I posted before about a stumbling/miss. It got better when the AC two pin connector was removed, but would come back intermittently - some
days were good, others it stumbled quite a bit.

Recently it started to have a rough idle which would resolve itself, then a few times it was harder to start. Now it won't start at all.

I tested the EGR Sensor and it seemed to fail one of the ohm meter tests, so I replaced it today and I have the same no start condition and the same Code 34. Any ideas?

Prior to the no start condition I the dash would flash Code 34 (KOER) "EVP, EGR did not respond properly during test."

Here were my multimeter tests on the old EGR sensor:

EVP Sensor tested 02/08/2015 Optimal Actual

• Harness Reference Voltage (5v at pins VREF and SIG RTN) 5v 4.86v
• EVP Sensor Resistance (< 5000 ohms at pins VREF and EVP) <5000 ohms 4.25 ohms
• EVP Sensor Resistance (> 100 ohms at pins SIG RTN and EVP) >100 ohms 36.4 ohms

The terminal pins are as follows:

• Voltage Reference (5v from the EEC)
• Signal Return (Sensor Ground)
• EVP Signal (Varying voltage to the EEC)

Orientation of the three pins on the Sensor:

SIG
RTN
EVP VREF

 

Extremely rare for a 1995 model year truck to display two digit codes. How are you retrieving them? Counting flashes or using a code reader?

I suspect you are counting flashes....KOEO test System Clear Code 111 (Spacer flash) CM System Clear 111. so 111 -1- 111 could be interpreted as 3 + 4 AKA 34...Which is wrong.

Even if Code 34 is valid it would not cause a no-start condition.

 

rla2005: The codes were flashed when it was running three days ago and they were definitely two digit codes flashed on the dash. I have the Innova Code reader on the way for delivery this Wednesday. I will read codes and post. I have heard that a Code 34 would not cause a no start condition as well, so I am not sure of the cause.


My guess is that the no start cause is related to the recent rough idle last week and then difficult starts on Friday and no start on Saturday.

 

If you somehow end up with two digit codes that means someone has swapped in an older computer (PCM). That has its own can of worms to deal with. The ignition system is very different and so is the solenoid pack in the E4OD transmission.

For the time being you need to check for spark and fuel. One or both are missing.

 

rla2005: I could run out and check for spark now. What is the best way to do it? (I the old days I held (and got shocked) the spark plug wire next to the manifold to see if it arc'd, but there has to be a better way now.)

 

Pull a spark plug, place the electrode on a ground such as the engine block then crank the engine over.

Some use the same technique but pull the coil wire instead of a spark plug.

 

Ok now for a stupid question. How do I get the sparkplug boot off?

In the old days when I did this, it was just a copper friction clip surrounded by the rubber boot which pulled off the top of the sparkplug.

Is it the same on this 5.8L? Because I pulled hard but it since it didn't come off as easily as I thought it should, I thought I had better ask...

 

This is an old technology truck. The rubber boot may be stuck to the plug. Twist it a bit as you pull on the boot. Do not tug on the plug wire....you will pull it apart.

 

10-4 be back soon...

 

We have spark!

rla2005, I know it is after 11 pm in NJ so if you need to call it, I understand. But if you have other tests you want me to run, I will do the either this evening or tomorrow.

For instance, I do have the AC disconnect tools somewhere so I could disconnect the frame rail filter and see if I get fuel pumping out but I have no way to monitor fuel pressure.

 

Does the fuel pump energize for one second when turning the key from Off to Run?

 

I heard it click but not "run" per se. Wait my wife and I are heading downstairs to check better...

 

Hmmm... Well when I am under the vehicle near the tank and my wife turns the key from on to off, I hear two distinct clicks nearly simultaneous:

1. First click is from up in the engine firewall area a little louder than the second click;
2. Second click is faint from the fuel tank area.

No hum. I.e., no hum like I would expect from an electric fuel pump pumping up. But if the line was already pressurized would I hear a hum? In other words, does the pump stop if the line is pressurized and resume when pressure drops? Or does it always run at a particular pressure letting the return line bleed off the excess pressure by returning the unused fuel to the tank?

 

The pump runs for one second based on a timing pulse from the computer. It is not pressure dependent.

Do you have dual tanks? If so does the fuel pump activate on either tank?

It is possible the fuel pump inertia switch got tripped off. It's located behind the passenger kick panel. There is a red button on the top, it should be pushed down.

 

Single tank. I will check it when I get home after work today. I just had the front on jack stands installing Mile Marker hubs, so I guess I could have tripped it while lowering it? Doesn't seem like it, but it is certainly worth checking. So I can assume that I should have heard a hum for a second? Thanks, I see you are from Illinois, I apologize for saying N.J.