P1133 Code
 

So last week I had the P1133 code, that's the only one.
I know what it means so I ask what have others done about this?
Tuesday it was 0 degrees and Wednesday it was 5. Tuesday no issue, Wednesday is when it came on. I let it warm up 10-15 minutes before driving. I was driving about 3 minutes when the SES light came on, nothing unusual about the running condition. Got it scanned later than day, cleared it and no light since.
Is it possible it was a fluke? due to cold weather?
I check the O2 (bank 1, before the cat)and it was plugged in, no wire rub through that I can see.
Its a new 02, approx. a month old.
I read it can have something to do with the vacuum? according to the code.
Again a week later and no light.
Suggestions???
Thanks

1995 had 3 different computer control systems. If yours gave you a DTC starting with "P", it narrows the possibilities down to two systems. Diagnostics are different between the two systems. Either way, P1133 is insufficient switching in the oxygen sensor. If there are no other DTC's in memory, and you just replaced the sensor a month ago, get another one. Avoid Bosch if at all possible and go with Denso or AC Delco.

I have installed the Denso brand, I thought it was Standard, but I checked the receipt.
It has not come on again, will it take multiple failures to trip the SES light?

If the PCM detects a failure during the test on 2 consecutive key cycles, it will turn the SES light on and set the DTC in memory. The PCM turns off the SES light after 3 consecutive drive trips with no failure detected. The DTC will clear itself from the history file after 40 consecutive warm ups without a failure.

So yesterday the SES light reappeared, check out the code and it was P1133 again.
I put that Denso O2 in on December 10th.
Yesterday I cleared the code and put the old O2 back in to see of I get a light again, since previous I never had a light on, even after the spider change. I'm thinking the Denso is defective so maybe this will help I'm chasing down the problem.
I can get a replacement Denso free, or do I go for a Delco?
I initially changed it to see if my gas mileage
improved, it has not.
Only get 10-11mpg, I know it should be better.

In post #2, I mentioned that your vehicle could have one of two different computer control systems... need to know which one you have;)

Does your engine look like this?

Attachment 31443

And, in the following image, which sensor did you replace?

Attachment 31444

Yes the engine is that same one pictured. Sorry I didn't reply about that.
For the 02 I replaced the one before the cat, I only have two (2) pre cat and post cat.

For future reference, your vehicle has CMFI, (Central Multiport Fuel Injection) and uses OBD1.5 engine controls. The system is not fully compliant with OBDII requirements. It has a unique protocol that it uses to communicate with scan tools. Not all scan tools will communicate with it.

1. Check for, and repair, any exhaust leaks from the engine to the rear of the converter.

2. Check fuel pressure and leakdown. Key on, engine off, fuel pump running, pressure must be 55psi to 61psi. Pressure must remain above 50psi for at least 10 minutes after the pump shuts off.

If all checks are ok, stick another sensor in there and see what happens.

Ok thanks a lot, I appreciate the insight.
I use a OBDII scanner and it works, I read some 95's it will work, others it wont.
I or others I know in the automotive industry don't even have an OBD1.5 I already asked all my friends with no luck.
I have not seen any leaks in the exhaust from the headers back at all, I have checked a few times for one.
The pressure "should" be fine, I just had a fuel pump installed in September, they did a leak down there, after the install, BUT I did the spider after the fuel pump.
When I asked about the pressure test he said it was fine, but I do know the regulator was leaking, SO that means the pressure couldn't have been fine, or they didn't do it for the 10-20 minutes.
I did not do a leak down after I installed the new spider assembly and nut kit, I assumed it would be fine. I have looked inside the engine though a week after the install of the spider through the top of the plenum with a flash light and had someone do a few key turns to see if I seen a leak or seen any fuel inside, it looked clean just as the day I took it apart and cleaned it when I replaced the spider.
however I will try to do a leak down test on the fuel line.
Again I appreciate the responses.
I like the Jimmy but its been a headache, I got it cheap but now im putting cash into it..to much it seems!
I'm waiting to head out to a friends tonight to do a coolant pressure test, I got some antifreeze down low on the crank sensor area...hoping its just the water pump gasket and not the you know what....I cant seem to pin point it, to much in the way...you know how it goes.

Just because the fuel pump is new, is no guarantee that it's good, especially if it's an aftermarket pump, (lotta problems with aftermarket pumps).

The fuel delivery system is the weak point on this engine, and it is crucial that it works correctly. If pressure and or leakdown are out of spec, it will have performance issues.

