Hey guys...so my sons 88gt is guzzling gas. The car runs solid but he has only been get 12-13 mpg. He deals with it because he loves the car but I knew something wasn't right. I went through all the vacuum lines and found a few leaks. Fixed them...car ran a little better and the cruise control worked again but same gas mileage. Poking around on the forums I checked all the suspects...oxy sensor is brand new. I pulled error codes and we got a consistent 32 even after resets. Pulled the egr solenoid and its 100% shot. Its so corroded inside I cant even get the solenoid out of the casing to attempt a repair. I cannot get a replacement not on ebay, amazon, obscure online parts stores...no where. ACDelco 214-361
The question....the car is exempted from emissions standards in Texas because its a classic...they don't even check it at inspections. Can I get better gas mileage at this point by blocking off the EGR Valve? Not sure if its relevant but we were getting high idle (2000-1500) till I replaced the engine temp sensors (Both) we now get 1100 rpms once warmed up. In summary to fix this we have Fixed Vacuum lines Replaced map sensor Oxy sensor is brand new Temp sensors
[This message has been edited by Forrest (edited 04-30-2020).]
You will see very little difference in MPG with the total elimination of the EGR system. Some have experienced burned pistons when they did.
You can totally eliminate your old EGR solenoid and replace the system with a new digital EGR valve which is more plentiful if you convert the car to a 7730 ECM.
The two temperature sensors report the engine temp, but only one of them has any effect on how the engine runs. The sensor in the corner of the cylinder head just below the ignition coil only operates the gauge and temperature light. That's it. No effect on the engine.
The temperature sensor below the thermostat housing that screws into the end of the lower intake manifold is read by the ECM. The ECM adjusts the air/fuel mixture based upon what that sensor is reporting. Every one that I have had to fail has failed to the cold side of its range. This causes the ECM to add fuel to the mix and mileage goes down. Often, they didn't set a trouble code, either.
The auto parts stores frequently list the wrong sensor for the applications. If you had to cut and splice the harness to either, then you have the wrong sensor. The coolant temperature sensor above the water pump should have an oval plastic head on it.
You can test the relative accuracy of the sensors with an ohmmeter. You would need to let the sensor lay out and come to room temperature. You would also need to know what the room temperature is to compare your resistance on a chart that I have on our message board at www.gafiero.org
The chart is in the Expert Tech Advice section about 7 or 8 items from the top. Titled GM Temperature Sensor Chart.
[This message has been edited by fierofool (edited 04-30-2020).]
Yep that is exactly why I replaced both of them. The first one I bought was supposed to be for the ECM on the battery side of the engine. When I found it was the wrong one I just replaced the guage sensor (left side of the motor facing tailights) I went back and got the correct part...I had to pull some sort of coupling off the old sensor and put it on the new one....after that everything screwed/snapped right in. No splicing. I did not however check it for accuracy. I reckon I can get my multimeter to it without having to pull it and test as you suggest. Thanks for responding m8. Much appreciated. With others posting 20+mpg on their cars I am shocked at how much this thing drinks.
Another note...The guy we bought it from had hacked up the catalytic or as he called it the "Cadillac" converter. It was cut in multiple places and welded back together. Looks like it was done on the car. I am not sure how good of a job they did and wondering if I should go ahead and cut that out as well in favor of a straight pipe.
[This message has been edited by Forrest (edited 04-30-2020).]
It's definitely a small shop, and as I understand it the guy rebuilds 'em in house. He sent me the rebuilt and a sticker to send back the core, easy to deal with. Not cheap, but I have California smog to deal with, so I kinda had to. I replaced that and the EGR valve proper and no longer see intermittent code 32's.
I know it doesn't answer your question about whether you can go entirely without, but it's an option, and info for you and other folks who may see this.
-- A
[This message has been edited by dremu (edited 04-30-2020).]
Hey guys...so my sons 88gt is guzzling gas. The car runs solid but he has only been get 12-13 mpg.
Have you done anything with the injectors? Perhaps they (or the fuel pressure regulator) are leaking? Do a fuel pressure leak-down test and see how quickly the fuel pressure drops when power to the fuel pump is turned off. It should actually hold pressure for quite awhile.
quote
Originally posted by Forrest:
Can I get better gas mileage at this point by blocking off the EGR Valve?
If anything, you'd get worse gas mileage if all EGR functions were to be deleted. A functional EGR system allows the engine to run leaner while cruising.
quote
Originally posted by Forrest:
Not sure if its relevant but we were getting high idle (2000-1500) till I replaced the engine temp sensors (Both) we now get 1100 rpms once warmed up.
Still seems a little high. I believe 900 RPM warm idle is the goal.
[This message has been edited by Patrick (edited 04-30-2020).]
IMO with 12-13 mpg, you've got a bigger problem than the EGR solenoid. You can run without the EGR system but that will only affect your mileage ever so slightly. If I were to guess you have a leaking fuel injector or cold start injector. Better fix the problem as rich mixtures tend to wash the cylinders down and cause wear to the piston rings. I've eliminated the EGR systems on several engines and didn't experience problems. I just run premium gas , a free flow exhaust , an improved CAI and a 180* stat to insure that there is no knock and that combustion temperatures are kept under control.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
sjmaye, if you're speaking of the EGR valve, it will get hot because it's attached to the exhaust manifold. To test it, you can apply a few inches of vacuum to the nipple to see if it holds. If you don't have a hand vacuum (MightyVac) remove the vacuum line, place your fingers underneath the cold valve and push up on the diaphragm. Cap the vacuum nipple with a finger and see if the diaphragm stays up or leaks down. The finger test only works on OEM valves. Aftermarket valves usually don't have openings on the underside so you can feel the diaphragm.
The EGR solenoid will be the same temp as most other engine compartment parts.
sjmaye, if you're speaking of the EGR valve, it will get hot because it's attached to the exhaust manifold. To test it, you can apply a few inches of vacuum to the nipple to see if it holds. If you don't have a hand vacuum (MightyVac) remove the vacuum line, place your fingers underneath the cold valve and push up on the diaphragm. Cap the vacuum nipple with a finger and see if the diaphragm stays up or leaks down. The finger test only works on OEM valves. Aftermarket valves usually don't have openings on the underside so you can feel the diaphragm.
The EGR solenoid will be the same temp as most other engine compartment parts.
I am working on a replacement EGR Solenoid. Would you be willing to try it for me? It doesn't look original but will fit in the original location and function like the original.
I am working on a replacement EGR Solenoid. Would you be willing to try it for me? It doesn't look original but will fit in the original location and function like the original.
my email
gofast@reddevilriver.com
Hey phonedawgz, actually my EGR solenoid is working fine. I think the OP is who you are looking for.
I am working on a replacement EGR Solenoid. Would you be willing to try it for me? It doesn't look original but will fit in the original location and function like the original.
my email
gofast@reddevilriver.com
Right now he is running with nothing at all and he is getting a service code so absolutly! Ill shoot you an email.
