Fastcamaro87

ok i am trying to set my base timing, however the hood on my car is not original, and does not have the emmission sticker that tells me the timing specs, does any one know or have them for the car in my sig, also my car seems to have jumped timing somehow, is this possible??are there any sensors that could cause this malfunction? etc. etc.thanks in advance..

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87 IROC-z 305 TPI 5spd 10-bolt 3.73 posi ,8.8 Accel wires , bosch platinum +4 plugs,MAF sensor screens removed, gutted air box, ram air, K&N air filters,TB coolant bypass ,polyurethane tranny and torque arm mounts, K&N oil filter,Mobil 1 synthetic oil 20w50, futura GLS super sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims ,

400 sbc and a 6 spd in the works

JakeJr

The 86 L98 TPI has a factory initial of 6 degreed BTDC. I just noticed you have a 305, not a 350.

Guess someone else will have to give you the specific setting you're looking for.

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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9



[This message has been edited by JakeJr (edited September 07, 2001).]

Fastcamaro87

heres a little more info, the car barely idles, stumbles and bogs real bad, backfires thru exhaust,and is making a sound that is either spark knock or the valves hitting the piston.. cmon guys somebody help me out,

i am thinking that the timing chain may have jumped a tooth ,,, any thoughts.....

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87 IROC-z 305 TPI 5spd 10-bolt 3.73 posi ,8.8 Accel wires , bosch platinum +4 plugs,MAF sensor screens removed, gutted air box, ram air, K&N air filters,TB coolant bypass ,polyurethane tranny and torque arm mounts, K&N oil filter,Mobil 1 synthetic oil 20w50, futura GLS super sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims ,

400 sbc and a 6 spd in the works

Fastcamaro87

hey does anyone have this information??? i know somebody has to know something, or dealt with a similiar problem..

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87 IROC-z 305 TPI 5spd 10-bolt 3.73 posi ,8.8 Accel wires , bosch platinum +4 plugs,MAF sensor screens removed, gutted air box, ram air, K&N air filters,TB coolant bypass ,polyurethane tranny and torque arm mounts, K&N oil filter,Mobil 1 synthetic oil 20w50, futura GLS super sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims ,

400 sbc and a 6 spd in the works

IROC&ROLL

Sounds like it could very well be that your timing chain has slipped. You should check that ASAP, as SERIOUS engine damage could occur should it slip further or fail!!

Base timing for your '87 LB9 is 6* btdc.

Bjase

You can check for slack in your timing chain by turning the crank with a wrench while someone watches the rotor in the distributor. You shouldn't be able to move the crank very far before the rotor turns. I don't think it's very likely the chain jumped if it's tight.

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88 IROC with cobbled together (not by me)drivetrain, 86 (?) TPI unit on an '83 305,CE subframe connectors, Edelbrock strut tower brace, polygraphite bushings all around...it handles like a dream, but man is it hard to push!!

Guest

The base timing is 6BTDC. Its not likely the chain jumped a tooth, but its alot more likely the balancer slipped. Take a look at your balancer, if it looks ok you may need to pull the #1 plug and put the engine at TDC and see if the marks line up.

Fastcamaro87

ok here is the latest on my car, today me and my buddy decided maybe it was the pickup coil on the distributor, so we set it up , marked it and yanked it out, changed the pickup coil, and cleaned up the distributor and stuff, took the ignition module to work and tested it like 15 times and it checked out fine.checked for slack in the timing chain by turning the crank and watching the rotor and it looked good, stabbed the distributor back in hooked everything up and it purred like a kitten,took it for a spin and it was perfect,we cleaned up all the tools and crap, grab something to eat and came back about 30 mins later , i started it up and once again it ran like crap,missing and backfiring, and surging, just like before, what the heck?? any thoughts??