Don't really have to worry so much about lower intake manifold gaskets leaking coolant on this engine. 1996 and newer, yeah, there a known problem... probably the water pump on yours;)

True, to many times people think "its new, so its good" Not the case, I have had issues with brand new parts in the past. just didn't have a tester for the fuel line, but now, I think ill go rent one or find one.
I used a Bosch pump, was told to stay away from Airtex.
maybe I got a defective injector, but as I said I had someone do a few key turns while I was watching for any leaks and didn't see any or raw fuel inside the plenum.


I hope, it appears to be coming from the area where the lower rad hose connects to the pump, but its to tight and I couldn't even see with a mirror, but I believe it right behind there.
So if I go tonight when he is done working ill do the coolant test and the fuel if he has a gauge.




Thanks

As for the leakdown, you might not see it in the plenum, but that doesn't mean it's not leaking in there. You definitely wouldn't see it if it's in the tank ;) Bosch pumps rank right up there with Airtex and Carter. Wouldn't surprise me a bit if you have some leakdown going on in the tank. In fact, it would surprise me if you don't have leakdown in the tank ;)

Oh geez...well if so its covered by the garage.
Would a fuel pump leak give bad mileage though?


How can I properly check the fuel pump?
I know for the regulator I was able to give the pump power so the gauge went up and then, after the fuel filter crimp off the two rubber lines to see if the regulator was holding, so what is the best way to check the pump?

If the fuel pressure is too high or too low, and/or leakdown too high or too low, it will absolutely cause poor fuel mileage.

Check fuel pressure and leakdown at the service port. Key on, engine off, fuel pump running: pressure must be 55psi to 61psi. Pressure must remain above 50psi for at least 10 minutes after the pump shuts off. Post your results. They will tell if the fuel delivery system is working as it should. If there's a problem, the source can be located rather easily. Crimping off lines can destroy the fuel pressure regulator. If there's a problem with pressure and or leakdown, we'll cross that bridge.

Thanks, I will work on this and post an update.
BTW I do have an ABS light on....not sure if it would be issue to cause poor mileage. I assume its a board issue that needs soldering. Wheel bearing good, checked the lines for the sensors on hubs, cleaned the sensors too and all seemed fine.

Took me a bit but today I got a Fuel Pressure tester.
Hooked it up, powered the fuel pump, the needle goes to 60-62, pump off and it drops to 20 almost instantly.
So, I pulled the plenum off, just to be sure its not the spider/fuel regulator and it is not. I had it opened up and powered the pump to check for leaks and there are not any.
So its the fuel pump, but how to I check before I drop the tank?
And easy ways to test it out? It is a Bosch pump.

A faulty FPR (fuel pressure regulator) can cause the symptoms you are experiencing without a noticeable leak in the plenum as it can dump into the return line to the tank. It could also be the check valve in the pump. The best way to tell which it is would be to install the gauge on the output from the pump, blocking off the rest of the system. The tech article on testing fuel pressure details this.

When I had the plenum opened and the pump had power, the spider assembly did sound like it was "leaking air" but no fuel.
Now I am not sure how it should sound due to it being pressurized but I'm sure there was no fluid leak.

I will try to make what is listed in the article to attach to the line where it would go into the fuel filter.
Then if there is no significant drop in pressure I will now its not the pump and the regulator.

So I attached the pressure gauge to the end of the filter with some fittings and here are the readings and times after 1:41 mark it still heald around 62-63 psi , it didn't drop at all even after 35 minutes.
https://blazerforum.com/forum/attach...ine=1391370549https://blazerforum.com/forum/attach...ine=1391370549https://blazerforum.com/forum/attach...ine=1391370549https://blazerforum.com/forum/attach...ine=1391370549

Here are fittings and part numbers I used to attach the pressure tester to the filter to test the fuel pump . I connected the 3/8 end to the fuel filter.
I bought these fittings at home Depot, cost was $7 and change.https://blazerforum.com/forum/attach...ine=1391370846 All together looks like https://blazerforum.com/forum/attach...ine=1391370846 attach the 1/4 fitting from the gauge and you are set.

Nice job with the "creative plumbing"! As long as it does not leak, it's fine.

From your readings, the pump is fine. The leakdown problem is inside the plenum. If there are no external leaks, the regulator could be leaking past the valve plate. To diagnose this, the return fuel line, (going back to the tank) must be sealed off from the regulator immediately after pressurizing the system. CAUTION: If the regulator is exposed to ~75psi or more, the diaphragm in the regulator is likely to rupture, requiring replacement of the regulator.

Attachment 31429

Or, one or more poppet valves/nozzles could be leaking into a combustion chamber. Each nozzle will need to be carefully removed from the lower intake manifold, then activate the fuel pump and watch for leaks from the nozzles.

