project 87 done but won't start lol. Help needed

[weider1717]

it's been over a year due to job etc but all i did was take all accessories off blasted and painted them.

put rebuilt water pump on restored exhaust manifolds and hardware, all new belts, hoses etc etc etc.

I can hear my LEFT tank prime and the right tank won't work so I made sure the switch didn't get bumped out of position and even tried it both ways then back to the left tank which again I can still hear prime as normal.

topped off with new coolant and dropped a new battery in when to fire her up and she just turns and turns over with nothing but turning over.

only a couple plug wires got unplugged during this and i made sure to look and what number went to what cylinder so thats not the prob although i WILL go back through to be sure.

besides older gas not sure on this one shoulda fired right up!

help appreciated guys

[chrismoore701]

You need three things. Fuel, air, spark. Start with spark, check your plugs for spark. Then go to gas. chase the problem.

[weider1717]

I agree and i just got back from having a helping hand turn it over as I look into the fuel bowls and although the left tank works and i can hear it prime I don't see any fuel while it is turning over and him giving it gas.

I'm not a FI expert but I should be seeing fuel come out from the injector during this correct?

I do see one connector not plugged up to anything with the air cleaner removed HOWEVER I don't believe I ever touched this and it looks like there is nothing it goes to I am guessing this is not used. see pic below

[weider1717]

OK, the only way it will start is manually dumping fuel into the fuel bowels so it is not getting fuel.

this is what I need advice on my 87 has the dual tank options and the right side does not work.

ok well during the detailing etc for no reason other than sitting in there I flipped it to the right side and BACK to the left operating tank while the battery was OUT.

That shouldn't have affected the "fuel switching valve" should it? I have my thoughts towards that because I can hear that left tank sending unit prime up but it's not getting fuel…

any thoughts with the given info / trouble shooting done. thanks

[weider1717]

also to the above post I removed the shield to the fuel switching valve and beat on the lines going to it and the top of it with a rubber mallet pretty good as I had someone trying to start the truck.

no start still no fuel...not a good thing I was headed to the mountains in this old gal tomorrow guess I have a change of plans! :/

[68Timber]

Since you don't really recall if you unplugged that, I'd find out what it is and go from there.

[bmchevy1979]

I believe that is the Tach feed from coil. It could easily be the injectors plugged with old fuel have you check to see if you have fuel to the throttle body crack one of the lines loose on back and see if there is fuel I would have ignition off but prime it before you try that way you can tell if there is pressure I can't remember which line is the feed off hand though. Also the injector wiring builds up corrosion and can loose its signal to fire injectors when I first got my 87 it was only running on one injector sounded like a v6 was kinda funny

[weider1717]

Originally Posted by bmchevy1979

I believe that is the Tach feed from coil. It could easily be the injectors plugged with old fuel have you check to see if you have fuel to the throttle body crack one of the lines loose on back and see if there is fuel I would have ignition off but prime it before you try that way you can tell if there is pressure I can't remember which line is the feed off hand though. Also the injector wiring builds up corrosion and can loose its signal to fire injectors when I first got my 87 it was only running on one injector sounded like a v6 was kinda funny

makes sense to that spare plug I don't have a tach.

I would like to check the connection on the injectors can you explain where I can locate it?

[bmchevy1979]

The two wires that go to the top of each injector that is a plug at the injector. White piece in pic there are two tabs you squeeze together with fingers and wiggle it a little and it should come right off there should be a little rubber grommet that goes under it to help seal out moisture on my 87 one was missing but they were both corroded

[weider1717]

thank you

but with my truck running fine when I started and not getting any fuel at all now don't think thats the issue but for the heck of it i'll check.

still in and out of the shop and on the internet trying to get this figured out

[cdub2010]

Disconnect the fuel line at the tank, hook up 12v directly to the pump and see what happens. If it pumps work thru the lines until you figure it out, Check your fuel filter as well. I had a kinked fuel line on mine after dropping the tank.

[weider1717]

Ok guys trying to read the codes on this 87 I shorted what I believe A & B pins together with a paper clip on the OBD1 connector and I don't see anything happening?

it shorted the 2 top left pins together I never even saw the "12" I read i would see when this performed?

[rs74]

Maybe check fuel pressure, fuel filter and if you have fuel pressure you can crack the fuel line at the back of throttle body to see if you are getting fuel up to it. Then might start looking at the throttle body itself. Check to see if injectors are pulsing.

