IMO 9 - 10 PSI is too low, s/b closer to 13. Even if the SES light isn't on there may be stored codes. Check that out too.
88 5.7 low on power
- Thread starter thered88
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
Thanks for all the great info! I will check the cat out but i would be surprised if that is my issue considering that the previous owner put a whole new exhaust which I’m pretty sure included the cat on my truck.i don’t really remember the actual value of my fuel pressure, I just remember that it was 1 psi higher than the minimum even while reving. The only stored code is for knock sensor which was replaced the same day the light came on. I replaced head gaskets in august and I did set the timing to 0 with the timing advance unplugged. Also the ICM has been replaced. also all major grounds under the hood have been cleaned but not the thermostat housing ground. The CTS sensor has not been replace and I know it is old. I did a lot of research on aldl to usb connectors so I can hook the truck up to my computer and use tunerpro so read the sensors. I ordered the parts to make one (because I’m cheap) based off of info from this video
xc_hide_links_from_guests_guests_error_hide_media
and they will be here tomorrow so hopefully by tomorrow night I will know for sure what’s happenin. Thanks again for the amazing info and if you have any other suggestions I would love to hear them!
How old are the usual "tune-up" parts and procedures? Cap, rotor, spark plug wires and spark plugs? Fuel filter? Air filter? PCV system inspected? O2 sensor replaced?
Removing the O2 sensor can be a way to diagnose exhaust back-pressure. If the engine runs better with it removed than with it installed...there's too much back pressure. Downside is that in this case, you'd likely be blowing red-hot exhaust gas all over the wire harness and brake tubing, and that can't be good.
If your fuel pressure gauge is accurate, we know that your fuel pressure is in spec, but lower than most on here would prefer.
Verify cranking compression, and assure that all the valves are opening and closing properly.
Brakes not dragging? Fan clutch not stuck engaged? What is the gear ratio of your truck vs. your Dad's truck--maybe it goes up the hill better because his is 3.73 and yours is 3.42?
Removing the O2 sensor can be a way to diagnose exhaust back-pressure. If the engine runs better with it removed than with it installed...there's too much back pressure. Downside is that in this case, you'd likely be blowing red-hot exhaust gas all over the wire harness and brake tubing, and that can't be good.
If your fuel pressure gauge is accurate, we know that your fuel pressure is in spec, but lower than most on here would prefer.
Verify cranking compression, and assure that all the valves are opening and closing properly.
Brakes not dragging? Fan clutch not stuck engaged? What is the gear ratio of your truck vs. your Dad's truck--maybe it goes up the hill better because his is 3.73 and yours is 3.42?
it has had a tune up within the year. The tune up did not include a o2 sensor tho. I will look into the o2 sensor soon but that probably won’t happen till after I get the parts in to make that cable. everything mechanically is good. Brakes are never warm, fan clutch isn’t stuck, and both trucks have 3.42 gears.
Well here is a little update. While waiting for the parts to make the aldl cable, I got and installed a new coolant temp sensor. That did nothing. when I did get the parts in for the cord, I followed the video exactly and looked at a couple of other forums and videos about tunerpro rt but I could not get it to work on my 88’ or my dad’s 90’. My main issues are that I can only find a ads file and not an adx file for my truck, and that I’m pretty sure turner pro is not recognizing my cable so it’s net even trying to read it. So if anyone has any suggestions on how to make this cable work i would love to hear them. also I forgot to mention that it was at the exhaust shop 2 times within the last week trying to find a possible leak, they were unsuccessful but they did mention that they felt it missing a little bit.
I've seen a lot of DIY cables that didn't work. You're better off buying one. You can download TunerPro RT v4 to run .ads files. There is a conversion utility that convert .ads to .adx but, I can't remember where it was I saw it.
I found it, unfortunately it was on moates.net who shut down last year. Anyone else know where to find one?
Throw the homemade cable in the trash, buy a commercially-available scan tool. Save yourself heaps of headaches and anger-management counseling sessions. It'll cost less in the long run.
an 88 is OBD1, scan tool is not going to be much help. You can jump A/B terminals in the OBD connector under the dash (
Fuel 9 to 10 psi is 1 psi too low. It should be rock solid at 11. Surging is usually a vac leak, or it's sucking air somewhere. Base gasket for the TBI. Gaskets (top and bottom ) of the middle engine breather (sits on the TBI between the air cleaner). If you've never cleaned the TBI, and "rebuilt" it (kits include new injector O-rings, screens, gaskets, and fuel pressure diaphragm)., now's a good time to do that. The base of the TBI has allot of veins like an auto trans that can get gummed up pretty good.
xc_hide_links_from_guests_guests_error_hide_media
), and the codes will flash though the service engine light.Fuel 9 to 10 psi is 1 psi too low. It should be rock solid at 11. Surging is usually a vac leak, or it's sucking air somewhere. Base gasket for the TBI. Gaskets (top and bottom ) of the middle engine breather (sits on the TBI between the air cleaner). If you've never cleaned the TBI, and "rebuilt" it (kits include new injector O-rings, screens, gaskets, and fuel pressure diaphragm)., now's a good time to do that. The base of the TBI has allot of veins like an auto trans that can get gummed up pretty good.
That is so entirely wrong.
How do you think these vehicles were fixed when they were new?
Here's an old post of mine detailing the info available from an old scan tool (Snap-On MTG2500) on an '88 K1500.
Posts 14 and 15, but the whole thread is kinda humorous.
www.automotiveforums.com/vbulletin/showthread.php?t=1146067
94 k2500 no low end power and horrible fuel mileage - Automotive Forums .com Car Chat
94 k2500 no low end power and horrible fuel mileage C/K
www.automotiveforums.com
Blinky-light diagnostics is crap compared to what's available with a scan tool.
I agree that an air leak between the air cleaner and the throttle body is bad (because that air isn't filtered) but not because it upsets the fuel mixture or causes a driveability problem in any way.
Huh? The base of the TBI is about as simple as it gets. A few vacuum channels leading to vacuum nipples, an Idle Air Control motor passage, and two throttle blades on a spring-loaded throttle shaft connecting to a Throttle Position Sensor.
You must be registered for see images attach
