but I just found a cracked exhaust manifold. Could this be causing my problem? I dont know yet if its causing a blockage inside.

 

[Bigcypresshunter]

Re: Isuzu Mechanic Needed- problem still not solved

Have you changed the crankshaft sensor?

No I dont show a crankshaft sensor trouble code. I changed the CMP camshaft position sensor because I had a trouble code. Ater a week or so of driving the CMP Camshaft sensor code has just today came back on.

 

[Bigcypresshunter]

Re: Isuzu Mechanic Needed- problem still not solved

I dont have time to respond to every question at this moment but I just found a cracked exhaust manifold. Could this be causing my problem? I dont know yet if its causing a blockage inside.

I would highly doubt it. It may have burnt some valves in the motor, but you would have noticed that along time back probably. Have you unplugged the mass air flow sensor yet, and test drive it ?

I havent tried disconnecting the MAP sensor, Ill try tommorrow thanks but my scanner says its good. Why would the MAP trouble code not come up?

At the exact moment my my truck started running bad, my exhaust got a different sound. Maybe this is throwing off the O2 sensor signal.

If I had a burnt valve wouldnt my compression be bad?

I think its possible to be a blockage inside from a broken piece of cast iron. Im heading to the junkyards to try and find one. I need to replace it anyway.

I really appreciate your help.

 

[Bigcypresshunter]

Re: Isuzu Mechanic Needed- problem still not solved

Codes can be tricky sometimes. Especially o2 codes. The o2 sensors are reading what is coming out of the engine, and telling the computer if it needs to rich or lean anything.

If you unplug the mass air flow sensor and it starts running better, it needs a mass air flow sensor. It will go into a limp mode. You can also try and spray it real good with some cleaner, and try that before you go out and buy one, if that is what's wrong.

Back to the o2 sensor codes though. I thought of the mass air flow, because of what I told you about what the o2 sensors do. If something is acually wrong with a sensor or injector, or not firing, or whatever else, it's not getting enough gas, or getting too much. It can read a o2 code, and not have a bad o2 sensor. So everything needs to be checked to see if it's getting enough fuel, or too much fuel.

Another question. How do I know its not already in limp mode? Except for cold start, it runs well. It just feels like Im pulling a heavy trailer. Thats why I thought the convertor was plugged. Im thinking the exhaust manifold leak is causing the O2 codes and this may be the whole problem. (I hope) It needs to be fixed anyway so I might as well do it first.

 

[Bigcypresshunter]

Re: Isuzu Mechanic Needed- problem still not solved

Running out of gas does not drain the tank.

Hello kenley. What do you mean? I ran the tank out of gas. Then I added a gallon to get home. I disconnected the line at the fuel filter. I clicked my key on and off until all the remaining gas was pumped out. I then dropped the empty gas tank and replaced the sensor. I visually confirmed the tank was completely empty.

That fixed my gas gauge, cooling fan and removed the P1 trouble code but it didnt solve the lack of power problem.

 

[Bigcypresshunter]

Re: Isuzu Mechanic Needed- problem still not solved

The leak at the exhaust manifold could be triggering the o2 code. This could be throwing the computer off and telling it to add more fuel, or even less fuel, by keeping the injectors either open or closed longer. There may very well be nothing wrong with the 02 sensors themselves, it's just that they are reading something different, and trying to tell the computer to compensate for the difference.

Thats exactly what Im thinking!! The crack is about 5 inches long. Ill take a picture tommorrow. I didnt see the crack at first because it was under a heat shield.

Only problem Im having trouble finding this 4 cyl at the junkyard. The junkyards were full of nice SUV cash for "clunkers" a few weeks ago but now they are all smashed. That was one of the worst government programs.

 

[Bigcypresshunter]

Re: Isuzu Mechanic Needed- problem still not solved

Heres the crack. I didnt see it until I removed the heat shield.

 

[mojjax]

Re: Isuzu Mechanic Needed- problem still not solved

Heres the crack. I didnt see it until I removed the heat shield.

Maybe you could put some furnace cement on it

 

[sniffer]

Re: Isuzu Mechanic Needed- problem still not solved

that's actually a minor crack. I don't think that's your problem.
it sounds electrical to me, check all your plugs going to your computer. unplug them completely and check for any kind of corrosion, because it sounds like you have a bad ground.
one other thing I just thought of, see if you can get someone to check your coil pack. it could have a short to ground inside

 

[lostcauses]

Re: Isuzu Mechanic Needed- problem still not solved

Is this still happening??


