I'm stumped. I can't seem to figure out why my 91 4runner w/ the 3.0L won't run. Here is the background. About 3 months ago I got some bad, possibly rusty, gas out of a 50gal drum my father-in-law had. Since then it has not run well. I ended up changing the filter and cutting the cat off, as I found out it was plugged. Well those changes did help and it would run and start better. But now at 200,100+ miles it is getting worse. I can barely get it to start and when it does start you have to wait for it to warm up first otherwise any throttle input will cause it to stall and die. Even when it does warm up if you stomp the throttle to the floor it bogs down and will die if you don't let off the throttle. You have to very slowly accelerate and then it is ok. I have checked the plugs & they were black. So I checked compression on all cyclinders and the average was 122psi. That right there tells me that my cyclinders are wearing out. What I want to know is besides the low compression, how can I tell if it is the fuel pump or injectors that are the culprit. Or is it something else. I would love to keep this awesome vehicle running so any help is greatly appreciated. I did notice that while testing the fuel pump, by jumping two wires in the diagnosis port, and letting it run for a long time as I tried to see if I was getting pressure, it did start up on the first crank. Weird huh? I can't get my hands on a fuel pressure gauge to verify my actual pressure, so any other ideas? Thanks.

sorry for the long thread

 

*sorry for my "longer" answer


You've got several things at issue here and there's a couple I read that point towards at least one significant problem: fouled plugs and low compression. Those are enough to contaminate the converter and cause it to overheat and/or plug up. And given those issues, there's a high likelyhood that the O2 sensor(s) have failed as well as they don't take kindly to rich mixtures and exposure to too much engine oil.

I would probably, in this order:

1) check for any engine trouble codes- just because the light isn't on doesn't mean the ECU hasn't picked up on a problem- and fix any problems associated with any codes you receive.

2) due to the issue with starting, idle and throttle response:
- a) check for any leaks/cracks/breaks in the pipe from the air filter housing over to the engine and replace anything found damaged.
- b) test and adjust/replace the throttle position sensor if necessary
- c) test and replace the air flow meter if necessary
- d) test and repair/replace the egr valve if necessary
**I'm going to add that fouled plugs and low compression can also contribute to poor engine response but we're going for extending what you have, not rebuilding your engine here.

3) clean the intake and fuel system:
- a) Get some good quality Throttle Body or MAF Sensor Cleaner, and using about 1/4 - 1/3 of the can: remove the duct from the throttle body and while holding the throttle plate open, spray MAF or Throttle Body cleaner into the intake (using the straw) and try to spray it all around; reconnect the duct and start the engine. Let it run for a minute or two then REPEAT again using part of the remaing cleaner... start... clean... start... etc. until you've used all of the cleaner. Alternately, you can disconnect a vacuum hose that has vacuum when the engine is running and spray the cleaner through the hose while the engine's running, or use Seafoam or Berryman's B-12 Chemtool cleaner and put the end of the hose in the can letting the hose suck the cleaner through until the engine stalls, restarting the engine without the cleaner being sucked in as neccessary, until the cleaner is gone. You may want to let the engine set 10-15 minutes if the engine happens to stall. Be warned- it will smoke A LOT!
- b) run the tank as low as you feel safe doing; fill up with 1/2 tank of good quality gas (not cheap 'corner-store' gas, but something like Chevron, Mobil or Arco/BP PREMIUM/92 octane) and add 1-2 cans of berrymans B-12 Chemtool cleaner or Seafoam (though it's not done anything for me, others swear by seafoam so I won't totally deny its efficacy) and run that tank through to almost empty (take note- the engine may run like crap, but likely no worse than it does now)... then fill up with good gas, change the O2 sensor(s), spark plugs, distributor cap, wires, rotor and PCV valve... then see how it goes.

4) valve adjustments

There are other issues that may be related to or cause the things mentioned above but they could be remedied by a good tank flush, injector cleaning and tune-up... or engine rebuild.

 

I would NOT use Arco gas, it leaves crap on your valves.

 

I write all that, and that's all you have to say?
I did say '1/2 tank and 1-2 cans of cleaner, no?"

 

lol, thats the only thing id change, your post was awesome.

I still wouldnt waste my money on arco even tho you are just gonna waste the gas.

Just my 0.02. Haha.

 

Thanks for the awesome input. I'll see what I can do. The big question is now, how much $$ do I want to put into a vehicle with 200,000+ miles and I only paid $500 for the vehicle in the first place. I'll definately go through and do some more testing. How can you check engine codes? The check engine light has never came on, so how do you read codes?