Thanks, hoping if others have fuel issues, or poor mileage they can try this out as well, relatively cheap, especially if they can borrow a gauge.
I will most likely have a gauge for sale too after I figure this out!
On a side note, I tested the poppets Saturday, took each one out and energized the pump, no issues with leaks there, except for the one that is under both fuel lines, that one I didn't pull out (tough to do with the fuel lines and didn't want to remove the spider)
So, now that it MUST be the regulator I thought today to
A. when I reopen the plenum to first test that poppet
B. to take off the fuel return line and plug the nut kit return to seal off the regulator (give the pump power and see if there is a drop in psi)because if the gauge then holds we know its the regulator leaking into the return line.
C. just replace the regulator after checking the one poppet and then retest while the plenum is opened.


Thanks for all the help guys, it sucks working on things you already fixed/replaced but its nice to get some satisfaction by figuring it out. Will be pretty bummed that I paid all that cash for the Spider assembly to only get one with a bad regulator....NEW PARTS DONT MEAN THEY ARE GOOD PARTS!


Ill repost what I do and what worked for me, and also what I did about replacing the full spider assembly or just the regulator...at this point I think I may go the junk yard, pull a spider assembly, return the junk yard one as defective to the parts store, for full price refund and just change the regulator on my spider for $30.

From post #22: "To diagnose this, the return fuel line, (going back to the tank) must be sealed off from the regulator immediately after pressurizing the system." If you activate the pump with the return line capped off, you will most likely destroy the regulator.

Ok, I was assuming if I crimped the line off it would mostly likely be the same, but I guess a crimp would have some give to it to slowly leak by.
But I think I have it worked out with the parts store , so im going to get a new regulator and put it in and test it right after with the plenum open. And if it still leaks down, I will be setting the Jimmy on fire haha

You can do it by crimping the return line, but as you say, it may leak past the crimp. If the pressure leaks down, you'll never know if it's the crimp, or something else. There's a special tool with a valve, and it connects inline, in the return line. The pump is activated to pressurize the system with the valve open. The instant the pump shuts off, the valve is closed. You can make the tool with some more of that creative plumbing that you did so well at ;) Just need to make sure the return line is unrestricted whenever the pump is activated, or it will trash the regulator.

ok, Got it. ill see what I can plumb up as soon as I get some time! Thanks for all the help....
Once I get it figured out, ill do a DIY post on how I did my trouble shooting and what I used.

There's already a post somewhere here, but if you post the parts in this thread, like the other ones you used, that would be cool. The results will tell if the regulator is leaking internally. Doesn't happen very often, but good to know how to check it.

Update.
Since 1-21-13 I have NOT seen the P1133 code with the "old" O2 back in, I believe the heater in the "new" Denso was faulty perhaps?
So I kept the old O2 in there for now, and returned the Denso for a new one, which I will install at a later date.
I also ordered the replacement Fuel Pressure Regulator today, will pick up tomorrow and hopefully install Friday or Saturday since its supposed to be 50 degrees!
After I install the new FPR I will again test the pressure at the test port (I know the pump is fine) and hope for no drops in pressure, I am confident this "new FPR will be fine. Fingers crossed. If so ....
Then I think ill change the oil and replace the O2 to the new Denso.... The oil does smell a bit gassy, But I believe there is also some Seafoam in there too so that can be what I am smelling.
I will fill the tank and check my mileage.
I may pull the EGR to deep clean it as well, I had it out when I did the spider and cleaned it, but I didn't push in on it and spray any cleaners in there so it may be a bit dirty.
May check the plugs as well, just to see how they are since I changed them.


I will post up results again this weekend.

If the EGR valve is electronic, (no vacuum line) don't push on the pintle valve, it will damage the valve. If it's vacuum operated, apply vacuum to the port to open it.

Ok
thank you!

Hope it works!
https://blazerforum.com/forum/attach...ine=1392853738

Lightly coat the O rings with clean motor oil. The regulator will go on much easier without damaging them.

I changed the FPR tonight and here's the results of the new one.
https://blazerforum.com/forum/attach...ine=1392953397 https://blazerforum.com/forum/attach...ine=1392953397
https://blazerforum.com/forum/attach...ine=1392953397




So I suspected an issue because it didn't stay above 50 psi for 10 minutes.
So, I tired it again. this time it did take longer to drop, but still went under 50 in less than 10 minutes.
I was thinking...how can I possibly get ANOTHER bad part?????
So I decided to keep it in and bolt everything up and then decide what to do next based off ideas here.
So here is what happens upon start up after assembly.
The idle was wacky, almost to the point of stalling. It was running rough and would not smooth out. So now I know its a bad FPR AGAIN!
So of course I couldn't drive it that way, so I put back the other FPR, which I know is leaking down instantly, but the truck runs and idles smooth.


