Hello ladies and gents:

I still have a starting problem, the car start right up but dies soon after, will run if I hold the gas 1/2 down but very ruogh ( backfire and such ). These are the mods I did on it over the winter:

1986 L98
ZZ9 cam
edelbrock 170 head ( from cast iron heads )
edelbrock manifold and runners ( EGR eliminated )
AIR pump eliminator bracket from MidAmerica
Headman headers
2.75 inch double exhaust ( without CAT )
Chip from pcmformless

I have reinstalled everything exect for a few vaccum which I have plugged (HVAC, CCV TB, PCV in intake manifold, fuel pres regulator is direct to plennum ) .

I have disconnected the ECM timing wire.

I have taken the cam cover off ( again ) to cherck the cam timing and both dots are in the up position ( #1 at TDC #6 the intake is just closing and the exhast is opening ) so I think that my cam timing is OK

I have set the distributor as per another thread ( a little before #1 when #1 at tdc ), then checks the compression to make sure all is OK ( 175 +- 8 psi on all 8)

Harmonic balancer is ok same one as when I drove in with the car

I can only think of one thing the spark plugs do not have the seal ring on them. Aluminium heads are listed with them but not the iron heads coul dthis be the cause???

PLEASE HELP want to drive the **** thing

 

Your timing has to be set with a timing light. You first disconnect the
connector, fire the engine and, if necessary, keep it running by playing with the throttle body lever until it'll idle on it's own.

The use then use the timing light to set the base timing a 6 degrees
btdc. You shouldn't guess at this setting.

Your TPS voltage should be verified as being .54 (+/- .075)

Your IAC counts should be between 20-40 counts' you'll need a scanner to check that.

After setting the timing, turn off the engine, disconnect the ground cable on the battery for about 30 seconds, then reconnect it. Then reconnect the timing connector.

The spark plug gasket issue is actually a sealing issue. If you don't hear or feel any compression gases leaking from around the plugs, I wouldn't worry about that for now.

Remember, a piston will be at TDC TWICE; once on the compression stroke and once on the exhaust stroke.

Keep us posted.

Jake

 

I agree that you need a light to set ign timing.

Have you verified fuel pressure is ok and holds?
Have you verified there are no vacuum leaks, use a gauge?
Have you double checked all the spark plug wires for proper routing?

When you get a chance, get new plugs to match the iron heads.

 

With all of the above.


That only gets the timing in the ball park so that you can start the engine. At this point, the ESC wire should be connected. Play with the timing by turning the distributor until you can get the engine to idle steadily. Once warmed up and at a slow idle, no more than 800 rpm (600 rpm would be better) disconnect the ESC wire and use your timing light to set the timing on the specified 6° BTDC.



Do you KNOW that or are you just ***-U-MEing? Verify that when the timing mark indicates TDC, that the piston REALLY is at TDC.

RACE ON!!!