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If the leaks are where it mates to the engine can I fix that without taking it out? I don’t got the time before registrations due to deal with broken studs. Or the money. If it’s just a crack I’ll get it welded or I’ll put one of those patches on it if it’s where a welder can’t get to.
Have you ruled out EGR as the issue yet? I think you said above you tested the EGR valve and were able to get the truck to die at idle by manually applying vacuum to it (correct me if I misread). That would rule out issues with the valve but still leave anything at the solenoid and beyond as potential error sources.
My truck failed for high NOx a couple years ago (I'm also in California). The PCM was the issue. It didn't send the signal to the EGR solenoid when it should have.
I would check the solenoid. I bet someone else here knows the procedure for that.
Have you ruled out EGR as the issue yet? I think you said above you tested the EGR valve and were able to get the truck to die at idle by manually applying vacuum to it (correct me if I misread). That would rule out issues with the valve but still leave anything at the solenoid and beyond as potential error sources.
My truck failed for high NOx a couple years ago (I'm also in California). The PCM was the issue. It didn't send the signal to the EGR solenoid when it should have.
I would check the solenoid. I bet someone else here knows the procedure for that.
it didn’t die but it tried to, which is good enough? Does anyone have the test procedure for the EVR? It passed ohms and volts last I tested it but I don’t trust that’s enough to see if it’s good. Does anyone know how to test if the computers sending the command?
it didn’t die but it tried to, which is good enough?
I think that's good enough, since the Haynes manual states:
Originally Posted by Haynes Manual
31 Apply vacuum to the EGR valve and observe the engine idle speed. Idle speed should slow (more than 100 rpm) and roughen. Upon release of vacuum, the idle speed should return to normal. (...)
Originally Posted by Anonymous12
Does anyone have the test procedure for the EVR?
Just to make sure, your truck uses fuel injection, right? I don't know when they switched from carbureted. If so, I've copied down the procedure from the Haynes manual for you here:
Originally Posted by Haynes Manual
Solenoid Checks (EVR, EGRC and EGRV)
(...) Electronic fuel injected systems - operation and checks
(...)
48 The conditions for testing are as follows: Engine not running, key off, EVR electrical connector disconnected.
49 Remove the vacuum supply line from the EVR solenoid. Install a vacuum gauge to the EVR outlet port and using a hand-held vacuum pump, apply vacuum to the manifold vacuum supply inlet port. Vacuum should not hold and no vacuum should be indicated at gauge. If not, replace valve.
50 Install ground jumper to one EVR solenoid terminal and a 12-volt source jumper to the other to open valve. Release trapped vacuum if required and repeat the vacuum pump test. Vacuum should now be indicated on the gauge and vacuum should hold. If not, replace the valve set. Caution: Do not leave the hot (battery) jumper installed any longer than necessary.
51 Remove the jumpers to close the valve and connect the vacuum pump to the EVR outlet port. Apply vacuum to the port to test venting. Vacuum should bleed. If not, replace the valve.
52 Measure the resistance of the solenoid valve at its electrical terminals. Resistance should be between 20 to 70 ohms except for the 7.5L engine, which should be between 100 to 135 ohms. If not, replace the valve.
53 If all checks pass, the EVR solenoid valve is operational.
The computer energizes the EVR based on input from the EVP sensor, which indicates the position of the EGR valve to the computer. So that's another potential source of issues. Here is how you check it:
Originally Posted by Haynes Manual
EVP circuit checks
54 Disconnect the EVP electrical connector at the EGR valve.
55 With the ignition in RUN position, check for reference voltage at EVP harness electrical connector pin (VREF) and pin SIG RTN. Voltage should be between 4 and 6 volts. If not, move probe from SIG RTN to a good ground source and recheck. If proper voltage is now indicated, service SIG RTN circuit to PCM for open. If voltage is still out of limit, proceed to Chapter 4 Section 15 and perform VREF checks to obtain proper voltage. EVP sensor - operation and checks
(...)
57 Disconnect the EVP electrical connector at the EGR valve.
58 Check resistance of EVP sensor between sensor pin VREF and sensor pin EVP. Resistance can be slightly less than, but no greater than 5000 ohms.
59 Check the resistance of the EVP sensor between sensor pin SIG RTN and sensor pin EVP. Resistance can be slightly greater than, but no lower than 100 ohms.
60 Connect a vacuum pump to the EGR valve and slowly pull the vacuum from zero to 10 inches-Hg to actuate teh sensor while observing the resistance at pins VREF to EVP. Resistance should change smoothly (no jumps or flat spots) from 5000 to 100 ohms. Caution: Vacuum should hold - if not, replace the EGR valve.
