CRUD,

I was working off of what my truck is (1994).
Sounds like you're looking in the right place for the relays though.

It may be that the 88's have specific relays for different circuits.

Sorry I made the assumption.

I'd still give some merit to the fuel pump relay or EEC relay failing............

Hopefully someone will jump in here and have a way for you to test ? those relays.

Got my fingers crossed for you,

Bob

 

Get the fuel pressure read seems to be the problem. Verify voltage is getting to the rear pump. If it is, the pump is probably shot. You'll have to drop the tank and clean it all up. Probably has old gas and crud inside.

 

Fellas, I can't thank you all enough for trying to help me. The saddle tank is easy enough to pull and it only has a few gallons of gas in it so if I can get a fuel PSI reading somehow and verify there is voltage going to all parts crucial then that is what I will do.

BTW, what should the fuel PSI be?

 

so ive had similar prpoblems with my truck it wound up being a few things together i cooked my coolant temp sensor and the pip module in my distributor was bad, as well as a poor wire repair at the fuel pump relay. after i got that all fixed up i only have a code for the egr and im not worried about that.

any how i read you over heated while driving i see you dont have a fuel pressure gauge and i also see that you were not succesfull in pulling out the codes? is this all correct so far?

again i know your in a bit of a pinch but you really gotta start with the simple basics first pull the codes and check your fuel pressure id suggest a big chain parts house that offers tool rentals or a local shop if you have a friend with a fuel pressure gauge. but your just shooting around in the dark without it.

 

Kris, thank you very much for pitching in here. I'm going to NAPA in the morning to see if they have a pressure gauge I can barrow. Can you give me an idea of what pressure is acceptable? They know me pretty good so I'm hoping there won't be any issue there. I will back track to the code ID video and try that also. You guys are great!

 

5.0? 35~ psi with vacuum . attached. Shouldn't bleed off for awhile when you shut it down. If it does it could be leaky injectors or a faulty check valve in the tank

 

Ray and all, it is a 5.0 liter. I just fashioned a gauge out of a 100 PSI glycerin gauge I have. I pulled the schrader valve insert out and attached a rubber line and then to the gauge. With the key in the on position I had zero PSI. I started it and it came up to about 30 PSI. Once I shut it off it stayed at 30 PSI. It did not drop off at all. Shouldn't it have PSI with just the key on since it is an electric pump? It did not fluctuate at all when revved.

 

Remove the vacuum line and see if it goes up at idle. That's a little low. Should be 35-37. Cycle the key on and off a few times without starting it to see if it gives you a reading. It should also go up when revved

 

On the the 5.0 40 psi is decent 30 is preatty low. I'm guessing you did change your fuel filter out. So you may on fact have a weak high pressure pump. Check to see that your getting 12 volts to the pump you can ground the fuel pump pin in the dlc under the hood to check it. But deffinately pull your codes!!!

 

I have changed the fuel filter. I got some help and had the key turned on and listened for the relay to click and it did. Next, turned the key on and listened for the in-tank pump to cycle and it did. I then started the truck and took it straight to high idle at about 2500 rpm and held it there. Surprisingly it did not start sputtering and did not die. I ran it long enough for the thermostat to open and stabilize the temperature.

Heck, it didn't die so I took it for about a 10 mile test drive. It ran cool (which I knew it would) but on the way home it started sputtering. Not real bad but just enough that I know it isn't right.

I think my next move will be dropping the saddle tank and giving it a thorough cleaning and clean the in-tank pump screen as well. I'll look into the rear tank not working at that time also.

I can not thank each and everyone of you enough for all the spot on and lightning fast advise and genuine concern. You guys are all that and a bag of chips! I will report back early next week as we are going out of town for the weekend on a camping trip. And no, I'm not taking this truck You guys rock!

BTW, was I supposed to head the embossed warning about disassembling the tank selector valve? That is one simple piece of equipment.