Fuel Delivery/ TPS Sensor problems

[franklin2]

You have narrowed it down to a fuel supply issue correct? It seems that way. The fuel pressure really should be tested while going down the road. What I do is get a regular pressure gauge of any type. put a hose barb on it, and get a long rubber hose and hook to the end of it. I then take the guts out of the schrader valve on the fuel pressure test port, and then slip the rubber gauge hose over the schrader valve and use a hose clamp to tighten it. I then run it as best I can through the back of the hood and tape it to the windshield.

But you don't have to do that if you already know it's a fuel problem.

 

[it_was_an_accident]

I did play with the idle set screw a bit wondering if that might be the issue. I backed it off and tightened it a full turn and it didn't change the symptoms in either direction. I did adjust the idle speed.... so before when it would periodically shudder it would drop about 300 rpm and die. I set it slightly higher so now it will still periodically shudder and drop 300 but it doesn't die. I've also tried two different throttle bodies with the exact same results - one is the stock small bore and the other is the larger (54mm I think....) from an 86 or 87. They use the same TPS.

To give a little more background - I replaced the rotted out relay harness with fresh wires and relays. When I initially bought the truck I had some insulation that rotted off the fuel pump relay and if jiggled in the right way would short. Some liquid electrical tape got me through for a long time but always with the intention of eventually replacing. The long term symptom with this truck was a little wispy white smoke and the smell of fuel at the tailpipe, along with horrendous mileage. Otherwise zero performance issues. When I replaced the relay harness ends, suddenly no more wispy white smoke or smell of fuel. I also double checked all of the fusible links at that time including the one behind the coil. Everything had continuity.

Where did you find a wiring harness? I have been searching for about a month for a wiring harness for my 88 2.9 ranger.

 

[aball4620]

Where did you find a wiring harness? I have been searching for about a month for a wiring harness for my 88 2.9 ranger.

I ordered aftermarket relay connectors with pigtails and soldered them in. From everything I’ve researched and read you’re headed to a junk yard if you need a full harness. I’ve also read posts from people who’ve had luck getting a harness from someone doing a 4.0 swap.

 

[it_was_an_accident]

I ordered aftermarket relay connectors with pigtails and soldered them in. From everything I’ve researched and read you’re headed to a junk yard if you need a full harness. I’ve also read posts from people who’ve had luck getting a harness from someone doing a 4.0 swap.

So I called around to the junkyards around here....there is 1 2.9 sitting in a salvage yard with a full wiring harness...and was going to cost me $300 + $40 in shipping....but I ended up wiring everything correctly, just had a bad diagram for spark plug wires to the distributor cap. THANK YOU for the info though

 

[aball4620]

So I called around to the junkyards around here....there is 1 2.9 sitting in a salvage yard with a full wiring harness...and was going to cost me $300 + $40 in shipping....but I ended up wiring everything correctly, just had a bad diagram for spark plug wires to the distributor cap. THANK YOU for the info though

Wow! Pick N Pull has their most expensive harness option at 38.99 and you can usually pay a yard picker to pull it out and ship it to you for not much more than that. Opens up the whole country. Not new, but on a 30 year truck....

Glad you got your plug wires in correctly!