95 tahoe wont stay running after replacing the o2 sensor

[adam74]

can keep it running if giving it gas. have to give it gas to start it. soon as I lift off gas it dies. even when going down road. once I slow down it dies. something I noticed was it seems to be at a very low rpm as if the trans is not engaged when coasting. runs fine with gas pedal applied. recently replaced the fuel pump and sending unit so its new and shouldnt be the problem, had been running fine before the o2 sensor. its the sensor just before the cat. also had to buy a new battery and installed it at the same time. well after putting the o2 sensor on

 

[lesterl]

What brand of pump did you install? EGR valve ok? Vacume leak (like TBI base gasket for instance?)

 

[adam74]

it was running fine before the battery crapped out and I replaced the o2 sensor. fuel pump was from oreilly which is usually good stuff, tbi base gasket has already been replaced and hadnt touched anything under the hood prior to the problem. had fixed a few vacuum leaks in the past and messed with the egr valve as far as cleaning it. I'll put the old o2 sensor back in tomorrow to see if it goes back to running right I guess.

 

[lesterl]

How does it run cold (when you first start it) as ECM ignores input from O2 then..... When you replaced the pump, did you put the whole assembly in, or did you just replace the pump motor inside the module?

 

[lesterl]

http://www.amazon.com/gp/product/B000CGI0KO/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

This is the one I put in my 95.....

 

[adam74]

i replaced the whole assembly. pump plus sending unit. put old o2 sensor back in and still have same problem. it will still start and run for maybe a second but then immediately die. wont restart/run unless I give it gas.

 

[adam74]

lester thats the pump they originally sold me but my truck has metal fuel lines so plastic top will not work. had to purchase the pump and sending unit seperate and put it together myself.

 

[lesterl]

95 is a bastard year, IIRC fuel pressure is higher, you need to match the pump module codes or you will get wrong pump...

 

[adam74]

I replaced the pump over a month ago. doubt it doesnt 'match up'. I dont drive it alot but would think that it would have had a problem from the start not later on. not trying to be a smart a** jus would think it would have been an imediate problem.

 

[adam74]

just remembered something. when I was hooking the battery up I started smelling a rotten egg smell (at least thats what I thought at the time). could that possibly be some wiring burning??? I know I hooked the battery up correctly.

 

[lesterl]

Well, knowing now the pump is not "NEW" but is in fact a month old is a little different, still does not rule out a bad pump as Parts store brand pumps are notorious for going bad, especially airtex junk.

Rotten egg smell, was it near battery, or as you rounded the front, or from the cabin?

 

[adam74]

yeah Im sure theres a possibility of it going bad. was just saying it wasnt an immediate deal. as far as the smell. I noticed it while I was hooking up the battery so no specific area other than standing on the front passenger side of the engine bay. didnt think to chase it down at the time.

 

[WisYukon]

Check engine light on? Sounds like a vacuum line is off or maybe mass airflow came unplugged or something like that.

 

[lesterl]

TBI does not use MAF sensor, it is MAP controlled.
That being said usually rotten egg smell is catalyst bad, but you wernt running you were hooking battery up.... Stumped on that smell unless it was more acrid than rotten... Different noses...

 

[WisYukon]

TBI does not use MAF sensor, it is MAP controlled.
That being said usually rotten egg smell is catalyst bad, but you wernt running you were hooking battery up.... Stumped on that smell unless it was more acrid than rotten... Different noses...

Good point. Totally spaced on the year and that it's tbi. I do know some times battery acid can have a suffer smell and you may have been smelling it from the battery vent. Probably Un related. Maybe try priming the fuel pump a couple times before starting.

 

[adam74]

yes tbi no maf. no cel. yeah maybe was just smelling the battery. I visualy checked the vacuum lines and all seemed to be good and no noticable vacuum leak sound when running. cant totaly check it by myself with it running though. I bought a fuel filter today so will change that tomorrow. by priming the fuel pump Im guessing you mean to turn the key on/off a few times? I have a good iac I can change out also to eliminate that.

 

[WisYukon]

Yes, priming by turning the key on, maybe a couple times just to see if that makes a difference. Maybe your pump isn't holding prime for some reason, but then again if giving it gas keeps it running I'm not sure if it would be a priming issue. Just thinking out loud here...

 

[lesterl]

When my pump was bad on mine, I ran some carb cleaner into mine, cranked it till it started and kept feeding it carb cleaner to keep it running indicating I had a fuel issue.....

 

[adam74]

changed the fuel filter, same result. put in my old iac and wala! fired right up! bought it about a month and a half ago and kept the old one. runs now but still stumbles at idle ocassionaly wich is why I had replaced the iac to begin with. will be taking the 'new' one back. gonna try to find an ac delco brand iac and egr valve if anyone can suggest a good place to get them. thanks for the help guys, glad I got it figured out finally.

 

[lesterl]

EGR stay OEM only.... I have been burned so many times on aftermarket crap....