HELP!!!! Isuzu down

[Larry Hampton]

Bypass tube maybe? What did the other end connect to and where did that go?

[drddan]

The tube attaches to the top of pump and goes back down along the pump, about even with the bottom of the strainer. The tube itself has a strainer on it. The bottom end where the strainer is, on the hose, attaches to nothing.

Is it a pressure relief, or return line? I dont know. Do I need it? I dont know.
Probably not?

[Fordverde]

I assume its a V6 right?

[Movin]

Electric motors of older styles would get warm if the truck is idling hot . This kept cool
fuel going through them. Newer pumps are more efficient and the normal fuel
return from the rail is sufficient to keep things cool.

[BigElCat]

While you have the tank dropped, you might want to mark out a square hole in the sheet metal of the bed floor. Cut it out, keep the piece and a put little brackets, or a flat bar frame, on it. Put the cut out back in place.

Quick access if the new pump does not work, or fails later.

[Fordverde]

attached is a pic of the tank and pump from a 98. May be you guys are right, that tube could be either a pressure relieve or for cooling

[FB71]

Electric motors of older styles would get warm if the truck is idling hot . This kept cool
fuel going through them. Newer pumps are more efficient and the normal fuel
return from the rail is sufficient to keep things cool.

ding ding ding! We have a winner!

You don't need the bypass line on the new pump. Also, just splice the new connectors onto the old wires, and seal with heatshrink. Doesn't need to be fuel-tight, just to keep from shorting against each other or pump housing.

[drddan]

Movin, Big El, Ford, and FB.....


Thanks so much! It is people like you that make life better!

That does include pretty much all of FF.com, too.

Cutting a hole in the bed, is sounding like a very good idea, at this point.

I will finish friday, had stuff to do today.

[drddan]

Friday I installed the fuel pump, put the tank back in, started it, and drove it!

Also replaced the strainer and the fuel filter.

It still has a stumble, when accelerating, and it does not rev well.
The stumble is almost like a carb with a bad choke.
I think that is a separate issue, though.

I think i'll try looking around the engine and the intake and stuff, clean a few things, look for stuff that may not be hooked or, not working properly.

I know squat about this Isuzu, but I did buy a chilton's manual. Seems haynes got bought by chiltons, or so the oreaillys guy said.

Thanks again to all, and any more suggestions are always welcome.

[drddan]

The Isuzu has a very dirty engine bay! Took the air filter out, couldnt even see through it! Its a K&N filter, just washed it out.
I am trying to find out why it is stumbling on acceleration.
I think a complete tune up is in order, some cleaning, and see if the vaf, or whatever it has, and things like that are working properly.
The chilton I have sucks compared to a haynes. No troubleshooting section.

So what would make it stumble? TPS? VAF? Dirty?
After warm up it improves, but still bogs down, mostly in 1st/2nd gears.

[FB71]

before you go chasing sensors and such, check the spark plugs. If the filter was that dirty, chances are the plugs haven't been changed in a LONG time, either...

[drddan]

Good point, Jim, and is on my list of things to check.
I've been working on it eve/nights so it isnt so hot.
The Isuzu has a MAF, which I can check with a meter. Manual says .5-1.5 v while blowing on though the sampling tube.
Dont wanna mess with it too much, I wanna get back to the B6 swap on the Festy!

[Movin]

Computer stuff; the MASS needs to be clean and to have NO air leaks between it and the intake. The TPS needs to be good, but if it is not a trouble code will likely be present.

Power transition stuff, like a accelerator pump.

the fuel pressure has to stay in spec while going through the transition where the problem
occurs.

Initial timing, computer timing and vacuum timing all have to be in spec.

cam timing, in spec.

No carbon build behind valves or in valve pocket.

[FB71]

Computer stuff; the MASS needs to be clean and to have NO air leaks between it and the intake. The TPS needs to be good, but if it is not a trouble code will likely be present.

Power transition stuff, like a accelerator pump.

the fuel pressure has to stay in spec while going through the transition where the problem
occurs.

Initial timing, computer timing and vacuum timing all have to be in spec.

cam timing, in spec.

No carbon build behind valves or in valve pocket.

so it has a MASS? I didn't realize it was Catholic.
Its EFI, so there is no accel pump.
If it has computer controlled timing, there is no vacuum advance, and vice-a-versa.
Cabon buildup on valves won't cause his concerns. That causes a hard start with immediate stall, followed by a normal restart.

[drddan]

so it has a MASS? I didn't realize it was Catholic

:laughing3:

I havent yet checked the timing, but it is a suspect.

I am back to working on the Festy, but this info is good, and I will be re-visiting it soon. The Isuzu plugs didnt look bad at all, but I bought new ones anyway. I may/may not put a timing light on it tonight.

Check it, the B3, the B6, and the Isuzu 4ZE1 2.6 all use the same spark plugs. I didnt expect that. Same plug for a 1.3, as 2.6.

As always guys ...Thanks!!!!