Emmisions test failed

74grabber · Jul 19, 2014

1999 Ford Ranger
4.0 OHV
manual transmission

UPDATE:

I seemed to have solved the po452, I took off the bed removed fuel pump and replaced o ring gasket. In doing so I also noticed the filler neck hose clamps on both ends were tight but I could still easily spin the hose on the fittings. So I removed old clamps on filler hose and vent tube and replaced. Cleared codes and went for about a 30 minute drive, with multiple stops and restarts. No more p0452, knock on wood that its fixed.

p1451 still pending, it shows up after about every second restart, I had changed out the solenoid yesterday. Solenoid (both old and new) shows 55 ohms across terminal, and 12 volts to solenoid/chassis ground with Key on engine off.

However I do also see 12 volts between both terminals in key on engine off as well. So I am kind of confused at this point does the PCM send the ground signal for the solenoid while engine is off or do I have a short to ground on that terminal and the PCM cannot turn it off?

How does the PCM know weather solenoid is open or closed?

Sorry long time lurker, first time poster.... And of course I need help LOL

Code P0452
pending p01451

I have went through all the vacuum lines and I cannot find a leak, anything that looked like a maybe I repaired. I changed out the vapor canister vent solenoid, as well as took off charcoal can and did full inspection on it.
After 5 minutes of idle and 2 restarts code comes right back.

I see where there is a low probability of the fuel tank pressure sensor going bad, but I have yet to see any how to on trouble shooting it.

And an annoying side note, cleaned the dang IAC valve but made no difference in this thing humming like a swarm of 10,000 BEES.

Any help GREATLY appreciated, need to pass emmisions for my camping trip at end of month

Spott · Jul 19, 2014

I've heard of the IAC buzzing thing before, the previous guy claimed it was hooked up backwards (which doesn't make much sense, but it apparently worked for him.)

A good way to search for vacuum leaks is with a spray can of starting fluid. Let your truck idle, and spray it around vacuum hoses and gaskets. If you spray near a leak, it will suck the starting fluid into the engine and rev up for a moment.

adsm08 · Jul 19, 2014

I can give you the instructions to troubleshoot your P0452, but the test relies heavily on live data from a scan tool.

Get at the sensor, check it's plug for dirt, fuel, corroded pins, etc. If all that is good you need a scanner because it tells you to start looking at the computer's interpretation of the signals being sent by the sensor.

You can try using a volt meter to obtain these readings.

First back probe pins 62 red/pink and 91 grey/red, you want to see almost no voltage, less than .22.

If that checks out jumper the two wires together at the sensor and check the voltage on the same pins at the PCM, you should see between 4 and 6 volts, usually around 4.99. If you get those results replace the sensor.

If you get that far and get some other results, post up and I will give you more test steps.

Here is the pinout chart for the PCM computer, as seen from the side opposite where you need to be probing.

The computer has to be plugged in for this test to work, it generates the voltages you are looking for.

The 1451, well if the solenoid didn't fix it, then I'm not sure, but it could be secondary to the 451.

74grabber · Jul 19, 2014

Spott said:
I've heard of the IAC buzzing thing before, the previous guy claimed it was hooked up backwards (which doesn't make much sense, but it apparently worked for him.)

A good way to search for vacuum leaks is with a spray can of starting fluid. Let your truck idle, and spray it around vacuum hoses and gaskets. If you spray near a leak, it will suck the starting fluid into the engine and rev up for a moment.

Ya lol I'm pretty sure my IAC isn't "hooked up backwards", I went through it cleaned it out and even tried adjusting the throttle stop trying to find a little different sweet spot but no luck. I assume its just "time" for a new one.

Yep I have went through the engine bay with carb cleaner, propane, and I even whipped out the homebrew smoke machine. None to be found. only visual inspection and the touch method on the EVAP system though. I have heard horror stories about using to much PSI on the evap system so I don't even go there.

I appreciate your help

adsm08 said:
I can give you the instructions to troubleshoot your P0452, but the test relies heavily on live data from a scan tool.

Get at the sensor, check it's plug for dirt, fuel, corroded pins, etc. If all that is good you need a scanner because it tells you to start looking at the computer's interpretation of the signals being sent by the sensor.

You can try using a volt meter to obtain these readings.

First back probe pins 62 red/pink and 91 grey/red, you want to see almost no voltage, less than .22.

If that checks out jumper the two wires together at the sensor and check the voltage on the same pins at the PCM, you should see between 4 and 6 volts, usually around 4.99. If you get those results replace the sensor.

