Loosing power

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kymeallion

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As i was driving down the interstate i kept having to push the gas down further and further to maintain speed, when i got up to the light @ the exit ramp it died. the only way i got it running was to put the gas to the floor. After i let it sit for 15 min or so it starts right up. can any one tell me what's going on
 
kymeallion said:
As i was driving down the interstate i kept having to push the gas down further and further to maintain speed, when i got up to the light @ the exit ramp it died. the only way i got it running was to put the gas to the floor. After i let it sit for 15 min or so it starts right up. can any one tell me what's going on
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Start with the simple and replace your fuel filter, a dirty fuel filter can restrict the fuel flow to your injectors enough to cause the issues your describing. Note also a dirty fuel filter will cause your fuel pump to work harder and cause it to run hotter and shorten it's life expectancy.

Good luck and keep us posted. ;)
 
Has a brand new fuel filter, I had to replace the housing for the fuel pump and the filter in the tank
 
kymeallion said:
Has a brand new fuel filter, I had to replace the housing for the fuel pump and the filter in the tank
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Did you replace the fuel sending unit wire harness from the tank to the frame?? Common for the wire in the harness to break and when it heats up from the electrical current, you lose current flow for a break. Start with checking your fuel pressure at the shredder valve, should be 58-66 PSI when fuel system primed and should drop about 5 PSI when engine is running.

Good luck and post back, the other issue also would be a bad ground to your sending unit. The ground wire is separate from the wire harness and when the ground is bad it will cause your fuel pump to be weak, you need at least 55 PSI to have your injector system to run the engine at idle. :eek:
 
I don't beleive so. When i took it all apart the wiring harness seemed fine. Didn't have any dry rot insulation around wires. I also had to replace lots of gaskets when i got truck. It had been sitting for a year. it will sit and idle all day long, it seems to me it starts after you have driven a long distance When i tried to restart it acted like the battery was low. I just went and started it, it started right up
 
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kymeallion said:
I don't beleive so. When i took it all apart the wiring harness seemed fine. Didn't have any dry rot insulation around wires. I also had to replace lots of gaskets when i got truck. It had been sitting for a year. it will sit and idle all day long, it seems to me it starts after you have driven a long distance When i tried to restart it acted like the battery was low. I just went and started it, it started right up
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Replace your fuel pump relay or swap it out with your A/C relay for now.

Keep me posted. ;)
 
is operating properly. I'm courious to ask because i have herd lots of ways and i want to make sure i did mine right. How do you adjust the valves on 1994 5.7l Z71. I have had to work on this truck a bit. It has only cost me time and i don't mind. I have replaced the EGR valve, PCV valve, all vacuum lines, all the gaskets around the valves, lifters, rocker arm nuts, intake gasket valve cover gaskets, fuel pump housing fuel lines, valve cover grommets, TBI gasket to intake, cleaned out old carbon build up from all kinds a spots, does not over heat, it shifts into overdrive too soon, when it shifts, at the hight of the shift it runs really good. I put a timming light on it, it's in perfect time. I think that is everything! So, DR can you tell me whats wrong with her or am i going to have to take her around the barn & shoot her.
 
kymeallion said:
is operating properly. I'm courious to ask because i have herd lots of ways and i want to make sure i did mine right. How do you adjust the valves on 1994 5.7l Z71. I have had to work on this truck a bit. It has only cost me time and i don't mind. I have replaced the EGR valve, PCV valve, all vacuum lines, all the gaskets around the valves, lifters, rocker arm nuts, intake gasket valve cover gaskets, fuel pump housing fuel lines, valve cover grommets, TBI gasket to intake, cleaned out old carbon build up from all kinds a spots, does not over heat, it shifts into overdrive too soon, when it shifts, at the hight of the shift it runs really good. I put a timming light on it, it's in perfect time. I think that is everything! So, DR can you tell me whats wrong with her or am i going to have to take her around the barn & shoot her.
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OK kool you got a 1994 TBI 5.7 engine, that would help. I though you had a 1996 and up vortec. Replace your TPS and since everything is cleaned out i going to guess that there is little amount of carbon in your engine.

Add a bottle of http://www.marvelmysteryoil.com/ in to your engine oil. This will dissolve any carbon in the engine like the lifters and oil journals. I use the Marvel oil 500 mile before i replace the oil and filter since day one i got the Jimmy. You may want to run it longer then that, once you do change the oil, you'll notice that it's black with all the extra carbon that was cleaned out.

You will notice a improvement as it works it way throughout the engine after a few days as you drive your Sierra. Just take note to keep a close eye on your engine oil level. The Marvel oil it much thinner and will burn it self out due to the heat from the engine.

Good luck and keep us posted. ;)
 
kymeallion said:
What is TPS?
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TPS, throttle position sensor located at your throttle body opposite side if the throttle cable linkage. Your transmission is electronically controlled by the ECM from signals from your TPS and input speed sensor.

