MPFI Upgrade with or without lower intake gasket replacement
#51
12-22-2018, 06:17 PM
That is a tough call. Whether you do it now or later, I would recommend replacing the LIM gaskets as soon as possible as when they fail, they fail catastrophically ruining the engine. However, the parts to get out of the way to only do the fuel injection spider I think are less messy and are mostly annoying to do. This is in contrast to what needs to be replaced to get to the lower intake manifold that also requires getting large brackets and their accessories out of the way and draining the cooling system.
I have the original GM Service Manual for my 99 but I found this super handy. How To Replace Intake Manifold Gaskets On A GMC Jimmy 4.3 Liter V6 To Fix A Coolant Leak - GM Truck Engine Repairs
Look at the above link and you should be able to determine the amount of extra work it takes to also replace the LIM gaskets in addition to the the FI-spider.
Several notes with respect to replacing the LIM:
I have the original GM Service Manual for my 99 but I found this super handy. How To Replace Intake Manifold Gaskets On A GMC Jimmy 4.3 Liter V6 To Fix A Coolant Leak - GM Truck Engine Repairs
Look at the above link and you should be able to determine the amount of extra work it takes to also replace the LIM gaskets in addition to the the FI-spider.
Several notes with respect to replacing the LIM:
- Study carefully how to undo the bolt/nut that secures the lower end of the AC bracket to the block. I spent way too much time trying to get it undone before going back to the instructions above and figured it out.
- Mark the orientation of the rotor and take pictures before your take out the distributor. (I used a sharpie and crawled onto the top f the engine to mark the rotor position directly from above.) Do NOT rotate the crank with the distributor out. When you put it back in, it is likely the shaft for the oil pump got rotated anyway. With I think 13 teeth on the cam gear, it is likely that the the only way to get the distributor in and to engage with the oil pump shaft will be with it being off by a multiple of 360*/13* ~ 1/12 of a rotation. Don't fret. Consider how the angled teeth on the gear cause the distributor shaft to rotate as it is installed. Then with a really big flat-blade screw-driver, rotate the oil-pump shaft to where it needs to be so that when you drop in the distributor it ends up pointing in the correct direction. It might take a couple tries but if you have not rotated the crank, it will work fine. Do not force it place. When lined-up, it will go in nice and easy.This is how I got mine back in.
- Cut off the heads of some of the old bolts for the LIM (did you get new bolts and an inch-lb torque wrench?) and install them loosely to use as guide pins for reinstalling the LIM. I wish I had thought of doing this. Someone else posted this hint and I was all "D'oh!" as I I have done that on my old Mustang for which on the old Ford 289s from the 60s, some of the intake manifold bolts instead were studs which really helped with getting the intake manifold lined up.
- Use fresh, name-brand RTV for the front and rear rails of the block. There have been reports of the RTV that comes with the Fel-Pro kit being sub-par in performance.
- Ditto on replacing the oil after replacing the LIM gaskets as there will be water in the oil.
- Do your best to protect the innards of the engine from contamination from debris associated with removing the old gaskets; lots of towels to protect the lifter valley and to plug off the intake ports and water passages.
Great advice Christine....I might add, instead of cutting the heads off bolts etc, go to home depot and buy a 1/4" wooden dowel and cut 4 pieces at 2'' long (1 for each corner of the manifold) works like a dream.
#53
12-26-2018, 09:28 PM
IAC counts PID in Torque Pro did not work in my Blazer, so I doubt it works for yours. But other than that things are not looking that bad. Have you tried the graphing function for the O2 sensors and Fuel Trims instead of making gauges with plots. I don't understand the time axis on yours in order to see if they are responding normally.
#54
12-26-2018, 09:34 PM
IAC counts PID in Torque Pro did not work in my Blazer, so I doubt it works for yours. But other than that things are not looking that bad. Have you tried the graphing function for the O2 sensors and Fuel Trims instead of making gauges with plots. I don't understand the time axis on yours in order to see if they are responding normally.
I will run that tomorrow morning on my cold start. Thanks
#55
12-27-2018, 06:08 AM
I was looking at that since I saw your images but I am not sure how to get the data points set. I hit setup and choose the line chat.. 1000 lines, when sensors refresh x axis,, but not sure where to select where it pulls from.. If you have short tutorial I will run that tomorrow morning on my cold start.
Thanks
I will run that tomorrow morning on my cold start.Thanks
How sure are you that you secondary air pump is working? They are a common failure - they get moisture in the pump and then lock up. If you had Car Gauge Pro you can toggle that particular pump on/off using the software and go listen/see if it will suck air in. Contrary to popular belief, there is some bidirectional control for a few select things, even in this Android app. Another thing it will do is toggle the fuel tank purge valve on/off. I have used both in repairs on my 2001. Everyone should keep in mind that Car Gauge Pro does not play well with 1996-1997 Blazers.