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87 IROC-z 305 TPI 5spd 10-bolt 3.73 posi ,8.8 Accel wires , bosch platinum +4 plugs,MAF sensor screens removed, gutted air box, ram air, K&N air filters,TB coolant bypass ,polyurethane tranny and torque arm mounts, K&N oil filter,Mobil 1 synthetic oil 20w50, futura GLS super sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims ,

400 sbc and a 6 spd in the works

edfirebird

bad connection on a sensor ? tighten the pins w a pick

JakeJr

TEST

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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9

Fastcamaro87

what do u mean ?? pick??



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87 IROC-z 305 TPI 5spd 10-bolt 3.73 posi ,8.8 Accel wires , bosch platinum +4 plugs,MAF sensor screens removed, gutted air box, ram air, K&N air filters,TB coolant bypass ,polyurethane tranny and torque arm mounts, K&N oil filter,Mobil 1 synthetic oil 20w50, futura GLS super sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims ,

400 sbc and a 6 spd in the works

rezinn

What did you set the timing at? Make sure your firing order is correct, and all the plug wires are attached?

Fastcamaro87

ok i have checked the firing order and the wires and everything is fine, i put in a new distributor, and module, i set the timing at 6* btdc with the est bypassed, it idles ok but when i rev it at all it has a miss any ideas? also i am getting a code 42

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87 IROC-z 305 TPI 5spd 10-bolt 3.73 posi ,8.8 Accel wires , bosch platinum +4 plugs,MAF sensor screens removed, gutted air box, ram air, K&N air filters,TB coolant bypass ,polyurethane tranny and torque arm mounts, K&N oil filter,Mobil 1 synthetic oil 20w50, futura GLS super sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims ,

400 sbc and a 6 spd in the works

[This message has been edited by Fastcamaro87 (edited September 11, 2001).]

JakeJr

Well, you've got to begin checking things one at a time.

First, attach your timing light to each plug wire and see that you are getting a regular, even flash from each wire.

Then plug the plugs and see how they look. Check the gaps and the color; they should be light tan.

Pull the distributor cap and look at the terminals. Check for corosion clean them with an emery board or piece of sandpaper.

Look at the rotor for signs of voltage leaks or spark jumping. Look for dark brown or black areas which would indicate heat build up or burning.

Check the wiring harness for signs that one or more wires has been cut or damaged. This can happen when the distributor cap is installed on top of a wire.

A fuel pressure gauge is needed to see if fuel pressure is holding when you shut down the engine. If it isn't, you could have a leaking injector.

Use an ohm meter to check the resistance of each injector; should be in the 16 ohm area.

You should use a ScanTool or Diacom to get a real time view of what all the sensors are doing.

Pull the valve covers and check for a broken spring, bent pushrod, rocker damage or flattened cam lobe (one rocker not moving as much as the others will identify the bad one).

I never memorized all the code and I don't have my manual to look up a code 42, but if you can post on it, I'll see what I can do.

Jake

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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9, TPIS Long Tube Headers and DynoMax Super Turbos (HATE 'em)

u r sofa king we tah did

bad computer. my 88 vette did this when the computer was going out. it was throwing code 42 all the time. sometimes it would start normal and sometimes it wouldnt. when it did run with the code 42 (Electronic Spark Timing Error), it ran like complete ****. it will eventually start getting worse to where it will die when you start it and it will take several times to get it to even run.

maksik7

Sofa King, tell me you're kidding. My 86 LB9/auto is experiencing the same problem (- the code 42) and it takes a couple of times to get the car to run (it idles for a second then dies for the first 2 or 3 times I start it)
Also how hard is it to replace a computer? Can I use the one from an 88 LB9/auto?

Please somebody help both of us out...

Fastcamaro87

ok guys first i just want to say thanks for everyones help, and second that i figured out the problem :
I figured id change the pickup coil in the distributor, since it is pretty cheap and was a good possibillity, well when i pulled the distributor, i noticed the magneto/stator i think that is what it is called(lil star wheel magnet thingy)was spinning on the shaft, so it wasnt pulsing the pickup coil so i bought a new distributor because i couldnt find just that peice, and dropped it in, set the timing to 7* btdc (figured id advance it a lil)now the thing runs fine i have not set any codes or had any problems..