If you get that far and get some other results, post up and I will give you more test steps.

Here is the pinout chart for the PCM computer, as seen from the side opposite where you need to be probing.

The computer has to be plugged in for this test to work, it generates the voltages you are looking for.

The 1451, well if the solenoid didn't fix it, then I'm not sure, but it could be secondary to the 451.

That is exactly what I was looking for thx! However, I do not see the PCM pinout chart :icon_confused:

And yes a live data scan tool I desperately need :sad:

I have not priced them out in a long time, last OBDII scan tool I purchased was close to 250.00 and it don't do shit as far as freeze framing data, no live feed....... It basically does what the 14.99 ones do today :sad:

I was thinking with a cold beer earlier, about a year ago I was battling a bad fuel gauge sender and had the fuel pump and stuff up top there moved around. I may pull the bed back off again tomorrow and double check everything. I may have not got the fuel pump ring on tight enough, vacuum leak in filler neck or vent hose or pinched a wire somewhere.

Dune Runner · Jul 20, 2014

While you are there check the hose on top of the tank that goes back to the charcoal can.

6ranger9 · Jul 20, 2014

If im not mistaken you can buy cheap OBDII scanners at auto parts stores for under 50 dollars...Its worth a look.

6ranger9 · Jul 20, 2014

Heres a USA based shipper from ebay..says its for 96 to current model years..has live data reading as well.

http://www.ebay.com/itm/MS509-OBD2-OBDII-Scanner-Code-Reader-Live-Data-for-GM-Ford-Toyota-96-Current-/390868543928?hash=item5b0194a9b8&item=390868543928&pt=Motors_Automotive_Tools&vxp=mtr

RonD · Jul 20, 2014

Have you checked to see if the fuel tank holds pressure?

You could just have a small leak in the filler tube or gas cap.

When you stop to put in fuel have you noticed lately that you don't hear that "whoosh" sound when unscrewing the gas cap?

When tracking down any engine noise, I find it very useful to unhook the fan belt.
This eliminates most of the noise in the engine bay.
Yes, it must be done with engine cold, lol, with no water pump turning you can run the engine for a few minutes, 2 or 3, without worrying.
If noise is gone with fan belt removed then noise was from a pulley or accessory, alternator can make the described noise

adsm08 · Jul 20, 2014

Let's try the chart again.

Also, as far as scanners go, if you already have a smart phone, look into a bluetooth-OBDII adapter and the Torque app.

I'd get it myself, but I just spent $600 to update my Solus so.... I'm pretty set.

74grabber · Jul 20, 2014

UPDATE:

I seemed to have solved the po452, I took off the bed removed fuel pump and replaced o ring gasket. In doing so I also noticed the filler neck hose clamps on both ends were tight but I could still easily spin the hose on the fittings. So I removed old clamps on filler hose and vent tube and replaced. Cleared codes and went for about a 30 minute drive, with multiple stops and restarts. No more p0452, knock on wood that its fixed.

p1451 still pending, it shows up after about every second restart, I had changed out the solenoid yesterday. Solenoid (both old and new) shows 55 ohms across terminal, and 12 volts to solenoid/chassis ground with Key on engine off.

However I do also see 12 volts between both terminals in key on engine off as well. So I am kind of confused at this point does the PCM send the ground signal for the solenoid while engine is off or do I have a short to ground on that terminal and the PCM cannot turn it off?

How does the PCM know weather solenoid is open or closed?

74grabber · Jul 20, 2014

Picture of the beast LOL

camburg 5.5 kit up front, mix and match leafs in the rear, 265/75/17 toyo open country 1's on bargain bin 17x8 wheels, tube front and rear bumpers with a flimsy aluminum skid plate. Bought the truck from a retired couple who pulled it around behind there RV, the bedsides show it from all the rock chips but I got a nine inch to throw in pretty soon so the bedsides will get new fiberglass anyways.

Just wish I had more time to drive it....... Sadly I have put less than 5,000 miles on it in 2 years I have had it. :dunno:

Emmisions test failed

New Member

Member

Senior Master Grease Monkey

New Member

New Member

New Member

New Member

Official TRS AI

Senior Master Grease Monkey

New Member

New Member

Attachments

Sponsored Ad

Sponsored Ad

Today's birthdays

Member & Vendor Upgrades

Truck of The Month

Recently Featured

Follow TRS On Instagram

TRS Events

25th Anniversary Sponsors

Check Out The TRS Store

Sponsored Ad

Sponsored Ad

Sponsored Ad

Amazon Deals