Author Topic: DTC 32 AND 44  (Read 1240 times)

Offline Jon87V20

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DTC 32 AND 44
« on: March 05, 2021, 04:57:44 PM »
I replaced the engine in my '87 Suburban V20 in the summer of 2019. I haven't used it too much since then (I don't really know the exact mileage right now). When I put the reman 5.7 in there, I replaced the EGR valve since I was putting a new TBI performer manifold on and the old EGR was looking pretty crusty.

Anyway, I started getting a DTC 32 (EGR not in expected position) here and there sometimes when I took it to work on the highway after driving for about 15 minutes or so. It was pretty infrequent for a while, but now it's popping up more often and it's accompanied by a DTC 44 (lean condition detected) as well.

So I got out the hand vacuum pump and connected it directly to the EGR valve. It will jump up to about 15 in., and the valve jumps up a bit, but it can't hold it and falls back down almost immediately.

I'm assuming my EGR valve is bad already? My question is, was there something I could've done incorrectly when I put the motor back together to cause premature failure on this? I realize sometimes there are just bad eggs and maybe that's what happened, but I don't want to replace it again and have it fail right away.

Also, I don't have the ~$70 to throw at this right away. Is it okay to drive it with the EGR inoperable for now? I will be fixing it sooner than later.

I should also mention I recently replaced the fuel pump and the O2 sensor. The DTCs were popping up before those changes were made.

Thanks!
« Last Edit: March 05, 2021, 04:59:56 PM by Jon87V20 »
1987 Chevrolet Suburban V20 Silverado
350ci TBI TH400 NP208

Offline VileZambonie

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Re: DTC 32 AND 44
« Reply #1 on: March 05, 2021, 07:18:29 PM »
With the engine running, apply vacuum to the EGR, does the engine stumble and stall?
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline Jon87V20

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Re: DTC 32 AND 44
« Reply #2 on: March 06, 2021, 11:51:51 AM »
Vile, no it doesn't seem to care at all. No noticeable change whatsoever. Also, I was reading the gauge wrong. It's only getting up to about 7 inches of vacuum and then falling down right away.
1987 Chevrolet Suburban V20 Silverado
350ci TBI TH400 NP208

Offline MIKE S

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Re: DTC 32 AND 44
« Reply #3 on: March 06, 2021, 02:44:21 PM »
There a two different types of egr systems used depending on GVW. Under 8500 uses a negative back pressures system and over 8500 uses a ported system. The original valve will have a P or an N stamped on it to designate what type it is. They are not interchangeable. They work completely different. If you don’t know what system you have look at the egr solenoid. If it has the cap with the removable filter it is the over 8500 gvw type. Verify that you have the correct valve for the truck.

Offline Jon87V20

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Re: DTC 32 AND 44
« Reply #4 on: March 06, 2021, 05:11:42 PM »
Thanks, Mike. Yeah it has the cap with the removable filter. Is there any visual method of identifying what type the valve is itself? I'm pretty sure I tossed the original one already.
1987 Chevrolet Suburban V20 Silverado
350ci TBI TH400 NP208

Offline Jon87V20

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Re: DTC 32 AND 44
« Reply #5 on: March 06, 2021, 05:36:45 PM »
Also, I'm not sure I understand how vacuum is supposed to be routed through this solenoid. I just have that filter cap on the one side, then two ports on the other side. If one of the ports is for the valve, and the other is for venting, where does it actually get vacuum from the engine?

Or on this particular solenoid type do you not use one of the ports for venting?

I can't find any good pictures of this setup anywhere.

EDIT: So yeah, I found a video of someone with the same solenoid. It looks like I just don't have it connected right at all... I thought one of those was supposed to be a vent and didn't think about where the signal was coming from. However, it doesn't hold vacuum with the hand pump either so... I don't know I'll see what happens with the other hose hooked up.
« Last Edit: March 06, 2021, 05:42:46 PM by Jon87V20 »
1987 Chevrolet Suburban V20 Silverado
350ci TBI TH400 NP208

Offline Jon87V20

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Re: DTC 32 AND 44
« Reply #6 on: March 06, 2021, 06:46:20 PM »
Well that's embarrassing. The vacuum signal line wasn't connected at all. I don't know if the the valve not holding vacuum and not affecting the engine when manually actuated is an issue still though. I'll take the big fella to work on Monday and see if it throws a code again. As far as the 44 code goes, I guess I'll look around for exhaust and vacuum leaks again.
1987 Chevrolet Suburban V20 Silverado
350ci TBI TH400 NP208