question - 87 V20 TBI - fuel injectors normal?

[crosby]

I finally got my truck running. Sounds like crap, probably needs to be run for a while. Anyhow, the vacuum lines are all making horrible sounds, I have no idea where they go . Lots of extra wires, somebody really screwed up the wiring, but I got everything working somehow. I am going to swap in a new harness when I switch everything to the new frame. BUT, I have a question. When the engine is running, you can see a spray of fuel coming down from the passenger side injector, into the intake manifold. But nothing is coming out of the driver side (that I can see). Is that normal? Are you supposed to see a stream of fuel normally? Does the driver's side kick in like secondarys in a carb, or is there something wrong? Thank very much for your help guys!!

[1976K5CHALET]

It seems the best thing to do with a tbi unit is to buy the $35 kit and clean it out. The passage ways underneath coke up. Clean her up really good and change out all the the gaskets. Before you do that check the injector connectors with a noid light and make sure its getting 12vdc from the ecm driver...then once you know the injectors are getting juice and the tbi is clean set the minimum idle as per the book...course make sure the timing is set at zero with the timing plug unplugged. Should make a big difference.

DW

[crosby]

Hi Doug, thanks for the reply. What kit are you talking about? Can you tell me where I can get one? I should probably get a factory manual since I don't know which plug is the timing plug (you mean for advance? I thought everything was run by the computer). I am sure once I get the bugs worked out the TBI will work better and probably use less gas too. Thanks very much for the info.

[1976K5CHALET]

Tbi rebuild kit. If i was at home i could give you the napa number as i have a brand new one in the garage. Not sure where the timing dis connect wire is on that rig as my K5's i have converted. I think gm put it on the drivers side between the brake booster and the wiring plug ...i believe its a tan wire with a black stripe. I'll walk down to the chalet tonight as i think i carry the helm 87 manual with me all the time.

Doug W.

[crosby]

Thanks alot Doug. Should I be seeing the fuel spray? Should both injectors be spraying like this always? I appreciate your help very much, have a good night.

[crosby]

Sorry, I forgot, one more question. Do I need the AIR tubes for the TBI to work properly, or are they just emissions extras? I don't have any cats either (yet, I will need them for a sticker here in NH) and I'm thinking of running the Edelbrock TES tubular exhaust so I can keep everything I have to. Therefore, I don't have the oxygen sensors, so that could be throwing the computer off too. Any suggestions? Thanks very much.

[1976K5CHALET]

You should see spray from both injectors. You can use a timing light to see the pulse as the ecm actually pulses the injectors. Air tubes are just emissions extra's. The ecm controls the divertor valve...disconnecting the valve will not set a light. Emissions can be a requirement depending on your states requirements and it will not hurt performance if hooked up and working.

Two things you will need to make it run properly is a oxygen sensor and a working vehicle speed sensor. O2 sensors make a small amount (Millivolts) of electricity the ecm uses to add or delete fuel (rich-lean). Very important.
I ran a howell harness with my 79 K5...and there 2 pulse vss that screws on at your transfer case. An 87 will have a green box behind the instrument cluster that was used as a vss...you will need a scanner or a laptop with win aldl so you can drive it and ensure that it is seeing vehicle speed input. I am assuming you are running a complete 87 V20 or is this a 87 V20 harness and motor in an older truck?

My first swap i did a stock 79 crate motor..i added a redrilled tbi intake and learned two lessons...timing was set to allmost 12 degree's advanced...and i removed the stock fpr and turned the nut counter clockwise about 3 turns to bump the fuel psi up and man alive did she run good. Ran 2 cats with no air pump and it ran so clean thru az emissions you'd think it wasn't running.

Without being there its hard to diagnose correctly what is going on. But having an operational vss...o2 sensor...and a correct 195 degree t-stat is essential to get her torun as designed. Headers are great but a sealing nightmare plus they the collector sits damn near on top of front spring shackles...something i never liked. A set of factory manifolds can be had at autozone for around $100 a side...the nice thing is the drivers side allready has a port for an o2 sensor. Careful when shopping for used manifolds...allways remove the shielding from the right manifold...you would be amazed how many hide a crack...


DW

[crosby]

Hi Doug, thank you for your help. I would like to put everything back the way it should be if I can. Here's the story, it's an 87 Jimmy engine, with an 87 V20 cab and bed, on a (late?) 70s frame and running gear. It has a 203 transfer case, and the dana 44 front axle. There is probably no provision for the VSS on the 203 xfer case, although I haven't had it moving fast enough to bring that into the picture yet. I just moved it back in my driveway a couple of feet. First, I will rebuild the TBI, and then see about getting the VSS and oxygen sensor working. I should probably dig the stock manifolds out of the truck I am sending to the junkyard before it goes . I just don't have the AIR tubes, nor do I know where they go, etc. Would there be a "correct" 205 I could use in this case that would have the VSS provision? For example, out of an 87 K30? Thanks again for all of your help.

[crosby]

Hey Doug, another angle for you... If I decided to wimp out and use a carburetor (and HEI), is this engine different than the older 350s? I have heard the heads are different, so you can't just bolt up an old Edelbrock aluminum intake. I have a 77 350 I just pulled out of a K10 stepside, I was planning to save for a Camaro. Are the blocks the same? Heads bolt on differently? I am just curious, but if it gets expensive, I will have to dumb it down and carb it. I can't justify spending $1000 to keep TBI in a $1000 truck, you know? Thanks very much!

[Metallicamaro]

However, I have a 1988 TBI 350 in my camaro, the 350 came from a 1988 pickup, and i know what your talking about! However the last posts were long and im lazy, first of all check your fuses theres one for each injector (2) well looks like the driver one isnt working! cause i always see a jet stream coming from injectors with a ticking noise, its like pulsed stream of gas and not steady.. this may be confusing..

[crosby]

Thanks guys, lots of good info here. I still have the original manifolds (from the Jimmy), just no air tubes. Not sure if I should just buy the AIR tubes and get everything the way it's supposed to be. I would like to run the Edelbrock TES, but I am sure it's expensive, and not sure if they have it for my truck. Thanks again!

[C&C Chevy]

You got an in-tank or electric in-line fuel pump, right? Just wondering if your getting enough fuel pressure for the TBI, cause it runs alot higher thand a carb set-up. Said you got it on an older frame, so just checking.

[C&C Chevy]

oh, yeah. You can run just fine with out the air pump. You might get a "check engine" light though. But the truck will run fine.

[crosby]

Hi Robert, thanks for the message. You raise a good point. I was assuming that the tanks and so forth were from an 87, but how would I know? They do have in tank pumps, and the mechanical pump boss is blocked off. I will probably rebuild the TBI this weekend and try to get the exhaust bolted on completely. I do have the original exhaust manifolds, so I am okay there for now. I did manage to round off one of the bleeder screws, so although I put a new line in, the brakes still don't work. I will have to fight with that too. I just don't like the shape of the brake and fuel lines, the lack of proper fasteners to the frame, fuel lines too close to the exhaust, etc. I really want to get the other frame going ASAP and transfer everything over, hopefully in the spring. I am going to try and keep the TBI, but if it ends up costing me too much money, I will just carb it. Does anybody know what the differences are in heads, intakes, etc.? Isn't 87 and inbetween year between the old style (through 86) and the new (88 and up, one piece rear main seal, center bolt valve covers, etc.). Thanks again for all your help!