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Testing Fuel Tank Pressure: P0452


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ratrace2
User

Mar 29, 2010, 6:58 AM

Post #1 of 3 (5228 views)
Testing Fuel Tank Pressure: P0452 Sign In

1998, Chevy S10 (2wd), 2.2L (LN2), Automaitc (M30).

Hello All,

Looking to do some work and learn as much as possible about PCM/ECM managment and diagnosis.
Currently, I'm working on a P0452 DTC. (fuel tank pressure low voltage)
I got an alldata and Chiltons subscription for the truck

I need some tools:
(1) to test for low/leaks fuel system. (EVAP system port states 1lb of pressure)
(2) to test/scan OBDII codes. (autozone......??? I don't know).

Got any recommendations on the tools?


Is this good enough to do everything I need for this truck????

No links...


(This post was edited by Sidom on Mar 29, 2010, 8:36 PM)


Sidom
Veteran / Moderator
Sidom profile image

Mar 29, 2010, 9:29 PM

Post #2 of 3 (5201 views)
Re: Testing Fuel Tank Pressure: P0452 Sign In

If you are going to be doing a lot of you own work then picking up some of these tools might not be a bad idea. You have an Alldata subscription which is very wise, get familiar with it. As HT mentioned in the other post, its "knowing where to looking".

The areas you are talking about can be expensive. Honestly evap leaks is really an area that won't make sense to tool up for unless you are doing smogs or a lot of diag work.... At the minimum you would need a smoker and scanner with bi-directional controls, between those 2 you would be close to 10k, way more if you went the OE scanner route.

With evap leaks you can do what you've already done, obvious stuff, new cap, look at all the hoses & connections, after that it would be cheaper just to take it in & get it diag'd. You're lucky, your code isn't an evap leak, it's a voltage problem...

If you are going to get a scanner, you should get one that lets you see a data stream, the more PIDs (parameter identification.....basically lines of data) the better, you see what the computer is seeing.... You can read up on what the PID should look like, see what is showing. Then verify your 5v ref & make sure the ground is good. Jump the ref to the signal wire to get a max reading which verifies the signal wire to the ECM and the would narrow it down to a sensor......

No 5v ref..problem..... too much resistance on the ground wire.....problem.... No signal change at the PCM when the 5v ref is jumped to the signal wire.....problem. If this all checks out with no other evap codes you are probably looking at a bad sensor

I really don't see a lot of FTP sensors go out in my area, I would check those wires real good. If it does turn out to be a bad sensor and the pump hasn't been changed recently, it wouldn't be a bad idea to just change out the whole pump assembly, they come with a new FTP sensor.....

The one bit of advise I will give you when you do get your scanner......play with it......look at as many pids as you can and get familiar with them because you won't know what bad looks like until you know what good looks like......

A lot of the info you are looking for is under the theory & description areas in Alldata, a lot of good info there. If you type in the code number it will lead you to a flow chart for the code. Those are good if you aren't familiar with a system but they have to be followed exactly and nothing skipped or it's easy to get a misdiagnosis. If you know the system a lot of times you can logically rule out a lot of the system the chart covers in a very short time. Also another very good tool to find info is google. There is a lot of good free info out on the web & google can help you find it........


ratrace2
User

Mar 30, 2010, 4:23 PM

Post #3 of 3 (5195 views)
Re: Testing Fuel Tank Pressure: P0452 Sign In

Sidom,
thanks so much for your input on this topic. You are really an inspiration
along with hammertime. between the two of you guys I should be able to get my little "pit crew" together for this truck. That would be great, got a problem, just plug in the scanner, look at the alldata/Chilton diagnosis charts, see the video and start wrenching.

I have all of the wrenches and tools that I need. I put on all new tie rods, center link and idler arm last week in about 2 hours.
Last month, I did small stuff, water pump, starter, hoses, filters, brakes (right down to the springs in the drum brakes), belts, plugs wires. ...etc. . . .

I just love working on this little truck. I have so much fun when I know what I'm doing. I just can't stop and wait two or three days for the mechanic to get me in to look at some DTC that popped up.......So here we go.....

today I bought:
Equus 3160 Innova ABS + Professional CanOBD2 Diagnostic Code
Scanner for OBDII Vehicles with Back-lit Screen and Enhanced Live Data
This scanner is "bi-directional" and shows all the sensors. Plus a few things.
it's going to take me a while to get up to speed with it.

Yesterday I rented:
Fuel pressure gauge and Digital Multimeter from Autozone.
I'll probably buy a Fluke DMM for myself.

AND, I bought a Chilton Online subscription for the truck:
This is good because they have a ton of diagnostic and testing procedures
Videos for the truck.

Also, I have a vacuum gauge and a pump from my vacuum infusion days
but I need something for the EVAP system to put it under pressure.

In addition, and finally,
I have an A/C rebuild video and a 4L60E transmissionn rebuild video.
Next I want to try to get some electric system videos.
I love that stuff,way better than TV car shows.

Thanks so much, RR2






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