[D13]

This is TBI. it runs with gas dumped down it, and makes no effort at all otherwise? Then you have a fuel system problem, either fuel itself or ECM signal.

TBI uses the TACH signal from the distributor to tell the ECM RPM and that in turn controls spark timing and fuel. Make sure that the TACH wiring is plugged in correctly at the distributor and harness.

Since you get spark (it runs with gas dumped in it) the problem is either ECM not seeing signal, ECM not firing injectors, or no fuel to injectors, which can be many things.

When you turn the key on you should hear the in-tank fuel pump prime for ~2 seconds. After that the engine must build oil pressure to close the switch to enable the fuel pump relay. FYI, there is a remote pump power connector buried in the harness, usually behind the distributor, that can be used to force run the pump to evaluate the fuel pressure. Look at your year wiring diagram.

There is a fuel pressure port on the TBI feed line. If you have it use a fuel pressure gage to check that the pump primes to 7-9psi. If you don't have a gauge, turn the key on to prime, then push in the valve (like a tire valve) with a rag over it. Gas should squirt out into the rag. No gas, bad pump or plugged filter. Gas, prime works, find why the ECM isn't firing the injectors.

[weider1717]

Originally Posted by D13

This is TBI. it runs with gas dumped down it, and makes no effort at all otherwise? Then you have a fuel system problem, either fuel itself or ECM signal.

TBI uses the TACH signal from the distributor to tell the ECM RPM and that in turn controls spark timing and fuel. Make sure that the TACH wiring is plugged in correctly at the distributor and harness.

Since you get spark (it runs with gas dumped in it) the problem is either ECM not seeing signal, ECM not firing injectors, or no fuel to injectors, which can be many things.

When you turn the key on you should hear the in-tank fuel pump prime for ~2 seconds. After that the engine must build oil pressure to close the switch to enable the fuel pump relay. FYI, there is a remote pump power connector buried in the harness, usually behind the distributor, that can be used to force run the pump to evaluate the fuel pressure. Look at your year wiring diagram.

There is a fuel pressure port on the TBI feed line. If you have it use a fuel pressure gage to check that the pump primes to 7-9psi. If you don't have a gauge, turn the key on to prime, then push in the valve (like a tire valve) with a rag over it. Gas should squirt out into the rag. No gas, bad pump or plugged filter. Gas, prime works, find why the ECM isn't firing the injectors.

you mention tach signal see above pic of a connector not connected someone mentioned this was to the tach.

I do not remember taking this loose had no need to with what I was doing and i don't see where it could even be connected to but since you mentioned tach thought I would make sure you noticed that picture.

I just picked up a new fuel filter from the dealer I also think it's ECM related because they're not giving any gas at all in tot he bowls.

is it ok to check the injectors with a 9v battery while in the truck?

headed to do some more trouble shooting. Also, here is a currently picture of MY truck I don't any test ports on any lines going to the TB? any help with where the port is you're talking about is appreciated. thanks

[f.monroe]

Take a wrench and tap on the injectors while trying to crank the truck. Like mentioned above they are probably stuck. I have seen them stick before. You should see gas spray out when cranking it over. Don't overlook the simple stuff and get too far into it . I bought an 87 and had the same issue . It had both injectors stuck. Light taps while cranking it over did it for me. Hope yours is that simple.
Frank

[SCOTI]

Pull the sending unit out from the tank & inspect the submerged transfer hose.

My dually was doing something similar. You could hear the pump prime for the ~3secs but it wouldn't start. I pulled the pump/sending unit out & the rubber transfer hose had deteriorated to the point that it burst open. The ethanol in todays fuels does not play well w/older/original transfer hose. I replaced it w/the proper ethanal rated submersible hose & it started like it should.

Since the primary tank was bad, I checked my 2nd tank (that I had ever used) & it was even worse.... The hose in the secondary tank was a sticky blod of partially dissolved rubber.

I went ahead & put new pumps, socks, & the proper ethanal spec'd transfer hose in both tanks.

[weider1717]

thanks for the replies guys

I just got back from changing the fuel filter. I cracked the upper end towards the front of the truck loose first there was a small bit of gas I left it cracked open when and cycled the switch a couple times then tried starting it about 3 secs.

went back under to look at the line where it was broke loose and I had plenty of gas puddled up on the frame rail so the fuel filter was fine and gas it good up to the engine end of the fuel filter so the replacement wasn't needed but that ruled one more thing out.

I'm lost! I'll try tapping on the injectors while it's turning over.