1987 GMC V1500 Longbed TBI issue
 

So from a little research;

TBI cam : 165in/175exh .382 int lift/.402 exh lift Lobe Sep: ?

Vortec Cam: 191int/196exh .414int lift/.428 exh lift Lobe Sep: 111

LT1 Cam (94-95) 203int/208ex 450 int lift/ 460exh lift Lobe Sep: 116
(96-97) 205 int/207 exh 447 int lift/459 exh lift Lobe Sep: 117

1987 GMC V1500 longbed, Currently my setup is 92 engine w/ swirl port heads (I'm guessing), vortec cam with roller setup, msd igntion coil, stock tbi, long tube headers with 3wire ac-delco o2 sensor, serpentine setup with higher amp alternator, stock spec fuel pump, I did an electric fan conversion, transgo shift kit with corvette servos, and also have swapped the front & rears to 3.42 gears w/ 32" tires, originally was 3.08s.

I have rebuilt the 92 engine, it was bored .030 over. I rebuilt the trans to stock spec w/ oem spec torque converter as well. Then added the rest of the stuff listed above.

Currently when it shifts to 45 when warm and torque converter locks up it feels like it has been kicked in the nuts, drops down to 1200ish rpms and lugs until I get back over 1500 which is over 55 mph. Now when the truck gets to 60mph + it feels like it has all the power it would ever need.

Also an issue that is happening is sometimes after its warm and I park it and let it idle, it will idle around 550ish rpms and then when I go to put it into gear it will shut off and die. Will start back up fine though, also it has just died in park twice from sitting at that low rpms.

Any ideas what could have gone wrong or is my setup bad? Need a tune? Anything you can think of? Is the vortec cam hurting me to the point I need to swap to an LT1 cam or something?

Any info is appreciated, I love this truck and want it to run correctly!

Also, how do yall tie into ign power? I kind of have it rigged for the 02 sensor and electric fans.

I have the Holley TBI but I didn't see a point in putting it on b/c I haven't really added any power that would need it, plus haven't really felt like Id need a tune unless I swap to vortec heads, but they are hard to come by for a decent price here. Plus I need to save $$ for LS swap.

Re: 1987 GMC V1500 Longbed TBI issue
 

just having a look at some of my winaldl data, when travelling between those speeds, tcc drops the RPM's about 100-125. it sits around 1350-1450rpm and drops from there. but nowhere near a 500 rpm drop.

my idle rpm's are the same as yours(but it doesn't die)

mines a totally stock 88 c1500 swb

Re: 1987 GMC V1500 Longbed TBI issue
 

What trans/rearend gear/tires are you running?

Re: 1987 GMC V1500 Longbed TBI issue
 

700r4/3.42/275 x 20inch

ive attached some of the winaldl data for you to have a look at

Re: 1987 GMC V1500 Longbed TBI issue
 

275 that is like a 33" tire, correct?
I see that at one point you were around 1250 rpms at 47mph. Does yours "lug" that low?

Your engine all stock?

Also, how did you datalog like that? I have winaldl and all but could never record what I have.

If you look in my other post, it's kind of long but I think on the last page I posted a couple videos of rpm drop while driving. Check it out please.

What I just heard from a tuner was this:
165-175 duration cam (stock tbi cam) makes all its power from 0-3000 rpms and you intalled a camshaft that runs from 1500-4800 rpms (vortec cam) and your gearing didn't increase the same percentage.

Re: 1987 GMC V1500 Longbed TBI issue
 

29 inch tall rears

mine goes ok, drives like she's 26 years old, but no noticeable "lug" at that rpm/speed compared to any other time

yep, couple of bolt on mods, throttle body space, injector spacer, twin electric fans, heated Oxygen sensor

click on datalogger and then start when the log data box pops up

Re: 1987 GMC V1500 Longbed TBI issue
 

Did you check out the videos I had posted on my other thread?

Re: 1987 GMC V1500 Longbed TBI issue
 

sounds like you might need a custom chip done

http://tbichips.com/

i'd shoot him an email at least

Re: 1987 GMC V1500 Longbed TBI issue
 

I've been emailing him, he's the tuner I spoke of earlier. So far he suggested I get rid of trash oem heads for vortecs before I get a tune.

