Code 32 and 33

[Ricktinfwb]

Getting a pretty steady SES light with codes32 and 33; I've got 18-20 hg of vaccum @ 1800 rpm...but only an errattic 0-5 hg @idle; I replaced all vaccum lines, checked the operation of the EGR valve; I'm thinking a faulty 'vent solenoid'...any of you experts got advice on this issue?

1995 K1500 6.5TD...new 'rebuilt block' with 40,000 on it..lots of upgrades.

[DmaxMaverick]

Getting a pretty steady SES light with codes32 and 33; I've got 18-20 hg of vaccum @ 1800 rpm...but only an errattic 0-5 hg @idle; I replaced all vaccum lines, checked the operation of the EGR valve; I'm thinking a faulty 'vent solenoid'...any of you experts got advice on this issue?

1995 K1500 6.5TD...new 'rebuilt block' with 40,000 on it..lots of upgrades.

If this is measured at the pump inlet, the pump is shot (your symptoms sound typical). It should be a stable 20"+ at idle, with ~15" at the WG actuator. If it's measured somewhere else, it doesn't say much. Measure at the pump inlet first.

[Robyn]

X2

Once the vacuum gets erratic it means bad pump.

The check valves or diaphram go south in the pump and all bets are off.

Get a fresh pump and life should be good again.


Missy

[Ricktinfwb]

Thanks Robyn and DMax.....the pump is only 2 years old, sooo I was hoping it was not that....but if both of you agree......I'll be getting a new pump!
I greatly appreciate both of you taking time to reply...it's nice to have a 'pro' around to steer us 'shade-tree' wrench-benders!

Rick T

[DmaxMaverick]

The pump should last longer than that. It's possible it didn't, but I would confirm it's gone, before replacing. The pump and its operation is very simple. A reciprocating diaphragm with in/out check valves. That's it. The drive bearing or cam can fail, but it'll be noisy, while still pumping until it seizes or shears. If you are sampling the vacuum at the inlet port, which should eliminate any possibility of leak and it still performs as you described, it's dead. However, if you are testing away from the pump, through a distance of lines, couplers, tees, etc, a leak can simulate a failed pump. Maybe it did die young, but I'd be sure.

[Ricktinfwb]

The pump should last longer than that. It's possible it didn't, but I would confirm it's gone, before replacing. The pump and its operation is very simple. A reciprocating diaphragm with in/out check valves. That's it. The drive bearing or cam can fail, but it'll be noisy, while still pumping until it seizes or shears. If you are sampling the vacuum at the inlet port, which should eliminate any possibility of leak and it still performs as you described, it's dead. However, if you are testing away from the pump, through a distance of lines, couplers, tees, etc, a leak can simulate a failed pump. Maybe it did die young, but I'd be sure.
Thanks DMax.....I AM checking it at the thick-walled rubber tube that comes off the pump inlet....and THAT tube could be the issue, but I have to tear all that mess out to get to it anyway...so I have a new pump on the way...if it is the tube, I'll just have a spare pump!!
Appreciate your concern and time...you are making it worth the membership dues with your contributions!!
Rick T

[Ricktinfwb]

Well...the pump was the problem....I now am showing 24 inches of vaccum....runs like new again and no DTC s. Thanks again for the guidance!