I have a 1991 2.6 fuel injected Isuzu pick up (space cab). Haven't driven it in over a year (I did drain the gas before I parked it) It idles well enough, but when I take it out on the road it has no acceleration. If feels like I am getting plenty of gas but no air. I also have spark. The check engine light only rarely flashes briefly and when I ran the codes I got 12 and 61. I changed the Oxygen sensor and the mass air flow sensor with no change in performance. I checked the wires from the MAF to the computer to see if it was connected and all looks well. I took out the computer to see if I could see any damage there and it looks brand new (no dust). The throttle valves open when I press the accerator, the Vacuum valve switching assembly seems fine, because I tested it by disconnecting it and when I did it gave me a code 25. Im at a complete loss. The exhaust has several rusted holes in it. Would lack of back pressure throw a code 61? If not what else can?
Country: United StatesMake: IsuzuModel: Pickup Normal CabYear: 1991Engine: 2.6 fuel injected
MAF sensor, oxygen sensor
sorry to hear of your misfortune :(
sounds like either a plugged fuel filter or plugged catalytic converter.
does running it with the air cleaner removed help at all?
I changed the fuel filter and I cut off the cat in order to get the right pipe size to reinstall it. I basically have no exhaust at the moment.
well its official you've stumped the auto psychic lol
relistling your question now so one our smarter experts can help.
good luck, gary
I've had a cat go out before on a bonneville with similar symptoms. But when the cat went out on the Bonneville I couldn't get over 15 mph. I can get the Isuzu occasionally up to 60 but only by barely holding down the accelerator and lightly tapping it. If I push down on it and give it the gas it will only bog down.
I should mention when I was driving it I had the cat on it, but the muffler was rusted through (basically no muffler). Like I said I haven't driven it in over a year. I'm trying to get it road worthy and put a new exhaust system on it. I should also mention that on Monday it completely died. Couldn't start it Monday or Tuesday which is the day I took out the computer. I put the computer back in tonight when I got home from work and I had nothing. No lights (computer lights check engine, seat belt, door chime no gauges, nothing. I gave up and threw in the towel since I put the computer back in EXACTLY the way I took it out. Was extremely gentle with it. But then a friend called tonight and asked how the truck was going. and I told him it was dead. But I went back out and tried one more time to turn it over and the computer fired up and the truck started. Came back to life like the terminator, although the no air problem hasn't changed. And code 61 still comes up when I run the codes. I
Relist: Other.I posted my question and Auto Psychic said he was stumped and would relist it. I got an email from TED-380676 who says he has an answer, but I don't see it on here.
Hello!New Expert here!Did you still need help?Can you get the vehicle to act up so we can run a few tests?
Yeah, its running but with the same problem, not enough air. The only code it throws is 61. I'm at work right now, but would love to hear any ideas you might have, when I get off this evening.
When you have some time, I will need to know what the o2 sensor voltage is at under a load when this problem happens. Let me know!
How am I going to get that? I also put in a known faulty O2 sensor and it threw a code 13 I believe. I since put the new one back in and no longer get that code. I know its getting gas because I can hear the crackle of vapors igniting in the exhaust. And when I had it out on the road and managed to get it to 60 with a struggle it would purr beautifully (relatively speaking for its age a little lifter noise) as long as I didn't try to accelerate, once I did that I would lose power and speed if I decelerated I would get the pop pop pop in the exhaust.
Hello! You will have to hook up a voltmeter to the o2 sensor voltage wire and take a reading while this problem is happening. You can get it to act up by doing a brake stand and getting a volt reading then or by running a wire from the o2 sensor to the voltmeter inside the vehicle while you take it for a test drive and get it to act up
ASE MASTER TECH ADVANCED LEVEL SPECIALIST
Hello!It looks like this question says waiting for Expert reply? I am not sure why but I just wanted to see if you have any further questions. If not, let me know the readings when you get a chance.AMEDEE
It was a bad O2 connector. Still sluggish though, but it will accelerate slowly. I think that might be another issue. You set me on the right track. I think I can figure out the rest. I really appreciate your help. About to leave cell phone coverage. Will try to write more on Sunday. Have a great weekend.
Thanks for honoring your good faith deposit by accepting my answer.Please let me know if you have any further questions!
The O2 sensor didn't work. I put in another one. Proper torque, ran a little better for about 30 miles, then back to the same thing (it was alweays the same thing, just a little better). I didn't have the O2 tight enough when we started and once I got it tight the code 61 went away. Now I have no codes. So what you did suggest helped, but now I'm getting 50 miles half a tank. Went from 11 mpg to about 6 mpg. Thinking it might be a bad fuel pressure regulator. I ordered a new one and should be in today. Let you know how it works.
That didn't work either. I tell ya, I get the hard problems. Next option is timings off or leaky injectors. Truck has 270K miles on it, I got it at 186K in 05 but driven it since 03. Bought it from the company I use to work for. I know in 95 it had 135K and in 03 it had 165K. I ASSUME someone working for the company blew the engine and then let it set for 7 years before they decided to get it fixed (possibly a rebuilt engine) and ship it to our office. Why else would it have 30K miles in 7 years? Also I think most of those were put on in 02? Since I've owned it I've only had the spindle fixed, timing belt replaced, fuel pump and a main pulley fixed in 100K miles. So I can't say it hasn't been a good truck. Not opposed to rebuilding it and putting money into it. Just wish I knew what the problem was. Although if the fuel injectors ar 21 years old they might need to be replaced (regardless if it fixes the problem or not)..
You will have to check the ignition timing by pulling the front cover. You can also see if the injectors are leaking fuel by checking fuel pressure. If it leaks down after the engine is turned off, this could be an indication of leaky injectors.