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87 IROC-z 305 TPI 5spd 10-bolt 3.73 posi ,8.8 Accel wires , bosch platinum +4 plugs,MAF sensor screens removed, gutted air box, ram air, K&N air filters,TB coolant bypass ,polyurethane tranny and torque arm mounts, K&N oil filter,Mobil 1 synthetic oil 20w50, futura GLS super sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims ,

400 sbc and a 6 spd in the works

u r sofa king we tah did

no kidding about it. the computer replacement is very simple. you just gotta unplug the old one and plug in the new one. simple as that. dont forget to put your eeprom in the new one though, thats even simpler. just pull it out of the old one and plug it in the new one. i got my ecm off of ebay for 45 bucks.

maksik7

Ok so are you saying I can use the ECM and Prom from the 88 on my 86? Also can anybody either explain to me where the Computer and prom are located (under the TA leather puch panel right?) or better yet post a nice picture. I would really appreciate it. Thanks for the help,
-Max

u r sofa king we tah did

i didnt say any where you could use an 88 prom in your 86. however, the ecm itself from 88 will work just fine. any 86-89 ecm from a camaro,firebird, or corvette will work. use the prom thats in your computer right now. to get to the computer, just take off the passenger side hush panel, right above where a passengers feet would be.

maksik7

Ok I got what I think is the computer. Its a small 3"-5"-1" black box, very light, with 12 plug connecting at the top. It has the word "AC" molded on top. Is this the actual ECM?

Is the prom inside it or is it mounted somehwer else casue I don't want to switch the proms accidentally.

Thanks for the help, hope that switching the ECM's will help,

-Max

maksik7

Well I switched the black boxes ont eh two cars, and no change at all. I'm guessing this isn't the ECM after all. On my 86 there is a slightly larger polished metal box to the left of it but the previous owner took it out of the 88. Is this the ECM with the black box being the prom or am I totally confused?

Thanks for the help,
-Max

u r sofa king we tah did

what you changed wasnt the ecm, im not sure what that is you changed out without seeing a picture of it. the ecm is the big silver box. sounds like your parts car has the ecm removed already. look on ebay for an 86-89 vette, camaro, firebird ecm from a TPI car only. if you have a digital camera and can take a picture of the car, i might be able to tell you what it is you changed. right off hand i can only think of it being the Theft Deterent Module, but i dont know if that was used in camaros and firebirds. i know my vette has one, havent looked on the iroc though.

maksik7

Can I use the ECM off a 350 car (I'm guessing so if I can use vette ones) but just making sure. Becasue I have a friend with a 88 350 GTA he's parting out, I'm sure he wouldn't mind me taking the ECM.

u r sofa king we tah did

vettes only came in 350s, so yes you can.

dom2606

hey guys i am building my first project witch is an 87 iroc z now it has a 305 with 100k on it i drove it 45min home when i traded my 98 mustang and only issue it had was the idle at every stop light i had to slap it in neutral and reb up the engine so it wont shut off. so i took it to a car wash and pressure washed the top and lower motor and under the car she idled fine i got out the car and it stayed put for 15 min while i was in advance auto. so when i arrived home the battery died witch is my alternator i knew for fact so i waited for the next day i charged it and cranked it after i cleaned all the filtersput everything back in and my roomate for no reason took my distributor out causing it not to start all i want to know is what i can do to get that idle issue fixed and on my valve covers oil was coming out from the screw holes causing minor smoke (this was when i had it runnig) so now i took the whole top motor off replacing gaskets and now working on intake manifold gaskets i got a new distributor and alternator i will be putting in tomorrow i just want some good advice again for my idle smoke from valve covers and ideas to make it run smooth. and can anyone send me a picture for the distributor layout for my plugs its been a month since its been sitting and im learning about cars on my own and need some help i can leave my cell for txt or email i just need some good advice for this is my first project car i plan on fixing and keeping

i appreciate the help in advance and have a good weekend everyone