87 tbi running horrible

[RednecK30]

I swapped a 95 tbi into my truck, and it has been running good, but lately I started to feel some stumbling on the highway, and on occasion when rescuing people from mud holes. then the other day after filling it up and driving 10 miles it wouldnt stay running. It will fire for about 2-3 seconds, and die. It will always fire back up just sometimes its a little harder to do. If I pump the gas I can barely keep it running. If I floor it makes a deep bogging sound and dies. It has shot a few flames out of the tbi as well.

I made sure all vacuum's were connected, and not broke, and put another EGR on it. I keep a spare TBI setup I put on it. New IAC, New coolant sensor on front of mani, new fuel filter, new plugs/wires/cap and rotor.

still wont stay running. with starter fluid runs like a champ.

on the intake manifold there are a few sensor, and maybe a computer (not sure) that sit on a bracket. I borrowed my buddies "bracket" with all the known working sensors on it, and will plug those in tonite to see if that resolves it... really those are the only thing I havent replaced minus the pump, and main computer, and o2...

Now I did put a fuel pump tester gauge where the fuel filter goes... Now I dont understand my gauge, but I am pretty sure its reading 15psi. (gauge reads 1-10 psig) assuming it goes by 10's? and it reads 1.5 and holds it for a good 5 minutes. I just assume it goes by 10's because most vehicles fuel pressure is 40-70 psi, and the gauge reads 1-10... I could be wrong. If I am then I assume my pump is bad.

Now i do have dual tanks, but the other pump is dead (or the switch doesnt work)...

any Ideas on what it could be. any experiences?

[03cobrakid]

You need a new fuel pump!!!
The fuel pressure guage you used was for a non FI system and only went up to 10psi.
you need about 15-20 for TBI to run.

[SBTork]

im no tbi expert so take this as just another idea. From your description it sounds like it's not getting enough fuel. I would really look into trying another fuel pump.

[RednecK30]

Originally Posted by 03cobrakid

You need a new fuel pump!!!
The fuel pressure guage you used was for a non FI system and only went up to 10psi.
you need about 15-20 for TBI to run.

ok that makes more sense. I didnt understand the 1-10 PSI thing. So carbs run off of less than 10psi? didnt know that.

I will get one tonite and try to put it in... I heard it may be easier to remove the bed than to drop the tanks? any thoughts?

[cjracing15]

Not on a 87. It is easier to drop the tank. I hope it's not full of gas.

[RednecK30]

well I had just filled it, but I didnt think it was the pump because I disconnected the filter, and let it pump itself empty. so I didnt think it was bad. I thought it was bad gas originally.

[rfmaster]

Originally Posted by RednecK30

well I had just filled it, but I didnt think it was the pump because I disconnected the filter, and let it pump itself empty. so I didnt think it was bad. I thought it was bad gas originally.

You need to verify working fuel pressure. Fuel pump develops fuel pressure in fuel delivery system by pushing fuel against fuel pressure regulator (in TB). Removing fuel filter you have effectively removed load from the fuel pump. Even a half dead pump will pump out fuel from a tank!
It is common for in-tank fuel pump to fail due to a burst in the output hose - between fuel pump output and feed-through. This happens slowly, over a period of time as fuel, instead of being delivered to injectors, leaks back into tank. As fuel leaks out from a bursted hose the pump tends to run at higher RPM eventually burning itself up. When replacing in tank pumps always replace output hose with a new in tank, fuel submersible rated hose (SAE 30R10) usually supplied with new pump.

//RF

[RednecK30]

thanks for all the info guys!

rfmaster - I did replace that 2 inch rubber hose. the other one had a tear in it, but when trying to blow through it I felt no leak, but replaced anyway.

I did it last night. What a Pain in the ass! by myself in the dark (boat is in the garage) in 20 degree weather. As strange as it sounds I actually do enjoy it (I guess I am weird).

Anyway I got it hooked up, and back in (had to extend one of the fuel lines because I couldnt make it reach)...

Now I just have to hook the fuel filter back up and try to start it.

We will see tonite what happens. I wanted to drive it today because its supposed to snow here in san antonio, and the drivers down here cant drive as it is, and I would rather play bumper cars with my truck than my impala, but oh well it was getting late last night.

[rfmaster]

Originally Posted by RednecK30

thanks for all the info guys!

rfmaster - I did replace that 2 inch rubber hose. the other one had a tear in it, but when trying to blow through it I felt no leak, but replaced anyway.

I did it last night. What a Pain in the ass! by myself in the dark (boat is in the garage) in 20 degree weather.

Did you apply about 15 PSI of air pressure? By mouth - hardly. FYI, if integrity of fuel hose is questionable fuel pump is not too far behind. Its just a question of time before it also fails.

Originally Posted by RednecK30

As strange as it sounds I actually do enjoy it (I guess I am weird).

Welcome to the club!

BTW people in SoCal can not drive either, and god forbid if it rains here! When it rains here all the oil and dirt that was absorbed into roadway surfaces creating a perfect, ice like conditions. We have couple big storms forecasted to hit us next week!

GL - and be well.

//RF

[RednecK30]

Originally Posted by rfmaster

Did you apply about 15 PSI of air pressure? By mouth - hardly. FYI, if integrity of fuel hose is questionable fuel pump is not too far behind. Its just a question of time before it also fails.



Welcome to the club!

BTW people in SoCal can not drive either, and god forbid if it rains here! When it rains here all the oil and dirt that was absorbed into roadway surfaces creating a perfect, ice like conditions. We have couple big storms forecasted to hit us next week!

GL - and be well.

//RF

thanks. yeah its the same here. just a little drizzle, and the roads turn slick, and everyone turns retarded. its not even snowing yet, and everyone is driving like it is.

as for the 15 psi you are absolutly right... I didnt think that through. there was an obvious tear/gash in the rubber hose. I am very very hopeful that this resolves the issue. If it does I may have to replace the other tanks pump just so I have a backup tank.

The truck doesnt get driven enough to fill both sides. Just out to the ranch and back.

[Damien]

Originally Posted by RednecK30

I did it last night. What a Pain in the ass! by myself in the dark (boat is in the garage) in 20 degree weather. As strange as it sounds I actually do enjoy it (I guess I am weird).

I think we all must enjoy it or we would drive something that either didn't need work or we would pay some one to do it. I think we are all fine. The people that don't are wierd.

[RednecK30]

well that fixed it. its running great now (especially since I have replaced everything else!)