"I am still getting 12 volts to one side of the camshaft sensor. I supposed to get 4-6 volts. Any ideas? I need someone familiar with these codes. "

 

[Bigcypresshunter]

Re: Isuzu Mechanic Needed- problem still not solved

Is this still happening??


"I am still getting 12 volts to one side of the camshaft sensor. I supposed to get 4-6 volts. Any ideas? I need someone familiar with these codes. "

After studying the wiring diagram, I realized that 12 volts to the sensor is normal because it comes directly from the fuse and the other side (input to computer) is also normal at 4-6 volts.

 

[Bigcypresshunter]

Re: Isuzu Mechanic Needed- problem still not solved

that's actually a minor crack. I don't think that's your problem.
it sounds electrical to me, check all your plugs going to your computer. unplug them completely and check for any kind of corrosion, because it sounds like you have a bad ground.
one other thing I just thought of, see if you can get someone to check your coil pack. it could have a short to ground inside

I pulled each spark plug wire off one at a time and with each wire the engine speed decreases and gets rough. Each wire is sparking. I have 2 coils and they both appear to be working.

The plugs to the PCM seemed good. I may need to check again. Ill try to recheck and test the coils.

I just got back, I am going to call around for the manifold. I dont think its coincidence that the problem started and the exhaust got louder at the same instant. I need to change it anyway. Its almost cracked completely in half! There could be a restriction inside from a cracked partition. Theres one on eBay.

http://cgi.ebay.com/ebaymotors/98-9...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

 

[Bigcypresshunter]

Re: Isuzu Mechanic Needed- problem still not solved

Maybe you could put some furnace cement on it

Maybe but I should be able to buy one cheap at a junkyard if I can find one. Im thinking a restriction inside. I notice there are two exhaust holes in the bottom and one side may be plugged.

Thanks Mojjax, sniffer, lostcauses, lincha, kenley, mcgearhead and everyone else who responded earlier.

 

[DCMatt]

Re: Isuzu Mechanic Needed- problem still not solved

Not sure this will help but I'll mention it anyway...

I drive an '88 4Runner. Had a new motor put in by the high school shop class. They did a great job and the teacher is a buddy who has worked on my cars for a while now. It ran OK but was sluggish and would sometimes "stumble" at highway speed. The teacher took it back (he moonlights at a local dealer shop) and did everything he could think of but it still had the trouble.

After TONS of research, I discovered it was a partially clogged EGR valve. I pulled off the vaccuum hose and ran a heavy twisted copper wire down it a few times. It came out black and gooey each time. That cured my problem. That was about 2 years ago.

Good luck

Matt

 

[Bigcypresshunter]

Re: Isuzu Mechanic Needed- problem still not solved

Not sure this will help but I'll mention it anyway...

I drive an '88 4Runner. Had a new motor put in by the high school shop class. They did a great job and the teacher is a buddy who has worked on my cars for a while now. It ran OK but was sluggish and would sometimes "stumble" at highway speed. The teacher took it back (he moonlights at a local dealer shop) and did everything he could think of but it still had the trouble.

After TONS of research, I discovered it was a partially clogged EGR valve. I pulled off the vaccuum hose and ran a heavy twisted copper wire down it a few times. It came out black and gooey each time. That cured my problem. That was about 2 years ago.

Good luck

Matt

I could check it thanks. The reason I didnt check it was because the EGR trouble code never came up. Im assuming the trouble code didnt come up for your friend the teacher either. I wonder why?

My symptons are a rough cold start. After warm up it runs smooth but no power. It feels like Im towing a heavy trailer. Top speed is 65 MPH downhill or level once Im up to speed. Up hill is a problem and the hills in South Florida are very small. Also it almost stalls when I stop. The idle RPM goes way down for a second and then back up to normal. Exhaust louder than usual, no smoke from tailpipe.

Its a 98 Rodeo 2.2 L 4 cyl Honda engine, 5 speed stick shift trans. 190, 000 miles but it was well taken care of for the majority of time. Oil change every 3000 by first owner. Good compression and a new cylinder head & timing belt by second owner. I have had it 1 year and it always ran great.