Re: 1987 GMC V1500 Longbed TBI issue
 

i did. mine def doesn't drop that much. are you sure the gauge is accurate?

if i were you i'd figure out how to log data with winaldl and go from there

Re: 1987 GMC V1500 Longbed TBI issue
 

Yeah it's pretty darn accurate, ill hookup laptop n datalog just to make sure. It is one hell of a drop in rpm when it shifts and almost locks up immediately after. Truck will lug and shudder a tiny but until I get over 55. After I hit 60mph and get above 1550-1600 rpms it feels like it has plenty of power.

Re: 1987 GMC V1500 Longbed TBI issue
 

so you've got a vortec cam, and vortec heads on your truck?

edit* sorry mis-read. he's suggesting going to the vortec heads b4 doing a custom chip?

Re: 1987 GMC V1500 Longbed TBI issue
 

Nope only vortec cam/roller setup. Still have stock style swirl port heads. Unfortunately.

Re: 1987 GMC V1500 Longbed TBI issue
 

hmmm but to go to vortec heads you'd also need a different intake too. and then custom chip plus installation if your not doing it all yourself

$$$$$$$

Re: 1987 GMC V1500 Longbed TBI issue
 

If you want to stay FI with Vortec heads, you will have to change the ECM also.

OEM Vortec FI uses a central sequential poppet valves that require a goofball connector. You would have to get all that setup. NOT CHEAP 2 major flaws are the intake gaskets (decent ones are now available) and the injectors (decent ones also available) See below:

http://www.summitracing.com/parts/fe...000t/overview/
Notice the metal intake gaskets in this kit. I never found these outside of a kit.

http://www.summitracing.com/parts/smp-fj504/overview/

Aftermarket systems to work with Vortec heads are available for between $3500 and $4K. Still requires another ECM that comes with the system.

http://www.summitracing.com/parts/edl-3528/overview/
Just one example. You could put together your own system, with intake, throttle body, wiring, ECU etc and you come out near the same price.

I advise changing the system you have (FI, controller etc) but stay with standard SBC intake bolt pattern. There are 100's of aftermarket heads that can give you better quench, etc but stay traditional bolt pattern.

For example a square bore intake, injected throttle body, ECU, wiring and sensors.

At the very least you can change the TB you have and ECU.

Good luck

Re: 1987 GMC V1500 Longbed TBI issue
 

After talking to Brian at tbichips, it seems like the only "bandaid" I can do to fix this issue is to get a 87-92 camaro 305 tbi roller cam, stock one, it will bring down my powerband and eliminate this issue. Currently with the vortec cam my "powerband" is 1500-4800 with the vortec cam. The stock tbi cam is 0-3000 rpms. The issue is I keep dropping way under the power band while driving which is causing crappy performance and not so good MPGs.

Anyone have one of those cams?

Only other thing is to swap heads out for better flowing heads and whatever it takes to accomodate those heads, such as intake, ecm, tune or whatever.

Since I am not building a high hp truck with this truck I just need to bandaid it. I will be keeping this truck forever so I really want it for reliability, longevity, and decent mpg. So eventually it will get an LS swap. So no point in dumping $1000s into it when I won't be keeping it.

However, currently I need this truck bc it is my only truck! I am trying to build a shop to replace one that burned down so I can get back to doing some serious projects.

What you guys think about the cam swap idea?

Try not to say "I told you so"
 

Believe I mentioned the parts were really not compatible in another thread you wrote.

http://www.summitracing.com/parts/crn-104201/overview/

Is a stock replacement for your cam price really sucks big time.

I think your original cam number is 14060651
found this
http://paceperformance.com/i-5146407...k-special.html

I would jump on it even if it were the wrong part.

Re: 1987 GMC V1500 Longbed TBI issue
 

Isn't that price ridiculous!!

Yes speedy you were absolutely correct!! I was wrong, I am an idiot.

Isnt that cam flat tappet not roller?
That is a great deal on that cam, I will try and get specs on it to see if it would work. I think it is atleast a roller cam! Thanks a bunch.

I gotta get her running right!

