90 chevy 4wheel steer/4wheel drive/4wheel independant suspension

[Mudbuster]

Use a fuel pressure guage and it should be around 14psi for a throttle body injected chevy.

[lapeer20m]

installed the new fuel pump and she runs!   whoo hoo!   

diid more work on the compressor today.  It shuts off about 150 psi.  Still have to mount the air tank and route the lines...

drove the truck for a half hour or so tonight.  Mechanically she is pretty much ready to go, i really want to start on the prep work for the paint...but it's too cold to paint, even with my 110,000 btu salamander heater. 

new phtoos on the way

[lapeer20m]

here's a shot of the small old chain verses the new large chain



in this photo, the small sprocket on the right is the old one, you can see the new sprocket is much much bigger





The chain and sprocket are no longer the weak link in the system!

[KORNBREAD]

that looks so confuseing!! lol keep it up. i still want to go for a ride in it.

[lapeer20m]

i really want to get the truck ready enough to bring to the mounds this sunday, but with this frigid weather things are moving really slow. 

I changed the oil yesterday, at this temperature 15/40 pours like honey.  I also changed out the trans fluid in an attempt to get more of the water out.  It's impossible to get water out of your auto trans once it's i there!  When it first filled up with water, i dropped the pan, drilled a hole in the torque converter and let it drain for 24 hours, then welded the hole closed in the converter and filled her up with new trans juice.  I've stayed out of the deep water since then, and the juice is still very pink.  The trans was rebuilt just before i got the truck.  this time i poured new trans fluid into the hole where the trans dipstick is while pumping the old stuff out through a line i disconected from the trans cooler.  I kept this up till i ran out of trans fluid.  I'm gonna continue flushing with another few gallons...this should make things better i think. 

I also fixed the brake line after accidentally blowing a hole in it with the welder the other day. 

still need to mount my air tank, find a permanent mount for the radiator, and a few other odds and ends......don't think i'll be painting anytime soon.  I've been driving her around i the snow, it's a lot of fun, and wow!  does she turn. 

[sschmidt48429]

nice

[lapeer20m]

i can't keep this truck running.......TBI is sucking the life out of me.  Mostly because i don't really understand it.  A carberator seems way more simple. 

this is my first chevy, so i've never really played around with one before.  I had a "no start" situation a while ago, installed a new fuel pump and she eventually started.  Everything was good for a few days.......I let her sit for the past couple weeks, and now she won't start.  I pulled the fuel pump because i couldn't hear it making noise, and it was about 200 degrees and not spinning.  Lifetime guarantee from murrays (murrays rocks when it comes to lifetime guarantee...they don't even ask your name or phone number or require a reciept)  replaced the fuel pump and still nothing.  She almost starts, sometimes she even runs for a few seconds on what sounds like a couple of cylinders, then stalls.  I'm quite certian it's a fuel delivery problem.  I bypassed the fuel filter just to make sure that wasn't restricting flow.....checked spark plugs on #1 and #2 cylinders and they are dry, a little black, but not bad.  She has new plugs/wires/cap/rotor about 6 months ago.  Timing is correct, lots of spark. 

how do i figure out why my tbi won't squirt fuel? 

one more note....i installed a stock fuel pump into a new fuel cell in the past month and direct wired the pump to the ignition.  The truck ran good with this setup.  Today i read somewhere that the fuel pump only stayes on for a couple seconds when you turn the key and the engine is not running.    Would everything be happier if i were to run the fuel pump off of the old fuel pump relay?  Does it turn on/off intermittently ? 

i'm very frustrated, any help is greatly appreciated.  I'm very dumb when it comes to chevy tbi, but i'm pretty handy when it comes to using tools 

it's a 90 chevy 350 TBI

[TBigLug]

From what I understand, the feul pump should kick on when you first turn on the key, then off when it reaches pressure, then when you crank it to start, should come back on and stay on til shutdown. I had a 1990 Caprice with about the same setup a couple years ago. Ended up with the same problem. I eventually (after 3 months) of not being able to figure it out, sold it to a mechanic. He worked on it for 2 more months, couldn't figure it out, ended up putting a carb on it. Then it ran great.

[lapeer20m]

i wonder what is involved in doing a carb swap....a new distributor perhaps, and how about the trans....does the auto trans (i don't know what it is) need the computer to shift?  I think that figuring out the tbi is probably a better solution. 

[J.C.]

maybe a relay? my 1988 chevy 350 had a bad fuel ppump relay and it wouldnt start. got a new on works great,

[Mudbuster]

You should be alright with it wired direct but I would use a relay because of the current draw and then control the relay with a toggle switch that way if you need to leave the key on for some unforseen reason the pump won't just sit there and run.  If you don't know how to wire a relay then look in the tech section YotaBill did a great write up on how they are wired. I hope that helps 

[TBigLug]

i wonder what is involved in doing a carb swap....a new distributor perhaps, and how about the trans....does the auto trans (i don't know what it is) need the computer to shift? I think that figuring out the tbi is probably a better solution.

