Bad gas mileage, runs lean, hesitates

[EDinNC]

My '92 EX, auto has been getting around 15mpg for quite a while. I've read the forum for quite some time and want to thank all the contributors for the very helpful info that I have learned.

This is what I've done so far for maintenance and to correct the problem:

Replaced O2 sensor (NTK)
Cleaned egr valve and egr ports
New fuel filter
New plugs and wires (NGK)
New distributor
Rebuilt TCU
Compression test (highest to lowest are within 10 percent of each other)
Seafoam in the gas tank

I have gotten a code 43 since the problem began and still do. The car runs very lean. Plugs are white after 1000's of miles. They are all the same color. Car hesitates, esp from a stop. It is so bad that with a/c on it will barely move from a stop. It also occasionally pops through the intake.

I am really at a loss as to what may be the problem. I'm thinking maybe FPR or ECU but I hate to continue throwing parts at the car. Any help would be greatly appreciated!

[mtnbikaah]

Even though you have replaced the O2 sensor I'd replace it again. Try a Denso one this time perhaps.

[deevergote]

Code 43 is most often an o2 sensor code, though it can indicate other fuel supply issues.

I would check your fuel pressure. Also, inspect your fuel lines for a leak.
Having your injectors professionally tested and cleaned might be worth a shot.

[High5er]

I would check your fuel pressure.

Defintely, I'd try disconnecting your fuel supply line and turning the car to the on position and see how much gas is comin out. It just makes sure your fuel pump is working properly. I've done this quite a few times

[deevergote]

Watching the fuel gush from an open fuel line is no way to gauge fuel pressure. Use a fuel pressure gauge.

[EDinNC]

Thank you all for your input.

I was thinking about trying another O2 sensor but it seems unlikely that the old and new one would both be bad. But hey, you never know.

I think having the injectors cleaned is a good idea, for maintenance, if nothing else. Any suggestions as to where to have that done, and cost? All the plugs are the same color. I would think that there would be some variance if the injectors were the problem but want to do that anyway.

At what point would I check the fuel pressure? Before the fpr? What should the pressure be?

Hopefully tomorrow I will be under the car replacing the oil cooler o ring and will check the O2 wires also. Started the car after work Friday and oil was leaking onto the exhaust. It is coming from where the cooler meets the block. Had to order the o ring, but thanks to the forum, I know what the problem is and how to fix it.

[wagon-r]

Thank you all for your input.
I think having the injectors cleaned is a good idea, for maintenance, if nothing else. Any suggestions as to where to have that done, and cost?

I used Mr. Injector and was extremely pleased with the results. $16 per injector plus $5 shipping.
http://www.mrinjector.us

[High5er]

Watching the fuel gush from an open fuel line is no way to gauge fuel pressure. Use a fuel pressure gauge.

Well if theres barely any fuel coming out.. but yeah a fuel pressure gauge would be a lot more accurate

[deevergote]

Thank you all for your input.

I was thinking about trying another O2 sensor but it seems unlikely that the old and new one would both be bad. But hey, you never know.

I think having the injectors cleaned is a good idea, for maintenance, if nothing else. Any suggestions as to where to have that done, and cost? All the plugs are the same color. I would think that there would be some variance if the injectors were the problem but want to do that anyway.

At what point would I check the fuel pressure? Before the fpr? What should the pressure be?

Hopefully tomorrow I will be under the car replacing the oil cooler o ring and will check the O2 wires also. Started the car after work Friday and oil was leaking onto the exhaust. It is coming from where the cooler meets the block. Had to order the o ring, but thanks to the forum, I know what the problem is and how to fix it.

Don't assume that just because your o2 sensor is new that it can't be faulty. I've seen many people on here over the years do just that, and they deal with constant frustration and expense before they realize it!

Here's a picture of a pressure gauge installed on an F22A (taken from a cardomain page belonging to swt_CB7.)

I've never actually installed one myself, so this is about the best I can offer. I don't know the proper pressure offhand, but a quick Google search says the proper range should be between 34 and 41 psi. You might want to confirm that by another source, but it will at least give you a ballpark estimate to work with!

I used Mr. Injector and was extremely pleased with the results. $16 per injector plus $5 shipping.
http://www.mrinjector.us

Wow, that's pretty cheap! I've seen injector cleaning and balancing services charging up to $80 per injector!

[EDinNC]

Thank you all for your input. The injector cleaning sounds like a good deal. I'm definitely going to get that done soon. Unfortunately, the oil cooler o ring now won't be in until Thur. so I will need some time to recover from having the car laid up for a week before I lay it up again.

Deevergote: The fauly O2 sensor idea has been rolling around in my head for a while. I might as well pop for another $40 to put that issue to rest. That will probably be my first step.

Thank you for the fuel pressure and gauge info. I will try to locate a gauge and check the pressure.

It might be a week or more, but I will report back and share my results with the forum.

[EDinNC]

Update: Installed the oil cooler o ring. That was pretty straightforward and just involved removing the oil filter and a bolt.

About the same time that the oil began leaking the car developed another problem. It would start from cold and then just die. Went into the fast idle mode fine but then just die.

Pulled the codes today and I'm getting a code 15 (along with the ever present code 43). From what I've read, the ecu is not getting a signal from the igniter.

So, I'm ordering a new Cardone dizzy, Denso O2 sensor, and a Standard ECT sensor from Rock Auto. I hate to just throw parts at it, but I am on a mission now

[Losiracer2]

It is highly unlikely that an OEM NTK (NGK) brand O2 sensor is bad. They're better quality than Densos.

I would also replace the PCV valve since they're under 3 bucks.

Its most likely your ECU that's bad since you've tried everything under the sun already. Try a new PT6 and see if it drives any different. Should be able to get one for <$50.

But before you do that, make sure your timing is correct; that'll have a HUGE affect on driveability and fuel economy. If its popping out the intake, you're most likely off by a tooth or two on the T-belt.

[EDinNC]

Thanks Losiracer2 for the info. I did replace the pcv, forgot to mention it. I am going to check the timing again. It shouldn't, but could, be a tooth off. The belt wasn't replaced when the problem began. Maybe it jumped somehow?

The ecu has been nagging at me lately. I'm beginning to think it may be the problem. I was hoping to find a rebuilt ecu for a decent, but can't find one yet. Probably have to get a used one.

[ThePhantum]

Wow. I hope you figure it out soon. I went threw 2 used ($5 each), then a new o2. I finally had a friend come over with his Àccord and barrowed his o2 sensor, sure enough all were bad. I returned the new and they gave me another. No problems after that. Good luck with it!!

[EDinNC]

OK, time for an update... this afternoon I replaced the ecu with a used one from ebay (pt6-a51), cost was $40. Drove it for about 15 miles afterwards. Mid range performance was much better. Before, at around 40mph, it had zero power until the tranny downshifted. Still a serious hesitation from stop with the ac on.

No cel and no codes, yet. Not sure about gas mileage. But the gauge did move quite a bit. I will fill up the tank and drive it more the next few days to check mileage and cel.

BTW, when I check for codes, the cel is a steady amber. I'm assuming that means there are no codes. Is that correct?