The Stupid Engine Questions Thread

[Schurkey]

Fuel economy can take a hit. EGR cools the peak cylinder temps, reduces detonation. Without EGR, knock sensor picks up additional detonation, retards timing--reduces both power and economy.

Removing/disabling the EGR would not be my first choice.

 

[Bu327]

Does anybody know the actual flywheel hp of a stock L31 motor? Not the factory rated number.

 

[Schurkey]

Does anybody know the actual flywheel hp of a stock L31 motor? Not the factory rated number.

Pretty-much whatever you want it to be. Pick a number, someone can figure out a test protocol to achieve it.

The factory number supposedly complies with an industry-standard test protocol, applicable to all engines sold in the USA. It's as good a figure as exists. It is likely to be a percent or three low, because production engines vary. GM got into trouble because some production engines were actually putting out less than advertised, leading to "deceptive advertising" concerns. So I don't doubt that the advertised horsepower is just a touch on the low side for most engines.

Aftermarket dynos generally come in higher, because they don't standardize intake air temperature, they may add extra ignition advance, and other "cheats". Aftermarket dynos are more like the old "gross" ratings than the current "net" ratings.

 

[Ivan90]

The EGR was developed to reduce NOx, by cooling the combustion chamber, so they could pass emissions. Some people say it increases MPGs too.


You obviously don't have emissions testing where you live? If so, you'll need to fix it. Otherwise, you could disconnect the electrical connector going to the EGR solenoid so you don't create a vacuum leak when the PCM tells it to open. You'll also get a MALF code (32) and an SES light if it doesn't work. On these older OBDI PCMs the light may not stay on but, it'll store the code for ~30 - 40 key cycles, or after you disconnect the battery for a while.

Thanks for the note. I want to do the right thing so I plan to replace the solenoid and EGR valve. I'm guessing the EGR valve isn't closing properly which is causing my engine to cough and stutter. Hopefully replacing the valve and solenoid will fix the problem.

 

[Ivan90]

Fuel economy can take a hit. EGR cools the peak cylinder temps, reduces detonation. Without EGR, knock sensor picks up additional detonation, retards timing--reduces both power and economy.

Removing/disabling the EGR would not be my first choice.

Thanks Schurkey. I'll replace the EGR valve and solenoid and see if that fixes the engine stutter problem.

 

[MSCustoms]

Thanks Schurkey. I'll replace the EGR valve and solenoid and see if that fixes the engine stutter problem.

I recommend AC Delco for the egr on TBI, mine doesnt like any other brand

 

[1500z71]

You must be registered for see images attach

EGR valve... over time my '93 K1500 5.7L engine started coughing/stuttering/surging especially at low idle. I changed spark plugs and wires, distributor cap and rotor, O2 sensor, map sensor, fuel pump, rebuilt the TBI, and fixed the timing, still the engine ran rough.

Then I accidentally broke the brittle EGR tube that connects the valve to the solenoid as shown in the picture - the problem went away, no more engine stutters. Funny breaking something seemed to fix the problem. I repaired the tube and the engine stutters returned, so I put the broken tube back on and let it be. I assume my EGR valve and/or EGR solenoid are causing problems, or maybe its something else.

Two stupid questions: 1) what does this EGR valve and solenoid do for me - are they important? and 2) should I replace them or just leave it alone with the broken tube? Appreciate any insight.

Hey buddy, mind checking my post out? I think we may be having similar issues, and I noticed today that my same EGR line plus one more was broke in almost the same place. It’s a ‘92. I’m hunting solutions as well.

https://www.gmt400.com/threads/stumbling-when-put-in-gear.51550/

 

[Schurkey]

For the record, I put a fresh engine in my '88 K1500. Had some issues with Code 32--EGR.

First, I discovered that the vacuum source for the EGR is paired with a vacuum hose to the AIR system. The vacuum hose at the AIR solenoid was broken. Therefore, no vacuum to the EGR, either.

Second, having repaired the vacuum hose, I discovered that the EGR valve wouldn't hold vacuum. Replaced with a matching negative-backpressure EGR valve. I think it was Standard Motor Parts EGV-628

 

[bigfutz]

Some have tool boxes. I remember asking what they were when I joined this forum.

Just the other day I was thinking that drivers side battery tray would be a good spot for a hide-a-safe that looks like a battery.

 

[Ivan90]

I recommend AC Delco for the egr on TBI, mine doesnt like any other brand

Uh oh, I just ordered an SMP EGV627, I'll give it a go and if it doesn't seem to work right I'll get an AC Delco valve, looks like ACDelco #214-1432 is the correct part. Thanks for the comment.