Last edited by LesMyer; 12-27-2018 at 06:26 AM.
#56
12-27-2018, 10:15 AM
I just used the default settings and entered the two PIDs under x axis sensors. Then you have to click the arrow on main screen to get things to start. I plotted o2bank1sensor1 and o2bank2sensor1 at same time. Same for fuel trim. Curious what you intend to do for reading IAC or is it now idling ok - or just no code? As far as the secondary air test - my understanding is that it is only run when vehicle is started, but in my experience not every time. A mind of its own. Took mine a week or two to pass after I replaced the secondary air pump and check valves. I think cold weather can affect when these tests run, but in CA I wouldn't think that would be a problem.
How sure are you that you secondary air pump is working? They are a common failure - they get moisture in the pump and then lock up. If you had Car Gauge Pro you can toggle that particular pump on/off using the software and go listen/see if it will suck air in. Contrary to popular belief, there is some bidirectional control for a few select things, even in this Android app. Another thing it will do is toggle the fuel tank purge valve on/off. I have used both in repairs on my 2001. Everyone should keep in mind that Car Gauge Pro does not play well with 1996-1997 Blazers.
How sure are you that you secondary air pump is working? They are a common failure - they get moisture in the pump and then lock up. If you had Car Gauge Pro you can toggle that particular pump on/off using the software and go listen/see if it will suck air in. Contrary to popular belief, there is some bidirectional control for a few select things, even in this Android app. Another thing it will do is toggle the fuel tank purge valve on/off. I have used both in repairs on my 2001. Everyone should keep in mind that Car Gauge Pro does not play well with 1996-1997 Blazers.
I will down load the app now and see if I can figure out the pump test and force it before starting but if you could put down the steps for car gauge i would appreciate it.
Thank you
#57
12-27-2018, 11:28 AM
Woah I am an idiot. I was reading that as a selection between what axis to read, not that was where you select the PIDs. As for the IAC, I never removed the monitor from when you were asking for that and before you had tried it on your own blazer to find it not an option in torque. It was a bit before that secondary tripped to complete the one time it did. As for knowing if it is working I am not positive. I only have the fact that the system did change to complete in the tests that one time to think it was at least working sometimes. I have, on the last few cold start attempts, hope out of the truck to see if I can hear it kick on but can't hear anything turning on or off. I have read the failure point and the TSB on the water, corrosion, and lock up of the pump. I may just get the car gauge pro as a supplimental tool and run the pump to test. Can you tell me the steps on that pump test and I will download it and run it right now before I waste my cold start for today. Its been getting down to low 30s overnight but afternoons are 60s so it doesn't cool down enough during the day to get a second cold start.
I will down load the app now and see if I can figure out the pump test and force it before starting but if you could put down the steps for car gauge i would appreciate it.
Thank you
I will down load the app now and see if I can figure out the pump test and force it before starting but if you could put down the steps for car gauge i would appreciate it.
Thank you
#58
12-27-2018, 12:43 PM
In comparison to Torque Pro, Car Gauge Pro is very painful to use at first. First you need to Connect/GM/powertrain and do a full auto scan. Then save the PID file so you can import the PIDs offline without connecting to the vehicle. This allows you to make gauges without being hooked up to the vehicle. Then on normal connection you just hit Connect/GM/Powertrain/No Scan/Import PIDs/import from file/then select your file and it won't have to scan the PIDs each time. You will find the control of the A.I.R. pump under diagnostics, once you have properly set things up and connected to the vehicle. Don't expect many of the items that you find in the listings to work on your Blazer - all this stuff is unfiltered. This particular control happens to work. You will definitely get frustrated, but once you get the hang of things it is easy to use and works well for more than what Torque Pro does.
I will go out and do the above steps and see what I can find on the air pump itself.
Parked idle after 45mile trip
cruise control at 65ish
cruise control at 65ish
cruise control at 65ish
#59
12-27-2018, 02:06 PM
I am able to connect and save the PID file. I can then follow the steps to load the save PID file but when I connect to the actual blue tooth it forces me down that same path to either load the PID or choose the device. I can go to Diagnostics> Active Test> Air Pump Solenoid or Air Solenoid and when I press on it pauses for a moment before saying "invalid/no data" in a small bubble at the bottom.
#60
12-27-2018, 04:42 PM
Just got home from another 45 miles. Attached are the fuel trim graphs for those.
I will go out and do the above steps and see what I can find on the air pump itself.
Parked idle after 45mile trip
cruise control at 65ish
cruise control at 65ish
cruise control at 65ish
I will go out and do the above steps and see what I can find on the air pump itself.
Parked idle after 45mile trip
cruise control at 65ish
cruise control at 65ish
cruise control at 65ish
Last edited by LesMyer; 12-27-2018 at 04:51 PM.