96 blazer runs.. but can't give more them 1/4 throttle
#1
09-11-2010, 10:55 AM
Join Date: Sep 2010
Location: Manchester, New Hampshire
Posts: 7
96 blazer runs.. but can't give more them 1/4 throttle
ok here's the list of stuff i did..before it started doin' it. New plugs, wires, cap rotor, and pcv.. and it ran good for 2-3 weeks then it stalled at a stop light.. pushed it to the side of road and waited.. it started a half hour later. but the truck fell on it's face after 1/4 throttle..i knew i needed o2 sensors so i changed all 4... that still didn't help.. so i read the cat could be givin' it problems so i put a new one on.. same problem..when it's in neutral or park you can hold it to the floor and the revs stay around 2-3000rrm.. i noticed my map sensor was fallin' out.. replaced it also,, no change.. within this year it's had 3 new fuel pumps in it..i really need some help with this thing it's draining my money.. it's probably something stupid and easy.. is fuel pump about to die again? egr or tps?
oh yeah after driving it for around 30min it will stall and start back up like 3 times then you have to wait 45 min to drive it again..
and when you start it in the morning it revs all the way and will drive normal for about 10 seconds..
oh yeah after driving it for around 30min it will stall and start back up like 3 times then you have to wait 45 min to drive it again..
and when you start it in the morning it revs all the way and will drive normal for about 10 seconds..
Last edited by Gurubreed; 09-12-2010 at 07:50 AM.
#3
09-13-2010, 09:15 AM
if i were to guess, i would suspect a faulty IAC or MAF. I have found out that faulty IAC is the main cause for stalling at stop lights. but i have also seen MAF sensors do very weird things to cars from no starts to high idle, try unplugging the maf and see if that does anything. i know you said you had a o2 code, did it go away after you replaced the o2's? and do you have any current codes? have you put a vacuum gauge on it?
#4
09-13-2010, 12:21 PM
lack of vaccuum would definetly stall it at a stop light(check air filter and vaccuum hoses). Generaly when MAF sensors go they won't even let you get anywere. Meaning the vehicle will start then almost immediatly die. IAC would also explain the stalling. IMO I would point twords the tps sensor. But before I would start checking it. take paperclips and back probe the sensore with them using a standard DMM. To check the tps the vehicle doesn't have to be running but the key has to be on the on position. see if you get a steady transition of voltages as you open the throttle. The sensor shouldn't read 5 volts (more like 4.8 volts I beleve) at wide open and i forget what base line is, for that you will need a table of reference voltages. It's amazing what you can do with a cheap DMM, and sensor guessing will probably never fix the problem and cost you a ton of $.
#5
09-15-2010, 11:29 AM
Join Date: Sep 2010
Location: Manchester, New Hampshire
Posts: 7
if i were to guess, i would suspect a faulty IAC or MAF. I have found out that faulty IAC is the main cause for stalling at stop lights. but i have also seen MAF sensors do very weird things to cars from no starts to high idle, try unplugging the maf and see if that does anything. i know you said you had a o2 code, did it go away after you replaced the o2's? and do you have any current codes? have you put a vacuum gauge on it?
#6
09-15-2010, 04:38 PM
Mine does the same thing. Try smacking the fuel tank at the rear with a 2x4 ( I know sounds a little caveman- ish) This fixed mine or awhile.What happens is the tank gets crud & junk settling at the bottom & the pump picks it up clogging the pick up sock. Also look at the filler neck, if its rusty than most likely its in the tank. Of course after a while the filter will clog and give the same problem (replaced mine 2 times both clogged shut).At some point you will have to clean it out, been putting it off my self.
Also, this will give faulse readings at pressure port-You have pressure but no volume.Give it a shot only thing to loose is time. If it works come fix mine! :-)
Also, this will give faulse readings at pressure port-You have pressure but no volume.Give it a shot only thing to loose is time. If it works come fix mine! :-)
Last edited by swartlkk; 10-14-2010 at 01:40 PM. Reason: *Combining Consecutive Posts* - Please use the EDIT feature to add additional information to your post if another member yet to respond.
#8
09-17-2010, 09:09 AM
Just because you get the MAP code doesn't mean it's bad. That just means you are out of the expected limits the sensor should be reading based upon calculations made off of TPS. For a given throttle position, your engine should be getting a certain amount of air. From that you should be within a given range of vacuum depending on RPM.
Checking TPS was my first idea. Clogged filter boot is possibility. Otherwise go over the engine with a fine tooth comb and make sure all your necessary sensors are plugged in. TPS, IAC, MAP/MAF,
There isn't any possibility you left the distributor wire unplugged from the module in the distributor is there? I'm not sure, but I think it will run with that unplugged. I'm pretty sure I did that when I changed my cap/rotor, along with getting 1&3 backwards. While it ran, it didn't run well.
Checking TPS was my first idea. Clogged filter boot is possibility. Otherwise go over the engine with a fine tooth comb and make sure all your necessary sensors are plugged in. TPS, IAC, MAP/MAF,
There isn't any possibility you left the distributor wire unplugged from the module in the distributor is there? I'm not sure, but I think it will run with that unplugged. I'm pretty sure I did that when I changed my cap/rotor, along with getting 1&3 backwards. While it ran, it didn't run well.
