Ok, I have a 1986 TA 305 TPI with center bolt valve covers and coil on cap. Is this common for this year? Also, Im sure the car has the hottest cam they offered speedo is 140 mph.
Any help would rock thanx

 

there was only one motor in 86, the tpi 305 LB9, it used the cam from the carbed L69, which had a reduced lift of .350, .385 versus .404, .415. Motor put out 190 hp, this was also the first year for a efi motor to be offered with a 5 speed, and the first year to have a 9 bolt rearend. Also offered this year for the first time, was the center mounted brake late grafted onto the hatch, backlit 140 speedo cluster you speek of for the t/a, revised calibrations and a new shift cable for the 700r4, lightweight a/c condensor and basecoat clearcoat finish, WS6 package got ane even larger 36MM front sway bar, but smaller 24mm in the rear.

As for the coil in cap, this was probably original.

 

Ok, thanx for the info cronsformula350. I have more of a problem now, or is it.
I called my local gm dealer looking for the updated prom so I can dump the Hypertech chip. He said he need some info.
1, is it fed or cali emission
2, does it have a/c
3, are the tires 215/65 15 or 235/65 15
my answers were
1 Fed emission
2, has a/c
3, 245/50 16 tire, as it says on the door tag, I checked the vin on the door tag it matches the vin of the car.
He says the tires size wasnt an option for my year, buts its on the door tag. Now, I cant find the RPO sticker so I have no clue whats goin on. Is there anyway I can find out what my car is, if its something special or just a GM retard.

Thanx again

 

I'm not quite sure why he would need the tire size anyway, just tell him what your motor is, and what rear end you have, and thats pretty much all he should need to know, where did you live again?

 

They need the tire size for proper VSS calibration.

Check the RPO info in the decoding section and see if it matches up. If you can give him and RPO he should be able to find the right chip.

BTW, the coil in cap was standard for '86. My Camaro has it ('86 IROC Z28 factory 305 TPI system). The coil in cap and remote coil systems are identical, except for the obvious physical differences, on all TPI cars. You can convert the coil in cap to remote coil and small diameter distributor with a kit from Accel, or using GM or aftermarket connectors.

 

yeah I forgot about that damn speed sensor, who needs it! Stupid speedometer, its still not as crucial though as it is with newer 4th gens, that need it to shift, our 700r4 4l60's computer and trans don't rely on that, rather just the tv cable lets the trans know when to shift, but you do need the speedo for obvious reasons.

 

True, it isn't as important as in the 4th gen system, but it is still important. Without a proper VSS signal to the ECM, or the ECMs ability to translate it in this case, the car can have all kinds of mystery problems like stalling while in gear and odd idle problems. The bad thing is that you'll never get a VSS code, so it will drive you nuts trying to figure out what's wrong.

 

Well in my experience no 2 3rd gens are the same. Every single one of them that i have seen has something different, could be something minor but still. It's like GM tried every possible combination possible.

 

Actually, the computer knows when the cars in gear, not by the speed sensor, thats for the speedo, rather by the sensor on the shifter in the console, this tells the car partially when to go into closed loop, and when to compensate for the load being placed on the motor by the trans, and tells the IAC when to compensate, and the EGR when to work.

 

My car didn't use the VSS for the speedo ('86 had a mechanical speedo and a VSS built into the back of the speedo). The ECM gets information based on the VSS built into the speedo. Everything else has merit.

I don't think that stick cars had a sensor to let the ECM know when they are in gear either. The two wires that go to this in an auto car are shown bridged in the diagram for a stick car.

The stuff about the IAC and EGR is spot on.

 

Well there is a sensor in the console for auto cars, for the stick versions, things are different. But stick versions don't matter anyhow, that stick trans sucked, and was behind a 305 anyhow!

 

Didn't centerbolt valve covers debut in '87?

 

Well, my T56 certainly doesn't suck, and it still needs to run like a factory 5-speed in terms of wiring and the ECM. A lot of guys on TGO are running T56s and stock T5s, so it's important to note the differences instead of just making blanket statements.

Technically centerbolt valve covers debuted in '87. That doesn't mean that some late '86 cars didn't get them as Chevrolet was making the changeover. Cutoff dates like this shouldn't be viewed as absolutes. I've seen '88 blocks that don't have provisions for roller cams, even though everyone claims it's a fact that all blocks have the valley stands starting in '87 even if they didn't get a roller cam. Also, it could be a non-original motor from a later model car. A lot can happen to a car in nearly 20 years.

 

mine are center bolt and the car has prod date of 11/85 so its early 86 . So what I did was I found a post with an email address, I emailed my vin and Im waiting on whatever she can dig up.

 

Yeah centerbolt heads came out in 87, first ever. So your heads on your 85, have probably been replaced by a previous owner. The earliest you would have seen them would have been late in 86, on the 87 model.