Bought 88 toyota truck few weeks ago that a mechanic had done a fair amount of work to. It ran great when I got it but the mechanic replaced the fuel damper and it was leaking. I tried tightening it with the motor running and it almost quit leaking. As I was about to take it to work I didn't have any power. I tried loosening the damper a tick and it was dumping fuel everywhere. Sent it to the mechanic who worked on it before and he said the fuel rail was cracked as of over tightening the damper. They put the rail in and when I got it back 2 weeks later I still don't have any power. They want to replace the fuel pump I couldn't figure how that would just go out. I checked everything vacuum lines, afm, tps, coolant sensor, cold start, spark etc. I

 

I haven't checked fuel pressure don't have anything to do that with. I did notice this truck does not have a cat but it looks like it hasn't for a long time. Is there anything I could be over looking or is it the pump

 

sounds like a test of the fuel pump is in order

Jumper Fp + B in the diag thing in the engine bay, when you turn the key to ON (not START, just ON) the pump will turn on. You can hear it running, it's kind of a whine.

It does sound weird that the FP would just go bye bye. I would also check the Fuel Pressure Regulator.

Why did the mech replace the damper? That thing is basically useless, toyota discontinued it on later models even. Was it leaking before they replaced it or just afterwards?

 

A fuel pressure test would be a great idea. I have a kit from LCE that mounts a fuel pressure gauge right on the cold start injector. It's about the same cost as any other gauge. $54 bux

http://www.lceperformance.com/Fuel-P...-p/2019128.htm

This is what it looks like installed / where it goes. Very handy, stupid easy to install

 

I haven't a clue why he replaced the damper in the first place. I think I might but that pressure gauge and see what my pump is putting out. The pickup idles fine starts a little tough now but seems like if I hit that gas quick it stalls or once you pass so far on the throttle it will stall so I'm starting to think that maybe he pump is going out

 

Yeah it does sound fuel line related, like it's not getting enough flow. Thats kinda why I suspected FPR.

It could also be a kinked metal fuel supply hose. Actually it's really common for the fuel supply line coming out of the fuel pump bracket to be kinked.. Usually happens when someone carelessly removes the fuel supply line from the bracket...

The pressure gauge will definitely help you diagnose this as well as future potential issues. If your fuel pressure is all good up at the CSI, then the pump and regulator are doing their jobs.. Then we probably start looking at injectors and ignition.

 

So I put the pressure gauge that was recommended in and it is only running at 33 or 34 at an idle hit the gas and it drops to practically nothing so I ordered a fuel pump hope that's the for sure problem

 

I put the new fuel pump in and it didn't fix a thing. I'm starting to get very frustrated what else could be wrong

 

Stop throwing parts at it. Start simple. An engine needs fuel, air, spark and compression.

Assuming you have everything but fuel, and you have fuel to the rail that bleeds off...where is the leak? It could be the injector o rings, you would smell the gas around the injectors. It could be you have rusted out fuel lines somewhere. It could be your fuel filter is plugged and not letting it have adequate flow. It could be your fuel pressure regulator.

If I was you I would check for obvious leaks. Change your fuel filter, use new copper crush washers. Inspect your fuel rail carefully, if damper threads are stripped get a new fuel rail. Instal new damper. Check your fuel pressure regulator. Make sure your AFM is working, that tells the computer to run your fuel pump. Finally check your injectors to make sure there firing.

This is probably not your problem, but test your cold start time switch to see if your cold start injector is working. It will run with a weak cold start injector, just not well. All part of the fuel system though.

 

With some more tinkering I noticed if I took the vacuum hose off the fuel pressure regulator pressure went up which was expected but throttle response was much better but still pressure would drop and eventually it would stall out after it required a certain amount of fuel but I can get more rpms out of it with the vacuum hose off vs being hooked up. I ordered a fpr and will be putting it on tomorrow

 

Did it help?

 

I finally got the fpr today and put it in. I got it started which seemed to take longer than I thought it would. It kept bogging out and dieing. Cranked it a few more times seemed to come out of it hit the gas and I had great throttle I could Rev it all the way up but fuel pressure would eventually drop and it was slow to come back. I let it run a bit and the next time I hit the gas it acted just like it used to bog out right away. Starting to wonder if the afm could be opening to far or something I tested it and it seemed to ohm out fine. What else could there be

 

On mine, I had very similar issues. It kept getting worse until it would not even start anymore. I ordered the fuel pressure gauge kit from LCE and found I had zero fuel pressure. I could hear the pump running, but thinking it was bad, I pulled it out of the tank. I should have done that earlier, as it's very easy on my 87 4runner. Found that the pump was fine, but the short fuel line that attaches it to the hard line in the tank was like play dough. So fuel was just pumping right back into the tank.

 

I have fuel pressure at the rail but as soon as I hit the gas it drops to practically nothing but let off and it slowly comes back up. This morning I took everything apart to look at the rail a little more and it seems like in getting decent fuel when I take the supply line off and was pumping it into pop can. It would fill the can in maybe 10 seconds. All of this started when the damper was tightened because it was still leaking after being replaced is it possible that maybe it is in to far in the rail not allowing enough fuel.

 

So it turns out that the mechanic used the wrong copper washer on the damper when he put the new fuel rail in. It was blocking half the flow somehow. I put a new one on that was bigger and it runs great. All this time and money lost for something so cheap and simple. Good to be on the road though.