Chokes/Hesitates on pedal push

[aeidian]

89 2.9 4x4

Running the truck at idle, warmed up or not it seems to choke before it revs up. In neutral I can punch the pedal and it seems like it just chokes, then revs up, does it if I do it by hand to. If it hasn't been run that day, when I go to start it, it takes a few tries to get it going. Giving it gas after it catches kills it right away. It'll usually fire up by the 3rd of 4th try, but I have to let it idle, then it'll die, because if I give it gas it'll die right away. Usually after that it starts up just fine. I've put a new fuel pump and filter in it, the tank was cleaned out when I put the pump in. I read on another post someone that was having a similar issue and everyone cited the TPS unit. Any ideas on that being the culprit for everything here?

 

[jhammel85]

It could be but best bet is to check for codes. Also, when you replaced the pump, did you also do the HP pump on frame? Have you checked fuel pressure?

 

[aeidian]

It's not showing any check engine lights, battery has been disconnected long enough to clear any that might have been there. I don't know what the HP pump on frame is. I haven't checked pressure with a gauge, just by pushing the needle valve on the fuel rail it squirts up.

 

[jhammel85]

Thats a good sign. Sorry for the abbreviation but HP = High Pressure. And actually, Now that I noticed that you have an 89, you don't have a second pump like my 87. Sorry about that!

You just may want to check the actual PSI though because it does sound to me like there is a fuel issue somewhere...Perhaps the Fuel Pressure Regulator.

As far as codes go, you have to check them yourself since I don't think you will get a CEL (don't quote me though). Either way, once the truck starts going for a while and you might have some codes in the ECU again, try this:

http://www.fordfuelinjection.com/?p=13

 

[aeidian]

When I did an R&R on the transmission, I had to cut the y pipe and ultimately remove it. I have a new y pipe I got from rockauto that I'm going to install next week. I noticed on the old y pipe that the o2 sensor (I'm assuming that's what it is, it's right after where the two down pipes come together) was broken off, and I couldn't find any wire to it. Since this is 89, I'm guessing this is the only 02 sensor the truck had. The truck runs fine except for that initial pedal push. Could the lack of O2 sensor be causing this? Where's the damn wire at?

 

[Bondo]

Yeah, that was the O2 sensor. The wire and plug should be hanging there somewhere above where it was. Its possible the sensor and wire encountered a stick or rock in its travels that ripped it apart/off though.

With no sensor readings, the computer was running the engine at the default settings and not at optimal levels.

Is this a new truck to you, or is this just a new problem you have noticed with the truck?

 

[aeidian]

Its a truck I bought used, and have done a fair share of work to.