So here's the question....I researched two different FPR on Advance site and it lists the BWD which I got and then the Dorman.
The Dorman comes with a hex tool to "adjust fuel Pressure" this BWD I have didn't come with one, but why would I have to adjust the fuel pressure anyhow? Does the BWD I have need adjustment or is it just bad?
Here is the Dorman link, with tool and you can see its for adjustment in the description part http://shop.advanceautoparts.com/p/d...985%7CL3*15355
here is the BWD I have http://shop.advanceautoparts.com/p/b...985%7CL3*15355


are these reman parts? it doesn't say.


Thanks

There is a problem in the plenum. Leakdown is excessive. Need to know what the pressure is with the pump running, and the engine off. But the fact remains, there is a leak somewhere in the plenum, could be the regulator even though it's new, could be the fuel lines, or it could be a leaky injector, or poppet nozzle.

After I installed the new FPR I checked each poppet, I pulled each out and checked to see if one was leaking, no leak. I checked each tube coming from the spider, no leak. I checked the fuel lines coming into the plenum, no leaks and also where they mount to the spider and no leaks.
Did you read about the start up? I went back and edited, so maybe you didn't catch that part

The BWD is adjustable as well, it just doesn't come with the tool. Pump running, engine off, pressure needs to be 55psi to 61psi, BUT, that's when there are no leaks, and yours has a leak. Gotta find and fix the leak before worrying about tweeking the pressure.

To check the regulator for internal leaks, you'll need to do some more creative plumbing. This time it needs to be in the return line. It needs to be connected inline, with a shut off valve. When the valve is open, fuel must be able to return to the tank.

Ok I will see what I can do with the return line tomorrow or Saturday. I am sure I can make something work by the fuel filter, although I don't recall if there is somewhere to do something like that.
But isn't it possible, based after the way it was idling that this new FPR is faulty? The old one leaks down instantly, but the truck does idle fine and smooth, this one I installed today...the engine runs rough!
So should I try a new FPR? Should I return this one for another new one to try to see if it leaks down again?
or can I adjust it? how do you know what to adjust it to so it idles normal?


Just trying to see whats best as of now....I understand I need to find the leak, but if its the FPR (new one that's bad) I don't have to figure a way to shut the return line down.


Believe me, I want to figure it out, but just want to do it the easy way and seems if I get another FPR and there is no leak then I know this one is bad.


Beyond frustrated with this already!
Thanks for the help.

Key on, engine off, fuel pump running, (regulated fuel pressure) needs to be 55psi to 61psi, when there are no leaks.

You can replace regulators until you're blue in the face, and if that's not the problem, you can try something else until you're blue in the face. OR, you can diagnose it and figure out exactly what's leaking, and fix the problem... your choice;) The inline tool must be installed in the fuel return line, not the pressure line. When it comes time to check it, open the valve and activate the pump to pressurize the system. The instant the pump shuts off, quickly close the valve. If leakdown remains above 50psi after 10 minutes, the regulator is leaking internally. If it drops below 50psi after 10 minutes, the spider assembly or the "nut kit", (fuel lines in the plenum) is leaking.

Update.
Friday after work I again took out the spider assembly.
This time I got a new spider from Advance.
Today I installed the spider, gave the pump power, gauge hits 60, down to 50 and slowly keeps going down....
check for leaks, and hear a sound I cant explain, well four of the six poppets are leaking! Enough that you see bubbles off the ends.
How awesome is that!?
Call A&A, and in 3 hours I got a Standard brand spider.
Install it, pump is powered up, gauge shows 60, pump off, and it stays for 20+ minutes, no leaks, no issues.


Had time to change the oil and rotate the tires and it held good pressure that long as well.

Put it all back together, start it up, and its running rough, SES light comes on....
Scan the code and it was a TPS issue, I don't recall the code entirely, so I took all connections off again, and reconnected, cleared the code and it fired right up as it should, no codes, smooth idle.
But I did notice the pump running AFTER I turned the truck off for a few seconds.
Took it around the block, filled it up with gas, runs great. Get home and opened the door, turned it off and the pump was not running, so maybe it was just due to taking it apart and having the battery disconnected I guess.


Anyhow, its fixed correctly, time to watch the mileage and see how it goes with a full tank.
I appreciate all the help guys!!!