Drumer919

iTrader: (2)

My 95 2500 (K series, 4WD 350) is having problems that I think may be injectors and if it is I'm going to buy the holley TBI unit but I want to make sure before I drop the money on it. The truck is all stock other than a K&N and full exhaust and has just over 120k on her.

First let me state that I did the fuel pump and filter in July.
Now the problem is that it stumbles when starting from a stop, once I get going I can get on it all I want and there are no problems but starting out from a stop if I go anything above 10% throttle the truck stumbles so bad that it dies. I am so skeptical because I have already tried swapping injectors with some I had laying around and it didn't help at all, if anything it hurt. I cleaned the original injectors as well as I could (just by taking them out and cleaning the screen) and put them back in and that seemed to help a little, after that I sea foamed the motor and didn't really notice much of a difference but I only drove it around the block (did that today). The PCM is throwing a lean code every now and then but it appears to be random and has done that since I owned it, when I hook up my snap-on scanner and watch the data feed I don't notice anything out of the ordinary. It does take a few seconds of cranking to get it to start but it has done that since I got it as well. Thanks in advance.

96lt1m6

iTrader: (31)

you need to check the fuel pressure at idle and while driving.
should be 12-18 psi

Drumer919

iTrader: (2)

The only way I can check the FP is to unhook the filter and test it there, there is no valve anywhere. It is 15PSI though, someone on camaroSS told me ideal pressure is 13 and its actually at 15 (at the filter) I dont know what it is with the regulator regulating.

8a8mfh

iTrader: (3)

Did you ever check the fuel pressure?
I've screwed with my TBI a lot from making the reg adjustable to burning chips.
The stock spring will only allow 15 psi max. With a stock engine you should be around 11 or 12 psi. Even though most read 8-10.

I made my own test port. I went to a junkyard and cut off a male fitting and an inch of fuel line down where it screws into the filter.
Then at a hardware store I got a tee with 3/8 npt holes in it, one 3/8 male npt to 3/8 hose barb, one 3/8 male npt to 1/4 male flare (std GM size fuel pressure gage test port size), and one 3/8 male npt to 5/16 compression fitting.

Put all that together and you can test it at the TB or the fuel filter. Just remove the fuel line, slide the nut down and put a piece of 3/8 fuel line over the factory steel line and clamp it, loop it around and connect the other side to the hose barb on the tee.
Then screw the fuel line nut you got from a junkyard (connected to the tee with the compression fitting) into the filter or TB, connect a gage to the 1/4 flare and read the pressure. You can also get a hose and run it from the tee placed down by the fuel filter to a gage temp mounted to the side mirror for driving tests.
This obviously is for testing only.

Drumer919

iTrader: (2)

I'll try making my own test port this week so I can test pressure with it running.

8a8mfh

iTrader: (3)

Yea, the problem with the way you tested it, it only tests the pump pressure and it deadheads the pump which some say will ruin it, I've done it before though.

When you tee off it you're testing the pressure the injectors are getting.
If the regulators messed up it could be pumping fuel right into the TB, through the regulator and back to the tank via the return line. The more resistance the regulator puts on the return seat, the less pressure bleeds through and out the return line.
Actually if you're getting a lean code 44 it's usually the O2 sensor.

'00Formula

iTrader: (2)

I had a problem like that with my 94 and thought it was fuel until I took the distributor apart and it was in a million pieces. Just a thought.

97badass

iTrader: (8)

check the oil and see if there is water in it we have been working on a truck that has the same problem it had a bad intake gasket and the timing was off when you try to start it does it take a long time?

chromeplated500

iTrader: (10)

yea I would consider a tune up, plugs wires cap and rotor. fairly cheap and the cap and rotor have been known to cause alot of problems.

01WS6/tamu

iTrader: (37)

If it is just doing it on throttle tip in then chances are the tps is bad. You can look at it all day with a scanner but the drop in tp voltage on throttle tip in is too quick for the scanner to see. We changed a bunch of them up until the point the old TBI trucks started coming in the shop less and less. If it does not lay down at WOT the fuel pump is fine. A new filter is recommended.

8a8mfh

iTrader: (3)

Good point, I had the problem when stomping the gas sometimes it would die, pop, or just bog, sometimes it would burn the tires. I pulled the cap and rotor off and looked at the magnet in the center right under the rotor, if the magnets cracked replace the dist, I got the best looking one from a junkyard and it fixed that problem.

Drumer919

iTrader: (2)

Yeah it takes a minute. Aparently this week is Ford timing belt week, I havent got a chance to look at it yet, maybe tomorrow. Thanks for all the ideas guys.