Re: 1987 GMC V1500 Longbed TBI issue
 

I confirmed the cam from Pace is the original L05 cam.

http://www.cfm-tech.com/GM_tbi_tuning_tips.htm

Re: 1987 GMC V1500 Longbed TBI issue
 

So the 305 tbi camaro from 87-92 had a roller cam. I found a replacement for it on eBay. Will this be ok since I need a roller cam close to stock specs?

http://www.ebay.com/itm/261315255090...84.m1423.l2649

Specs for the cam
http://aftermarket.federalmogul.com/...0-%20cs793.pdf

Re: 1987 GMC V1500 Longbed TBI issue
 

Man I don't know. Your using a different engine. The 92 you're talking about was roller cam. Your truck 1987 was flat. I never saw a roller cam have the same specs as a flat cam. You're on your own there.

One thing I want to emphasize is that you get the push rod geometry correct no matter what you do.

Re: 1987 GMC V1500 Longbed TBI issue
 

The 92 wasn't originally a roller cam engine. It was just a standard flat tappet motor out of a truck but it had bosses drilled and all so we had a spare vortec cam so we changed it to roller.

Does the roller cam I provided match specs of the cam you provided?

Re: 1987 GMC V1500 Longbed TBI issue
 

http://www.thirdgen.org/mods3 the one at the bottom of the page ending in 155 is stock 305 tbi roller cam specs

Re: 1987 GMC V1500 Longbed TBI issue
 

Which of these cam information is correct for the stock 350 5.7 tbi truck cam?
Because I failed to make the right decision before I want to be 100% sure that I make the correct cam decision this time.
Also, after I figure out this cam stuff I am sure I would benefit someway from a tune of some sort.
Stock 305 TBI roller cam specs (10088155): 179/194 .350/.384 .373/.410 LSA: 109deg
Vortec Cam: 191int/196exh .414int lift/.428 exh lift Lobe Sep: 111
TBI cam : 165in/175exh .382 int lift/.402 exh lift Lobe Sep: ? (FROM TBICHIPS SITE)
Sealed Power Cam CS793:
Cam Lift / Intake: .2336" Cam Lift / Exhaust: .2565"
Valve Lift / Intake: .350" Valve Lift / Exhaust: .385"
Valve Lash Int.:HYD Valve Lash Exhaust: HYD Cam Type: H
Lobe Intake Centerline: 106 / Lobe exhaust Centerline : 112 / Separation Angle: 109
Lobe Centers| R.R. = 1.5 | I.O. (BTC)| I.C. (ABC)| E.O. (BBC)|E.C. (ATC)| DURATION|OVERLAP
----- INT. 106 | SAE J604D |---- 16 --- | -- 56 -- | -- 57-- | ---- 25-- | 252 INT, 262EXH| 41 |
----- EXH. 112 |.050 CAM LIFT|---- -17 --- |-- 16 -- | -- 29-- |-- -14 -- | 179INT, 195 EXH| -31 |

L03 & LO5 TBI TRUCK Engine Spec's
FOUND HERE (http://www.cfm-tech.com/GM_tbi_tunin...LHPCompression Camshaft .050" I/E - Lift I/E - LSAInjector Size lb/hr
L03-305-5.0L1709.3:1 179/194 - .350"/.385" - 10940*
L05-350-5.7L2108.3:1 194/202 - .385"/.403" - 11255*

This is what Brian at Tbi chips told me about the sealed power cam.
"yes that should work. That was in the 190hp 300lb of torque non cop car caprice engines. GM didn't make near as many of those cars as they did 305 TBI camaros so I figured the camaro cam would be easier to find and certainly cheaper."

Re: 1987 GMC V1500 Longbed TBI issue
 

This is what Brian at tbichips said about the L05 cam specs you provided speedy.


"I have never seen those cam specs on a L05 engine EVER anywhere. Jegs still sells the engine http://www.jegs.com/i/Chevrolet-Perf...oductId=753961 which clearly shows the cam in those motors was 165/175 .382/.402 camshaft. GM did bump the compression ratio to 9.4 on those replacement numbers to help get that 210hp rating as the stock motors sure didn't make the claimed 210hp unfortunately since they kept the tiny cam that compression ratio means it HAS to run on at least 91 octane fuel or it WILL ping."