61 If the above tests fail, remove the EVP sensor and check it using the same procedure as in Step 60, but resistance values should be between no greater than 5,500 ohms (sensor shaft extended) to no less than 100 ohms (sensor shaft retracted). If not, replace the EVP sensor.
62 If the sensor is acceptable, the EGR valve must be keeping the sensor from its proper idle and/or full open position. This could be caused by improper EGR seating, EGR stuck, EGR damaged, carbon buildup, etc. Perform the EGR valve check procedure as outlined in this section and replace the valve if necessary.
63 If all EVP sensor checks pass, the EGR system malfunction is probably the PCM module itself. At this point it would be a good idea to have further diagnosis performed by a dealer service department or other repair shop, since they can try a new PCM module (which may or not (sic) be the problem) without the risk of you having to buy one.
Hope this helps. I probably made a couple spelling mistakes because I typed fast copying this down.
Haynes manual? Really? Grab yourself a PCED and check into the EVP code pinpoint tests
You simply have low (or no) EGR flow causing the high NOx
I have been doing I/M testing in UT since 1984 myself
Cal sure does suck for I/M compliance
Has forever
Took a 72 Super Beetle down to LA for a tune up school in 1980
I just about got ran out of town when they hooked my Bug up to their I/M machine
Wonderful the trying to help
Haynes and Chilton just have missing info
Nothing incorrect really but they are for laymen only IMO
When the going gets tough, like diagnosing HVAC airflow distribution and I need a vacuum schematic
Those books say things like "refer to qualified personnel"
Gets me going because I am qualified personnel, and they have missing info like the vacuum schematic I need
Reading through that section posted, I see nothing wrong with it other than it is not the actual Ford pinpoint test procedure
That Ford procedure is in the PCED (hundred-dollar big thick binder book)
Using the Ford procedure, you take the particular code and that sends you to different sections of the pinpoint tests
Code 34 sends you to pinpoint test D98
By now, even Haynes and Chilton have the old EGR systems figured out hopefully.
Here are the Ford pages for you to compare,
note the end where they have you disconnect and plug the line and rerun the test looking for code 34 again
If the numbers were a little closer, I would say to find some ethanol free gas to run and it might get you passed the test. But I don't know if it would make those numbers. That is a trick some guys on my Nova forums use when testing their late 70s cars that are modded some, but the other way to leaner mix. They usual test once to see where they are at, then blend in e85 to lean things out enough to pass. Since you are lean, you would want less ethanol, so E0 or ethanol free could bandaid your issue if you can't find it in reasonable time.
I found another broken vacuum line when I repaired the broken red one, it went to that circled thing I believe. What is that’s purpose?
I would replace all the vacuum lines with 5/32" rubber hose, rather than repair them. If you do them one at a time, it's not that difficult.
That way you'll at least eliminate one source of problems.
When I started troubleshooting my EGR system, the valve wouldn't move. I was applying pulmonary vacuum to the EGR valve, like drawing on a cigarette, using 5/32" vacuum line.
I sprayed a little WD 40 in it and gently moved the center pintle, working through the small openings in the side of the valve and got it freed up, so it moved with vacuum.
I tested for key on voltage at the EVR solenoid and read resistance through the coil of the solenoid. Those readings were both good.
I took the EVR solenoid off and removed the top. Inside, it was basically dry rotted and crumbling.
After I replaced it, when my engine is warm, I can see slight pintle movement when I rev the engine.
In the process of replacing my vacuum lines, I tested my vacuum canister by running a vacuum line from the manifold Port of the canister, into a bottle of water and blowing through a vacuum line connected to the other port of the canister.
If the vacuum canister had leaks, the air wouldn't bubble in the bottle of water, it would leak out of the canister instead.
My point is, with just some basics, you can get this stuff working, if you don't have access to service manuals and vacuum gauges.
Haynes manual? Really? Grab yourself a PCED and check into the EVP code pinpoint tests
You simply have low (or no) EGR flow causing the high NOx
I have been doing I/M testing in UT since 1984 myself
Cal sure does suck for I/M compliance
Has forever
Took a 72 Super Beetle down to LA for a tune up school in 1980
I just about got ran out of town when they hooked my Bug up to their I/M machine
had a few like that myself. 70 bettle with a 2000 cc motor we used a old trick to trick the machine, a old Holley carb jet stuck into the hose of a windshield washer bottle of methanol alcohol run to the air cleaner over the carb throttle plates . leaned the emissions to almost zero when jetted the right amount for the motor, leave inspection pulled the hose .
