1987 tbi Blazer almost stalls under load

[diesel_lv]

Ok, missed a step. Didn't apply vacuum to EGR and try to start and see if vacuum dropped. Just did that and vacuum would not drop quickly. Engine would not start as too much exhaust going into intake. Troubleshooting guide says take off EGR and check for obstructions and replace if no obstructions. I had taken EGR off a couple days ago and cleaned it so I know there are no obstructions. I guess its replace EGR time. And the tale continues.

 

[4WDKC]

4WDKC, Thank you for the suggestions though. Ya, I've put in 2 IAC valves. Had a Duralast in it from Autozone. A friend who is a retired GM tech said that it was bad and to put in an ACDelco one. I got one and put it in and did all the steps. It still did same thing. So now I have a spare IAC valve in case the ACDelco one goes bad. I will try the pin out of A4 though just for good measure. No one in the area has an ACDelco EGR valve and Chevy has to order one at $130ish. RockAuto has the correct ACDelco one per Chevy parts guy at only $55. Thats only $3 more than the Duralast one from Autozone. So I will order it tomorrow if the A4 pinout works properly.

What did the GM tech say about TPS voltage being below the .50v minunium?

 

[diesel_lv]

Got the new ACDelco EGR valve. Installed it and works great. Got new ACDelco oil pressure 0-60 sending unit in also and it still reads about 15-20 psi. So gauge is bad. At least the test with the mechanical gauge showed it had great oil pressure. Never asked my tech about the TPS voltage, just adjusted it today to .54 volts. Thank you everyone for the suggestions and help.

 

[Honky Kong jr]

Stop putting a load on top of it......

 

[4WDKC]

Got the new ACDelco EGR valve. Installed it and works great. Got new ACDelco oil pressure 0-60 sending unit in also and it still reads about 15-20 psi. So gauge is bad. At least the test with the mechanical gauge showed it had great oil pressure. Never asked my tech about the TPS voltage, just adjusted it today to .54 volts. Thank you everyone for the suggestions and help.

why does everyone think they have to have 60psi at idle?

 

[1987 GMC Jimmy]

Mine’s about fifteen, give or take, at warm idle. It starts out at about 55 ice cold. I didn’t think SBCs were supposed to run that high.

 

[4WDKC]

Mine’s about fifteen, give or take, at warm idle. It starts out at about 55 ice cold. I didn’t think SBCs were supposed to run that high.

they arent, infact most engines arent. There is a bypass in the oil filter mount that is spring loaded and if you have to much pressure the oil over powers the spring and oil bypasses the filter. If you have any metal in your oil, you just pumped it right into your bearings. I blocked mine off in the vette so it wouldnt do that again. I have always heard a minimum of 10 psi for every 1k rpm warm.

 

[1987 GMC Jimmy]

they arent, infact most engines arent. There is a bypass in the oil filter mount that is spring loaded and if you have to much pressure the oil over powers the spring and oil bypasses the filter. If you have any metal in your oil, you just pumped it right into your bearings. I blocked mine off in the vette so it wouldnt do that again. I have always heard a minimum of 10 psi for every 1k rpm warm.

Yeah, that’s what I thought, too. Some filters can be wonky, too, I guess. My mom’s 5.3 had a Delco filter on it (can’t remember the number), and it would do around 75 psi driving down the highway when it was cold. It never did less than fifty, I don’t think. I switched to the Delco PF61E filter that Walmart sells, and it’s pretty much always 45 pounds. A lot better than damn near 80 cold.

 

[diesel_lv]

Im not worried about oil pressure. I was wondering if it was correct. When I hooked up a test gauge, it read 50+ cold and then went down to about 20 warm. That seems normal. But my gauge in the truck shows 15 at idle cold and about 10 hot. I had replaced the sending unit with a brand new one and the gauge still showed the same. So, its a bad gauge.

 

[RustyPile]

Im not worried about oil pressure. I was wondering if it was correct. When I hooked up a test gauge, it read 50+ cold and then went down to about 20 warm. That seems normal. But my gauge in the truck shows 15 at idle cold and about 10 hot. I had replaced the sending unit with a brand new one and the gauge still showed the same. So, its a bad gauge.

The gauge can be easily repaired if you want to save the money spent on a new one.. The gauge resistor is bad, gone extremely high in resistance or blown open. Grounding the sender wire and watching the needle swing does not reveal a bad gauge resistor, but will lead one to believe the gauge is good and the sender is bad. Remove the gauge, the resistor is mounted on the back of the gauge, it's the little white ceramic block with a rectangular "sticker" attached.. Go to Radio shack (if there's still one in your town), or any electronics store, Fry's, Ralph's, Mouser, etc.. Buy an 80 ohm, 1 or 2 watt resistor.. Using a small Dremel die grinder (or similar tool) cut through the trace on the bad resistor near one of the bolt holes.. On the new resistor, bend each wire near the body of the resistor approximately 45 degrees. Mount the bad resistor and then wrap each leg of the new resistor around the terminal lugs of the gauge. Position the resistor so that neither the body of it nor the legs touch any metal of the gauge or surrounding objects.. Tighten the 2 nuts and you're done.. Install the repaired gauge and enjoy it's now accurate readings....

GM temperature and some fuel gauges can be repaired using this technique...

I have repaired numerous GM gauges using this technique and have never failed to have it work....