New intake, carb, dist., fuel pressure regulator, slim air cleaner should be all you need. The tranny should be a hydraulically controlled 700R4 so no computer input needed. We did essentially the same swap on the '88 I have for sale in the F/S section. Not hard. Always something you can keep as an option if you can't get the TBI issue straightened out.

[Smithingell]

oh god...Please dont swap to a carb!!! EFI is SO MUCH BETTER!!! and TBI is about the easist system there is!!!!

yes, the fuel pump should come on for 3-5 seconds when the key is on, engine not started (it doesnt read pressure, its just a timed thing) and it will also come on as soon as the starter is engaged, and then stay on when the engine is running...it does not cycle....now, I'm not a GM guy (so I'm not sure if this is all of them) but it is also dependant on the oil pressure switch...not enough oil pressure, no fuel pump...so a faulty oil pressure switch could keep the truck from running because the fuel pump is disabled...this is often misdiagnosed and alot of people replace fuel pumps because of this...

first off, unplug the fuel pump, and test for 12V as someon turns the key on (pos and neg) if nothing, try a different ground spot...if you have no power, continue to the relay, and then to the oil pressure switch, and then to the ignition switch (on the steering column, not the igntion module)

if you do have power, and the pump is working, but you have no pressure, start looking at the pressure regulator...

[Smithingell]

You should be alright with it wired direct but I would use a relay because of the current draw and then control the relay with a toggle switch that way if you need to leave the key on for some unforseen reason the pump won't just sit there and run. If you don't know how to wire a relay then look in the tech section YotaBill did a great write up on how they are wired. I hope that helps

you wouldnt need the toggle switch, you could do it with a self-latching relay that is only energized when the starter is engaged...that way its automatic, and the fuel pump would not come on until the starter is engaged, and then it would stay on till the key is shut off, but that would add an extra second or two to the time taken to start...but at least you wouldnt have to remember to shut the fuel pump off...

[lapeer20m]

thanks for all the suggestions.....

i got her running again.  found an excellent site the describes in detail problems and solutions for gm tbi

http://www.chevythunder.com/gm_throttle_body_injection_pg_1.htm

The noid light is something i've never heard of before...costs about $3 at murrays, well worth the investment.  Turns out the fuel pump failure problem is unrelated to the truck not starting.  Went back to the basics, pulled all of the plugs.  2 of them had so much carbon and other crap built up on them there was no possible way for them to fire.  don't i feel silly! 

As far as the fuel pump....I am not sure why i had the old one and two brand new ones fail in such a short period of time.  The fuel pump relay is still under the hood.  I think tomorrow i'm gonna wire the fuel pump back into the old fp circuit and hopefully everything should be goovy.  I replaced the little strainer on the fuel pump too just in case debris were getting past the old one thus destroying the pumps.  Sure am glad the pump is in a fuel cell and not mounted in a stock tank.  Dropping the tank multiple times would be very uncool!

now i have the truck in a heated garage, and hopefully will get her painted this week. 

HERE ARE THE LATEST PHOTOS





still need to re-attach the truck "bed" as seen in some earlier photos


i'd like to get her out to the mounds before they close in the next couple weeks.  like most projects, she's overbudget and behind schedule

[drew454u]

sweet rig, you should put a front end on the back and on the front so it could be drove both ways. that would be awesome. also if ya dont mind me askin how much did the ifs front system cost. just curious i wanna straight axle my 98 chevy and curious what it is worth.

[lapeer20m]

i got the ifs unit for $250 from the scrap yard.  I only payed $150 plus a $100 credit for a scrap vehicle i turned in.  Basically it inluded the entire frame from the torsion bars foward. 

it's the HD ifs unit, i think the 9.5" or something.  It's significantly larger than the 1/2 ton units. 

if you found a guy who blew out the front diff in his truck, i'm sure he'd gladly spend $250 for a new one.  Not to mention the complete unit with axle shafts, hubs, ect. 

[crazyhausk1500]

i had a problem with my 90 4x4 tbi not spraying fuel and it was the ignition control module (ICM) under the rotor under the  distributor cap.the icm reads of the pickup coil which is under the icm ,and tells the fuel injectors when to spray fuel, if this is faulty it wont spray fuel

[scramblerman72]

lOOKS LIKE A GREAT iDEA!

[lapeer20m]

got her all sanded, and a coat of primer applied.  Hopefully i'll get the first coat of paint on tomorrow.  Flat black.  couldn't think of an easier color to paint. 

if all goes as planned we should have her out at the mounds this sunday