I have a problem... stalls at temp...

[mhavoc]

Hi Folks...

I have posted about my 86 2.9 4x4 here before... I still have the same problem after getting my engine rebuilt (had been planning to do that anyway). In summary, once the engine gets up to temp, the engine loses all power, it won't die but it run badly and will backfire if I attemp to rev it. Also, the wierd thing is that when it is in this state, when I do floor it, the rpms will go up gradually but it just makes it have less power, when I release the pedal, the rpms rise a little for about a second then idle resumes (poorly). Eventually it dies and won't restart until the gauge hits the C.

so, pretty generic, however when it dies and I push fuel rail schrader valve pin, I get lots of *air*. I can cycle the ignition many many times and I get nothing but air and after the initial release, not much air. So... replaced the fuel pump and the FPR. Same problems.

Right now the truck is sitting about 2 miles from my house until I can wait until it cools completely and I will bring it home tonight to get FP readings when runnable and non-runnable.

What next... Tank pump? Well... I have double tanks and it happens on both tanks so Im going to assume for now that my tank pumps are okay.

Does anyone know of a reason relating to temp why my fuel would be gone at the rail?

TIA

jess

 

[rangerfan3]

Someone help

Iam having the exact same problem. Have you checked the timing. Thats what Im always told. I have put so much time and money into this Im ready to junk it. I hope someone can give us the answer.

 

[mhavoc]

Here is a little more info... looks like I have to change my definition of the problem a little.

So, the truck sat for about 4 hours. It was 47 degress out when I started it up this evening and figured that I should be able to easily get it home (about 5 miles) before it reached my troublesome engine temp (normal operating temp).

Well, oddly about .75 miles on the way home, it started missing and losing power, I started to pull over while intermittently revving the engine to see if I could get some power and after about 10 seconds, it started to come back, I pulled back into traffic and kept heading towards my house. Well, about .5 mile later, same thing, but it went to no power within about 5 seconds and then was at the all too familiar, idle rough, worse on depress of gas, rev on release of gas. It died there. Fuel rail was full of air and engine was still pretty cool.

I left it for the night and will try again in the morning to get it all the way home, but this at least *removes* my assertion that it was temperature related.

The pattern is certainly cyclic tho, drives good for about a minute, then goes through a 15 second period of missing... if I can pull it out of this stage by revving and keeping it alive, I may get another 1 minute before it starts happening again.

Im now suspecting the timing too... after I had the engine rebuilt, I noticed that the distributor wires were not in stock position on the dist cap. I put them back into stock position but the truck wouldn't even start that way.

I will pull the plugs tomorrow and put the engine at TDC (#1) and make sure that my timing mark on the fan pully is right and see where the distributor is pointing for reference. I will verify that timing is correct and that homeslice that built my engine didn't put it together wrong.

How could timing cause air in the fuel rail? will the computer turn off the fuel pump if things are really really out of whack?

Im going to pull codes tomorrow too and see what I get, just for fun.

oh yeah, also... here is the list of stuff *already* replaced... Im getting poor.

TPS
Cleaned IAB (Idle Air Bypass? - side of throttle body)
Rebuilt Injectors
New Distributor
New wires
New coil
New Plugs
New module on side of dist (can't remember name now)
New Exhaust
New O2 Sensor
New Fuel Pump
New Fuel Pressure regulator
New Battery
New Engine

 

[rangerfan3]

its geeting aggrevating

I finally found out that my #6 cyl was dead I removed the wire from the dist and it runs better but wants to die everytime I take my foot off the gas. Im giving up on it.

 

[mhavoc]

and some more info... now the truck won't start at all. Unfortunately it is still 2 miles from the house but it is easier to troubleshoot a non-intermittent problem.

I still have air in the fuel rail and no fuel at all. I verifed that my Fuel Pump Relay is activating and passing 12V through to the Inertia Switch. I tested the intertia switch and actually just left it jumpered for now to eliminate the problem. I applied battery power to the LT-BLUE/ORANGE wire at the fuel pump relay and verified that the HP fuel pump runs while I have that connected (I was doing it for 2-6 seconds only). Still no fuel in rail.

So, the HP Fuel Pump must not be getting any fuel. I am going to have to take out some extra tools to get the protective cross plate off the bottom of the truck in order to get at the fuel filter (cartridge type) and then I have one other oddity.

This is a dual fuel tank Ranger. Right before the filter is the unit that switches between tanks and also changes the connection for the fuel gauge on the dash. I had some problems with this about 5 years ago but it is no longer available and I cant find a replacement. I took it out, drilled the rivets and repaired it (had a bad internal contact on the moter wiper), I screwed it back together and it has been fine since. There is nothing in there that actively has to have power to pass gas through, it is simply a gate valve that physically moves the pass through from one set of gas lines to the other. As long as it is in one extreme or other, gas will pass. It should be working fine as my gas gauge switches levels.

what is the best way for me to test if I have gas at the high pressure fuel pump... just disconect the inlet and see if gas sprays out when I turn the key? doesn't seem like a very good way to do it tho. have a pressure gauge for the rail but nothing to hook onto those plastic fuel lines.

If anyone has some tips, please let me know... Im desperate!! I don't want to drop my tanks if I don't have to.

thanks.

 

[mhavoc]

Problem solved...

Okay, it all made sense when I started disconecting my fuel tank selector valve. The front tank lines were bone dry while the rear tank lines poured gass all over me until I got them plugged up. Looks like I had a double failure.

The fuel selector switch was dead on the front tank (even tho it was working just days before) and the front tank sender/pump was also apparently dead.

I never was able to get my fuel filter replaced as it was behind a steel shield plate which I couldn't get all the bolts out of, so I guess it stays as is for now.

I just wanted to post a solution here in case anyone else ran into this issue.

Also, of special note is that the original fuel tank switching valve for this ('86 4x4 2.9) is non-existant and the generic replacement doesn't fit right. I had previously rebuild mine by drilling the rivets and fixing the contacts on the slider plates but this time I stripped everything out and just expoxied the front tank lines shut and then epoxied the innards too so Im rear tank only at this point.