Your Sierra being a 1994, there is no programmer for your ECM but different chips to alter the performance of your engine and transmission performance also. Here is a link for one is the better company that burn performance Chip for your OBD1 ECM system. http://www.gmtuners.com/eprom/index.htm

Give them a call and they will be more then happy to answer any questions you may have. :D
 
as i was tinkering with truck today, i had the breather cover off and let it run & watched it. I noticed both fuel injectors were not amiting a spray. 1 would drip or do very little. could this be my problem? Also, i did a resistance test on the coil, per Haynes manual, & it did test very good. Could it, as well, be part of my problem, heating up then as i let off gas at low RPM it kills the truck & acts like battery has been drained?
 
kymeallion said:
as i was tinkering with truck today, i had the breather cover off and let it run & watched it. I noticed both fuel injectors were not amiting a spray. 1 would drip or do very little. could this be my problem? Also, i did a resistance test on the coil, per Haynes manual, & it did test very good. Could it, as well, be part of my problem, heating up then as i let off gas at low RPM it kills the truck & acts like battery has been drained?
Click to expand...

Try running half a can of http://www.seafoamsales.com/ in your gas tank and the other in you your intake. Also clean out your throttle body with throttle body cleaner, the injectors may just be gummed out with varnish and carbon.

Start with that and keep us posted, at worst. Your going to have to replace the injectors. :eek:
 
finally got around to replacing tps. also took apart tbi, cleaned, new gaskets & filters on fuel injectors. it still dies @ the stop sign @ the end of my street, it doesn't seem to want to start unless you touch the gas. when you put it in gear it idles so low that it wants to die. when its cold it starts right up. any more ideas?
 
kymeallion said:
finally got around to replacing tps. also took apart tbi, cleaned, new gaskets & filters on fuel injectors. it still dies @ the stop sign @ the end of my street, it doesn't seem to want to start unless you touch the gas. when you put it in gear it idles so low that it wants to die. when its cold it starts right up. any more ideas?
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Can't recall, but did you clean your EGR valve????? If you have not cleaned your EGR valve. Remove it and clean the carbon from it and post us back. A clogged EGR valve, keeping the pintle open which is a huge vacuum leak that will give you the issues you have described.;)

Was also thinking, have you checked the timing on the engine??? The stock timing is 0", also use 89-93 octane and set the base timing at 8 BTDC and this should really woke it up the engine. It was a slug on 87 when the engine was new, especially on a hot day as the ECM will retard spark when it hear knock before you do and that will cut into power/response a good bit. That engine has 9 to 1 compression ratio and it will do a lot better on 89 or higher octane fuel.

Also if you have no torque and can't pass with a darn or pull on a hill, it's the map sensor or a part related to the map. With you saying you replaced the maps, i would check the parts related to the map. The map is unless where it's mounted to the manifold is a thin piece of vacuum hose that can clog with oil or just plain break, this would also explain your surge at idle and stalling. The vacuum leak would also make it run richer decreasing fuel economy too.

Keep us posted
 
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new egr valve, truck sat for about a year. after i put it all togeathere, it sucked the diaphram out! lol caught that 1 was listenin to it run. Not changed map sensor yet! is there something you have to un-hook, or does everything have to be working proper to hook a timing light up? I cleaned & put new gaskets on the hole TBI. As soon as i put it in gear after starting it, it runs like shit! it does sound like it's drawing alot of air threw the TBI after that. It has run alot better since i have done all this, but its still not right. thank you all for all your help.
 
kymeallion said:
new egr valve, truck sat for about a year. after i put it all togeathere, it sucked the diaphram out! lol caught that 1 was listenin to it run. Not changed map sensor yet! is there something you have to un-hook, or does everything have to be working proper to hook a timing light up? I cleaned & put new gaskets on the hole TBI. As soon as i put it in gear after starting it, it runs like shit! it does sound like it's drawing alot of air threw the TBI after that. It has run alot better since i have done all this, but its still not right. thank you all for all your help.
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Hope this helps. I pulled it straight from Alldata.

Set timing under the following conditions:

* Normal operating temperature.
* Air cleaner installed.
* A/C "OFF."
* Transmission in neutral.
* Disconnect SET TIMING connector.

The location of the set timing connector is inside the cab where the heater box and the carpet meet on the passenger side floor. Pull carpet back to expose the single wire and connectors on the outside of the control module harness. The wire colors are tan with a black stripe. DO NOT disconnect 4 wire connector at distributor. (connector is sometimes found hanging right in front of the blower motor)

Connect timing light and adjust as necessary by loosening hold down bolt and rotating distributor. Tighten hold down and recheck the timing. Stop the engine and connect SET TIMING connector. Clear control module trouble code by disconnecting control module power source. With engine at operating temperature, drive vehicle at part throttle with moderate acceleration and decelerate to idle condition. This will "teach" the control module and return the engine to normal performance.

Set base timing from 0 BTDC (factory spec) up to around 4 to 8 BTDC or so. Higher you go more likely it is to ping. Snug down distributor, re-check, shut engine off, reconnect bypass wire. Remember to always test drive after you make any adjustments to get the most out of your engine.

Check all your vacuum lines and replace any that are damaged.
 
I don't see anything that resembles that single wire. There is a big wiring harness with lots of wires. could it be somewhere else on a 94' Z71 1500 4x4?I also notice, when you put it in gear then back into park or neutral it runs ruff. But after a restart it’s back to running good!
 
what code scanner will work on my truck? something that has a digital read out screen
 
I tried the paperclip, & it blinks. I SUCK @ morris code! is there not a code reader/scanner that has a digital face that the code pops up on?
 
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